.beta.-D-Xylofuranoside, (3.beta.,4.beta., 5.alpha.,6.alpha.,15.beta.,24S)-3,4,6, 8,15-pentahydroxy-6-(sulfooxy)cholestan-24-yl 2-O-(2,4-di-O-methyl-.beta.-D-xylopyranosyl)- AIDS-168490 AIDS168490 Certonardoside F