Cesium carbonate → Tert-butyl N-[(4-cyanophenyl)methyl]-N-[(2-methylpropan-2-yl)oxycarbonyl]carbamate

Participants

Reaction Steps

4-(Bromomethyl)benzonitrile (5 g, 25.5 mmoles) and di-tert-butyliminodicarboxylate (5.54 g, 25.5 mmoles) were dissolved in anhydrous THF (50 mL) and cesium carbonate (16.62 g, 25.5 mmoles) and lithium iodide (170.5 mg, 1.275 mmoles) were added. The mixture was stirred at 70° C. for 23h and the reaction was worked up as described in Preparative Example 244, Step B above. The residue was chromatographed on a silica gel column (50×5 cm) using 5% ethyl acetate in hexane as the eluant to give 4-(di-tert-butoxycarbonylaminomethyl)benzonitrile (7.07 g, 83%): FABMS: m/z 333.2 (MH+); HRFABMS: m/z 333.1816 (MH+). Calcd. for C18H25N2O4: m/z 333.1814; δH (CDCl3) 1.45 (18H, s, —COOC(CH3)3), 4.81 (2H, s, CH2), 7.37 (2H, d, Ar—H) and 7.62 ppm (2H, d, Ar—H); δC (CDCl3) CH3: 28.1, 28.1, 28.1, 28.1, 28.1, 28.1; CH2: 49.2; CH: 127.8, 127.8, 132.3, 132.3; C, 83.2, 83.2, 111.1, 118.9, 144.1, 152.4, 152.4.

Provenance & Evidence