Synthesis of 2-Mercapto-(2-Oxoindolin-3-Ylidene)Acetonitriles from 3-(4-Chloro-5H-1,2,3-Dithiazol-5-Ylidene)Indolin-2-ones

Alkylidene oxindoles are important functional moieties and building blocks in pharmaceutical and synthetic chemistry. Our interest in biologically active compounds focused our studies on the synthesis of novel oxindoles, bearing on the exocyclic double bond at the C8, CN, and S groups. Extending the potential applications of Appel’s salt, we developed a new synthetic approach by investigating the reactions of C5-substituted 2-oxindoles with 4,5-dichloro-1,2,3-dithiazolium chloride (Appel’s salt) to give original (Z)-3-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)indolin-2-one derivatives, and new 2-mercapto-(2-oxoindolin-3-ylidene)acetonitriles via a dithiazole ring-opening reaction. The work described in this article represents further applications of Appel’s salt in the conception of novel heterocyclic rings, in an effort to access original bioactive compounds. Fifteen new compounds were prepared and fully characterized.

2-benzothiazoleacetonitrile based two-photon fluorescent probe for hydrazine and its bio-imaging and environmental applications

A novel turn-on two-photon fluorescent probe NS-N 2 H 4 was developed with the 2-benzothiazoleacetonitrile as a new recognition site for the detection of hydrazine (N2H4). The two-photon probe exhibited favorable properties including high selectivity, low cytotoxicity and almost 16-fold fluorescence enhancement in the presence of N2H4 in solution. The probe could be used to image hydrazine in the living cells. Notably, we also used the two-photon fluorescent probe to image hydrazine in the tissue imaging for the first time. Furthermore, by the way of probe-loaded TLC plate, we further monitored vapor of hydrazine. Therefore, the novel two-photon probe is expected to be employed to detect N2H4 in biosamples and environmental pollution and the new recognition site will be widely applied to construct fluorescent probes for the detection of N2H4.

Dioxol and dihydrodioxin analogs of 2- and 3-phenylacetonitriles as potent anti-cancer agents with nanomolar activity against a variety of human cancer cells

A small library of (Z)-2-(benzo[d][1,3]dioxol-5-yl) and (Z)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl analogs of 2- and 3-phenylacetonitriles has been synthesized and evaluated for their anti-cancer activities against a panel of 60 human cancer cell lines. The dihydrodioxin analog 3j and dioxol analogs 5e and 7e exhibited the most potent anti-cancer activity of all the analogs synthesized in this study, with GI50 values of <100 nM against almost all of the cell lines in the human cancer cell panel. Of these three, only compound 3j inhibited tubulin polymerization to any degree in vitro. The binding modes of 3j and the structurally related tubulin-inhibitor DMU-212 were determined by virtual docking studies with tubulin dimer. Compound 3j docked at the colchicine-binding site at the dimer interface of tubulin. The Full-Fitness (FF) score of 3j was observed to be substantially higher than DMU-212, which agrees well with the observed anti-cancer potency (GI50 values). The mechanism by which dioxol analogs 5e and 7e exert their cytotoxic effects remains unknown at this stage, but it is unlikely that they affect tubulin dynamics. Nevertheless, these findings suggest that both dioxol and dihydrodioxin analogs of phenylacrylonitrile may have potential for development as clinical candidates to treat a variety of human cancers.

Bi-anchoring organic sensitizers of type D-(π-A)₂ comprising thiophene-2-acetonitrile as π-spacer and malonic acid as electron acceptor for dye sensitized solar cell applications

Two new bi-anchoring organic sensitizers of type D-(π-A)2 comprising the identical π-spacer (thiophene-2-acetonitrile) and electron acceptor (malonic acid) but different aryl amine as electron donors (diphenylamine and carbazole) were synthesized, characterized and fabricated metal free dye-sensitized solar cell devices. The intra molecular charge transfer property and electrochemical property of these dyes were investigated by molecular absorption, emission, cyclic voltammetric experiments and in addition, quantum chemical calculation studies were performed to provide sufficient driving force for the electron injection into the conduction band of TiO2 which leads to efficient charge collection. Among the fabricated devices, carbazole based device exhibits high current conversion efficiency (η=4.7%) with a short circuit current density (JSC) 15.3 mA/cm(2), an open circuit photo voltage (VOC) of 0.59 V and a fill factor of 0.44 under AM 1.5 illumination (85 mW/cm(2)) compared to diphenylamine based device.

Chlorination and chloramination of tetracycline antibiotics: disinfection by-products formation and influential factors

Formation of disinfection by-products (DBPs) from chlorination and chloramination of tetracycline antibiotics (TCs) was comprehensively investigated. It was demonstrated that a connection existed between the transformation of TCs and the formation of chloroform (CHCl3), carbon tetrachloride (CCl4), dichloroacetonitrile (DCAN) and dichloroacetone (DCAce). Factors evaluated included chlorine (Cl2) and chloramine(NH2Cl) dosage, reaction time, solution pH and disinfection modes. Increased Cl2/NH2Cl dosage and reaction time improved the formation of CHCl3 and DCAce. Formation of DCAN followed an increasing and then decreasing pattern with increasing Cl2 dosage and prolonged reaction time. pH affected DBPs formation differently, with CHCl3 and DCAN decreasing in chlorination, and having maximum concentrations at pH 7 in chloramination. The total concentrations of DBPs obeyed the following order: chlorination>chloramination>pre-chlorination (0.5h)>pre-chlorination (1h)>pre-chlorination (2h).

