TRITERPENE GLYCOSIDES OF ALFALFA. III. MEDICOSIDE I

Article abstract of DOI:10.1007/BF00599263

On the basis of chemical transformations and with the aid of physicochemical results, the structure of glycoside I isolated from the roots of the plant Medicago sativa has been established as hederagin 3-O-2)-β-D-glucopyranosyl(1->2)-α-L-arabinopyranoside> 28-O-β-D-glucopyranoside.Compound (I), C52H84O22, mp 210-212 deg C, <α>_D²¹ +38.4 deg (c 1.48; methanol).Acid hydrolysis of (I) led to hederogenin (II) - C30H48O4, mp 326-330 deg C, <α>_D²³ +84.2 deg (c 0.19; pyridine).The Hakomori methylation of glycoside (I) yielded the permethylate (IV) - C65H11O22 <α>_D²³ +41.6 deg (c 1.79; methanol).The GLC analysis of the products of the methanolysis of compound IV showed the presence of 3,4,6-tri-O-methyl-D-glucopyranose, 2,3,4,6-tetra-O-methyl-D-glucopyranose, 3,4-di-O-methyl-L-arabinopyranose, and 2,3,4-tri-O-methyl-L-arabinopyranose.The alkaline hydrolysis of glycoside I gave compound (III) with mp 230-233 deg C, <α>_D²¹ +35.2 deg (c 0.21; methanol), which was identified as medicoside C.Details of the PMR spectrum are given for compound (IV) and of the IR spectrum for compound (I).