5-Phenyl-3-ureidobenzazepin-2-ones as cholecystokinin-B receptor antagonists

Electrochemical Dehydrogenative [3 + 2]/[5 + 2] Annulation of N-Arylacrylamides with γ,σ-Unsaturated Malonates via Direct C(sp3)-H/C(sp2)-H Functionalization

Herein, we introduce an electrochemical dehydrogenative [3 + 2]/[5 + 2] annulation of easily available N-arylacrylamides with γ,σ-unsaturated malonates through C(sp3)-H/C(sp2)-H functionalization. The employment of inexpensive ferrocene as the redox catalyst allows access to diverse benzo[b]azepin-2-ones in moderate to excellent yields without stoichiometric oxidants. This protocol features broad substrate scope and excellent selectivity, and mechanistic studies indicated that the reaction proceeded through the oxidation of a C(sp3)-H bond to generate an alkyl radical, radical addition across the C═C bond, [3 + 2]/[5 + 2] annulations, and C(sp2)-H functionalization cascades.

Visible-Light-Induced Regioselective Cascade Radical Cyclization of α-Bromocarbonyls: Access to Benzazepine Derivatives

Visible-light-induced regioselective cascade radical cyclization of α-bromocarbonyls for the synthesis of benzazepine derivatives is described. In the presence of fac-Ir(ppy)3 (2.0 mol %) as a photocatalyst, 2,6-lutidine as a base, and dichloromethane as a solvent, the reactions proceed smoothly to afford seven-membered rings in good yields. This protocol features a broad substrate scope, excellent functional group tolerance, and mild reaction conditions. Preliminary mechanistic studies reveal that the generation of the α-carbon radical is more prone to react with the 1,1-diphenylethylene tethered acrylamide to generate the stable seven-membered heterocycle.

I2-Mediated [6 + 1] Annulation of Alkynes with MsONH3OTf: Direct Synthesis of Benzo[b]azepines

The synthesis of benzo[b]azepines using protonated aminating reagent (MsONH₃OTf) and alkynes through I₂-mediated [6 + 1] annulation reaction has been developed. This protocol features excellent functional group tolerance and mild reaction conditions and affords the benzo[b]azepines in moderate to good yields under metal-free reaction conditions.

I2 -Promoted Intramolecular Oxidative Cyclization of Butenyl Anilines: A Facile Route to Benzo[b]azepines

A metal-free approach for the synthesis of seven-membered N-heterocycles has been developed by the I₂ -promoted intramolecular cross-coupling/annulation of butenyl anilines. This cyclization reaction involves C-H activation and C-C bond formation and exhibits good functional group tolerance. A series of benzo[b]azepine derivatives are obtained in moderate to good yields.

Biocatalytic asymmetric synthesis of (R)-1-tetralol using Lactobacillus paracasei BD101

Asymmetric bioreduction of ketones is a fundamental process in the production of organic molecules. Compounds containing tetralone rings are found in the structure of many biologically active and pharmaceutical molecules. Biocatalytic reduction of ketones is one of the most promising and significant routes to prepare optically active alcohols. In this study, the reductive capacity of Lactobacillus paracasei BD101 was investigated as whole-cell biocatalyst in the enantioselective reduction of 1-tetralone (1). In biocatalytic reduction reactions, the conversion of the substrate and the enantiomeric excess (ee) of the product are significantly affected by optimization parameters such as temperature, agitation rate, pH, and incubation time. Effects of these parameters on ee and conversion were investigated comprehensively. (R)-1-tetralol ((R)-2), which can be used to treat disorder such as obsessive compulsive, post-traumatic stress, premenstrual dysphoric, and social anxiety, was manufactured in enantiopure form, high yield and gram-scale, using whole-cell biocatalysts of L. paracasei BD101. The 7.04 g of (R)-2 was obtained in optically pure form with 95% yield. Also, to our knowledge, this is the first report on production of (R)-2 using whole-cell biocatalyst in excellent yield, conversion, enantiopure form and gram scale. This is a clean, eco-friendly and cheap method for the synthesis of (R)-2 compared with chemical catalyst.

Bifunctional N-heterocyclic carbene catalyzed [3 + 4] annulation of enals with azadienes: enantioselective synthesis of benzofuroazepinones

The bifunctional N-heterocyclic carbene catalyzed [3 + 4] annulation of enals with aurone-derived azadienes was developed to afford benzofuroazepinones with excellent enantioselectivities.

