Trifluoroacetic acid → 2-methylpropyl[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]carbamate

Participants

Reaction Steps

2-Methylpropyl [3-fluoro-4-(tetrahydro-4-hydroxy-2H-thiopyran-4-yl)phenyl]carbamate (IV, EXAMPLE 2, 50 g, 152.7 mmol) is slurried in 150 ml methylene chloride. Trifluoroacetic acid (21.1 ml, 274.9 mmol, 1.8 equiv.) is added and the resulting mixture is stirred at 25° for 3 hr. The reaction is quenched with 75 ml of 47% aqueous potassium carbonate and stirred at 25° for 2 hr to dissolve any salts. Water (75 ml) is added and the phases are separated. The organic layer is collected, washed with 75 ml saline followed by 75 ml water. The organic phase is then concentrated and dried under reduced pressure over night to give 2-methylpropyl[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]carbamate. TLC Rf=0.85 (methanol/methylene chloride, 5/95); mp=99-100°; NMR (CDCl3) d 7.28, 7.12, 6.99, 6.74, 5.99, 3.95, 3.33-3., 2.84, 2.63, 2.02-1.91 and 0.96; CMR (CDCl3) d 159.5, 153.4, 138.4, 134.5, 129.6, 126.8, 124.0, 113.8, 106.2, 71.5, 29.3, 27.9, 25.8, 25.1 and 18.9; MS (CI, NH3) m/z (relative intensity) 327 (80), 310 (100), 309(87), 281 (23), 264 (38), 235 (30), 224(33), 189 (20), 165(25) and 161 (23).

Provenance & Evidence