In Vivo Bioimaging and Photodynamic Therapy Based on Two-Photon Fluorescent Conjugated Polymers Containing Dibenzothiophene-S,S-dioxide Derivatives

As a critical component for photodynamic therapy toward cancer treatment, photosensitizers require high photoinduced reactive oxygen species generation efficiency, good biocompatibility, and high phototoxicity. Herein, a series of donor-acceptor conjugated polymers containing dibenzothiophene-S,S-dioxide derivatives are designed and synthesized, which can be used as effective photosensitizers. The resulting copolymer PTA5 shows strong green light emission with high photoluminescence quantum yields owing to the intercrossed excited state of local existed and charge transfer states. The PTA5 nanoparticles can be fabricated by encapsulation with a biocompatible polymer matrix. Upon excitation at 800 nm, these nanoparticles present a relatively large two-photon absorption cross section of 3.29 × 10⁶ GM. These nanoparticles also exhibit good photostability in water and thus can be utilized for bioimaging. The tissue-penetrating depths of up to 170 μm for hepatic vessels and 380 μm for blood vessels of mouse ear were achieved using PTA5 nanoparticles. Furthermore, PTA5 nanoparticles show impressive reactive oxygen species generation capability under the irradiation of a white light source. This can be attributed to the effective intersystem crossing between high-level excited state. Upon irradiation with white light (400-700 nm) at 50 mW cm^-2 for 5 min every other day, the tumor growth can be effectively suppressed in the presence of PTA5 nanoparticles. These findings demonstrate that PTA5 nanoparticles can be used as a photosensitizer for photodynamic therapy.

Formulation of Stattic as STAT3 inhibitor in nanostructured lipid carriers (NLCs) enhances efficacy of doxorubicin in melanoma cancer cells

Nowadays, nanoparticle-based combination therapy has been emerging as huge innovation in cancer treatment. Here, we studied the effect of Stattic (STAT3 inhibitor) loaded in nanostructured lipid carriers (NLCs) on enhancing the efficacy, cytotoxicity, and induction of apoptosis of doxorubicin in B16F10 mouse melanoma cancer cell. The evaluation of Stattic-loaded NLCs has been done in terms of zeta potential, particle size, scanning electron microscope (SEM), and cellular uptake. MTT assay was applied to evaluate the cell proliferation. Apoptotic cell death and identification of early and late apoptosis were assessed by DAPI staining and Annexin V/PI staining, respectively. Real-time RT-PCR was applied to measure the effects of doxorubicin and/or Stattic on key apoptotic genes such as Bad, Survivin, HIF1, and STAT3. The Stattic formulated into NLCs shown mean particle size of 56 ± 7 nm which was confirmed by SEM. The IC50 values for Stattic and doxorubicin were 2.95 ± 0.52 μM and 1.21 ± 0.36 μM, respectively. Stattic-loaded NLCs diminished percent of cell proliferation from 68 ± 6.8 to 54 ± 3.7% (p < 0.05). Combinational treatment of the cells with Stattic-loaded nanoparticles and doxorubicin give rise to a significant increase in the percentage of apoptosis (p < 0.05). The study of gene expression profile has shown a remarkable decrease in anti-apoptotic gene, Survivin, along with smooth decline in HIF1 as angiogenesis intermediator and increase in Bad mRNA levels. Our results recommend that NLCs as novel technology have potent strategy to augment efficacy of current chemotherapeutic agent in melanoma cancer cells.

First Example of Catalytic Synthesis of Cyclic S-Containing Di- and Triperoxides

An efficient method for the synthesis of tetraoxathiaspiroalkanes, tetraoxathiocanes, and hexaoxathiadispiroalkanes was developed by reactions of pentaoxacanes, pentaoxaspiroalkanes, and heptaoxadispiroalkanes with hydrogen sulfide in the presence of a catalyst, Sm(NO3)3·6H2O. We found that the synthesized S-containing di- and triperoxides exhibit high cytotoxic activity against Jurkat, K562, U937, and HL60 tumor cultures, and fibroblasts.

Macrocyclic glycopeptide chiral selectors bonded to core-shell particles enables enantiopurity analysis of the entire verubecestat synthetic route

Verubecestat is an inhibitor of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) being evaluated in clinical trials for the treatment of Alzheimer's disease. Synthetic route development involves diastereoselective transformations with a need for enantiomeric excess (ee) determination of each intermediate and final active pharmaceutical ingredient (API). The analytical technical package of validated methods relies on enantioselective SFC and RPLC separations using multiple 3 and 5 μm coated polysaccharide-based chiral stationary phases (CSPs) and mobile phases combinations. Evaluation of recently developed chiral columns revealed a single chiral selector (Teicoplanin) bonded to 2.7 μm core-shell particles using H₃PO₄ in H₂O/ACN and triethylammonium acetate: methanol based eluents at different isocratic compositions allowed good enatioseparation of all verubecestat intermediates. EE determination of verubecestat is easily performed on NicoShell, another macrocyclic glycopeptide chiral selector bonded to 2.7 μm superficially porous particles. This approach enables fast and reliable enantiopurity analysis of the entire verubecestat synthetic route using only two chiral columns and mobile phases on a conventional HPLC system, simplifying technical package preparation, method validation and transfer to manufacturing facilities.

Design, Synthesis, and Pharmacology of Novel 7-Substituted 3,4-Dihydro-2H-1,2,4-benzothiadiazine 1,1-Dioxides as Positive Allosteric Modulators of AMPA Receptors

A series of 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides have been synthesized and evaluated as potentiators of AMPA receptors. Attention was paid to the impact of the substituent introduced at the 7-position of the heterocycle. The biological evaluation was achieved by measuring the AMPA current in rat cortex mRNA-injected Xenopus oocytes. The most potent compound, 4-ethyl-7-fluoro-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (12a) was found to be active in an object recognition test in rats demonstrating cognition enhancing effects in vivo after oral administration.

