(4,4'-Dehydrophenylalanine)gramicidin S 112209-92-4 2-((Z)-alpha,beta-didehydrophenylalanine)-7-((Z)-alpha,beta-didehydrophenylalanine)gramicidin S Gramicidin S, 2-((Z)-alpha,beta-didehydrophenylalanine)-7-((Z)-alpha,beta-didehydrophenylalanine)- Phe-gramicidin S