Selective tritylation
of methyl /I-sophoroside (1) and subsequent acetylation gave the 3,4,2',3',4'-penta-0-acetyl-6,6'-di-0-trityl derivative, which was O-detritylated, and the product p-toluenesulfonylated, to give methyl 3,4,2',3',4'-penta-Oacetyl-6,6'-di-O-p-tolylsulfonyl-/Gsophoroside (4) in 63 "/', net yield. Compound 4 was also obtained in 69 7: yield byp-toluenesulfonylation of 1, followed by acetylation. Several 6,6'-disubstituted derivatives of 1 were synthesized by displacement reactions of 4 with various nucleophiles.
Treatment of 4 with sodium methoxide afforded methyl 3,6 : 3',6 '-dianhydro-/?-sophoroside. Several 6-and 6'-monosubstituted derivatives of 1 were prepared, starting from the 4,6-0-benzylidene derivative of 1.
K. TAKE0
which was U-detritylated with aqueous acetic acid to afford, in 81% yield after column chromatography, the 3~4,~~,3',4'-penta-O-a~etyl derivative 3 as an amorphous material having the I-IO-6 and -6' groups free. p-Toluenesulfonylation of 3 gave 4 in crystalline form in 93 % yield. The overall yield of 4 was 63 s1/,, based on 1. In the second route, treatment of 1 with 2.4 mol. equiv. of ~-to~ue~esulfo~yl chloride in pyridine, and subsequent acetylation, gave a mixture from which 4 was directly obtained in crystalline form in 69% yield. The compounds obtained by the two routes were identical in all respects.