Water → HCID 20191014, compound

Participants

Reaction Steps

Lithium bis(trimethylsilyl)amide (10 ml. of a 1M solution in THF) was cooled to -75° under argon and freshly distilled EtOAc (0.88 g.) was added over 5 minutes. Crude 3-(3-nitropyrazol-1-yl)propionaldehyde (1.75 g.) in dry THF (10 ml.) was added at -75° over 10 minutes and the mixture was kept at -75° for a further 15 minutes then allowed to warm to 20° . Water (200 ml.) was added and the mixture was extracted with EtOAc (3×60 ml.). The extracts were dried (MgSO4) and evaporated in vacuo to give crude ethyl 3-hydroxy-5-(3-nitropyrazol-1-yl)valerate as an oil (2.41 g.) which was used in the next stage without further purification. The n.m.r. spectrum in CD3OD included the following resonances: 7.76 (d, 1H): 6.86 (d, 1H); 4.36 (t, 2H); 4.1 (q, 2H); 3.9 (m, 1H); 2.47 (d, 2H); 2.1 (m, 2H); 1.24 (t, 3H).

Provenance & Evidence