| 摘要 |
1,127,927. Pyrroles. FUJISAWA PHARMACEUTICAL CO. Ltd. 30 Sept., 1965 [12 Oct., 1964; 22 Oct., 1964; 2 Feb., 1965], No. 41623/65. Heading C2C. Compounds of the formula (wherein X is H, halogen, NO 2 or C 1-6 alkoxy; Y is halogen, NO 2 or C 1-6 alkoxy; R<SP>1</SP> is H, C 1-6 alkyl or esterified carboxyl; R<SP>2</SP> is H or C 1-6 alkyl; and R<SP>3</SP> is H or halogen; and at least one of R<SP>1</SP>, R<SP>2</SP> and R<SP>3</SP> is H), which excluding 3-(2- nitro - 3 - chloro - phenyl) - 4 - chloro - pyrrole, are novel, are prepared by decarboxylation, with heating, of corresponding 3-phenyl-pyrroles containing at least one free or esterified carboxyl group in the 2-, 4- and 5-positions. The decarboxylation may be effected in the presence of an acid or base, and if it is effected in the presence of, for example, aqueous sodium hydroxide, esterified carboxyl groups are hydrolysed and subsequently removed. In 2,5-dicarboxylic acids, decarboxylation occurs first at the 5-position. Other groups readily hydrolysable to carboxyl groups, e.g. trihalomethyl, may also be present in the starting materials.
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