Synthesis and Metabotropic Glutamate Receptor Activity of S-Oxidized Variants of (−)-4-Amino-2-thiabicyclo-[3.1.0]hexane-4,6-dicarboxylate: Identification of Potent, Selective, and Orally Bioavailable Agonists for mGlu2/3 Receptors

(-)-4-Amino-2-thiabicyclo-[3.1.0]hexane-4,6-dicarboxylate (LY389795, (-)-3) is a highly potent and selective agonist of metabotropic glutamate receptors 2 (mGlu2) and 3 (mGlu3). As part of our ongoing research program, we have prepared S-oxidized variants of (-)-3, compounds (-)-10, (+)-11 (LY404040), and (-)-12 (LY404039). Each of these chiral heterobicyclic amino acids displaced specific binding of the mGlu2/3 receptor antagonist 3H-2S-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3-(xanth-9-yl)propanoic acid (3H-LY341495) from membranes expressing recombinant human mGlu2 or mGlu3 and acted as potent agonists in cells expressing these receptor subtypes. Docking of the most potent of these derivatives, (+)-11, to mGlu2 revealed the possibility of an additional H-bond interaction between the sulfoxide oxygen of (+)-11 with tyrosine residue Y236. Pharmacokinetic analysis of mGlu active enantiomers (+)-11 and (-)-12 in rats showed each to be well absorbed following oral administration. Consistent with their mGlu2/3 agonist potency and pharmacokinetic properties, both (+)-11 and (-)-12 blocked phencyclidine-evoked ambulations in a dose-dependent manner, indicating their potential as nonclassical antipsychotic agents.

Synthesis and anti-HIV-1 activity of a novel series of 1,4,2-benzodithiazine-dioxides

Previously, we discovered a series of novel benzodithiazines-dioxides with both antiviral and anticancer activities. In order to design compounds with distinct antiviral properties, we prepared new compounds with modifications on the imidazole and pyrimidine rings. Herein, we present the synthesis and antiviral activity of 8-chloro-2,3-dihydroimidazo[1,2-b][1,4,2]benzodithiazine 5,5-dioxides (22, 23, 30, and 31) and 9-chloro-2,3,4-trihydropyrimido[1,2-b][1,4,2]benzodithiazine 6,6-dioxides (14, 24, 25, and 27). We successfully identified a lead compound with remarkable anti-HIV-1 activity (EC(50)=0.09microM). These compounds showed minimal cytotoxicity and are therefore suitable for antiviral development.

New 3-Alkylamino-4H-thieno-1,2,4-thiadiazine 1,1-Dioxide Derivatives Activate ATP-Sensitive Potassium Channels of Pancreatic Beta Cells

Compound 1a (NN414) is a potent opener of Kir6.2/SUR1 K(ATP) channels. Compound 1a inhibits insulin release in vitro and in vivo and preserves beta cell function in preclinical animal models suggesting that such a compound could find use in treatment or prevention of type 1 and type 2 diabetes. The crystal structure and a convergent synthesis of 1a are presented together with a range of new analogues of 1a. Several compounds, e.g., 6-chloro-3-(1-methyl-1-phenylethyl)amino-4H-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxide (1h), were found to be potent openers of Kir6.2/SUR1 K(ATP) channels and were able to suppress glucose-stimulated insulin release from rat islets in vitro (EC(50) = 0.04 +/- 0.01 muM) and in vivo after intravenous or peroral administration to hyperinsulinemic obese Zucker rats (ED(50) = 4.0 mg/kg). Structural modifications of this series of K(ATP) channel openers have provided compounds with promising pharmacokinetic properties indicating that brief periods of beta cell rest can be achieved.

Highly Chiral Muscarinic Ligands: The Discovery of (2S,2‘R,3‘S,5‘R)-1-Methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine 3-sulfoxide Methyl Iodide, a Potent, Functionally Selective, M2 Partial Agonist

By further steric complication of previously studied highly chiral muscarinic agonists, we have obtained a small chiral library of enantiomeric and diasteromeric 1-methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine 3-sulfoxides. Binding studies on cloned human muscarinic receptors expressed in CHO cells show that the introduction of a fourth stereogenic center gives undetectable affinity for hm1, hm3, hm4 and hm5 subtypes while leaving a quite modest affinity only for hm2 subtypes. However, functional studies on model M1-M4 muscarinic tissues have shown that three compounds of the series [(-)-5, (-)-7, (+)-8] are endowed with functional activity and behave as M2 selective partial agonists. Among them, compound (2S,2'R,3'S,5'R)-1-methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine 3-sulfoxide methyl iodide [(+)-8] is particularly interesting, as it is a potent partial agonist on guinea pig atrium (force) (M2; pD2=7.65, alpha=0.41) while being a poor antagonist on M1, M3, and M4 model tissues (pKb<5).

Novel benzopyridothiadiazepines as potential active antitumor agents

The synthesis of novel thiadiazepine derivatives, that could be considered as constraint analogues of E-7010, are reported. These molecules were evaluated for their antiproliferative activity toward the murine L1210 leukemia cell line. Flow cytometric studies performed on L1210 cells with the most cytotoxic compounds showed an accumulation of the cells in the G2/M phases of the cell cycle with a significant percentage of tetraploid cells (8N DNA content). Submicromolar cytotoxicities were observed with compounds 2b, 4b, 4e, 4g, and 4i. Two of them, compounds 2b and 4b, were found to be potent inhibitors of tubulin polymerization with IC50 of respectively 3.8 and 2.4 microM compared to 2.4 microM for desoxypodophyllotoxin. A 4-methoxyphenylethyl substitution on the pyridinyl nitrogen of the benzopyridothiadiazepine was found to be essential for the antiproliferative activity. The in vitro activities of compounds 2b and 4b make benzopyridothiadiazepine dioxides a promising new class of tubulin binders which warrant further in vivo evaluation.

3-Alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides as ATP-sensitive potassium channel openers: effect of 6,7-disubstitution on potency and tissue selectivity

A series of 6,7-disubstituted 4H-1,2,4-benzothiadiazine 1,1-dioxides bearing a short alkylamino side chain in the 3-position were synthesized. These compounds were tested on rat pancreatic islets and on rat aorta rings. In vitro data indicated that in most cases substitution in the 6 and the 7 positions increased their activity as inhibitors of insulin secretion, while the myorelaxant potency of the drugs was maintained or enhanced according to the nature of the substituent in the 7-position. The presence of either chlorine or bromine atoms in the 6 and 7 positions did not improve the apparent selectivity of the drugs for the pancreatic tissue. By contrast, the introduction of one or two fluorine atoms, as well as the presence of a methoxy group in the 7-position, generated potent and selective inhibitors of insulin release. Radioisotopic and fluorimetric experiments performed with the most potent compound inhibiting insulin release (34, BPDZ 259, 6-chloro-7-fluoro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide) confirmed that the drug activated K(ATP) channels. 34 was found to be one of the most potent and selective pancreatic potassium channel openers yet described.

