Crystal Structures of β‐1‐N‐Chloroacetamido Derivatives of d‐Glucose and d‐Galactose

Abstract

Crystal structures of 1‐N‐(β‐d‐glucopyranosyl)chloroacetamide (1), an inhibitor of glycogen phosphorylase, and the corresponding galactopyranosyl amide (2) have been determined. Both crystals belong to P2₁2₁2₁ space group with 1 having the unit cell dimensions of a = 7.939(3), b = 9.547(3) and c = 14.157(2) Å, while those of 2 are, a = 7.636(10), b = 9.004(8) and c = 14.807(5) Å. The sugar ring takes a ⁴ C ₁ conformation and the amide linkage exists in Z‐anti conformation in both crystals. The torsion angle O5–C1–N1–C1′ is − 93.9(5) for 1 and − 111.5(3)° for 2. The conformational preference of Cl and N1 in 1 and 2 is found to be between anti and gauche. The molecular assembly in both 1 and 2 is stabilized by a finite chain of hydrogen bonds starting from N1H and ending at O1′, whereas a ten membered hydrogen‐bonded ring involving O4H and O5 is observed in 1.

Keywords:

• X‐ray crystal structure
• β‐1‐N‐Chloroacetamido sugar derivatives
• d‐Glucopyranose
• d‐Galactopyranose
• Conformation

Acknowledgments

Funding provided by the Department of Science and Technology, New Delhi, for the purchase of the 400 MHz NMR instrument under IRPHA Scheme is gratefully acknowledged. The authors thank the Regional Sophisticated Instrumentation Centre, IIT Madras for the X‐ray data collection. One of us (UA) is thankful to the Council of Scientific and Industrial Research (CSIR), New Delhi, for award of a Junior Research Fellowship. The authors are grateful to the reviewers for their very valuable comments and suggestions.