| 摘要 |
PURPOSE:To produce a new 3-sulfonyl-2,5-thiophenedicarboxylic acid derivative and a new 2,3-thiophenesaccharin-5-carboxylic acid or its ester derived from this derivative and useful as a raw material for 2,3-thiophenesaccharin known as a sweetener. CONSTITUTION:The 3-sulfonyl-2,5-thiophenedicarboxylic acid derivative of formula I (R is H or 1-4C alkyl; X is OY, Cl, Br or NH2; Y is H, Na, K or NH4), e.g. 3-sulfo-2,5-thiophenedicarboxylic acid dimethyl ester of formula II. The 2,3-thiophenesaccharin-5-carboxylic acid of formula III or its carboxylic acid ester, e.g. 2,3-thiophenesaccharin-5-carboxylic acid methyl ester of formula IV. The compound of formula I can be produced e.g. according to the reaction formula by using 2,5-thiophenedicarboxylic acid or its ester as a raw material and subjecting the compound to sulfonation, chlorination and finally amidation, etc. The compound of formula III, e.g. a compound wherein R is alkyl can be produced by the dealcoholation of a compound of formula I wherein R is alkyl. |
