| 摘要 |
1460536 Thiophene derivatives LABAZ 14 Aug 1974 [30 Aug 1973] 35877/74 Heading C2C Novel thiophene derivatives of the formula wherein R 1 is a methyl, ethyl, cyclohexyl or benzyl radical; R 2 is hydrogen or an ethyl, allyl, cyclohexyl or benzyl radical, and R 3 is a methyl or ethyl radical, provided that (i) when R 1 and R 3 are ethyl, then R 2 is hydrogen, ethyl or allyl, (ii) when R 1 is benzyl and R 3 is methyl or ethyl, then R 2 is hydrogen or benzyl, (iii) when R 1 is cyclohexyl and R 2 is hydrogen, then R 3 is methyl or ethyl, and (iv) when R 1 and R 3 are methyl, then R 2 is cyclohexyl, are prepared by a novel process for preparing such compounds of the above formula wherein R 1 and R 2 are alkyl, alkylene, alkenyl, optionally substituted cycloalkyl, cycloalkenyl or aralkyl, or R 2 is hydrogen, or R 1 plus R 2 and the carbon atom to which they are attached together represent cyclopolymethylene, and R 3 is alkyl, which comprises reacting a compound of the formula wherein R 4 is an alkali metal or a group as defined for R 1 and R 5 is hydrogen or an alkali metal, provided that when R 5 is hydrogen then R 4 is an alkali metal, with a compound of the formula: R 6 X wherein X is fluorine, chlorine, bromine or iodine and R 6 is a group as defined for R 1 or a radical of the formula wherein n is an integer equal to or greater than 1, in the presence of a solvent at a temperature of from - 20‹ C. to + 80‹ C. |
