A CONVENIENT APPROACH TO THE SYNTHESIS OF FURO- AND THIENO-[3,2-c]PYRIDINE DERIVATIVES

作者：Maruoka Hiroshi^*; Okabe Fumi; Yamasaki Keishi; Masumoto Eiichi; Fujioka Toshihiro; Yamagata Kenji

来源：Heterocycles, 2010, 82(1): 867-880.

DOI：10.3987/COM-10-S(E)47

• Furo[3,2-c]pyridine
• Thieno[3,2-c]pyridine
• Dihydrofuran
• Dihydrothiophene
• Heterobicycle

The title compounds were prepared from 4,5-dihydro-3-furan- and -3-thiophene-carbonitriles having an active methylene group at C-2 position 1, 2, 7, and 8 as key starting materials. Compounds 1 and 2 condensed with N,N-dimethylformamide dimethyl acetal to give the corresponding enamines 3 and 4. This condensation was followed by exchange reaction of amines and subsequent intramolecular cyclization reaction in the presence of ammonium acetate to lead the corresponding furo- and thieno-[3,2-c]pyridines 5 and 6. On the other hand, the reactions of compounds 7 and 8 with amines such as aqueous ammonium hydroxide and benzylamine afforded the intermediate acetamide derivatives A, without isolation of them, which underwent intramolecular cyclization reaction in the presence of sodium methoxide to yield the corresponding furo- and thieno-[3,2-c]pyridin-6(2H)-ones 9-12.

• 出版日期2010-12-31