Synthesis and glycosidase inhibitory activity of novel (2-phenyl-4H-benzopyrimedo[2,1-b]-thiazol-4-yliden)acetonitrile derivatives

A series of (2-phenyl-4H-benzopyrimodo[2,1-b][1,3]thiazol-4-yliden-4-yliden)acetonitrile derivatives have been prepared by ring transformation reaction of 4-(methylthio)-2-oxo-6-aryl-2H-pyrane-3-carbonitriles. The yield of ring transformation product is moderate to good. Furthermore the glycosidase inhibitory activities were tested by using α-amylase and α-glucosidase pancreatic, intestinal and liver enzymes, responsible for hyperglycemia in type II diabetes. The results revealed that all compounds exhibit significant glycosidase inhibitory activity.

Precursors and nitrogen origins of trichloronitromethane and dichloroacetonitrile during chlorination/chloramination

The formation of trichloronitromethane (TCNM) and dichloroacetonitrile (DCAN) was investigated during chlorination and chloramination of 31 organic nitrogen (org-N) compounds, including amino acids, amines, dipeptides, purines, pyrimidones and pyrroles. Tryptophan and alanine generated the greatest amount of TCNM during chlorination process and asparagine and tyrosine yielded the highest amount of TCNM during chloramination process. Tryptophan, tyrosine, asparagine, and alanine produced more DCAN than other org-N compounds regardless of chlorination or chloramination. TCNM and DCAN formation was higher by chlorination than by chloramination. NH(2)Cl:org-N molar ratios, reaction time, and pH affected N-DBPs formation in varying degrees. TCNM and DCAN yields were usually high during chloramination of tyrosine, asparagine, and methylpyrrole under the following reaction conditions: NH(2)Cl:org-N molar ratios greater than 10, reaction time for 1d, and at pH 7.2. NH(2)Cl as a major nitrogen origin in TCNM and DCAN was confirmed via labeled (15)N-monochloramine during chloramination of tyrosine, asparagine and methylpyrrole. In contrast, the majority of nitrogen in TCNM originated from glycine, and that in DCAN originated from pyrrole. Based on the intermediates identified by gas chromatography/mass spectrometry (GC/MS), a pathway scheme was proposed for TCNM and DCAN formation.

Impact of UV disinfection combined with chlorination/chloramination on the formation of halonitromethanes and haloacetonitriles in drinking water

The application of UV disinfection in water treatment is increasing due to both its effectiveness against protozoan pathogens, and the perception that its lack of chemical inputs would minimize disinfection byproduct formation. However, previous research has indicated that treatment of nitrate-containing drinking waters with polychromatic medium pressure (MP), but not monochromatic (254 nm) low pressure (LP), UV lamps followed by chlorination could promote chloropicrin formation. To better understand this phenomenon, conditions promoting the formation of the full suite of chlorinated halonitromethanes and haloacetonitriles were studied. MP UV/postchlorination of authentic filter effluent waters increased chloropicrin formation up to an order of magnitude above the 0.19 μg/L median level in the U.S. EPA's Information Collection Rule database, even at disinfection-level fluences (<300 mJ/cm(2)) and nitrate/nitrite concentrations (1.0 mg/L-N) relevant to drinking waters. Formation was up to 2.5 times higher for postchlorination than for postchloramination. Experiments indicated that the nitrating agent, NO(2)(•), generated during nitrate photolysis, was primarily responsible for halonitromethane promotion. LP UV treatment up to 1500 mJ/cm(2) did not enhance halonitromethane formation. Although MP UV/postchloramination enhanced dichloroacetonitrile formation with Sigma-Aldrich humic acid, formation was not significant in field waters. Prechlorination/MP UV nearly doubled chloropicrin formation compared to MP UV/postchlorination, but effects on haloacetonitrile formation were not significant.

Evolution of multi-component anion relay chemistry (ARC): construction of architecturally complex natural and unnatural products

Efficient construction of architecturally complex natural and unnatural products is the hallmark of organic chemistry. Anion relay chemistry (ARC)-a multi-component coupling protocol-has the potential to provide the chemist with a powerful synthetic tactic, enabling efficient, rapid elaboration of structurally complex scaffolds in a single operation with precise stereochemical control. The ARC tactic can be subdivided into two main classes, comprising the relay of negative charge either through bonds or through space, the latter with aid of a transfer agent. This review will present the current state of through-space anion relay, in conjunction with examples of natural and unnatural product syntheses that illustrate the utility of this synthetic method.

