γ-BROMOACETOACETANILIDES IN HETEROCYCLIC SYNTHESIS: A CONVENIENT SYNTHESIS OF POLYFUNCTIONALLY SUBSTITUTED 2,3-DIHYDROTHIAZOLE, PYRIDIN-2-ONE, 1,2,3-TRIAZINE, OXAZOLO[3,4-b]PYRIDINE AND PYRAZOLO[3,4-b]PYRIDINE DERIVATIVES

Abstract

The active methylene reagents la-d reacted with phenyl isothiocyanate in basic DMF at room temperature to yield the non-isolable 1:l adducts 2a-d. In-situ cyclization of the latter with y-bromoacetoacetanilides afforded the 2,3-dihydrothiazoles 3a-h. The reactivity of 3a towards a variety of chemical reagents has been undertaken. Thus, on smooth alkaline hydrolysis, with benzaldehyde and with benzenediazonium chloride, the thiazole derivatives 4, 5, 7 and 9 were obtained. With acetylacetone, malononitrile, ethyl cyanoacetate and cinnamonitriles it gave the corresponding thiazol-4-yl-pyridine derivatives 10, 11, 12, and 13 respectively. 13 Reacted with hydroxylamine hydrochloride and phenyl hydrazine to give the corresponding fused ring systems 15 and 17 respectively.

Syntheses of 1,3-Imidazoline-2-thione and 2-Phenylimino-1,3-thiazoline Combinatorial Libraries through Different Sequences of the Same Components

“…Third, the chloride can serve as a good leaving group in nucleophilic displacement. Examples of heterocycles synthesized from γ-chloroacetoacetanilides 1 are pyridopyrimidines, substituted pyridines, quinolones, dihydrothiazoles, pyridin-2-ones, dihydrooxathiins, and oxadiazolyl derivatives . However, examples of combinatorial synthesis using γ-chloroacetoacetanilides 1 are limited.…”

New approaches for the synthesis, cytotoxicity and toxicity of heterocyclic compounds derived from 2-cyanomethyl benzo[c]imidazole

“…The latter undergoes heterocyclization when reacted with α-halocarbonyl compounds to give either thiophene or thiazole derivatives depending on the nature of the α-halocarbonyl compound and the reaction conditions. [30][31][32] Thus, the reaction of 5 with phenylisothiocyanate in DMF/KOH solution gave the intermediate potassium sulphide salt 10. The latter intermediate underwent heterocyclization when reacted with any of α-chloroacetone, ethyl chloroacetate or α-bromoacetophenone to give the thiophene derivatives 11a-c, respectively.…”

Synthesis of N-(3-alkyl-4-phenyl-3H-thiazol-2-ylidene)Benzamide Derivatives by Reaction of Phenacyl Bromide and Aroyl Isothiocyanates in the Presence of Primary Amines

“…5 Other methods have been reported for the synthesis of thiazoles. [6][7][8][9][10][11][12] As a part of studies on the development of new routes in organic synthesis, [13][14][15][16][17][18][19] I now report an efficient one-pot synthesis of N-(3-alkyl-4-phenyl-3H-thiazol-2-ylidene)benzamide derivatives employing readily available starting materials.…”