Dimethyl Sulfoxide → HCID 86701123, compound

Participants

Reaction Conditions

Reaction Steps

A solution of DMSO (9.2 g, 118 mmol) in dry dichloromethane (70 mL) was treated with (COCl)2 (11.6 g, 92 mmol) at −78° C. for 30 minutes, followed by addition of tert-butyl N-[(3aR,5R,6S,7R,7aR)-6,7-bis(benzyloxy)-5-(hydroxymethyl)-3aH,5H,6H,7H,7aH-pyrano[3,2-d][1,3]thiazol-2-yl]-N-(prop-2-en-1-yl)carbamate (8 g, 15 mmol) in dichloromethane (15 mL) slowly. The resulting solution was stirred for 3 hours at −30° C., then cooled down to −78° C. again before addition of triethylamine (20 g, 180 mmol). After additional 30 minutes at −50° C., the resulting mixture was quenched by water (50 mL), and the aqueous layer was extracted with dichloromethane (3×50 mL). The combined organic layer was dried over sodium sulfate, and concentrated to afford crude 140 as a light yellow syrup, which was dissolved into anhydrous THF (100 mL). The solution was treated with bromo(methyl)magnesium (20 ml, 40 mmol, 2M in THF) at 0° C. overnight. The reaction was then quenched with saturated aqueous NH4Cl solution (100 mL), and extracted with ethyl acetate (3×100 mL). The combined organic layer was washed with brine (2×50 mL), dried over anhydrous magnesium sulfate and concentrated under vacuum. The residue was purified by flash column chromatography with 10%-20% ethyl acetate in petroleum ether to afford 143 as a yellow syrup (7 g, 87%, two isomers, the ratio is 1:3.8 determined by 1HNMR). (ES, m/z): [M+H]+ 555.0; 1H NMR (300 MHz, CDCl3): 7.38-7.25 (m, 10H), 6.13-6.11 (m, 1H), 5.82-5.70 (m, 1H), 5.99-4.96 (m, 2H), 4.76-4.56 (m, 2H), 4.54-4.27 (m, 6H), 4.13-3.73 (m, 3H), 1.50 (s, 9H), 1.28-1.20 (m, 3H).

Provenance & Evidence