反应详情

温度

60 °C

Step-1: To a stirred solution of N—BOC 4-hydroxypiperidine (7.50 g, 0.0373 mol) in dry DMF (50 mL) was added 95% NaH solid (1.12 g, 0.047 mol) in small portions over 5-10 min. After the evolution of gas had subsided, 4-chlorobenzonitrile (5.18 g, 0.0376 mol) was added in one portion, and the mixture heated to 60° C. overnite. The mixture was diluted with tBuOH (about 5 mL) and neutralized to pH 7 using glacial AcOH. The DMF was concentrated in vacuo, and the crude product chromatographed over a 120 g Isco column using 20% DCM/hexanes to DCM as an eluent to get step-1 product, 4-(4-cyanophenoxy)piperidine-1-carboxylic acid tert-butyl ester, as a white solid (10.33 g, 92%): LC Rt=3.40; 1H NMR (300 MHz, CDCl3) δ 1.46 (s, 9H), 1.74-1.80 (m, 2H), 1.89-1.97 (m, 2H), 3.40 (ddd, J=10.3, 7.6, 4.0 Hz, 2H), 3.68 (ddd, J=10.3, 8.7, 4.0 Hz, 2H), 4.55 (septet, J=3.6 Hz, 1H), 6.94 (d, J=9.0 Hz, 2H), 7.58 (d, J=9.0 Hz, 2H).

1. concentrationThe DMF was concentrated in vacuo
2. customthe crude product chromatographed over a 120 g Isco column