Conformational Study of Heteropentapeptides Containing an α??Ethylated α, α??Disubstituted Amino Acid:(S)??Butylethylglycine (= 2??Amino??2??ethylhexanoic Acid) …

…, M Oba, N Imawaka, Y Tanaka, M Kurihara…

Index: Tanaka, Masakazu; Oba, Makoto; Imawaka, Naoto; Tanaka, Yoshitsugu; Kurihara, Masaaki; Suemune, Hiroshi Helvetica Chimica Acta, 2001 , vol. 84, # 1 p. 32 - 46

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Citation Number: 15

Abstract

Abstract Heteropentapeptides containing the α-ethylated α, α-disubstituted amino acid (S)- butylethylglycine and four dimethylglycine residues, ie, CF 3 CO-[(S)-Beg]-(Aib) 4-OEt (4) and CF 3 CO-(Aib) 2-[(S)-Beg]-(Aib) 2-OEt (7), were synthesized by conventional solution methods. In the solid state, the preferred conformation of 4 was shown to be both a right- handed (P) and a left-handed (M) 3 10-helical structure, and that of 7 was a right-handed ( ...