(2S,5R)-1-Boc-2,5-dimethylpiperazine → (2S,5R)-2,5-dimethyl-4-[4-methyl-3-oxo-2-(2-trimethylsilanyl-ethoxymethyl)-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-yl]-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of (2S,5R)-2,5-dimethyl-piperazine-1-carboxylic acid tert-butyl ester (1.5 g, 7.00 mmol), 6-bromo-4-methyl-2-(2-trimethylsilanyl-ethoxymethyl)-2,10-dihydro-9-oxa-1,2,4a-triaza-phenanthren-3-one (Preparation #1, Step E, 1.990 g, 4.67 mmol), Pd(OAc)2 (0.210 g, 0.933 mmol), 2-(dicyclohexylphosphino)-2′,4′,6′-triisoproplylbiphenyl (0.667 g, 1.400 mmol) and t-BuONa (0.897 g, 9.33 mmol) in toluene (120 mL) was heated at 100° C. for 3 h. The reaction mixture was cooled to ambient temperature and concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 0-50% EtOAc in petroleum ether) to give (2S,5R)-2,5-dimethyl-4-[4-methyl-3-oxo-2-(2-trimethylsilanyl-ethoxymethyl)-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-yl]-piperazine-1-carboxylic acid tert-butyl ester (0.5 g, 19%) as a solid. LC/MS (Table 1, Method 25) Rt=1.072 min.; MS m/z: 560 [M+H]+.

Provenance & Evidence