Synthesis and structure-activity relationships of a novel series of 2,3,5,6,7,9-hexahydrothieno[3,2-b]quinolin-8(4H)-one 1,1-dioxide K(ATP) channel openers: discovery of (-)-(9S)-9-(3-bromo-4-fluorophenyl)-2,3,5,6,7,9- hexahydrothieno[3,2-b]quinolin-8(4H)-one 1,1-dioxide (A-278637), a potent K(ATP) opener that selectively inhibits spontaneous bladder contractions

Structure-activity relationships were investigated on a novel series of sulfonyldihydropyridine-containing K(ATP) openers. Ring sizes, absolute stereochemistry, and aromatic substitution were evaluated for K(ATP) activity in guinea pig bladder cells using a fluorescence-based membrane potential assay and in a pig bladder strip assay. The inhibition of spontaneous bladder contractions in vitro was also examined for a select group of compounds. All compounds studied showed greater potency to inhibit spontaneous bladder contractions relative to their potencies to inhibit contractions elicited by electrical stimulation. In an anesthetized pig model of myogenic bladder overactivity, compound 14 and (-)-cromakalim 1 were found to inhibit spontaneous bladder contractions in vivo at plasma concentrations lower than those that affected hemodynamic parameters. Compound 14 showed approximately 5-fold greater selectivity than 1 in vivo and supports the concept that bladder-selective K(ATP) channel openers may have utility in the treatment of overactive bladder.

[Studies on the new antiarthritic drug candidate S-2474]

Various 1,2-isothiazolidine-1,1-dioxide (gamma-sultam) derivatives containing an antioxidant moiety, 2,6-di-tert-butyl-phenol substituent, were prepared. Some compounds that have a lower alkyl group at the 2-position of the gamma-sultam skeleton showed potent inhibitory effects on both cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LO), as well as production of interleukin-1 (IL-1) in in vitro assays. They also proved to be effective in several animal arthritic models without any ulcerogenic activities. Among these compounds, (E)-(5)-(3,5-di-tert-butyl-4-hydroxybenzylidence)-2-ethyl-1,2- isothiazolidine-1,1-dioxide (S-2474) was selected as an antiarthritic drug candidate. The structure-activity relationships examined and some pharmacological evaluations are described. Furthermore, we have developed an efficient and E-selective synthesis of S-2474, in which alpha-methoxy-p-quinone methide is used as a key intermediate. alpha-Methoxy-p-quinone methide was revealed to be equivalent to a p-hydroxy-protected benzaldehyde. It reacts smoothly with alpha-sulfonyl carbanion to give 1,6-addition intermediates, which can be further processed to provide S-2474 directly in the presence of a base. This procedure gives S-2474 as an almost single isomer on the benzylidene double bond in excellent yield and thus is a very practical method adaptable to large-scale synthesis. The detailed mechanistic aspects are studied and discussed.

Short synthesis of tert-butyl-hydroxylated 3,5-di-tert-butyl-4-hydroxybenzaldehyde: Synthesis of tert-butyl-hydroxylated S-2474

We have developed a very short synthesis of tert-butyl-hydroxylated di-tert-butyl-4-hydroxybenzaldehyde in which the HBr-DMSO system is used as an effective oxidant (overall yield of 45% for the entire four-step process from 2-tert-butyl-p-cresol). We also accomplished the synthesis of a major metabolite of the antiarthritic drug candidate S-2474.

Synthesis and pharmacological profile of 6-methyl-3-isopropyl-2H-1,2-benzothiazin-4(3H)-one 1,1-dioxide derivatives: non-steroidal anti-inflammatory agents with reduced ulcerogenic effects in the rat

The new anti-inflammatory agents 6-methyl-3-isopropyl-2H-1,2-benzothiazin-4(3H)-one 1,1-dioxide 6a and its analogues 6b-f were synthesized from L-valine. All compounds were characterized by physical, chemical and spectral studies. Preliminary pharmacological evaluation of the resulting products showed that compounds 6a-f (5-20 mg/kg, i.p.) are active anti-inflammatory agents in carrageenan-induced rat paw oedema assay in albino rats, and their effects are comparable to that of piroxicam (5 mg/kg, i.p.), used as a reference drug. The nature of the substituents on the sulfonamide nitrogen and those on position three had a pronounced effect on the anti-inflammatory activity. Studies of structure-activity relationships have led to selection of compound 2,6-dimethyl-3-isopropyl-1,2-benzothiazin-3,4-diol 1,1-dioxide 6 f which exhibited the most potent activity (61.7% inhibition at 5 mg/kg, i.p. and ED(50)=4.5 mg/kg, i.p.). Comparison of the gastrointestinal safety of compounds 6a-f with that of piroxicam showed a far better tolerability for our products. This comparison was based on the ulcer index and the pH of gastric content.

[Creation of functional organic compounds and their applications]

Our studies on creation of functional organic compounds and their applications, have focused on three areas, namely, (A) organic chemical studies on VD (vitamin D) analogues, (B) studies on solitary wasp venoms, and (C) studies on functional building blocks for organic synthesis. In the first area, several novel and important vitamin D analogues were synthesized and biologically evaluated, and their high VDR (vitamin D receptor) binding affinities were discussed on the basis of conformational analysis and docking study by Molecular Mechanics Calculation to the LBD (ligand binding domain) of VDR: These compounds include 24,24-difluoro-1 alpha,25-dihydroxy-VD3 (2) (an antimetabolism agent, the first VD analogue having higher potency than the natural hormone (1)), 2 alpha-methyl-1 alpha,25-dihydroxy-VD3 (42b) (the first A-ring-modified VD analogue exhibiting stronger VDR affinity than 1) and its 20-epimer (43b) (a VD analogue having a highest HL-60 cell differentiation inducing activity with a relatively low calcemic effect), and 2 alpha-(omega-hydroxypropyl)-1 alpha,25-dihydroxy-VD3 (exceptionally high calcemic effect). In the second area, we isolated and determined the structure of pompilidotoxins (76, 77), novel peptide neurotoxins in solitary wasp venoms. In the third area, we created furan-fused 3-sulfolene, 4H, 6H-thieno [3,4-c]-furan 5,5-dioxide and pyrrole-fused 3-sulfolene (96), 3,5-dihydro-1H-thieno[3,4-c] pyrrole 2,2-dioxide (125), and studied their inter- and intramolecular Diels-Alder reactions.

