124780-62-7

Upstream product

• 3396-99-4 methyl α-D-galactopyranoside 
• 100-39-0 benzyl bromide 
• 104477-38-5 methyl 2-O-benzyl-3,4-O-isopropylidene-6-O-(1-methoxy-1-methylethyl)-α-D-galactopyranoside 
• 27851-16-7 methyl 2-O-benzyl-3,4-O-isopropylidene-α-D-galactopyranoside 
• 114217-35-5 methyl 6-O-(tert-butyldiphenylsilyl)-α-D-galactopyranoside 
• 124780-61-6 ((3aS,4R,6S,7R,7aS)-7-Benzyloxy-6-methoxy-2,2-dimethyl-tetrahydro-[1,3]dioxolo[4,5-c]pyran-4-ylmethoxy)-tert-butyl-diphenyl-silane 
• 131089-35-5 (3aR,4S,6R,7S,7aS)-6-(tert-Butyl-diphenyl-silanyloxymethyl)-4-methoxy-2,2-dimethyl-tetrahydro-[1,3]dioxolo[4,5-c]pyran-7-ol 
• 104530-14-5 Methyl 3,4-O-isopropylidene-6-O-(1-methoxy-1-methylethyl)-α-D-galactopyranoside 

Downstream Products

• 124780-53-6 (3aS,4R,6S,7R,7aS)-7-Benzyloxy-6-methoxy-2,2-dimethyl-4-((E)-propenyl)-tetrahydro-[1,3]dioxolo[4,5-c]pyran 

Relevant academic research and scientific papers

A new synthesis of L-ascorbic acid from D-galactose

1,5-Anhydro-D-galactitol, easily available from D-galactose, was selectively protected in positions 2, 3 and 4 and converted into 5-O-acetyl-2,6-anhydro-3-deoxy-L-threo-hex-2-enonic acid methyl ester, which, on reaction with MCPBA in acetic acid gave 2,5-di-O-acetyl-α-L-lyxo-hex-2-ulopyranosonic acid methyl ester. Reaction of the latter with sodium methoxide produced sodium L-ascorbate in high yield. Several side-reactions and the conformations of some of the intermediates are also discussed.

Stereocontrolled lincomycin synthesis

The synthesis from methyl α-D-galactopyranoside (6) of methyl thiolincosaminide (2), the direct synthetic precursor to lincomycin (1), is presented. The key step for controlling the off-pyranose stereocenters C-6 and C-7 is a novel intramolecular nitrogen delivery reaction using epoxy alcohol 10. Reaction of 10 with dimethylcyanamide in the presence of sodium hydride and imidazole leads to the oxazoline 14, a protected vicinal amino alcohol. The synthesis is completed by efficient exchange of acetal for thioacetal, followed by hydrolysis of the oxazoline and removal of the benzyl groups. The target 2 is obtained in 22 steps and 28% overall yield from 6.