REACTIONS WITH HYDRAZIDOYL HALIDES VII¹: SYNTHESIS OF SEVERAL NEW ANNELATED PYRAZOLE, QUINAZOLINE AND THIAZOLE DERIVATIVES

Abstract

Several new pyrazolo(5, I-c] triazine, selenadiazoline, thiadiazolme, selenadiazolo[3,2-a]quinazolone, and arylazothiazole derivatives were synthesised by the reaction of hydrazonoyl halides with different reagents. The structure of new heterocycles were assigned on the basis of their elemental analysis, spectral data, and alternate synthesis whenever possible. INTRODUCTIONScheme I

Hydrazonoyl halides: Useful building blocks for the synthesis of arylazoheterocycles

“…The reactions of N-aryl 2-oxopropanehydrazonoyl chlorides 2, 2-oxo-2-phenylethanehydrazonoyl bromides 5A [35] and N-aryl 2-heteroaryl-2-oxo-ethanehydrazonoyl bromides 6B,D,G [21,23,36] each with cyanothioacetamide were reported to give the respective 5-arylazo-4substituted thiazole derivatives 40 (Scheme 13). The latter products 40 were reported to couple with diazotized anilines to give 41 (Scheme 14) [23,35,36], and to condense with salicylaldehyde to afford 5-arylazo-2-(coumarin-3yl)-4-substituted thiazoles 42 (Scheme 14) [35,36].…”

Preparation of New Derivatives of Thiazole, Thiazolidine, and Thiazol-2-Ylpyrazolo[3,4-D]pyrimidine Sulfonamido Conjugates

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The thiazolidine moiety occurs in different bioactive substances as an important pharmacophoric group, for instance, the imidazo[2,1-b]thiazole system in the main moiety of the well-known antihelmintic and immunomodulatory agent levamisole. 16,17 Thiazol[2,3-a]pyrimidines bear a structure analogous to levamisol and have been well studied as immunomodulatory, anticancer, analgesic, and psychotropic agents.…”

Reactions with Hydrazonoyl Halides. Part 16.1 A Convenient Synthesis of 1,4-Benzothiazine, Triazolo[4,3-a]-benzimidazole, Thiazolo[3,2-a]benzimidazole and 2,3-Dihydro-1,3,4-thiadiazole Derivatives

“…Hydrazonoyl halides are versatile reagents which have been extensively utilized in the synthesis of numerous heterocycles. [2][3][4][5][6][7] Here we report the results of our study of the reaction of 2-aminobenzenethiol, benzimidazole-2-thiol, 2-methylsulfanylbenzimidazole, dithiocarbamates, phenyl thiourea and dithiocarbazate with the hydrazonoyl bromide 1.…”