Factors affecting formation of haloacetonitriles, haloketones, chloropicrin and cyanogen halides during chloramination

Effects of contact time, monochloramine doses, monochloramine application modes, pH, temperature and bromide ion concentrations on formation of disinfection by-products (DBPs), including haloacetonitriles, haloketones, chloropicrin, cyanogen halides and trihalomethanes, during chloramination were investigated using model solutions containing 5 mg/L (as DOC) Suwannee River natural organic matter (NOM). Chloramine speciation and some DBPs were measured using membrane introduction mass Spectrometer (MIMS). Longer reaction times led to continued formation over time for dichloroacetonitrile (DCAN), 1,1-dichloro-2-propanone (1,1-DCP) and chloroform. Cyanogen chloride (CNCl) formation occurred over time, but after reaching a peak concentration CNCl concentrations decreased over longer time periods. Linear relationships were observed between the formation of DCAN, 1,1-DCP, CNCl or chloroform and the dosage of monochloramine. Chloramination modes (addition of preformed monochloramine or variable sequential additions of free chlorine and ammonium salts) exhibited the largest impact on chloroform formation but displayed little effect on the formation of DCAN, 1,1-DCP and CNCl. Over the range in pH from 4 to 9 profound differences in DBP formation were observed; pH values between 5 and 6 resulted in the highest DBP concentrations. An increase in temperature enhanced the formation of chloroform but did not affect DCAN, 1,1-DCP and CNCl formation. Chloropicrin concentrations were always low (around detection limits) under all conditions. Increasing the concentrations of bromide ions enhanced the formation of bromine-substituted DBPs.

An investigation of the reduction in aqueous acetonitrile of 4-methoxybenzenediazonium ion by the tetrakis(acetonitrile)Cu(i) cation catalysed by hydrogenphosphate dianion

In aqueous acetonitrile containing a phosphate buffer, 4-methoxybenzenediazonium ion is reduced by one or more of the partially aquated cations derived from tetrakis(acetonitrile)Cu(I) cation in this medium. Investigation of the reaction mechanism indicates the rate determining step to be the association of the diazonium ion with the hydrogenphosphate dianion to give an adduct which then undergoes reduction by Cu(I). The reaction gives a range of products which have been identified and quantified by GC. One of these, 4-methoxyphenol was unexpected in the reducing conditions; its presence could be explained by the disproportionation of a 4-methoxyphenylcopper(II) complex giving bis(4-methoxyphenyl)copper(III) which reacts with water to produce the phenol and an equivalent amount of methoxybenzene. A scheme is proposed which accounts for all the observed products and computer modelling gives a satisfactory description of the distributions of the five major products as functions of the relative proportions of the reactants for dilute conditions and those where the reductant is in excess. When the diazonium ion is in excess, the behaviour of the model and the experimental reactant accountability suggest the occurrence of additional reactions which give products unobserved by GC.

Three-dimensional quantitative structure-activity relationship (3 D-QSAR) and docking studies on (benzothiazole-2-yl) acetonitrile derivatives as c-Jun N-terminal kinase-3 (JNK3) inhibitors

Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were developed for 44 (benzothiazole-2-yl) acetonitrile derivatives, inhibiting c-Jun N-terminal kinase-3 (JNK3). It includes molecular field analysis (MFA) and receptor surface analysis (RSA). The QSAR model was developed using 34 compounds and its predictive ability was assessed using a test set of 10 compounds. The predictive 3D-QSAR models have conventional r2 values of 0.849 and 0.766 for MFA and RSA, respectively; while the cross-validated coefficient r(cv)2 values of 0.616 and 0.605 for MFA and RSA, respectively. The results of the QSAR model were further compared with a structure-based analysis using docking studies with crystal structure of JNK3. Ligands bind in the ATP pocket and the hydrogen bond with GLN155 was found to be crucial for selectivity among other kinases. The results of 3D-QSAR and docking studies validate each other and hence, the combination of both methodologies provides a powerful tool directed to the design of novel and selective JNK3 inhibitors.

Pre-cometary ice composition from hot core chemistry

Pre-cometary ice located around star-forming regions contains molecules that are pre-biotic compounds or pre-biotic precursors. Molecular line surveys of hot cores provide information on the composition of the ice since it sublimates near these sites. We have combined a hydrostatic hot core model with a complex network of chemical reactions to calculate the time-dependent abundances of molecules, ions, and radicals. The model considers the interaction between the ice and gas phase. It is applied to the Orion hot core where high-mass star formation occurs, and to the solar-mass binary protostar system IRAS 16293-2422. Our calculations show that at the end of the hot core phase both star-forming sites produce the same prebiotic CN-bearing molecules. However, in the Orion hot core these molecules are formed in larger abundances. A comparison of the calculated values with the abundances derived from the observed line data requires a chemically unprocessed molecular cloud as the initial state of hot core evolution. Thus, it appears that these objects are formed at a much younger cloud stage than previously thought. This implies that the ice phase of the young clouds does not contain CN-bearing molecules in large abundances before the hot core has been formed. The pre-biotic molecules synthesized in hot cores cause a chemical enrichment in the gas phase and in the pre-cometary ice. This enrichment is thought to be an important extraterrestrial aspect of the formation of life on Earth and elsewhere.

