Studies on Seven-membered Ring Compounds. VII

Reaction of 2-amino-3-bromotropone (I) with active methylene compounds having a ketone group was examined. It was found that (I) undergoes condensation with the methylene and ketone groups in the active methylene compound and forms a cyclohepta[b] pyrrol-8(1H)-one derivative. It was also revealed that if an ester group is also present in the active methylene compound, ketone group undergoes preferential condensation. From 2-methylcyclohepta[b] pyrrol-8(1H)-one (IV) obtained by this reaction, a seven-membered compound having similar structure similar to tryptophan, 3-(2-methyl-8-oxo-1, 8-dihydrocyclohepta[b] pyrrol-3-yl) alanine (XV), was prepared by a method same as in the preparation of indoles.