1,4-Dioxane → HCID 178497014, compound

Participants

Reaction Conditions

Reaction Steps

According to a modification of a literature procedure (Suzuki, A. et al Tetrahedron Lett. 1986, 27, 6369–6372) a mixture of 43 mg (0.1 mmol) of 5-(4-bromo-phenyl)-6-cyclohexyl-7-oxo-4,7-dihydro-pyrazolo[1,5-a]pyrimidine-2-carboxylic acid methyl ester, 7.3 mg (0.01 mmol) of Pd catalyst, 0.4 mL (0.2 mmol) of B-Benzyl-9-BBN 0.5 M solution in THF, and 63 mg (0.3 mmol) of potassium phosphate, was purged with argon, 1 mL of 1,4-dioxane was added, and the resulting mixture was shaken at 80° C. in a sandbath overnight. The reaction mixture was then diluted with dichloromethane, filtered through a small pad of Celite, dried over sodium sulfate and evaporated to give a residue, which was purified via reverse-phase chromatography (Gilson) to afford desired 5-(4-benzyl-phenyl)-6-cyclohexyl-7-oxo-4,7-dihydro-pyrazolo[1,5-a]pyrimidine-2-carboxylic acid methyl ester as a solid as indicated by LC-MS—calcd for C27H27N3O3 [M++H]+: 442.21, found: 442.2. This material was then converted to 5-(4-benzyl-phenyl)-6-cyclohexyl-7-oxo-4,7-dihydro-pyrazolo[1,5-a]pyrimidine-2-carboxylic acid (581) via a LiOH saponification (33% yield over 2 steps); LC-MS—calcd for C26H25N3O3 [M++H]+: 428.19, found: 428.2.

Provenance & Evidence