Reactions of nitrilimines with heterocyclic amines and enamines. Convenient methodology for synthesis and annulation of heterocycles

Abstract

This review summarizes the reactions of nitrilimines, genearted in situ by base-catalyzed dehydrohalogenation of the respective hydrazonoyl halides, with aminoazoles, aminoazines and various types of enamines. It also presents the highlights of recent developments in the utility of such reactions for synthesis of a variety of heterocycles which are not obtainable by other synthetic means. Such reactions provide convenient strategies for synthesis and annulation of heterocycles. It covers the literature from 1985 to mid 2006.

One-pot synthesis of novel 1,2,3,4,5a,7,8,8b-octaaza-acenaphthylenes

“…In continuation of our previous work [1][2][3][4][5][6][7][8][9] dealing with the utility of hydrazonoyl halides as synthons for various fused heterocycles, we report here a facile one-pot synthesis of the title ring system by reaction of 4-amino-4H-1,2,4-triazole-3,5-dithiol 1a or 4-amino-3,5-dimethylthio-4H-1,2,4-triazole 1b with hydrazonoyl halides 2. Such a ring system has not been reported hitherto.…”

Synthesis, reactions, and antimicrobial activity of some novel pyrazolo[3,4‐d]pyrimidine, pyrazolo[4,3‐e][1,2,4]triazolo[1,5‐c]pyrimidine, and pyrazolo[4,3‐e][1,2,4]triazolo[3,4‐c]pyrimidine derivatives

“…Cl,8.34;N,19.78. Found: C,68.23;H,4.38;Cl,8.10;N,19.01. 6,120.7,121.5,122.2,126.3,127.0,127.9,129.0,129.1,130.8,132.4,133.3,138.0,139.8,145.8,147.9,150.6,154.1;MS (EI,70 eV) m/z (%): 438 (M + , 47.6), 77 (100).…”

“…Furthermore, attempts to prepare the isomeric pyrazol [4,3-e] [1,2,4]triazolo [4,3-c] pyrimidines via dehydrative cyclization of the 4-acylhydrazinopyrazolo [3,4-d]pyrimidines were reported to give the corresponding pyrazolo [4,3-e] [1,2,4]triazolo [1,5-c]pyrimidines. [7] In the light of these findings and in continuation of our ongoing research work on the chemistry of hydrazonoyl halides, [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] it was thought interesting to synthesize new series of pyrazolo [3,4-d]pyrimidine and pyrazolo [4,3-e] [1,2,4]triazolo [3,4-c]pyrimidine derivatives. Evaluation of antimicrobial activity against some microorganisms was investigated.…”

Synthesis and Tautomeric Structure of Novel 3-Arylazo-Imidazo[1,2-b]Pyrazolo[4,3-d]Pyridazines

“…In recent years, arylazo derivatives of various heterocyclic ring systems have received much attention from organic chemists and dye manufacturers. 1 In conjunction with our continuing interest in azo-hydrazone tautomerism of azo colouring materials 2 and the chemistry of hydrazonoyl halides, [3][4][5][6][7][8][9][10][11][12][13] , we studied the utility of the latter for the synthesis of arylazo derivatives of a new triheterocyclic system namely imidazo [1,2-b]pyrazolo [4,3-d]pyridazine which has not been reported previously. In addition, our objective with such a study was to shed some light on the site-selectivity in the reactions to be studied and to investigate the tautomerism of the target colorants.…”