1,10-Phenanthroline → 4-[7-(2-Chloro-4,6-dimethylphenyl)-2-methyl-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridin-3-yl]heptan-4-ol

Participants

Reaction Conditions

Reaction Steps

3-Bromo-7-(2-chloro-4,6-dimethylphenyl)-2-methyl-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridine (1-1; 122 mg) and a crystal of 1,10-phenanthroline were dissolved in 3 mL of dry tetrahydrofuran and the solution was chilled to −78° C. under an atmosphere of argon. To the cooled solution was added n-butyllithium (2.0 M in cyclohexane) until the dark color of the organolithium/phenanthroline complex persisted. An additional 0.17 mL of the butyllithium solution then was added. After 10 m, a solution of 4-heptanone (42.6 mg) in 1 mL tetrahydrofuran was added via syringe. The reaction mixture was allowed to stir at −78° C. for 15 m, then was allowed to warm to 0° C. After quenching with aqueous ammonium chloride, the reaction mixture was partitioned between ethyl acetate and brine. The ethyl acetate was dried with magnesium sulfate and concentrated on the rotary evaporator. The residue was chromatographed on silica gel eluting with 9:1 hexane/acetone to afford 76.0 mg of 4-[7-(2-chloro-4,6-dimethylphenyl)-2-methyl-4,5,6,7-tetrahydro-2H-pyrazolo-[3,4-b]pyridin-3-yl]heptan-4-ol (2-1) which was recrystallized from hexane: mp 129-130° C.

Provenance & Evidence