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The Crystal and Molecular Structure of tert – Butoxycarbonyl ‐ α‐aminoisobutyryl‐ leucyl ‐ methyl ester
Author(s) -
Nilofar Nissa M.,
Banumathi S.,
Velmurugan D.,
Ramasubbu N.
Publication year - 2001
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/1521-4079(200106)36:4/5<499::aid-crat499>3.0.co;2-v
Subject(s) - orthorhombic crystal system , dipeptide , dihedral angle , crystal structure , chemistry , molecule , crystallography , residue (chemistry) , stereochemistry , peptide , hydrogen bond , organic chemistry , biochemistry
The crystal structure of a dipeptide Boc – Aib – Leu – OMe (C 16 H 30 N 2 O 5 ) has been determined by X ‐ ray diffraction analysis (CCDC # 144425). The crystals are orthorhombic, space group P2 1 2 1 2 1 with a = 9.674(5), b = 13.642(2), c = 30.496(6) Å, V = 4025(2) Å 3 , Z = 8, D calc = 1.09 Mgm ‐3 . Crystal structure was solved by direct methods and refined by full‐matrix least‐squares method to an R value of 0.067 (λ=1.5418 Å) for 2389 reflections with I ≥ 3σ (I). The dihedral angles of the peptide backbone show that the Aib residue adopts a right handed (α R ) and a left handed (α L ) helical conformation in molecules A and B respectively, whereas the Leucine residue takes an extended and folded conformation in molecules A and B respectively.