proline dl-form → HCID 58392275, compound

Participants

Reaction Steps

1.44 g (9.31 mmol) of 4-chloro-2-methylbenzaldehyde, 1.34 g (9.31 mmol) of Meldrum's acid and 48.7 mg (0.42 mmol) of D,L-proline were added to a solution of 1.50 g (8.46 mmol) of the compound from Example 8A in 70 ml of acetonitrile. The reaction mixture was stirred at RT overnight. It was concentrated, and the residue was taken up in ethyl acetate, washed with saturated aqueous sodium bicarbonate solution, water and saturated aqueous sodium chloride solution, dried over magnesium sulfate, filtered and concentrated. 3.43 g of a crude product were obtained and were introduced into 53 ml of pyridine and 14 ml of ethanol, and 4.8 mg (75 μmol) of copper powder were added. The reaction mixture was heated under reflux for 1 h. It was concentrated, and the residue was taken up in ethyl acetate, washed with 1N hydrochloric acid, dried over magnesium sulfate, filtered through silica gel and concentrated. The crude product was purified by preparative HPLC (RP18 column; mobile phase: acetonitrile/water gradient with addition of 0.1% formic acid) to result in 1.68 g (49% of theory) of the title compound.

Provenance & Evidence