Synthesis of 6,6'-di-O-mycoloyl- and corynomycoloyl-(alpha-D-galactopyranosyl alpha-D-galactopyranoside) via triflates.
Tritylation of 2,3,2',3'-tetra-O-benzyl-(alpha-D-galactopyranosyl alpha-D-galactopyranoside) (4) (A. Liav, H.M. Flowers and M.B. Goren (1984) Carbohydr. Res. 133, 53-58) followed by benzylation and acid hydrolysis gave 2,3,4,2',3',4'-hexa-O-benzyl-(alpha-D-galactopyranosyl alpha-D-galactopyranoside) (6). Triflation of 6 with triflic anhydride gave the ditriflate 7. Treatment of 7 with potassium mycolate or potassium corynomycolate in toluene, followed by catalytic hydrogenolysis afforded the respective cord-factor analogs 6,6'-di-O-mycoloyl-(alpha-D-galactopyranosyl alpha-D-galactopyranoside) (10) and 6,6'-di-O-corynomycoloyl (alpha-D galactopyranosyl alpha-D-galactopyranoside) (11). An alternative approach, based on the debenzylation of 2,3,2',3'-tetra-O-benzyl-6,6'-di-O-p-tolylsulfonyl- (alpha-D-galactopyranosyl alpha-D-galactopyranoside) (1) and conversion of the latter into the corresponding 3,4,3',4'-diisopropylidene derivative 3 failed to yield satisfactory results.
Liav
A
A
Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.
Goren
M B
MB
D003311:Cord Factors / Q000138:chemical synthesis*; D006017:Glycolipids / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009904:Optical Rotation; D013329:Structure-Activity Relationship
C043397:6,6'-di-O-mycolyl galactopyranosyl-galactopyranoside; D003311:Cord Factors; D006017:Glycolipids; D007202:Indicators and Reagents; C043398:6,6'-di-O-corynomycolyl galactopyranosyl-galactopyranoside