Tetrahedron

Bridgehead nitrogen heterocycles from 2, 4, 6-triphenyl-pyrylium cation and thiosemicarbazide or thiocarbohydrazide

P Molina, A Tarraga, C Serrano

Index: Molina, P.; Tarraga, A; Serrano, C. Tetrahedron, 1984 , vol. 40, # 23 p. 4901 - 4910

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Citation Number: 8

Abstract

2, 4, 6-Triphenylpyrylium with thiosemicarbazide and thiocarbohydrazide, gives 2- pyrazolines 3a and 3b which undergo cyclization yielding pyrazolo (1, 5-c] pyrimidine 5 and pyrazolo [2, 3-d]-1, 2, 4-triazepine 7 derivatives, respectively. Reaction of 7 with phenacyl bromides gave 1, 3-thiazolo [3, 2-b] pyrazolo [2, 3-d]-1, 2, 4-triazepin-4-iums 10. Compound 3a on treatment with phenacyl bromides gave 1-(4'-aryl-thiazol-2'-yl)-2-pyrazoline ...