Triethylamine → 3-(4-Methyl-3-oxo-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-ylmethylene)-azetidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

A solution of 6-bromo-4-methyl-2,10-dihydro-9-oxa-1,2,4a-triaza-phenanthren-3-one (Preparation #1, Step D, 0.30 g, 1.013 mmol), 3-methylene-azetidine-1-carboxylic acid tert-butyl ester (0.343 g, 2.026 mmol), Pd(OAc)2 (0.023 g, 0.101 mmol), tri-O-tolylphosphine (0.0617 g, 0.203 mmol) and triethylamine (0.308 mg, 3.04 mmol) in CH3CN (10 mL) was heated at 110° C. for 14 h. The mixture was cooled to ambient temperature and the solvent was removed in vacuo. The residue was purified by preparative TLC (eluting with 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-ylmethylene)-azetidine-1-carboxylic acid tert-butyl ester as yellow solid (0.201 g, 52%), which was used directly in the next step. LC/MS (Table 1, Method 2) Rt=1.264 min; MS m/z: 385 [M+H]+.

Provenance & Evidence