SYNTHESES WITH 5-DIBROMOMETHYL- AND 5-FORMYL-PYRROMETHENES

Abstract

With many 5,5′-dimethyl- and 5-bromo-5′-methyl-pyrromethenes the sequence CH3 → CH2Br → CH2O Me had been possible. With two such pyrromethenes the following new sequences have been developed: (1) CH3 → CHBr2 → CH(OMe)2 or CHO (cf. IIIe and IVe), (2) CH(OMe)2, CHO, or CH2OMe → Br (cf. IIIf and IVf), (3) (dimethoxy-methyl-)pyrromethene → formyl-dipyrrylmethane (cf. IX and VII). These provide new intermediates for new porphyrin syntheses and alternative or improved routes to established intermediates.