Basanta G. Chatterjee

Studies on Lactams

The activating influence of a nitrophenyl substituent in the intramolecular alkylation of compounds of the type 3 and 5 has been studied. The investigation establishes that the activation afforded by a 4-nitrophenyl substituent is intermediate between that of a carbonyl and ester functions. The role of the N-aryl substituent in the alkylation of N-aryl, N-α haloacetamino esters and ketones has also been studied. A number of hitherto unreported lactams have been synthesized and characterized. Synthesis of the compound 4 c using a weak base is of special interest, since this lactam possesses only a single electronegative substituent at the 4-position.

A Facile and Convenient Method for the Synthesis of 8-Methoxy 10,11-Dihydronaphtho [1,2-b]Quinolines

Abstract Dihydronaphthoquinolines are relatively rare polycyclic heterocyclic compounds. We wish to report a simple and convenient preparative method for hitherto unknown compounds with these new structural features. 6-methoxy tetralone1 (I) 3.5g (.02 mole) in 3 ml DMF was added slowly to 4.6g (.02 mole) of POCl3 in 3ml DMF at 0°C. The mixture was stirred for 5 hrs. and the temp. was then gradually raised from 0° to 60–65°C. The resultant complex was treated with aq. sodium acetate solution till pH5–6 was reached. The extract on usual purification, furnished 3.2g (80°%.) of 1-chloro, 6-methoxy, 1,2,3,4 tetrahydro naphthalene-2-aldehyde(II)+2

STUDIES ON POLYCYCLIC AZAARENES - 1. SYNTHESIS OF ACENAPHTHO(1,2-B)QUINOLINES

Abstract A simple synthesis of acenaphthoquinolines by thermal cyclization of anils is described.

Synthesis of substituted β-lactams

Abstract Two new methods for β-lactam formation from various systems (type I) where the activating influence on the methine hydrogen is by groups other than two ester functions have been developed and several new β-lactams synthesized. These compounds together with the various intermediates have been characterized by analysis and in most cases by IR spectra.

A Convenient Synthesis of Tricyclic Gamma-Lactams, Simulating B-C-D Rings of Azasteroids Via Michael Addition Reaction

Abstract Cinnamolychloride on treatment with arylaminomalonates produced the δ-lactam diester derivatives. Highly stereoselective hydrolysis of the diester, produced the trans acid, which on homologation by Arndt-Eisterts method followed by PPA cyclization generated the tricyclic δ-lactam derivatives simulating B-C-D ring of many azasteroids in good overall yield.

Synthesis of substituted β- and γ-lactams

Abstract The synthesis of substituted β-lactams has been successfully extended to substituted γ-lactams. Two new β-lactams have been obtained from a system where CO·Ph group alone supplies activation for the intramolecular alkylation. The β- and γ-lactams and the intermediates have been characterized by analysis and IR or NMR spectra.

Synthesis of Some 9-Aryl-9-Aza-2,8-Dioxo-4,5-Benzo-Bicyclo [4.3.0] Nonane, A New Keterocyclic System

Abstract A new and versatile synthetic procedure for the title compound is reported. Two routes for the cyclisation of diazoketones (4) have been developed.

Some derivatives of β-lactams

Abstract Twelve new derivatives of β-lactams such as carboxamides salicylates, ureas and thioureas have been synthesized and characterized by analysis and IR or NMR spectra. It has been observed that sodium azide can bring about intramolecular alkylation of N-substituted α-haloacetamidomalonates.

Studies on γ-Lactams: Synthesis of some3-Aryl-1,3a,4,9b-tetrahydrobenzo[e]indole-2,5-dioneDerivatives and its Implication in the Total Synthesis ofFunctionalized 17-Azasteroids

The γ-lactam esters 3 and 10, prepared from anilinomalonates and 3-arylacryloyl chloride, are hydrolysed and selectively decarboxylated to the trans-acids 4 and 11; further homologation and cyclization produce the tri- and tetra-cyclic γ-lactam derivatives 8 and 15 that simulate the B-C-D/A-B-C-D ring system of many azasteroids.

Studies on beta-Lactams

Since the discovery 11 of the activating effect of the N- (p-Nitro-phenyl)-group on the methine hydrogen of halogenacetamino esters, it has been found that the p-Acetyl-phenyl and m-Nitro-phenyl groups exert a similar effect. It has been shown that the delocalisation of the N-non-bonded electrons across the orbitals of the N-Aryl substituent is the governing factor in the cyclisation of the above systems, and the effect of the bulk of the N-Aryl substituent is relegated to a minor position.