(-)-Benzomalvin A

Eguchi et al. have successfully applied the intramolecular aza-Wittig method to the synthesis of the neurokinin receptor antagonists (-)-benzomavin A 18 and B 90, which contain a 1,4-benzodiazepine ring and a 4-quinazolinone ring, and can be regarded as L-phenylalanine derivatives composed of two anthranilic acid moieties [233,234]. This synthesis utilized the 1,4-benzo-diazepine synthesis [235, 236] combined with the quinazolinone annelation reaction as explained in Scheme 19. Amino acid ester 85 provided (-)-ben-zomalvin A 18 with 99.7% ee (based on HPLC analysis) [237-239]. Bromi-

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