Dimethylformamide → 4-Ethyl-7,8-difluoro-5-[(4-methoxy-3-methylphenyl)sulfonyl]-4,5-dihydropyrrolo[1,2-a]quinoxaline-1-carbonitrile

Participants

Reaction Conditions

Reaction Steps

To a 250 ml round bottom flask with addition funnel was added 2 g (4.8 mmol) of the product from Example 4 and 50 ml of THF. The solution was cooled to −78° C. and 0.50 ml (5.76 mmol) of chlorosulfonyl isocyanate in 20 ml of THF added dropwise via the addition funnel. After the addition was complete the solution was stirred at this temperature for 3 hr until all of the product had disappeared by TLC. Added 1 ml of DMF and allowed the solution to warm to room temperature, whereupon product begins to form. After stirring overnight the reaction was quenched with saturated sodium bicarbonate solution, then extracted 3 times with ethyl acetate. The organic layers were combined, dried (MgSO4) and concentrated to afford an oil, which was chromatographed on silica gel eluting with 30% ethyl acetate:hexane to afford 1.81 g (83%) of product as a solid, which was recrystallized from ethyl acetate hexane, mp 176-178° C.

Provenance & Evidence