Hexamethyldisilazane → 1-(4-Methylphenyl)-4-[2-(6-aminocarbonylisochroman-1-yl)ethyl]piperazine

Participants

Reaction Steps

An oven dried 5 ml micro vial, equipped with a Claisen condenser, water cooled condenser, and hose adapter, is charged with 1-(4-methylphenyl)-4-[2-(6-bromoisochroman-1-yl)-ethyl]piperazine (CXXVI, EXAMPLE 127, 103 mg, 0.25 mmol), palladium acetate (98%, 2.9 mg, 0.012 mmol) and 1,3-bis-diphenylphosphinopropane (97%, 6.4 mg, 0.015 mmol). Carbon monoxide atmosphere is established in the vial. To the reaction vessel is introduced via syringe DMF (0.62 ml), 1,1,1,3,3,3-hexamethyldisilazane (98%, 0.38 ml, 1.8 mmol), and diisopropylethylamine (0.087 ml, 0.5 mmol). The mixture is heated to 100° over 18 hr. After cooling to 20°-25°, the reaction mixture separates into two phases. The reaction mixture is poured into methylene chloride (pH=12). The mixture is washed one time with aqueous sodium hydroxide (1N). The organic phase is then concentrated under reduced pressure to remove excess solvents and reactants. The residue is dissolved in methylene chloride again and the mixture is washed twice with aqueous hydrochloric acid (1N). The aqueous acidic phases are combined, made basic with concentraged aqueous sodium hydroxide (pH>14). The basic mixture is extracted four times with methylene chloride, the organics phases are combined and concentrated. The product crystallized out of the crude and the mother liquor is purified by flash chromatography (silica gel, 13 g; eluting with methanol/ethyl acetate (10/90) to give additional title compound, HRMS Calcd for C23H29N3O2 =379.2260, found=379.2269.

Provenance & Evidence