Carbon tetrabromide → HCID 135730596, compound

Participants

Reaction Steps

Triphenylphosphine (110 mg, 0.42 mmol) in dichloromethane (1 mL) was added slowly to an ice cooled solution of 5-(2-butoxy-5-glycoloyl-3-pyridinyl)-3-ethyl-2-(2-methoxyethyl)-2,6-dihydro-7H-pyrazolo[4,3-d]-pyrimidin-7-one (Example 33) (150 mg, 0.35 mmol) and carbon tetrabromide (140 mg, 0.42 mmol) in dichloromethane (3 mL). The solution was allowed to warm to room temperature. After 2 h further carbon tetrabromide (25 mg, 0.075 mmol) and triphenylphosphine were added and stirring continued for 2 h. Concentration and purification of the product by flash column chromatography (gradient elution with ethyl acetate/pentane (10:90-70:30) gave 5-[2-butoxy-5-(2-bromoacetyl)-3-pyridinyl]-3-ethyl-2-(2-methoxyethyl)-2,6-dihydro-7H-pyrazolo[4,3-d]-pyrimidin-7-one which was used without any further purification (slight contamination with triphenylphosphine oxide). 5-[2-Butoxy-5-(2-bromoacetyl)-3-pyridinyl]-3-ethyl-2-(2-methoxyethyl)-2,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (205 mg, 0.42 mmol) was dissolved in dichloromethane and the solution cooled to 0° C. Morpholine (54 mg, 0.62 mmol) and triethylamine (84 mg, 0.83 mmol) were added and the mixture was allowed to warm to room temperature and stirred for 2 h. The solvent was evaporated and the residue dissolved in ethyl acetate, washed with water (twice), saturated sodium bicarbonate (twice) and brine, dried (MgSO4) and concentrated. Purification by flash column chromatography (gradient elution 20% ethyl acetate/pentane:100% ethyl acetate:3% methanol/methyl acetate) gave 70 mg product.

Provenance & Evidence