Design and synthesis of the first generation of novel potent, selective, and in vivo active (benzothiazol-2-yl)acetonitrile inhibitors of the c-Jun N-terminal kinase

Several lines of evidence support the hypothesis that c-Jun N-terminal kinase (JNKs) plays a critical role in a wide range of diseases including cell death (apoptosis)-related disorders (neurodegenerative diseases, brain, heart, and renal ischemia, epilepsy) and inflammatory disorders (multiple sclerosis, rheumatoid arthritis, inflammatory bowel diseases). Screening of our internal compound collection for inhibitors of JNK3 led to the identification of (benzothiazol-2-yl)acetonitrile derivatives as potent and selective JNK1, -2, -3 inhibitors. Starting from initial hit 1 (AS007149), the chemistry and initial structure-activity relationship (SAR) of this novel and unique kinase inhibitor template were explored. Investigation of the SAR rapidly revealed that the benzothiazol-2-ylacetonitrile pyrimidine core was crucial to retain a good level of potency on rat JNK3. Therefore, compound 6 was further optimized by exploring a number of distal combinations in place of the chlorine atom. This led to the observation that the presence of an aromatic group, two carbons away from the aminopyrimidine moiety and bearing substituents conferring hydrogen bond acceptor (HBA) properties, could improve the potency. Further improvements to the biological and biopharmaceutical profile of the most promising compounds were performed, resulting in the discovery of compound 59 (AS601245). The in vitro and in vivo anti-inflammatory potential of this new JNK inhibitor was investigated and found to demonstrate efficacy per oral route in an experimental model of rheumatoid arthritis (RA).

The Development Research of Oxidase Functional Model Iron Complexes

This paper describes research performed in the Laboratory of Organic Chemistry, Showa Pharmaceutical University. Oxidation reactions involving the oxidase can be divided roughly into two kinds of reactions: The first involves electron removal from an aromatic ring or an active CH-bond. The other reaction involves hydrogen abstraction from an inactive CH-bond. The oxidase models, Fe(DMF)(3)Cl(2)(1+) and Fe(AN)(6)(3+)/AN, which we have synthesized, have been shown to work by the former mechanism, and the models Fe(AN)(6)(3+)-IO(4)(-)/AN, Fe(AN)(6)(2+)-Ac(2)O-H(2)O(2)/AN, Fe(AN)(6)(2+)-2PAH-5Py-Ac(2)O-H(2)O(2)/AN, Fe(PA)(3)(OH(2))-H(2)O(2)/AN and Fe(PA)(3)(OH(2))-O(2)-electrolysis/AN do so by the latter mechanism. Further, we found some iron (II or III)picolinate-H(2)O(2)/AN complexes have the 7 alpha-hydroxylase-like activity.

Intramolecular [4 + 2] cycloadditions of iminoacetonitriles: a new class of azadienophiles for hetero Diels-Alder reactions

Iminoacetonitriles participate as reactive dienophiles in stereoselective intramolecular hetero Diels-Alder reactions which afford substituted quinolizidines. The cycloadduct with exo-oriented cyano group is obtained as the major or exclusive product of the reaction as a consequence of the alpha-amino nitrile anomeric effect The alpha-amino nitrile moieties incorporated in the cycloadducts constitute latent iminium ions, which upon exposure to mild protic or Lewis acids are unmasked, setting the stage for further useful synthetic transformations. For example, reductive decyanation with NaBH3CN excises the cyano group, while Bruylants reaction with Grignard reagents and acetylides lead to alpha-substituted amines. The substrates for these [4 + 2] cycloadditions are prepared from readily available alcohols via a Mitsunobu coupling reaction with the previously unknown, easily prepared reagent HN(Tf)CH2CN followed by cesium carbonate promoted elimination of trifluoromethanesulfinate.

Development of a process model to describe the synthesis of (R)-mandelonitrile by Prunus amygdalus hydroxynitrile lyase in an aqueous-organic biphasic reactor

A process model for the enzymatic synthesis of (R)-cyanohydrins in an aqueous-organic biphasic-stirred tank reactor was developed. The conversion of benzal-dehyde into (R)-mandelonitrile, catalyzed by Prunus amygdalus hydroxynitrile lyase at 5 degrees C and pH 5.5, was chosen as a model system with methyl tert-butyl ether as the organic phase. The process model consisted of a description of the reaction kinetics, mass transfer kinetics, and the mass balances for both the aqueous and the organic phase. Values for the enzyme kinetic parameters, according to ordered bi-uni kinetics, the lumped mass transfer coefficient for benzaldehyde, and the partition coefficients were determined separately. The process model is validated by using 11 experimental data sets of batch conversions in the aqueous-organic biphasic-stirred tank reactor. In these 11 experiments, different enzyme concentrations and phase volume ratios were used. The model was found to be valid with respect to both the conversion and the enantiomeric excess. To synthesize cyanohydrins with a high enantiomeric excess, the enzyme is required to work at mass transfer limited conditions. The developed process model will be used to investigate other process concepts and other substrates.

