A Facile Synthesis of 1-Substituted β-Carboline Derivatives via Minisci-Reaction

A mild and efficient one-pot reaction for the synthesis of 1-substituted β-carboline derivatives via the Minisci reaction has been developed with good yields and selectivity. In addition, the mechanism of the 1-substituted β-carboline derivatives by means of the nucleophilic radical is described.     

Mg(ClO4)2, an Efficient Catalyst for Synthesis of β-Amino Alcohols by Ring Opening of Epoxides with Amines under Solvent-Free Conditions

Abstract

Commercially available magnesium perchlorate is reported as an extremely efficient catalyst for the ring-opening reaction of epoxide with various primary and secondary amines, especially diphenyl amine, under solvent-free conditions at room temperature.     

Syntheses of Novel Chiral Calix[4]crown: Lariat Calix[4]-1,3-aza-crowns with Chiral Amino Acid Groups as Branched Chains

The first examples of lariat calix[4]-1,3-aza-crowns with chiral amino acid groups as branched chains (5a and 5b) were designed and synthesized via a 1 + 1 addition reaction of calix[4]-1,3-substituted benzaldehyde derivative (4) and amino acid hydrazide derivatives (3a and 3b) in yields of 70% and 75%, respectively. The preliminary extraction experiments suggested that hosts 5a and 5b possessed good complexation abilities for α-amino acids.      

Synthesis of Pyrazolo[3,4-b]- and Pyrido[2,3-b]-1,5-benzodiazepines

Abstract

3-Dimethylaminomethyleno-4-phenyl-1H-1,5-benzodiazepin-2-one (1) was synthesized and reacted with hydrazines, active nitriles, and amino-heterocyclic compounds to give fused heterocyclic compounds 2–14.     

Nontemplate Synthesis of Two Novel 23-Membered N3O4-Donor Macrocycles

Abstract

A novel 23-membered heptadentate N₃O₄ Schiff base ligand has been prepared by [1 + 1] cyclocondensation of 1,2-bis(2′-aminophenoxy)-4-t-butylbenzene with 2,6-bis(2-formylphenoxymethyl)pyridine by a nontemplate procedure. Treatment of L₁ with NaBH₄ in EtOH/CHCl₃ gave the di-amine macrocycle L_2.     

Task-Specific Ionic Liquid as the Recyclable Catalyst for the Rapid and Green Synthesis of Dihydropyrano[3,2-c]chromene Derivatives

Abstract

A task-specific ionic liquid, [H₃N⁺–CH₂–CH₂–OH][CH₃COO^?], was successfully applied as an efficient and reusable catalyst for the one-pot domino to approach to dihydropyrano[3,2-c]chromene derivatives with atom economy in a condensation reaction of 4-hydroxycoumarin, aldehydes, and malononitrile in a combinatorial fashion. The reaction gave excellent yields within short reaction times at room temperature under solvent-free grinding conditions. The products and ionic liquid could be conveniently separated from the reaction mixture, indicating that the whole process was performed as a green chemical transformation.      

A New Approach to the Efficient Method for the Asymmetric Synthesis of (S)-O-, M-, P-Fluorophenylalanines and Their 2-Methyl-substituted Analogs

Abstract

The reactions of asymmetric C-alkylation of glycine and alanine in Ni^II complexes of their Schiff's bases with modified chiral auxiliaries (S)-2-N-[(N′-2-chlorobenzylprolyl)amino]benzophenone and (S)-2-N-[N′-(3,4-dimethylbenzylprolyl)amino]benzophenone by fluorine-substituted benzyl halogenides have been studied. As a result, a highly stereoselective and relatively rapid method for the asymmetric synthesis of (S)-o-, m-, p-fluorophenylalanines and their 2-methyl substituted analogs has been developed.     

Acid catalyzed aldol condensations of ketones with glyoxylic acid: A simple single-step synthesis of 4-oxo-2,5-heptdienedioic acids

Abstract

The acid catalyzed condensations of ketones with glyoxylic acid at 80?°C, under neat conditions gives 4-oxo-2,5-heptdienedioic acids in 56–88% yield. The solid state photochemical dimerization of 4-oxo-2,5-heptdienedioic acid under UV light gives 2,7-dioxo-tricyclo[6.2.0.0^3,6]decane-4,5,9,10-tetracarboxylic acid in 90% yield.

     

Excellent Synthesis of Adipic Acid

Abstract

A simple, straightforward, and environmentally benign protocol for the synthesis of adipic acid from oxidation of cyclohexanone with Oxone® in the presence of 0.5 mol% RuCl₃ · nH₂O is reported. The reaction completes within a very short time even at room temperature. The generality of the method is shown successfully for synthesis of other C-5 to C-8 dicarboxylic acids.     

Stannous Chloride–Promoted Synthesis of S-Allyl-N-aryl Dithiocarbamates under Solvent-Free Conditions

Abstract

A highly efficient method of synthesis of S-allyl-N-aryl dithiocarbamates using SnCl₂ as a catalyst under solvent-free conditions is described. The mild reaction conditions, high yields, and shorter reaction period illustrate the good synthetic utility of this method.     

The Reaction of 2-Arylvinamindinium Perchlorates with Sodium Borohydride and Sodium Cyanoborohydride

In the last few years, numerous efforts have been directed to the development of acetonylation methods¹. Recent works in this laboratory have shown that O, O-t-butyl and O-isopropenyl peroxycarbonate 1 can be regarded as a good acetonylation reagent; its decomposition in solution results in the substitution of an hydrogen atom by an acetonyl group on each compound Σ-H able to undergo free radical addition reactions to alkenes². The following free radical chain reaction mechanism has been proposed:      

Model Route to 5-Bromo-3,4-dihydro-4-hydroxy-7,9,10-trimethoxy-1,3-dimethyl-1H-naphtho[2,3-c]pyran: A Potential Precursor to Extended Quinones

A protocol has been developed for the synthesis of the linear naphthopyran 16, by the TiCl₄-catalyzed isomerization of 2,5-dimethyl dioxolane 1, having a methoxy group at position 1′ and a bromine atom at position 4′ of the naphthyl precursor to favor isomerization at position 2′.

Some Novel Thiopyrimidine Nucleoside Analogs: Synthesis and In Vitro Antimicrobial Evaluation

Some new S-alkyl derivatives of indeno[1′,2′:4,5]thieno[2,3-d]pyrimidine 2–8 were prepared starting with pyrimidine-2(1H)-thione derivative (1). Also, treatment of compound 1 with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide or 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose afforded nucleosides 9 and 12, respectively. Furthermore, deprotection of the latter blocked nucleosides was achieved in methanolic ammonia to afford the desired free S-nucleoside derivatives 10 and 13, respectively. Some prepared products were screened for antimicrobial activity, and some of them showed promising activity.     

Synthesis and Crystal Structure of (Z)-Ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate

The compound (Z)-ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate 3 has been synthesized by the reaction of ethylacetoacetate 1 and phenylisothiocyanate 2. Its structure has been established by ¹H NMR, ¹³C NMR, infrared, mass spectra, and x-ray crystallography.      

REDUCTION OF N -2-SUBSTITUTED BENZIMIDAZOYL IMIDATES

ABSTRACT>

Cathodic reduction of several iminoesters ( 1 ) and ( 2 ) has been investigated by cyclic voltammetry and controlled potential electrolysis at mercury electrode in aprotic DMF, leading to the formation of two reduction steps. The appropriate choice of the nature of R² groups allowed the reductive cyclisation when R² is an ethoxy (or alkoxy) group.