First synthesis of 4-oxo-6-trifluoromethyl-4H-thiopyran-2-carboxylic acid and its derivatives
作者:B. I. Usachev、S. A. Usachev、G.-V. Röschenthaler、V. Ya. Sosnovskikh
DOI:10.1007/s11172-010-0171-7
日期:2010.4
Treatment of 6-trifluoromethylcomanic acid with sodium hydrosulfide afforded for the first time 4-oxo-6-trifluoromethyl-4H-thiopyran-2-carboxylic acid (6-trifluoromethylthiocomanic acid). When heated or treated with H2SO4, this acid easily underwent decarboxylation leading to 2-trifluoromethyl-4H-thiopyran-4-one. Because of this, both ethyl and methyl 6-tri-fluoromethylthiocomanates were obtained in low yields (15–23%). Decarboxylation of 6-tri-(di)fluoromethylcomanic acids gave 2-tri(di)fluoromethyl-4H-pyran-4-ones in 77–80% yields.
用硫氢化钠处理6-三氟甲基香豆酸,首次得到4-氧代-6-三氟甲基-4H-噻喃-2-甲酸(6-三氟甲基硫代香豆酸)。当加热或用 H2SO4 处理时,该酸很容易发生脱羧反应,生成 2-三氟甲基-4H-噻喃-4-酮。因此,6-三氟甲硫代康马酸乙酯和甲酯的产率较低(15-23%)。 6-三(二)氟甲基香豆酸脱羧得到2-三(二)氟甲基-4H-吡喃-4-酮,产率77-80%。