Synthesis of 1,1-disubstituted alkenes via a Ru-catalyzed addition

The synthesis of 1,1-disubstituted alkenes typically involves reactions that lack atom economy such as olefination protocols. The use of various ruthenium complexes to effect the addition of terminal alkynes to alkenes is explored as an atom economical strategy. Two new ruthenium complexes have been discovered that effect this reaction at ambient temperature, cyclopentadienylruthenium (triphenylphosphine) camphorsulfonate and cyclopentadienylruthenium tris(acetonitrile) hexafluorophosphate. Using these complexes as catalysts, reactions proceed at ambient temperature in acetone or DMF, respectively. Regioselectivity favoring the formation of a 1,1-disubstituted over a 1,2-disubstituted alkene typically ranges from 9:1 to >25:1. The reaction demonstrates extraordinary chemoselectivity-even di- and trisubstituted alkenes such as present in the products do not compete with the starting monosubstituted alkene. Free hydroxyl groups as well as silyl and PMB ethers are tolerated as are ketones, esters, and amides. The mechanism of the reaction is believed to invoke formation of a metallacyclopentene. To account for the chemo- and regioselectivity, the initial formation of the metallacycle is believed to be reversible. While formation of the 2,5-disubstituted ruthenacyclopentene, which produces the linear product, is believed to be kinetically preferred, the rate of beta-hydrogen elimination from the 2,4-disubstituted ruthenacyclopentene, which produces the branched product, is believed to be faster. Thus, the competition between the rate of beta-hydrogen elimination and cycloreversion rationalizes the results.

Synthesis and biological evaluation of aeroplysinin analogues: a new class of receptor tyrosine kinase inhibitors

Receptor tyrosine kinases (RTKs), such as the epidermal growth factor receptor (EGFR) and the platelet-derived growth factor receptor (PDGFR), are critically involved in the transduction of mitogenic signals across the plasma membrane and therefore in the regulation of cell growth and proliferation. Enhanced RTK activity is associated with proliferative diseases such as cancer, psoriasis and atherosclerosis, while decreased function may be associated for instance with diabetes. EGFR and PDGFR are selectively inhibited by analogues of the marine natural product aeroplysinin. The synthetic inhibitors display IC50 values in the low micromolar range and in contrast to the natural product show pronounced inhibitory activity in cultured cells in vivo. The mechanism of inhibition is likely based on a covalent modification of the target enzymes by reaction of epoxy ketone 8 with various nucleophiles.

Glycolonitrile oligomerization: structure of isolated oxazolines, potential heterocycles on the early earth

A study of glycolonitrile polymerization has led to the isolation and characterization of two 2,5-dihydro-4-aminooxazoles, 4 and 5. Previous reports have misassigned these structures as s-triazines or pyrimidines. X-ray diffraction analysis of crystals of 4 and an acetylated oxazole derivative of 5 (6) confirm the proposed structures. Ab initio computations are used to assess the relative thermodynamic stability of three trimer isomers (an s-triazine, an aminohydroxypyrimidine, and an aminooxazoline), and the results indicate that 4 is a novel kinetic product. Mechanistic considerations rationalize kinetic oxazole formation over the more customary triazine or pyrimidine trimers.

Synthesis and antiparasitic activities of amidinic azolated derivatives

A set of heterocyclic N-acetamidinium hydrochlorides were prepared from the corresponding N-acetonitriles. The antiparasitic screening showed that, while all amidines are practically inactive, some nitriles present leishmanicide properties.

Ketomethylene and (cyanomethylene)amino pseudopeptide analogues of the C-terminal hexapeptide of neurotensin

A series of pseudopeptide analogues of the C-terminal hexapeptide of neurotensin (NT8-13), namely [Tyr11 psi[COCH2]Phe12]-, [Ile12 psi[COCH2]Phe13]-, and [Tyr11 psi[CH(CN)NH]Ile12]NT8-13 with different stereochemistries, has been synthesized and evaluated for its potency in displacing labeled NT from rat cortex membranes. Ketomethylene pseudohexapeptides were prepared from the corresponding Boc-protected ketomethylene dipeptide derivatives, previously formed, using different solid phase synthesis (SPS) conditions, while (cyanomethylene)amino analogues were directly prepared by SPS using Fmoc strategy. H-Arg-Arg-Pro-Tyr psi[COCH2]-Phe-Leu-OH was nearly as potent as NT8-13 and [Phe12]NT8-13 in binding to the receptor. Comparison of the affinities for the pseudohexapeptides, here reported, with those of the psi-[CH2NH] analogues indicates the importance of the CO group in the amide or surrogate linkage at 11-12 and 12-13 positions in the receptor binding process.

