p-Toluenesulfonic acid → HCID 68115506, compound

Participants

Reaction Steps

For the preparation of the starting material compound 43.1, see Example 43. Into a 50-mL round-bottom flask containing a solution of tert-butyl N-methyl-N-(4-[[(3R)-3-(2-oxoethyl)-7-thia-9,11-diazatricyclo[6.4.0.0[2,6]]dodeca-1(8),2(6),9,11-tetraen-12-yl]oxy]cyclohexyl)carbamate (460 mg, 1.03 mmol, 1.00 equiv) in methanol (15 mL) was added trimethoxymethane (548 mg, 5.16 mmol, 5.00 equiv) and 4-methylbenzene-1-sulfonic acid (18 mg, 0.10 mmol, 0.10 equiv) at room temperature under nitrogen. The reaction mixture was stirred for 4 hr at ambient temperature. After completion, the reaction was quenched with saturated aqueous NaHCO3 and extracted with 3×50 mL of ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column with ethyl acetate/petroleum ether (1:8) to afford the desired tert-butyl N-(4-[[(3R)-3-(2,2-dimethoxyethyl)-7-thia-9,11-diazatricyclo[6.4.0.0[2,6]]dodeca-1(8),2(6),9,11-tetraen-12-yl]oxy]cyclohexyl)-N-methylcarbamate (470 mg, 93%) as a colorless oil. LC-MS (ES): m/z 562 [M+H]+.

Provenance & Evidence