A Mild One-Pot Synthesis of Thieno [3, 4-c] pyrazoles and Their Conversion into Pyrazole Analogs of o-Quinodimethane

…, H El-Kashef, S Manfredini, MJP de las Infantas…

Index: Baraldi, Pier Giovanni; El-Kashef, Hussein; Manfredini, Stefano; Pineda De Las Infantas, Maria J.; Romagnoli, Romeo; Spalluto, Giampiero Synthesis, 1998 , # 9 p. 1331 - 1334

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Citation Number: 10

Abstract

Abstract: The reaction of alkyl or aryl hydrazine hydrochlorides with 4-cyano-3- oxotetrahydrothiophene (1) in refluxing ethanol afforded, in a regioselective manner, the corresponding 2-alkyl-or 2-aryl-3-aminothieno [3, 4-c] pyrazoles 3a–l with good yields. As representative examples, the compounds 3a, 3e, and 3k, after standard acetylation procedure, have been efficiently converted into the corresponding sulfolenes 6a, 6e, and ...