Trifluoroacetic acid → HCID 68183042, compound

Participants

Reaction Conditions

Reaction Steps

In a 500 mL round bottomed flask was placed 4-(4-chlorophenyl)-2-(2-methylpyrazolo[1,5-a]pyridin-3-yl)-4,5,6,7-tetrahydro-1,3-benzothiazol-4-ol prepared above. The material was suspended in 1,2-dichloroethane (50 mL) and the suspension was stirred for 60 min at 90° C. To the hot solution were added triethylsilane (2 mL, 10 mmol) and trifluoroacetic acid (3 mL, 40 mmol). The mixture Was stirred for 2 days at the same temperature. The mixture was allowed to cool to rt and then concentrated under reduced pressure. The residue was diluted with EtOAc (100 mL) and then washed with a saturated aqueous solution of NaHCO3 (50 mL). The aqueous phase was extracted with EtOAc (50 mL). The combined organic phases were dried over anhydrous MgSO4. Insoluble materials were removed by filtration and the filtrate was concentrated under reduced pressure. The residue was purified by pre-packed silica gel (40 g) column chromatography, eluting with 30% to 100% EtOAc/hexane to yield the title compound (622 mg; 91.8%) as a yellow crystalline solid. 1H NMR (400 MHz, d6-DMSO) δ ppm 8.66 (dt, 1H), 7.95 (dt, 1H), 7.33-7.37 (m, 3H), 7.16 (d, 2H), 6.96 (td, 1H), 4.27 (t, 1H), 2.84-2.93 (m, 2H), 2.56 (s, 3H), 2.15-2.21 (m, 1H), 1.77-1.88 (m, 3H).

Provenance & Evidence