o-(Trifluoromethyl)benzaldehyde → HCID 23503270, compound

Participants

Reaction Conditions

Reaction Steps

A solution of lithium diisopropylamide (11.3 mmol) in tetrahydrofuran/hexane (2:1, 16 ml) was added dropwise to a solution of 5-methyl-7-(2-methylpropyl)thieno[2,3-d]pyridazin-4(5H)-one (Example 6 step b, 1.00 g) in tetrahydrofuran (20 ml) at −78° C. under nitrogen. After 5 minutes, 2-trifluoromethylbenzaldehyde (1.57 g) was added. The mixture was stirred at −78° C. for 3 hours, then saturated sodium hydrogen carbonate solution (50 ml) was added, and the mixture was warmed to room temperature and extracted with ethyl acetate (50 ml). The organic extracts were washed twice with saturated sodium hydrogen carbonate solution, then with brine, then dried, filtered and evaporated. The residue was dissolved in trifluoroacetic acid (5 ml) and triethylsilane (2 ml) was added. After 24 hours, additional trifluoroacetic acid (5 ml) and triethylsilane (2 ml) were added. After a further 3 days, the mixture was diluted with water (50 ml) and extracted with ethyl acetate (50 ml). The organic extracts were washed twice with 1M sodium hydroxide solution, then with brine, and then dried, filtered and evaporated. The residue was purified by column chromatography, eluting with an ethyl acetate/isohexane gradient, followed by preparative normal-phase HPLC with gradient dichloromethane/ethanol elution and then with gradient ethyl acetate/isohexane elution to give the title compound (0.055 g).

Provenance & Evidence