Sodium Hydroxide → 2-(1-carboxy-3-phenylpropylamino)-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylic acid

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Reaction Steps

0.51 g of 2-amino-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylic acid (racemate B) was dissolved in 4 ml of water. 1.37 g of 2-oxo-4-phenylbutyric acid were added and the mixture was adjusted to pH 6 using 2N aqueous sodium hydroxide solution. 0.33 g of sodium cyanoborohydride was then added and the mixture was left to stir at room temperature for 22 hours. The product was absorbed on to a strong acidic ion-exchange resin and eluted with water containing 2% pyridine to give 0.62 g of crude product. Crystallization from water gave 0.3 g (32%) of 2-(1-carboxy-3-phenylpropylamino)-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylic acid (2 racemates: racemates C and D) in the form of a white solid.

Provenance & Evidence