Synthesis of modified partial structures of the bacterial cell wall. 1. Lipopeptides containing nonproteinogenic amino acids
摘要:
Two stereoisomeric lipopeptides 1 and 2 which can be regarded as modified peptidoglycans have been synthesized by using three different reaction sequences. The ene reaction of the alpha-allylated dipeptide 12 with butyl glyoxylate was used as a key step. The required enantiomerically pure substrates 9, 10, and 23 were obtained by enzymatic hydrolysis of the corresponding racemic alpha-allylated esters. The absolute configuration of both stereoisomers 1 and 2 was assigned by oxidative cleavage of the double bond in 18 and 19 followed by comparison of the esterified degradation products 28 and 29 with samples of authentic configuration, derived from (R)- and (S)-malic acid.
Synthesis of modified partial structures of the bacterial cell wall. 1. Lipopeptides containing nonproteinogenic amino acids
摘要:
Two stereoisomeric lipopeptides 1 and 2 which can be regarded as modified peptidoglycans have been synthesized by using three different reaction sequences. The ene reaction of the alpha-allylated dipeptide 12 with butyl glyoxylate was used as a key step. The required enantiomerically pure substrates 9, 10, and 23 were obtained by enzymatic hydrolysis of the corresponding racemic alpha-allylated esters. The absolute configuration of both stereoisomers 1 and 2 was assigned by oxidative cleavage of the double bond in 18 and 19 followed by comparison of the esterified degradation products 28 and 29 with samples of authentic configuration, derived from (R)- and (S)-malic acid.
Two stereoisomeric lipopeptides 1 and 2 which can be regarded as modified peptidoglycans have been synthesized by using three different reaction sequences. The ene reaction of the alpha-allylated dipeptide 12 with butyl glyoxylate was used as a key step. The required enantiomerically pure substrates 9, 10, and 23 were obtained by enzymatic hydrolysis of the corresponding racemic alpha-allylated esters. The absolute configuration of both stereoisomers 1 and 2 was assigned by oxidative cleavage of the double bond in 18 and 19 followed by comparison of the esterified degradation products 28 and 29 with samples of authentic configuration, derived from (R)- and (S)-malic acid.