Reactions with thiaxanthen-9-ol: new thiaxanthene derivatives with molluscicidal and nematocidal activity

Thiaxanthen-9-ol (1) was condensed with nitriles 2a-e to yield the thiaxanthen-9-yl-acetonitriles 3a-e. With the thiols 7a-d, 1 yielded the thioethers 8a-d.

Archean geochemistry of formaldehyde and cyanide and the oligomerization of cyanohydrin

The sources and speciation of reduced carbon and nitrogen inferred for the early Archean are reviewed in terms of current observations and models, and known chemical reactions. Within this framework hydrogen cyanide and cyanide ion in significant concentration would have been eliminated by reaction with excess formaldehyde to form cyanohydrin (glycolonitrile), and with ferrous ion to form ferrocyanide. Natural reactions of these molecules would under such conditions deserve special consideration in modeling of primordial organochemical processes. As a step in this direction, transformation reactions have been investigated involving glycolonitrile in the presence of water. We find that glycolonitrile, formed from formaldehyde and hydrogen cyanide or cyanide ion, spontaneously cyclodimerizes to 4-amino-2-hydroxymethyloxazole. The crystalline dimer is the major product at low temperature (approximately 0 degrees C); the yield diminishes with increasing temperature at the expense of polymerization and hydrolysis products. Hydrolysis of glycolonitrile and of oxazole yields a number of simpler organic molecules, including ammonia and glycolamide. The spontaneous polymerization of glycolonitrile and its dimer gives rise to soluble, cationic oligomers of as yet unknown structure, and, unless arrested, to a viscous liquid, insoluble in water. A loss of cyanide by reaction with formaldehyde, inferred for the early terrestrial hydrosphere and cryosphere would present a dilemma for hypotheses invoking cyanide and related compounds as concentrated reactants capable of forming biomolecular precursor species. Attempts to escape from its horns may take advantage of the efficient concentration and separation of cyanide as solid ferriferrocyanide, and most directly of reactions of glycolonitrile and its derivatives.

Cinnamamide analogs as inhibitors of protein tyrosine kinases

Protein tyrosine kinases (PTK) are important signal transducing enzymes involved in the modulation of normal cellular growth and differentiation and have been associated with the etiology of various human cancers. The development of properly designed inhibitors, which block their function by interfering with the substrate binding, may therefore offer an unique target for selective anticancer chemotherapy. Here we describe synthesis and biochemical testing of a novel series of non-peptide PTK inhibitors which have as characteristic active pharmacophore the cinnamamide moiety. For testing we used an exogenous substrate kinase assay based on the phosphorylation of (Val5)-angiotensin II with radiolabelled ATP by the catalytic domain of the PTK encoded by the v-abl oncogene (p45 v-abl). The most potent compounds were found in the class of 3-arylidene-2-oxindoles (II) with IC50 values in the 1 microM range. Among these the 2-tetralylmethylene-, 4-quinolylmethylene-, 5-quinolylmethylene- and 3-indolylmethylene-2-oxindole compounds of formulae 16, 20, 21 and 24 respectively were selected for further investigation.

Inactivation of monoamine oxidase B by analogues of the anticonvulsant agent milacemide (2-(n-pentylamino)acetamide)

Analogues of the anticonvulsant agent milacemide (1,2-(n-pentylamino)acetamide), in which the carboxamide group is changed to a nitrile (2), a carbethoxy group (3), a carboxylic acid (4), a cyanomethyl group (5), and a trifluoromethyl group (6), were synthesized and tested as substrates and inactivators of monoamine oxidase B (MAO B). The carboxylic acid was neither a substrate nor an inactivator. The trifluoromethyl compound was not soluble in buffer even when organic cosolvents were added, so it could not be tested. All of the other compounds were both substrates and time-dependent irreversible inactivators of MAO B. A plot of the logarithm of kcat/k(inact) (a measure of the efficiency of the inactivators) versus sigma I (Figure 1) shows a linear free energy relationship between the inactivator efficiency and the electron-withdrawing ability of the substituent. As the electron-withdrawing ability increases, the partition ratio decreases indicating that inactivation is becoming more efficient relative to substrate turnover to product. Milacemide was the least efficient of the compounds tested; the nitrile 2 was the most efficient.

Verapamil analogues with restricted molecular flexibility: synthesis and pharmacological evaluation of the four isomers of alpha-[1-[3-[N-[1- [2-(3,4-dimethoxyphenyl)ethyl]]-N-methylamino]cyclohexyl]]-alpha- isopropyl-3,4-dimethoxybenzene-acetonitrile

The synthesis and pharmacological activities of the four isomeric racemates of alpha-[1-[3-[N-[1-[2-(3,4-dimethoxyphenyl)ethyl]]-N- methylamino]cyclohexyl]]-alpha-isopropyl-3,4-dimethoxybenzene-acetoni trile are reported (2a-d). The compounds are verapamil analogues with restricted molecular flexibility designed to gather information on the active conformation(s) of the parent drug. The relative stereochemistry of the four racemates was established by X-ray crystallography and by 1H NMR spectroscopy; conformational analysis was supported by theoretical calculations. Negative inotropic and chronotropic activities were evaluated on guinea pig atria, while vasodilatory activity on smooth muscle was tested on guinea pig aortic strips. Binding studies on cat ventricles were performed using (-)-[N-methyl-3H]desmethoxyverapamil (D888) as a reference ligand. The results seem to support the hypothesis that cardiac depressant and vasorelaxant activities are due to different conformations of the verapamil molecule.

