Cesium carbonate → 3-[4-Methyl-3-oxo-7-trifluoromethyl-2-(2-trimethylsilanyl-ethoxymethyl)-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-ylamino]-azetidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

A mixture of 6-bromo-4-methyl-7-trifluoromethyl-2-(2-trimethylsilanyl-ethoxymethyl)-2,10-dihydro-9-oxa-1,2,4a-triaza-phenanthren-3-one (2.0 g, 4.05 mmol), tert-butyl 3-amino azetidine-1-carboxylate (1.39 g, 8.09 mmol), diacetoxypalladium (0.27 g, 1.21 mmol), Cs2CO3 (1.32 g, 4.05 mmol) and BINAP (1.0 g, 1.62 mmol) in toluene (10 mL) was heated at reflux for 2 h. The reaction mixture was cooled to ambient temperature and filtered. The filtrate was concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 20% EtOAc in petroleum ether) to give 3-[4-methyl-3-oxo-7-trifluoromethyl-2-(2-trimethylsilanyl-ethoxymethyl)-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-ylamino]-azetidine-1-carboxylic acid tert-butyl ester (2.1 g, 89%) as a pale yellow solid. 1H NMR (CDCl3, 400 MHz): δ 7.14 (s, 1H), 5.86 (s, 1H), 5.10 (q, J=9.2 Hz, 2H), 4.63 (m, 2H), 4.51 (m, 2H), 4.33 (m, 2H), 4.18 (m, 1H), 3.77 (m, 2H), 3.65 (t, J=8.4 Hz, 2H), 1.47 (d, J=6.4 Hz, 3H), 1.45 (s, 9H), 0.99 (t, J=8.4 Hz, 2H), 0.00 (s, 9H).

Provenance & Evidence