A new type of mixed anhydride and its applications to the synthesis of 7-substituted 8-chloro-5,5-dioxoimidazo[1,2-b][1,4,2]benzodithiazines with in vitro antitumor activity

A new series of 8-chloro-5,5-dioxoimidazo[1,2-b][1,4,2]benzodithiazine derivatives 8-25 with heteroaryloxycarbonyl or heteroarylcarbamoyl substituents at position 7 have been synthesized as potential antitumor agents. In this procedure a novel type of mixed anhydride 7 was prepared from 8-chloro-5,5-dioxoimidazo[1,2-b][1,4,2]benzodithiazine-7-carboxylic acid 6 and methanesulfonyl chloride, which in turn was condensed either with heteroarylamines or heteroarylhydroxy compounds. All the compounds prepared were screened at the National Cancer Institute (NCI) for their activities against a panel of 60 tumor cell lines, and relationships between structure and antitumor activity in vitro are discussed. The amides 8, 10, 12, 13, 21, and ester 25 were inactive, whereas the other compounds exhibited rather moderate activity against one or more human tumor cell lines. The prominent compound with remarkable activity (log GI(50) < -8) and selectivity for the leukemia HL-60(TB) cell line was 2-methyl-8-quinolyl 8-chloro-5,5-dioxoimidazo[1,2-b][1,4,2]benzodithiazine-7-carboxylate 24.

Highly E-selective and effective synthesis of antiarthritic drug candidate S-2474 using quinone methide derivatives

We have developed an efficient and E-selective synthesis of an antiarthritic drug candidate (E)-(5)-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2-ethyl-1,2-isothiazolidine-1,1-dioxide (S-2474; 1), in which alpha-methoxy-p-quinone methide is used as a key intermediate. alpha-Methoxy-p-quinone methide was revealed to be an equivalent to a p-hydroxy protected benzaldehyde. It reacts smoothly with alpha-sulfonyl carbanion to give 1,6-addition intermediates, which can be further processed to provide S-2474 directly in the presence of a base. This procedure gives S-2474 as an almost single isomer on the benzylidene double bond in excellent yield and thus is a very practical method adaptable to large-scale synthesis. The detailed mechanistic aspects are studied and discussed.

1,2-Benzothiazine 1,1-dioxide P(2)-P(3) peptide mimetic aldehyde calpain I inhibitors

A series of peptide mimetic aldehyde inhibitors of calpain I was prepared in which the P(2) and P(3) amino acids were replaced by substituted 3,4-dihydro-1,2-benzothiazine-3-carboxylate 1,1-dioxides. The effect of 2, 6, and 7-benzothiazine substituents and the P(1) amino acid was examined. Potency of these inhibitors, 15c-p, against human recombinant calpain I is particularly dependent upon the 2-substituent, with methyl and ethyl generally more potent than hydrogen, isopropyl, isobutyl, or benzyl. The more potent diastereomer of 15m possesses the (S) absolute configuration at the 3-position of the 3,4-dihydro-1,2-benzothiazine. Potency of the best inhibitors in this series (IC(50) = 5-7 nM) compares favorably with that of conventional N-benzyloxycarbonyl dipeptide aldehyde inhibitors bearing L-Leu or L-Val residues at P(2). The achiral unsaturated 1,2-benzothiazine analogues 26a-d are also potent calpain I inhibitors, while 3,4-dihydro-2,1-benzoxathiin (15a,b), 1,2,4-benzothiadiazine (32a,b), and tetrahydroisoquinolinone (36a,b) analogues are less potent.

Novel enantioselective fluorinating agents, (R)- and (S)-N-fluoro-3-tert-butyl-7-nitro-3,4-dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides

Enantioselective fluorinating agents, (R)- and (S)-,N-fluoro-3-tert-butyl-7-nitro-3,4-dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides (BNBT-F, 2) are readily prepared in 3 steps from racemic 3-tert-butyl-7-nitro-3,4-dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides (5) via optical resolution and fluorination. These agents make accessible both enantiomers of optically active quaternary alpha-fluoro carbonyl compounds in modest to high enantioselectivities. X-ray crystallographic analysis of chiral 2 reveals a unique structure wherein the nitrogen atom is highly pyramidalized and fluorine occupies an axial position.

Nonnucleoside human cytomegalovirus inhibitors: synthesis and antiviral evaluation of (chlorophenylmethyl)benzothiadiazine dioxide derivatives

A second generation of benzothiadiazine dioxide (BTD) derivatives was synthesized employing benzylation reactions mainly. The chlorophenylmethyl BTD derivatives showed activity against human cytomegalovirus (HCMV) with IC(50) values ranging from 3 to 10 microM. Their 50% cytotoxic concentrations were often >200 microM to lung fibroblast HEL cell proliferation and between 20 and 35 microM for lymphocyte CME cell growth. When cytotoxicity for cell morphology was considered, the minimum cytotoxic concentration for the different BTD derivatives varied between 5 and 200 microM. Some of the anti-HCMV compounds also showed activity against HIV-1 and HIV-2. The chlorophenylmethyl derivative 21 was active against a variety of HCMV clinical isolates from patients with different clinical manifestations and fully maintained its activity against a ganciclovir-resistant HCMV strain. The dibenzyl BTD derivatives did not inhibit HCMV protease, and preliminary pharmacological experiments revealed that their anti-HCMV action stems from interference with an early stage of the viral replicative cycle.

