THE VILSMEIER-SYNTHETIC-ROUTE TO INDOLYLPYRROLES

Some 2-(7-indolyl)pyrroles have been synthesised from the 4,6-dimethox yindoles 4, 19 and 20 using the modified Vilsmeier reaction. The indol ylpyrrole 8 was formed by dehydrogenation of the 2-(7-indolyl)pyrrolin e 7, which was obtained from indole 4, methyl pyrrolidin-2-one-5-carbo xylate and bromopyrrolidin-2-one 11 and phosphoryl chloride to give th e 3-chloro-2-(7-indolyl)pyrrolines 12, 29 and 30, which undergo subseq uent dehydrohalogenation to give the indolylpyrroles 13, 33 and 34. (C ) 1997 Published by Elsevier Science Ltd.