Synthesis and cardiotonic evaluation of R-sulfonyl derivatives of azaheterocycles

A series of alpha-sulfonyl-2-(3-chloro)hetarylacetonitriles was prepared by the interaction of dichlorodiazines and R-sulfonylacetonitriles. Reaction of nucleophilic substitution of chlorine by different N-H-azoles has been studied. The compounds obtained showed 3 types of activity on cardiac papillary muscles: 1. a biphasic activity with increase in cardiac contractility at low concentration and inhibition in high concentration (1, 2, 4, 12-15), 2. a monophasic inhibitory activity (3, 5, 8-10), 3. non-active compounds (6, 7, 11). The preliminary SAR studies indicate the importance of chlorine atom at position 3 in diazine nucleus and of alkyl substituents in benzimidazole moiety for positive inotropic effects.

Imidazo[4,5-b]pyridine derivatives of potential tuberculostatic activity, II: Synthesis and bioactivity of designed and some other 2-cyanomethylimidazo[4,5-b]pyridine derivatives

Based on the analysis of Quantitative Structure--Activity Relationships (QSAR) three representatives of imidazo[4,5-b]pyridine derivatives of predicted high antibacterial activity against Mycobacterium tuberculosis were synthetized and tested bacteriologically. Excellent agreement of the predicted and experimentally observed bioactivity was noted. Additional new derivatives of 4-methyl-4H-2-cyanomethylimidazo[4,5-b]pyridine (7) and 2-(alpha-methylcyanomethyl)imidazo[4,5-b]pyridine (22) were also synthesized and some of them were tested for tuberculostatic activity. The compounds synthesized according to a standard "trial and error" approach appeared generally inactive.

[Study of the phytoiatric antifungal activity of derivatives of 2- and 4-aminophenylthioacetonitrile and ethyl 4-aminophenylthioacetate]

Some N-acyl and N-carbamoyl-derivatives of 2-, of 4-amino-phenylthioacetonitrile and of ethyl 4-aminophenylthioacetate, and also some N-thiocarbamoylderivatives of the latter were prepared in order to test their antimycotic activity against representative plant parasites. The substances, (I-XXVI), mostly unknown, were subjected to in vitro and in vivo tests (in preventive phase). Some of the compounds studied, especially the 2-aminophenylthioacetonitrilic derivatives, showed in the in vivo tests interesting activity and good specificy against P. viticola.

Theoretical investigation of the interstellar CH3NC/CH3CN ratio

Calculations have been performed to determine the abundance ratio of the metastable isomer CH3NC to the stable isomer CH3CN in dense interstellar clouds. According to gas phase, ion-molecule treatments, these molecules are both synthesized via protonated ion precursors. We have calculated the ratio of the formation rates of the protonated precursor ions-- CH3NCH+ and CH3CNH+ --synthesized via the radiative association reaction between CH3+ and HCN, which is thought to the dominant formation process of the two isomeric ions. Our calculations, which involve both ab initio quantum chemistry and equilibrium determinations, lead to a predicted CH3NCH+/CH3CNH+ formation rate ratio between 0.1 and 0.4. If this ratio is maintained in the neutral species formed from the precursor ions, theory predicts a sizable abundance for methyl isocyanide (CH3NC) and lends credence to its tentative observation.

[Synthesis and spectrum of pharmacologic action of aryl-arylamino- and aryl-aryliminoacetonitriles]

Aminoacetonitriles were synthetized from arylaldehyde, arylamine and cyanhydrogene. Their dehydrogenation led to the iminoderivatives. The compounds were evaluated for spasmolytic activity in vitro. Some aryl-arylaminoacetonitriles showed significant inhibition of the histamine-induced contraction in guinea-pig ileum and acetylcholine-induced contraction in rat ileum. Structure-activity relationships are discussed.

Antitumor and antiinflammatory agents: N-benzoyl-protected cyanomethyl esters of amino acids

A series of N-protected cyanomethyl esters of various amino acids was synthesized and tested for antineoplastic and antiinflammatory activity in rodents. Utilizing the L-phenylalanine cyanomethyl ester and varying the N-protecting moiety demonstrated that the N-tosyl and the N-Cbz analogues were the most active against Ehrlich ascites cell proliferation. The N-(carbobenzyloxy)- and N-benzoyl-L-phenylalanine cyanomethyl esters were the most active against carrageenan-induced inflammation. In the N-benzoyl series of cyanomethyl esters, L-alanine, DL-valine, and L-leucine amino acid analogues were the most active against Ehrlich ascites cell proliferation. The glycine and L-alanine analogues possessed the best inhibitor activity in the antiinflammatory screen. The cyanomethyl esters also demonstrated immunosuppressive activity and the ability to suppress the writhing reflex which is associated with inflammatory pain. However, no antipyretic or narcotic analgesic activity was demonstrated by these agents.