Synthesis and pharmacological evaluation of thiopyran analogues of the dopamine D3 receptor-selective agonist (4aR,10bR)-(+)-trans-3,4,4a,10b-tetrahydro-4-n-propyl-2H,5H [1]b enzopyrano[4,3-b]-1,4-oxazin-9-ol (PD 128907)

Benzopyranoxazine (+)-7 (PD 128907) is the most dopamine (DA) D3 receptor-selective agonist presently known. The only structural feature which distinguishes 7 from the analogous nonselective naphthoxazines is an oxygen atom in the 6-position. To extend this series of tricyclic DA agonists we used a classic bioisoster approach and synthesized thiopyran analogues of 7, which have a sulfur atom in the 6-position. We prepared trans-4-n-propyl-3,4,4a,10b-tetrahydro-2H,5H-[1]benzothiopyrano[4, 3-b]-1,4-oxazin-9-ol (9, trans-9-OH-PTBTO), its enantiomers ((+)-9 and (-)-9), the racemic cis-analogue (10), and the racemic trans-sulfoxide (11) and studied the potency and selectivity for DA receptors of these compounds. As with other rigid DA agonists, the highest affinity for DA receptors resided in one of the enantiomers, in this case the (-)-enantiomer of 9. On the basis of a single-crystal X-ray analysis of a key intermediate, the absolute configuration of (-)-9 was found to be 4aS,10bR, which is homochiral with (+)-(4aR,10bR)-7. In contrast to (+)-7 however, (-)-9 displayed no selectivity for any of the DA receptors. In addition, it has affinity for 5HT1A receptors. (+/-)-cis-4-n-Propyl-3,4,4a,10b-tetrahydro-2H,5H-[1]benzothiopyrano++ +[4,3-b]-1,4-oxazin-9-ol (10), which was expected to be inactive, displayed affinity and selectivity for the DA D3 receptor, whereas the sulfoxide 11 displayed some DA D3 selectivity, but with a lower affinity. Further pharmacological evaluation revealed that (-)-9 is a very potent full agonist at DA D2 receptors and a partial agonist at DA D3 receptors. The cis-analogue (+/-)-10 displayed the same profile, but with lower potency. These findings were confirmed in vivo: in reserpinized rats (-)-9 displayed short-acting activation of locomotor activity (DA D2 agonism) and also lower lip retraction and flat body posture, (5HT1A agonism). Compound (+/-)-10 had no effect on locomotor activity. In unilaterally 6-OH-DA lesioned rats, (-)-9 gave short-acting locomotor activation. Furthermore, in microdialysis studies in rat striatum, (-)-9 potently decreased DA release, confirming its activation of presynaptic DA D2 receptors.

Novel antiarthritic agents with 1,2-isothiazolidine-1,1-dioxide (gamma-sultam) skeleton: cytokine suppressive dual inhibitors of cyclooxygenase-2 and 5-lipoxygenase

Various 1,2-isothiazolidine-1,1-dioxide (gamma-sultam) derivatives containing an antioxidant moiety, 2,6-di-tert-butylphenol substituent, were prepared. Some compounds, which have a lower alkyl group at the 2-position of the gamma-sultam skeleton, showed potent inhibitory effects on both cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LO), as well as production of interleukin (IL)-1 in in vitro assays. They also proved to be effective in several animal arthritic models without any ulcerogenic activities. Among these compounds, (E)-(5)-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2-ethyl-1, 2-isothiazolidine-1,1-dioxide (S-2474) was selected as an antiarthritic drug candidate and is now under clinical trials. The structure-activity relationships (SAR) examined and some pharmacological evaluations are described.

3-Alkylamino-4H-pyrido[2,3-e]-1,2,4-thiadiazine 1,1-dioxides structurally related to diazoxide and pinacidil as potassium channel openers acting on vascular smooth muscle cells: design, synthesis, and pharmacological evaluation

A series of 3-alkylamino-4H-pyrido[2,3-e]-1,2,4-thiadiazine 1, 1-dioxides structurally related to diazoxide and pinacidil were synthesized and tested as possible K(ATP) channel openers on isolated pancreatic endocrine tissue as well as on isolated vascular, intestinal, and uterine smooth muscle. In contrast to previously described 3-alkylamino-4H-pyrido[4,3-e]-1,2,4-thiadiazine 1, 1-dioxides, most of the new compounds were found to be poorly active on B-cells but exhibited clear vasorelaxant properties. 3-(3, 3-Dimethyl-2-butylamino)-4H-pyrido[2,3-e]-1,2,4-thiadiazine 1, 1-dioxide (4d) and 7-chloro-3-(3, 3-dimethyl-2-butylamino)-4H-pyrido[2,3-e]-1,2,4-thiadiazine 1, 1-dioxide (5d), two compounds bearing the alkyl side chain of pinacidil, were found to be the most active representatives of their respective series on rat aorta rings. 3-Cycloalkylalkylamino- and 3-aralkylamino-7-chloro-4H-pyrido[2,3-e]-1,2,4-thiadiazine 1, 1-dioxides also expressed myorelaxant activity on electrically stimulated guinea pig ileum and on oxytocin-induced contractions of the rat uterus. Further biological investigations ((86)Rb efflux measurements, vasodilator potency on 30 and 80 mM KCl-induced contractions in the absence and presence of glibenclamide) revealed that compounds 4d and 5d, but not compound 5f, expressed the pharmacological profile of classical K(ATP) channel openers. In conclusion, by changing the position of the nitrogen atom in the pyridine ring, we now have obtained a family of drugs expressing an opposite tissue selectivity. Taken as a whole, the present findings also suggest that 3-alkylamino-4H-pyrido[2,3-e]-1,2,4-thiadiazine 1, 1-dioxides such as 4c, 4d, 5c, and 5d may be considered as new examples of K(ATP) channel openers expressing a pharmacological profile similar to that of pinacidil and diazoxide.

A practical and efficient preparation of the releasable naphthosultam side chain of a novel anti-MRSA carbapenem

A practical large-scale synthesis of the naphthosultam-based side chain of the anti-MRSA antibiotic 1 has been achieved in 29% overall yield over seven steps from 1-methylnaphthalene. The synthesis was completed without the use of protecting groups, featuring a novel naphthosultam annelation, a chemoselective acid-catalyzed triflation, and the use of a novel naphthosultam dianion to effect functionalization through benzylic metalation.

