7493-95-0

Off-White Crystalline Solid

p-Nitrophenyl α-D-Galactopyranoside (cas# 7493-95-0) is a compound useful in organic synthesis.

ChEBI: An alpha-D-galactopyranoside having a 4-nitrophenyl substituent at the anomeric position.

Purify 4-nitrophenyl--D-galactopyranoside by recrystallisation from H2O or aqueous EtOH. The monohydrate has m 85o which resolidifies and melts again at 151-152o (the hemihydrate), then resolidifies again and melts at 173o to give the anhydrous form. Drying the monohydrate at 60o yields the hemihydrate, and drying at 100o gives the anhydrous compound. The tetraacetate has m 147o after drying at 100o. [Jermyn Aust J Chem 15 569 1962, Helfreich & Jung Justus Liebigs Ann Chem 589 77 1954.] It is a substrate for galactosidase [Dangelmaier & Holmsen Anal Biochem 104 182 1980]. [Beilstein 17/7 V 55.]