Dimethyl Carbonate → HCID 46942028, compound

Participants

Reaction Conditions

Reaction Steps

A solution of LDA (2M in THF/heptane/ethyl benzene, 44 ml, 88 mmol) was added dropwise to a stirred solution of 4-methyl-2-[4-(trifluoromethyl)phenyl]pyridine (10.5 g, 44 mmol) in dry THF (300 ml) under N2, such that the internal temperature remained <−70° C. After 1 hour at this temperature, dimethyl carbonate (8.9 ml, 106 mmol) was added. After 30 minutes the cooling bath was removed. When the internal temperature had reached −20° C. the reaction was transferred to a cold bath at −10° C., and then allowed to warm slowly to 0° C. After 1 hour at 0° C. the reaction was quenched with aqueous NH4Cl (half saturated, 100 ml). The reaction mixture was concentrated in vacuo. The residue was diluted with H2O (200 ml) and extracted with EtOAc (2×200 ml). The combined extracts were washed with brine (×1), then dried (MgSO4), filtered and evaporated. The residue was purified by chromatography on silica, eluting with 10-30% EtOAc/isohexane to give the ester (9.2 g, 71%) as a pale yellow liquid. 1H NMR (400 MHz, CDCl3) δ: 3.72 (2H, s), 3.75 (3H, s), 7.24 (1H, dd, J 1.4, 5.0), 7.72 (3H, t, J 8.4), 8.11 (2H, d, J 8.2), 8.68 (1H, d, J 5.0).

Provenance & Evidence