Triethylamine → (5-ethyl-2-(1-methyl-4-nitro-1H-pyrazol-5-yl)-1,3-dioxan-5-yl)methyl methanesulfonate

Participants

Reaction Steps

To a solution of (5-ethyl-2-(1-methyl-4-nitro-1H-pyrazol-5-yl)-1,3-dioxan-5-yl)methanol (trans isomer) (610 mg, 2.25 mmol, intermediate 66) in dry DCM (15 mL) at 0° C. was added Et3N (0.45 mL, 3.38 mmol) followed by methanesulfonyl chloride (0.21 mL, 2.70 mmol). The reaction mixture was slowly warmed to room temperature over 1.5 hr. The mixture was re-cooled to 0° C. and diluted with aqueous 1 M HCl (10 mL) and DCM (20 mL). The organic layer was washed with aqueous saturated NaHCO3 (15 mL) and water (15 mL), separated, dried over Na2SO4 and concentrated under reduced pressure to give (5-ethyl-2-(1-methyl-4-nitro-1H-pyrazol-5-yl)-1,3-dioxan-5-yl)methyl methanesulfonate as a white solid (816 mg, quantitative). 1H NMR (400 MHz, CDCl3) δ 8.01 (s, 1H), 6.38 (s, 1H), 4.14 (s, 3H), 4.05-3.88 (m, 6H), 3.22-2.92 (m, 3H), 1.96 (q, J=7.6 Hz, 2H), 1.03 (t, J=7.6 Hz, 3H).

Provenance & Evidence