Decarbonylative Formation of Homoallyl Radical Capable of Annulation with N-Arylpropiolamides via Aldehyde Auto-oxidation

A new metal-free aldehyde auto-oxidation strategy that allows the decarbonylative formation of homoallyl radical capable of cascade annulations with alkynes is described. By using various N-arylpropiolamides, the oxidative radical [3 + 2]/[5 + 2] cascade annulation reaction was achieved to produce benzo[ b]cyclopenta[ e]azepin-4(1 H)-ones, which represent a powerful new platform for the intermolecular cycloadditions of alkyne with broad substrate scope and high selectivity.

Synthesis of Unsymmetrical α,α-Diarylacetates

Ethyl bromofluoroacetate has been developed as a precursor for the convenient synthesis of unsymmetrical α,α-diarylacetates featuring indoles, anilines, and other electron-rich aromatics. In conjunction with a mild Lewis acid catalyzed C-N → C-C exchange, intermediate arylglycines can be synthesized and transformed into α,α-diarylacetates in a one-pot protocol, resulting in a net diarylation reaction exhibiting a wide scope. In the context of diarylacetates, the synthetic equivalence of the fluorinated reagent with α-nitro-α-diazo carbonyls was established.

Templated C-C and C-N Bond Formation Facilitated by a Molybdenum(VI) Metal Center

Preparation of molybdenum dioxido complexes with novel iminophenolate ligands bearing pendant secondary amide functionalities led to unprecedented C-C and C-N coupling reactions of two α-iminoamides upon coordination. The diastereoselective cyclization to asymmetric imidazolidines occurs at the metal center in two consecutive steps via a monocoupled intermediate. A meaningful mechanism is proposed on the basis of full characterization of intermediate and final molybdenum-containing products by spectroscopic means and by single-crystal X-ray diffraction analyses. This process constitutes the first example of a diastereoselective self-cyclization of two α-iminoamides.

A highly efficient and eco-friendly method for the synthesis of 1,3-indandione ring-fused 3-oxindoles bearing two contiguous quaternary stereocenters via an aldol reaction in aqueous media

The synthesis and antitumor activity evaluation of 1,3-indandione ring-fused 3-oxindoles.

Asymmetric decarboxylative 1,4-addition of malonic acid half thioesters to vinyl sulfones: highly enantioselective synthesis of 3-monofluoromethyl-3-arylpropanoic esters

An asymmetric decarboxylative 1,4-addition of malonic acid half thioesters (MAHTs) to 2-aryl-substituted vinyl sulfones has been developed, yielding adducts with excellent enantioselectivity (up to 97 % ee). In view of tuning pKa values, a quinine-based benzyl-substituted thiourea was designed and demonstrated as the most efficient catalyst. The enantioselective synthesis of 3-monofluorinated analogues of 3-methyl indanone and (+)-turmerone has been accomplished from decarboxylative 1,4-addition adducts with satisfactory results.

Catalytic Stereoselective Synthesis of Highly Substituted Indanones via Tandem Nazarov Cyclization and Electrophilic Fluorination Trapping

A new catalytic stereoselective tandem transformation via Nazarov cyclization/electrophilic fluorination has been accomplished. This sequence is efficiently catalyzed by a Cu(II) complex to afford fluorine-containing 1-indanone derivatives with two new stereocenters with high diastereoselectivity (trans/cis up to 49/1). Three examples of catalytic enantioselective tandem transformation are presented.

Stereoselective construction of fluorinated indanone derivatives via a triple cascade Lewis acid-catalyzed reaction

A one-pot three-component cascade reaction proceeds by way of a Lewis acid-catalyzed Knoevenagel condensation/Nazarov cyclization/electrophilic fluorination sequence to afford fluorinated 1-indanone derivatives in moderate to good yields with high diastereoselectivities.

Hydroacylation of 2-Vinyl Benzaldehyde Systems: An Efficient Method for the Synthesis of Chiral 3-Substituted Indanones

Asymmetric rhodium-catalyzed hydroacylation has been utilized in the synthesis of 3-substituted indanones with high conversions and enantioselectivity. The hydroacylation reaction of 2-vinyl benzaldehyde had been previously reported to give a low yield of indanone and an unidentified product. We have identified this compound as a dimer of the starting material. Substitution at the alpha-position of the 2-vinyl benzaldehyde substrates blocks the competitive dimerization reaction and allows the reaction to proceed with yields generally greater than 90%. Utilization of BINAP as a chiral ligand results in good chemical yields and enantioselectivity greater than 95% in most cases.

