Triethylamine → HCID 21476920, compound

Participants

Reaction Conditions

Reaction Steps

An oven dried 500 mL three necked round bottom flask was equipped with a magnetic stir bar, a nitrogen inlet, a septum, and a stopper. The flask was purged with nitrogen then charged with a solution of 5.083 g (28.2 mmol) of 3,4-methylenedioxyphenylacetic acid and 220 mL of anhydrous tetrahydrofuran. The contents were stirred at -78° C. and 5.11 mL of triethylamine (36.7 mmol) and 3.82 mL (31.0 mmol) of trimethylacetyl chloride were successively added. The reaction mixture was stirred at -78° C. for 15 minutes, then at 0° C. for one hour. In a separate oven dried flask, a solution of 10.120 g (50.8 mmol) of 4-(i-propyl)benzenesulfonamide dissolved in 110 mL of tetrahydrofuran was treated with 20.31 mL of a 2.5N solution of n-butyllithium in hexane at -78° C. A heavy precipitate of the deprotonated sulfonamide formed during the addition which prevented stirring. The flask and its contents were then warmed to room temperature and 60 mL of dimethylsulfoxide were added which effected solution of the lithiated sulfonamide. The solution of the lithiated sulfonamide was then transferred via cannula to the stirred 0° C. reaction mixture containing the mixed anhydride. After the addition was complete, the reaction mixture was stirred an additional 3 hours, then it was quenched by addition of excess 10% aqueous NaHSO4. The majority of the THF was next removed in vacuo, and the remainder of the mixture was partitioned between EtOAc and saturated brine. The organic layer was extracted, separated, dried (MgSO4), filtered and evaporated. The residue was purified on a silica gel flash chromatography column eluted with 2.5% MeOH--CHCl3. The purified fractions were combined, evaporated and then recrystallized from methylene chloride-hexane to afford 6.623 g (65%) of the title compound as an off-white crystalline solid which had: mp=262°-3° C.

Provenance & Evidence