3-Oxo-azetidine-1-carboxylic acid tert-butyl ester → HCID 86727290, compound

Participants

Reaction Steps

A solution of 6-amino-4-methyl-2,10-dihydro-9-oxa-1,2,4a-triaza-phenanthren-3-one (Preparation #2, Step E; 5 g, 21.6 mmol) and 3-oxo-azetidine-1-carboxylic acid tert-butyl ester (7.37 g, 43.1 mmol) in MeOH (90 mL) and HOAc (10 mL) was stirred at rt for 2 h. Sodium cyanoborohydride (2.7 g, 43.1 mmol) was added in portions and the resulting dark solution was stirred at rt for 2 h. The solvent was removed in vacuo and the residue was washed with aqueous Na2CO3 (100 mL) and extracted with EtOAc (4×100 mL). The combined organic phase was dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 10-50% EtOAc in petroleum ether) to give 3-(4-methyl-3-oxo-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-ylamino)-azetidine-1-carboxylic acid tert-butyl ester (4.48 g, 54%) as a solid. 1H NMR (CDCl3, 400 MHz): δ 8.28 (brs, 1H), 6.87 (d, J=8.4 Hz, 1H), 6.15 (s, 1H), 6.13 (d, J=8.4 Hz, 1H), 4.70 (m, 1H), 4.58 (d, J=13.2 Hz, 2H), 4.30 (m, 2H), 4.17 (m, 1H), 4.01 (m, 1H), 3.75 (m, 2H), 1.51 (d, J=6.8 Hz, 3H), 1.47 (s, 9H).

Provenance & Evidence