Design, synthesis, and biological evaluation of potent thiazine- and thiazepine-based matrix metalloproteinase inhibitors

The synthesis and enzyme inhibition data for a series of thiazine- and thiazepine-based matrix metalloproteinase (MMP) inhibitors are described. The thiazine- and thiazepine-based inhibitors were discovered by optimization of hetererocyclic sulfonamide-based inhibitors. The most potent series of inhibitors was obtained by modification of the amino acid D-penicillamine. This amino acid provides a gem-dimethyl group on the thiazine or thiazepine ring which has a dramatic effect on the in vitro potency of this series. In particular, the sulfide 4a and the sulfone 5a were potent, broad-spectrum inhibitors of the MMPs with IC(50)'s against MMP-1 of 0.8 and 1.9 nM, respectively. The binding mode of this novel thiazepine-based series of MMP inhibitors was established based on X-ray crystallography of the complex of stromelysin and 4a.

Human chymase inhibitors based on the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold

A series of compounds that utilize the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold was synthesized and shown to be highly effective inhibitors of recombinant human skin chymase.

Preparation and pharmacological evaluation of the R- and S-enantiomers of 3-(2-butylamino)-4H- and 3-(3-methyl-2-butylamino)-4H-pyrido[4,3-e]-1,2,4-thiadiazine 1,1-dioxide, two tissue selective ATP-sensitive potassium channel openers

The preparation and the pharmacological evaluation of the R- and S-isomers of 3-(2-butylamino)-4H-pyrido[4,3-e]-1,2,4-thiadiazine 1,1-dioxide (BPDZ 42) and 3-(3-methyl-2-butylamino)-4H-pyrido[4,3-e]-1,2,4-thiadiazine 1,1-dioxide (BPDZ 44), two potassium channel openers, is described. Their optical purity was estimated by means of capillary electrophoresis (R- and S-BPDZ 42) and chiral HPLC (R- and S-BPDZ 44). The absolute configuration of each isomer of BPDZ 44 was deduced from crystallographic data. Pharmacological assays performed with the R- and S-isomers of BPDZ 44 revealed only slight differences in their activity on pancreatic B-cells but significant differences in their activity on vascular smooth muscle cells: the R-isomer being sixfold more potent than its corresponding S-isomer. The R-isomer of BPDZ 42 was shown to be more potent than its corresponding S-isomer on the endocrine pancreas. S-BPDZ 44 as well as R- and S-BPDZ 42 were found to exhibit tissue selectivity for the pancreatic versus the vascular smooth muscle tissue.

Novel arylpyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxides as inhibitors of platelet aggregation. 1. Synthesis and pharmacological evaluation

A series of N-1-substituted derivatives of pyrazino[2,3-c][1,2, 6]thiadiazine 2,2-dioxides bearing aryl groups at the pyrazino moiety have been prepared. The synthesis involves ring formation between the diaminothiadiazine and suitable dicarbonyl compounds and subsequent introduction of the substituent at N-1. The compounds have been tested in vitro, as inhibitors of rabbit and human platelet aggregation, and ex vivo against rat platelet aggregation induced by arachidonic acid, ADP, collagen, U46619, and I-BOP. The results obtained indicate that some pyrazino[2,3-c][1,2, 6]thiadiazine derivatives show significant platelet aggregation inhibition similar to other antithrombotic agents and that the antiplatelet properties may be mediated by interference with the arachidonic acid pathway.

Novel potential agents for human cytomegalovirus infection: synthesis and antiviral activity evaluation of benzothiadiazine dioxide acyclonucleosides

The first acyclonucleosides based on the benzothiadiazine dioxide system were synthesized following the silylation procedure. Several acyclic moieties, including acetoxyethoxymethyl, benzyloxymethyl, and propargyloxymethyl groups, were introduced. Two synthetic strategies were designed to selectively obtain the N-1 or N-3 derivatives. Lipase-mediated deacylation was used for the deprotection of the acyclonucleosides. Some of the benzothiadiazine dioxide acyclonucleosides, in particular 16, proved active against human cytomegalovirus (CMV) at concentrations slightly higher than that found for ganciclovir [50% inhibitory concentration (IC50) = 3. 5-3.7 micrograms/mL, cytotoxicity (CC50) >/= 40 micrograms/mL, MCC = 20 micrograms/mL]. Additionally, compound 16 inhibited the replication of human immunodeficiency virus type 1 (HIV-1) and HIV-2 in CEM cells at concentrations that were 5-fold lower than its cytotoxic concentration.

1,2-Benzisothiazol-3-one 1,1-dioxide inhibitors of human mast cell tryptase

A library of compounds were prepared by reacting 2-(bromomethyl)-1, 2-benzisothiazol-3(2H)-one 1,1-dioxide (5) with commercially available carboxylic acids in the presence of potassium carbonate or a tertiary amine base. From this library, (1,1-dioxido-3-oxo-1, 2-benzisothiazol-2(3H)-yl)methyl N-[(phenylmethoxy)carbonyl]-beta-alanate (7b) emerged as a potent inhibitor of human mast cell tryptase (IC50 = 0.85 microM). Extension of the side chain of 7b by two carbons gave (1, 1-dioxido-3-oxo-1,2-benzisothiazol-2(3H)-yl)methyl 5-[[(phenylmethoxy)carbonyl]amino]pentanoate (7d) which was an 8-fold more potent inhibitor (IC50 = 0.1 microM). Further modification of this series produced benzoic acid derivative (1, 1-dioxido-3-oxo-1,2-benzisothiazol-2(3H)-yl)methyl 4-[[(phenylmethoxy)carbonyl]amino]benzoate (7n) which is the most potent inhibitor identified in this series (IC50 = 0.064 microM). These compounds exhibit time-dependent inhibition consistent with mechanism-based inhibition. For 7b, the initial enzyme velocity is not a saturable function of the inhibitor concentration and the initial Ki could not be determined (Ki > 10 microM). The steady-state rate constant, Ki, was determined to be 396 nM. On the other hand, compounds 7d and 7n are time-dependent inhibitors with a saturable initial complex. From these studies, an initial rate constant, Ki, for 7d and 7n was found to be 345 and 465 nM, respectively. The steady-state inhibition constants, Ki, for 7d and 7n were calculated to be 60 and 52 nM, respectively. Compound 7n is a 13-fold more potent inhibitor than 7b, and these kinetic studies indicate that the increase in inhibitory activity is due to an increase in initial affinity toward the enzyme and not an increase in chemical reactivity. These inhibitors generally show high selectivity for tryptase, being 40-fold weaker inhibitors of elastase, being 100-fold weaker against trypsin, and showing no inhibition against thrombin. These compounds are not inhibitors of thrombin, plasmin t-PA, urokinase, and factor Xa (IC50 > 33 microM). In the delayed-type hypersensitivity (DTH) mouse model, a model of skin inflammation, a 5% solution of 7d reduced edema by 69% compared to control animals.

