Bridgehead nitrogen heterocycles from 2,4,6-triphenyl- pyrylium cation and thiosemicarbazide or thiocarbohydrazide
1984; Elsevier BV; Volume: 40; Issue: 23 Linguagem: Inglês
10.1016/s0040-4020(01)91325-0
ISSN1464-5416
AutoresPedro Molina, Alberto Tárraga, Concepción Rodríguez Serrano,
Tópico(s)Synthesis of heterocyclic compounds
Resumo2,4,6-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 derivatives 6. Compound 3b reacts with acyl chlorides to give pyrazolo[1,5-c]pyrimidine derivatives 14, and with aromatic aldehydes giving the 2-(Δ2'1 pyrazolin-1-yl)-5-aryl-1,3,4-Δ2-thiadiazolines 12 which were easily converted to the corresponding 2-(Δ2-pyrazolin-1-yl)-5-aryl-1,3,4-thiadiazoles 13.
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