Formaldehyde → 1-[4-(1,3,3-Trimethyl-6-aza-bicyclo[3.2.1]octane-6-carbonyl)-phenyl]-pyrrolidine-3-carboxylic acid methyl ester

Participants

Reaction Steps

[4-(1,3,3-Trimethyl-6-aza-bicyclo[3.2.1]octane-6-carbonyl)-phenylamino]-acetic acid (1.3 g, 3.93 mmol), methyl acrylate (275 μl, 3.03 mmol) and paraformaldehyde (636 mg, 21.18 mmol) were dissolved in toluene (180 ml) in a three necked reaction flask equipped with a water separator. The mixture was stirred at reflux temp. for 3 hrs at which time a small portion of methyl acrylate (40 μl) was added. The resulting mixture was stirred at reflux temp. for an additional 16 hrs. and evaporated. The residue was dissolved in EtOAc (50 ml) and washed with water (2×25 ml), dried (Na2SO4), filtered and evaporated in vacuo. The resulting residue was purified by column chromatography (silica gel) using first pure heptane (300 ml) followed by a mixture of EtOAc-Heptane (1:1) as eluents. Pure fractions were collected and evaporated to dryness affording 603 mg (52%) of 1-[4-(1,3,3-trimethyl-6-aza-bicyclo[3.2.1]octane-6-carbonyl)-phenyl]-pyrrolidine-3-carboxylic acid methyl ester as an oil.

Provenance & Evidence