4H-1,2,4-Pyridothiadiazine 1,1-dioxides and 2,3-dihydro-4H-1,2, 4-pyridothiadiazine 1,1-dioxides chemically related to diazoxide and cyclothiazide as powerful positive allosteric modulators of (R/S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid receptors: design, synthesis, pharmacology, and structure-activity relationships

A series of 4H-1,2,4-pyridothiadiazine 1,1-dioxides and 2, 3-dihydro-4H-1,2,4-pyridothiadiazine 1,1-dioxides bearing various alkyl and aryl substituents on the 2-, 3-, and 4-positions was synthesized and tested as possible positive allosteric modulators of the (R/S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. Many compounds were found to be more potent than the reference compounds diazoxide and aniracetam as potentiators of the AMPA current in rat cortex mRNA-injected Xenopus oocytes. The most active compound, 4-ethyl-2,3-dihydro-4H-pyrido[3,2-e]-1,2, 4-thiadiazine 1,1-dioxide (31b), revealed an in vitro activity on Xenopus oocytes not far from that of cyclothiazide, the most potent allosteric modulator of AMPA receptors reported to date. Moreover, 31b, but not cyclothiazide, was found to potentiate the duration and the amplitude of the excitatory postsynaptic field potentials induced by electric stimulation in rat hippocampal slices. Such an effect could indicate, for 31b, but not for cyclothiazide, a possible interaction with postsynaptic AMPA receptor binding sites located on hippocampal CA1 neurons. Structure-activity relationships indicated that the structural requirements responsible for a biological activity on AMPA receptors are different from those responsible for an inhibitory activity on the insulin releasing process (putative ATP-sensitive K+-channel openers). For instance, 31b and other related dihydropyridothiadiazines were found to be ineffective as inhibitors of insulin release from rat pancreatic B-cells, in contrast to diazoxide and known pyridothiadiazines reported as ATP-sensitive K+-channel openers. Conversely, the pyridothiadiazines active on B-cells were found to be ineffective as potentiators of the AMPA currents in Xenopus oocytes. Thus, 31b appeared to be more specific than diazoxide as an AMPA receptor modulator. This compound may be considered as a new pharmacological tool, different from diazoxide and cyclothiazide, for studying AMPA receptors. Moreover, 31b can also constitute a new therapeutic agent for the treatment of cognitive disorders.

Synthesis and antifungal activity of 1,3,2-benzodithiazole S-oxides

The preparation of 1,3,2-benzodithiazole S-oxide analogs exhibiting in vitro antifungal activity against several strains of Candida is described. For the preparation of derivatives bearing aromatic substituents, a novel electrophilic aromatic thiolation reaction was utilized which produced substituted aromatic 1,2-dithiol intermediates. The reactions of nucleophiles with the parent heterocyclic system have led to an efficient transamidation process which allows for the direct production of these analogs. The S-oxide bond exhibits poor stereochemical stability and has been found to epimerize under ambient conditions. The structure-activity data report that a side chain of greater than 10 carbons effects a loss in activity as does the placement of polar groups in this chain.

Substituted 3-oxo-1,2,5-thiadiazolidine 1,1-dioxides: a new class of potential mechanism-based inhibitors of human leukocyte elastase and cathepsin G

A series of substituted 3-oxo-1,2,5-thiadiazolidine 1,1-dioxides has been synthesized and their in vitro inhibitory activity toward human leukocyte elastase and cathepsin G was investigated. These compounds were found to inactivate the two enzymes efficiently and in a time-dependent fashion.

Naphthosultam derivatives: a new class of potent and selective 5-HT2 antagonists

A series of 2-(aminoalkyl)naphth[1,8-cd]isothiazole 1,1-dioxides was synthesized and examined in various receptor binding tests. Most compounds demonstrated high affinity for the 5-HT2 receptor with moderate to high selectivity. A member of this series, compound 24 (RP 62203), displays high 5-HT2 receptor affinity (Ki = 0.26 nM), which is respectively more than 100 and 1000 times higher than its affinity for alpha 1 (Ki = 38 nM) and D2 (Ki greater than 1000 nM) receptors. This compound is a potent orally effective and long lasting 5-HT2 antagonist in the mescaline-induced head-twitches test in mice and rats.

Heteroarylalkanoic acids with possible antiinflammatory activities. Part 8: The scavenging of the oxygen-free radicals

The scavenging activity of some isosteric antiinflammatory heteoarylalkanoic acids with respect to oxygen-free radicals has been studied. All the compounds were found to inhibit the depolymerization of hyaluronic acid due to enzymatically or chemically generated hydroxyl radicals. The reduced consumption of oxygen by xanthine oxidase indicates a cotemporaneous phenomenon of enzymatic inhibition.

Synthesis and structure-activity relationship of substituted tetrahydro- and hexahydro-1,2-benzisothiazol-3-one 1,1-dioxides and thiadiazinones: potential anxiolytic agents

Several novel substituted tetrahydro- and hexahydro-1,2-benzisothiazol-3-one 1,1-dioxides and thiadiazinones were prepared and examined in a series of in vitro and in vivo tests to determine their pharmacological profile. Most compounds were orally active in blocking the conditioned avoidance response (CAR) but did not antagonize apomorphine-induced stereotyped behavior. Several compounds demonstrated moderate to high affinity for the 5-HT1A receptor binding site, with compounds 37 and 38 containing 2-pyrimidinylpiperazinyl and [3-(trifluoromethyl)phenyl]piperazinyl moieties and compound 47 containing the 2-pyrazinylpiperazinyl moiety displaying the highest affinity (Ki values of 10, 4, and 9 nM, respectively). Compound 37, 3-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]hexahydro-4, 7-etheno-1H-cyclobut [f]-1,2-benzisothiazol-3(2H)-one 1,1-dioxide, buspirone, and ipsapirone showed similarities in their neurochemical and behavioral profiles. They were similar in potency in blocking CAR with AB50 values of 39, 32, and 42 mg/kg, respectively. They also demonstrated high affinity and selectivity for the 5-HT1A receptor site (Ki = 10 nM) and exhibited partial agonist/antagonist activity in the serotonin syndrome test. In addition, compound 37 inhibited apomorphine-induced climbing behavior much more potently (ED50 of 3.4 mg/kg) than stereotyped behavior (ED50 of 32.2 mg/kg) and will be evaluated further. Structure-activity relationships within this series of compounds are discussed.

