Phosphoric Acid → Dicyclohexylamine

Participants

Reaction Conditions

Reaction Steps

To a mixture of 3.3 g of orthophosphoric acid in 67 mL of methyl isobutyl ketone were added 2.1 g of tri-n-butylamine and 6.6 g of molecular sieves 4A, and the mixture was cooled to 5° C. with stirring. To the mixture was added 6.6 g of 2,3,5-O-tris(4-chlorobenzoyl)-α-D-arabinofuranosyl chloride. After 1 hour, precipitation of crystals initiated and then a thick suspension was provided. After 8 hours, the ratio of α-form/β-form for compound (25) in the reaction suspension was 10:1. To the suspension was added 6.3 g of tri-n-butylamine to dissolve the precipitated crystals and molecular sieves were removed by filtration. The filtrate was washed with 55 mL of water. The organic layer was ice-cooled. To the mixture was added 2.4 g of cyclohexylamine for crystallization with stirring. After 1 hour, the precipitated crystals were collected by filtration and dried in vacuo at room temperature to provide 6.72 g of a dicyclohexylamine salt of compound (25) as a colorless powder (Yield: 70.5%; α-form:β-form=99:1).

Provenance & Evidence