Methanol → 5-Azido-2-(2-methyl-4-nitro-pyrazol-3-yl)oxepan-4-ol

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-(4,8-dioxabicyclo[5.1.0]octan-5-yl)-1-methyl-4-nitro-pyrazole (1.04 g, 4.35 mmol) in 4:1 MeOH:water (30 mL) was added ammonium chloride (0.58 g, 10.88 mmol) and sodium azide (1.41 g, 21.75 mmol). The mixture was heated at 70° C. behind a blast screen for 16 hr. The MeOH was removed under reduced pressure and EtOAc (20 mL) added. The organic layer was washed with saturated aqueous NaHCO3 (20 mL), passed through a phase separation cartridge and concentrated under reduced pressure. Purification via silica gel chromatography (0-60% EtOAc/isohexane) gave 5-azido-2-(2-methyl-4-nitro-pyrazol-3-yl)oxepan-4-ol as a pale yellow gum (718 mg, 58% yield). 1H NMR (400 MHz, CDCl3) δ 8.03 (s, 1H), 5.76 (dd, J=9.3, 3.2 Hz, 1H), 4.18-4.10 (m, 1H), 4.08-4.04 (m, 4H), 3.91 (ddd, J=9.4, 6.6, 6.2 Hz, 1H), 3.79 (ddd, J=12.6, 8.6, 3.5 Hz, 1H), 2.44 (ddd, J=15.3, 9.4, 3.8 Hz, 1H), 2.37-2.29 (m, 1H), 2.24 (d, J=3.2 Hz, 1H), 2.12 (ddd, J=15.3, 5.7, 3.2 Hz, 1H), 2.06-1.96 (m, 1H).

Provenance & Evidence