Activation arylazo compounds

The preparation of 2-phenylazo-l,3-indandione (m.p. 192°-193°C) by condensation of benzenediazonium chloride with 1,3-indandione is an example of azo formation from an active methylene compound [24]. With an active methinyl compound such as the methyl 1,3-indandione-2-carboxylate, the corresponding 2-arylazo-l,3-indandione-2-carboxylate ester has been prepared [25] (see Eq. 8). 

Compounds tested and found active in vitro against M. tuberculosis include 5-arylamino-3-pheny1thiazolidin-2,4-diones 2,3-diaryl-5-arylazo-4-thiazolidinethione-1,1-dioxides N-substituted benzisothia-zolin-3-thiones 5 4-(indol-3-yl)-imidazoles , indol-3-ylcarboxylic acids and hydrazides 3-halophenylazoindoles , 3,4-dihydropyrido[2,3-d]pyri-dazin-1[2H]-one 5, Schiff bases from isoniazid and substituted benzalde-hydes °, 5-n-butylpyridine-2-carboxylic acid hydrazide, 4-thiosemicar-bazido-2-[(5-nitrofuryl)vinyl]quinolones and butadiene analogs3-thio-4 3H)quinazolone derivatives, and N- ji-tolyl)-N -(2-benzothiazolyl)-N "-alkylquanidines. ... 

Studies concerning the activating effect of arylazo groups on olefins have been recorded and these have afforded a convenient synthesis of 2,2-diamino- from 2,2-dichloro-enazo compounds and amines,Addition and cyclisation reactions of 3-chloro-azo... 

Amino-2-arylazo-2-butenoic acids (289) have been prepared by two pathways from acetoacetic esters. The reaction of these compounds with bligomeric a-mercapto-aldehydes leads to substituted thiazoleacetic esters (290), which appear to be useful intermediates for the synthesis of penicillin analogues. Most syntheses of 2,4-dioxa-l,3-thiazolidines (292), which show an interesting spectrum of biological activity, involve oxidation of thiol precursors. A new method uses readily available dihydropyrimidine thiones in reaction with chloro-acetic acid. The reaction does not proceed if R = H in (291). 

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