Methyl N-(triethylammoniosulfonyl)carbamate → 6,7-dihydro-2-(phenoxymethyl)-oxazolo[4,5-c]pyridine-5(4H)-carboxylic acid 1,1-dimethylethyl ester

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Reaction Conditions

Reaction Steps

A suspension of 4-oxo-3-[(phenoxyacetyl)amino]-1-piperidinecarboxylic acid 1,1-dimethylethyl ester (0.36 g, 1.0 mmol) and Burgess reagent (0.30 g, 1.25 mmol) in THF (4 mL) was stirred at 120° C. for 10 minutes under microwave irradiation. Then additional Burgess reagent (0.30 g, 1.25 mmol) was added and the mixture stirred at 150° C. for a further 5 minutes under microwave irradiation. The mixture was diluted with a saturated solution of NaHCO3 and extracted with AcOEt. The organic layer was separated, dried (Na2SO4), filtered and the solvent evaporated in vacuo. The crude product was purified by flash column chromatography (silica; AcOEt in DCM 99/1 to 80/20). The desired fractions were collected and the solvents evaporated in vacuo to yield 6,7-dihydro-2-(phenoxymethyl)-oxazolo[4,5-c]pyridine-5(4H)-carboxylic acid 1,1-dimethylethyl ester (0.11 mg, 33% yield). C18H22N2O4 LCMS: Rt 2.87, m/z 331 [M+H]+ (using method, LC-MS Method 3).

Provenance & Evidence