Potential antiarthritic agents. 2. Benzoylacetonitriles and beta-aminocinnamonitriles

Benzoylacetonitrile and beta-aminocinnamonitrile are shown to possess potent antiinflammatory activity in the rat adjuvant arthritis model. In a series of phenyl-substituted analogues, only o-, m-, and p-fluorobenzoylacetonitrile and m- and p-fluoro-beta-aminocinnamonitrile retained activity. Additionally, beta-amino-2- and beta-amino-3-thiopheneacrylonitrile and beta-oxo-2- and beta-oxo-3-thiophenepropionitrile exhibited similar activity. These agents are not believed to be acting via prostaglandin synthetase inhibition. The metabolic profile of benzoylacetonitrile is also described.

Antineoplastic agents. 1. N-Protected vinyl, 1,2-dihaloethyl, and cyanomethyl esters of phenylalanine

A series of N-protected vinyl, 1,2-dihaloethyl, and cyanomethyl esters of phenylalanine was synthesized and these compounds were evaluated for antitumor activity against the growth of Ehrlich ascites carcinoma in CF1 male mice (33 mg/kg/day), Walker 256 carcinosarcoma in Sprague-Dawley male rats (2.5 mg/kg/day), and P388 lymphocytic leukemia in DBA/2 mice (20 mg/kg/day). Structure-activity relationships were evaluated and acute toxicity studies (LD50 determinations) in male CF1 mice were also carried out on selected compounds. Carbobenzoxy-L0phenylalanine vinyl ester (5), N-carbobenzoxy-L-phenylalanine 1,2-dibromoethyl ester (12), and N-carbobenzoxy-L-phenylalanine cyanomethyl ester (8) were found to be very potent inhibitors of Ehrlich ascites tumor growth at nontoxic doses cited above. Compounds 5 and 12 also tripled survival time in the Walker 256 system. LD50 values for compounds 5, 12, and 8 were greater than 2000 mg/kg (greater than 6.15 mmol/kg), 74 mg/kg (0.15 mmol/kg), and 150 mg/kg (0.44 mmol/kg), respectively.

Relationship of chemical structure and solvent to in vivo scintigraphic distribution patterns of 11C compounds. II. 11C aminonitriles

The preparation and scintigraphic evaluation of the distribution patterns in dogs of a series of structurally related aminonitriles labeled with 11C is described. Carbon-11-HCN was collected in water containing carrier NaCN following 22 MeV proton bombardment of 99% N2 and 1% H2 gas mixture for 1 hr. Ten 11C alphaN-alkylaminophenylacetonitrile hydrochlorides and 12 11C alpha-N-arylaminoarylacetonitriles were prepared from 11C-NaCN and the corresponding Schiff base, Ar-CH=N-R(Ar). Those 11C aminonitriles that were administered intravenously in aqueous solution showed some initial accumulation of activity in the liver followed by diffuse whole-body distribution and some small accumulation in urine. Aqueous insoluble 11C aminonitriles, which were administered intravenously in ethanol, ether, or DMSO, showed variable initial partial retention of activity in the lungs with prominent accumulation of activity in liver and excretion in bile. Several of these compounds showed pronounced and rapid accumulation of activity in the brain. Such activity in the brain was largely cleared within 15 min. Concentration of activity in the cerebrospinal fluid following clearance from the brain was 30 times greater than blood and equivalent in concentration to that noted in bile 18 min after intravenous administration of 11C alpha-anilinophenylacetonitrile in ethanol. These results suggest the possible correlation of regional brain uptake of activity of certain 11C aminonitriles with regional brain perfusion. Use of these or similar materials could permit assessment of brain tissue morphology followed by scintigraphic imaging of the bulk flow characteristics of cerebrospinal fluid.

Antiradiation compounds XV: condensations of carbon disulfide with amino, chloro, cyanomethyl, and sulfonamido heterocycles

Condensations of carbon disulfide were carried out with amino, chloro, and diamino heterocycles to give condensed ring thiazoline-2-thiones and imidazoline-2-thiones, with cyanomethyl heterocycles to give dithio acid derivatives, and with heterocyclic sulfonamides to give sulfonyldithiocarbamates. Of several examples tested, pyrido[3,2-d]thiazoline-2-thione, disodium 2-(5-chloro-2-thienyl)-3,3-dimercaptoacrylonitrile, triethylammonium 4-sulfamoylphenyldithiocarbamate, ammonium beta-phenethyldithiocarbamate, and methyl N-(thiophene-2-sulfonyl)dithiocarbamate, only the last-named compound showed any radiation protection for mice. Several compounds gave negative tests for antimalarial activity.