Hydrochloric Acid → HCID 14167821, compound

Participants

Reaction Steps

To a solution of methyl 4-acetylamino-2,2-dimethoxy-6-methyl-3,4-dihydro-2H-pyran-5-carboxylate (13.7 g) (Example 23) in methanol (100 ml) at 20°-25° C. was added water (4.0 ml) and 1N HCl (0.4 ml). The mixture was stirred at 20°-25° C. for five hours, then the solvents were evaporated at reduced pressure and the residual gum (13 g) was redissolved in trifluoroacetic acid (100 ml), to which was added methylene chloride (25 ml) and triethylsilane (25 ml). The mixture was stirred at 20°-25° C. for 70 hours and then the solvents were evaporated at reduced pressure. The residue was purified by chromatography on K60 silica eluting with ethyl acetate to give methyl 2-oxo-4-acetylamino-6-methyl-3,4,5,6-tetrahydro-2H-pyran-5-carboxylate (4.0 g) m.p. 135°-6° C. (EtOAc/hexane) (4,5-trans: 5,6-trans isomer).

Provenance & Evidence