Cholecystokinin antagonists: pharmacological and therapeutic potential

Cholecystokinin (CCK) is a regulatory peptide hormone, predominantly found in the gastrointestinal tract, and a neurotransmitter present throughout the nervous system. In the gastrointestinal system CCK regulates motility, pancreatic enzyme secretion, gastric emptying, and gastric acid secretion. In the nervous system CCK is involved in anxiogenesis, satiety, nociception, and memory and learning processes. Moreover, CCK interacts with other neurotransmitters in some areas of the CNS. The biological effects of CCK are mediated by two specific G protein coupled receptor subtypes, termed CCK(1) and CCK(2). Over the past fifteen years the search of CCK receptor ligands has evolved from the initial CCK structure derived peptides towards peptidomimetic or non-peptide agonists and antagonists with improved pharmacokinetic profile. This research has provided a broad assortment of potent and selective CCK(1) and CCK(2) antagonists of diverse chemical structure. These antagonists have been discovered through optimization programs of lead compounds which were designed based on the structures of the C-terminal tetrapeptide, CCK-4, or the non-peptide natural compound, asperlicin, or derived from random screening programs. This review covers the main pharmacological and therapeutic aspects of these CCK(1) and CCK(2) antagonist. CCK(1) antagonists might have therapeutic potential for the treatment of pancreatic disorders and as prokinetics for the treatment of gastroesophageal reflux disease, bowel disorders, and gastroparesis. On the other hand, CCK(2) antagonists might have application for the treatment of gastric acid secretion and anxiety disorders.

Efficient kinetic resolution in the asymmetric hydrosilylation of imines of 3-substituted indanones and 4-substituted tetralones

Kinetic resolution of the N-methyl imines of 3-substituted indanones and 4-substituted tetralones could be accomplished by hydrosilylation with a chiral titanocene catalyst. N-Methyl imines of 4-substituted tetralones were resolved to yield, after hydrolysis of the unreacted starting materials, ketones with high ee's and the amine products with high diastereomeric and enantiomeric purity. The utility of this process was demonstrated in the synthesis of sertraline.

Analysis of the behaviour of selected CCKB/gastrin receptor antagonists in radioligand binding assays performed in mouse and rat cerebral cortex

1. The previously described complex behaviour of the CCKB/gastrin receptor antagonist, L-365,260, in radioligand binding assays could be explained by a variable population of two binding sites. We have investigated whether other CCKB/gastrin receptor ligands (PD134,308, PD140,376, YM022 and JB93182) can distinguish between these sites. 2. In the mouse cortex assay, Hill slopes were not different from unity and the ligand pKI values did not differ when either [125I]-BH-CCK-8S or [3H]-PD140,376 was used as label as expected for a single site (G2). 3. In the rat cortex, where previous analysis of replicate (n=48) L-365,260 data indicated the presence of two CCKB/gastrin sites (G1 and G2), the competition data for PD134,308, PD140,376, YM022 and JB93182 could be explained by a homogeneous population of CCKB/gastrin sites because the Hill slope estimates were not significantly different from unity. However, the estimated affinity values for JB93182 and YM022 were significantly higher and that for PD134,308 was significantly lower than those obtained in the mouse cortex when the same radioligand was used. In view of our previous data obtained with L-365,260, the rat cortex data were also interpreted using a two-site model. In this analysis, SR27897 expressed approximately 9 fold, PD134,308 approximately 13 fold and PD140,376 approximately 11 fold selectivity for the G2 site. In contrast, JB93182 expressed approximately 23 fold and YM022 approximately 4 fold selectivity for the G1 site. If the two-site interpretation of the data is valid then, because of its reverse selectivity to L-365,260, JB93182 has been identified as a compound which if radiolabelled could provide a test of this receptor subdivision.

Solution-phase combinatorial synthesis of ureas using nitrophenylcarbamates

Nitrophenylcarbamates were reacted with various amines to yield ureas. A high throughput purification of these crude products was achieved by using polymer bound scavengers.