Home Physical Sciences Crystal structures of N-benzylcarbonyl-α-aminoisobutyric acid mono- and tripeptide methyl ester derivatives
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Crystal structures of N-benzylcarbonyl-α-aminoisobutyric acid mono- and tripeptide methyl ester derivatives

Published/Copyright: August 25, 2010
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Abstract

The crystal structures of N-benzylcarbonyl-α-aminoisobutyric acid methyl ester (1) and N-benzylcarbonyl-α-aminoisobutyryl-α-aminoisobutyryl-α-aminoisobutyric acid methyl ester (2) have been determined by X-ray diffraction techniques. The compounds possess the following parameters: (1) orthorhombic, space group Pbca (No. 61), a = 20.124(3) Å, b = 9.497(1) Å, c = 13.825(2) Å, and Z = 8; (2) orthorhombic, Fdd2 (No. 43), a = 31.454(3) Å, b = 34.132(3) Å, c = 8.448(1) Å, and Z = 16. The crystal structures were solved by direct methods. The least-squares refinements led to R values of 0.061 and 0.057 for 1112 and 1131 reflections with I ⩾ 3σ(I) for (1) and (2), respectively. The conformation of the N- and C-blocking groups is similar in the two compounds. However, the conformation of the Aib residue in (1) is semi-extended, while those of the three Aib residues in (2) are helical.

Published Online: 2010-08-25
Published in Print: 1989
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