Cardiovascular activity of 1,2,4-benzothiadiazine-1,1-dioxide derivatives. Part 10(3): Dialkylamino-, pyrrolidyl- and morpholyl-alkyl-derivatives of 3-amino-1,2,4-benzothiadiazine-1,1-dioxide, 7- or 5,7-halogen substituted

A series of dialkylamino, pyrrolidyl and morpholyl-alkyl-derivatives of 3-amino-1,2,4-benzothiadiazine-1,1-dioxide, 7- or 5,7-halogen substituted in the benzenoid moiety, was prepared and their cardiovascular activity studied. Most of the substances in question were capable of inducing a significant decrease in mean arterial blood pressure; some of them tended to increase pulse pressure or to cause bradycardia, an effect which was noted particularly in the case of compound 10 which reduced heart-rate by 85%. The structure/activity relationship of these substances, of the 6- and 6,7-halogen substituted isomers and of their corresponding non-substituted progenitors is examined.

A novel system: 2H-pyrido[3,2-e]-1,2-thiazine-1,1-dioxide. Synthesis and properties of some derivatives

A rearrangement of 2H-2-acetonyl(phenacyl)-4,6-dimethyl- pyrido[3,2-d]isothiazoline-3-one-1,1-dioxides (I), (II) to derivatives of the unknown system of 2H-pyrido[3,2-e]-1,2-thiazine-1,1-dioxide (V), (XIII) is described; the synthesis of 2-N-substituted derivatives (VI - XII), (XIV - XVI) is also given. The structures of the new compounds were confirmed with elemental analyses and spectral data (I.R., N.M.R., MS). Some of the newly obtained compounds showed strong analgesic activity upon pharmacological screening.

Inhibition of liver alcohol dehydrogenase and ethanol metabolism by 3-substituted thiolane 1-oxides

3-Substituted thiolane 1-oxides (methyl, n-butyl, n-hexyl, and phenyl) were prepared and tested as inhibitors of horse, monkey, and rat liver alcohol dehydrogenases and of ethanol metabolism in rats. These compounds inhibit alcohol oxidation in an uncompetitive manner with respect to ethanol as a varied substrate. Lengthening the alkyl substituent increased the inhibitory potency because of tighter binding in the hydrophobic substrate binding pocket of the alcohol dehydrogenases. Thus, the 3-hexyl derivative was the most potent inhibitor of the purified rat liver alcohol dehydrogenase, with a Kii value of 0.13 microM. The 3-butyl derivative was the best inhibitor of ethanol metabolism in rats, with a Kii value of 11 mumol/kg. The acute toxicity in mice of the butyl derivative was 1.4 mmol/kg. Since high concentrations of alcohol do not prevent the inhibitory effects of these compounds, they may be particularly useful for preventing poisoning by methanol or ethylene glycol.

Studies on 1,2,3-triazoles. 10. Synthesis and antiallergic properties of 9-oxo-1H,9H-benzothiopyrano[2,3-d]-1,2,3-triazoles and their S-oxides

Selected derivatives of 9-oxo-1H,9H-benzothiopyrano[2,3-d]-1,2,3-triazole, a new heterocyclic ring system, and their S-oxides have been prepared and evaluated for antiallergic activity in the rat passive cutaneous anaphylaxis screen. Several of the compounds show intravenous potencies similar to or greater than that of disodium cromoglycate, the most potent being 6,7-dimethyl-9-oxo-1H,9H-benzothiopyrano[2,3-d]-1,2,3-triazole and its 4,4-dioxide.

Synthesis, isolation, and characterization of two stereoisomeric ring sulfoxides of thioridazine

A selective oxidation of thioridazine to give exclusively its ring sulfoxides and a separation of the resulting products as diastereoisomeric pairs of enantiomers (DL, LD and DD, LL) are reported. These pairs were characterized by TLC, high-performance liquid chromatographic, IR, UV, 1H-NMR, 13C-NMR, GC-MS, and elemental analyses, and by reduction to thioridazine by lithium aluminum hydride. Structural data for the separated diastereoisomeric pairs or their nitric acid salts were obtained from NMR and IR studies. Gram quantities of each of the two diastereoisomeric pairs of enantiomers were isolated in better than 99% purity.

Steroid cyclicsulfites. III. Conformational and configurational aspects of steroid 3,5-cyclicsulfites

The reaction of 3beta, 5beta-dihydroxy cholestanes with thionyl chloride is shown to yield cyclicsulfite esters containing boat heterocyclic rings with the S=O oxygen axial or equatorial, depending upon the mode of formation. Treatment of a diol in pyridine at low temperature favors an equatorial S=O conformation while higher reaction temperatures in chloroform solution yield a mixture of axial and equatorial epimers. In the case of a 7alpha-bromo-6-oxo 3,5-sulfite, it has been shown that the S=O equatorial isomer may be converted to the axial isomer upon treatment with acid.

[Iodo-derivatives of 2-aminobenzensulfonamide and 1,2,4-benzothiadiazine-1,1-dioxide]

A series of iodo derivatives of 2-aminobenzensulfonamide and its derivatives has been prepared by reaction with iodine chloride in N,N-dimethylformamide or N,N-dimethylacetamide. The structure of each compound was confirmed by transformation with formic acid into the corresponding 1,2,4-benzothiadiazine and comparison with the same compounds prepared via the Sandmeyer reaction starting form amino derivatives of known structure. It was found that the iodination reaction in N,N-dimethylformamide, can lead, depending on the nature of the starting material, to the formation of benzothiadiazine derivatives apparently generated from sulfonamide via a formylation reaction due to N,N-dimethylformamide.