Reaction Steps
To a stirred suspension of (X) (3.49 g, 12 mmol) in dry DCM (10 ml) was added dry triethylamine (10 ml). After 0.25 h. stirring a solution of phenyl isocyanate (2.14 g, 18 mmol) in dry DCM (10 ml) was added in one portion. The mixture was stirred for a further 16 h. then quenched with water (10 ml). The organic layer was collected and washed sequentially with water, 2M HCl, and water. The organic layer was dried over MgSO4 and purified by flash chromatography on silica gel eluting with 2:1 petrol 40/60:ethyl acetate (Rf=0.1) to yield (XI) (3.01 g, 67%) as a white solid; m.p. 129-132° C.; δH (DMSO-d, 200 MHz) 3.39 (q, 2H, J=5.1 Hz, NHCH2), 3.58 (t, 2H, J=5.0 Hz, OCH2CH2), 4.65 (s, 2H, OCH2Ar), 6.32 (t, 1H, J=5.2 Hz CH2NHC(O)NHAr), 6.90 (t, 1H, J=7.3 Hz, 4″-H), 7.24 (t, 2H, J=7.4 Hz, 3″-, 5″-H), 7.44 (d, 2H, J=7.6 Hz, 2″-, 6″-H), 7.56 (m, 4H, 3-, 5-, 3′-, 5′-H), 7.70 (m, 5H, 2-, 4-, 6-, 2″-, 6″-H) 8.63 (s, 1H, CH2NHC(O)NHAr) ppm; δC (DMSO-d, 400 MHz) 39.9 (CH2CH2NH), 70.4 (CH2CH2O), 72.1 (ArCH2O), 118.4 (2″-, 6″-C), 121.9 (4″-C), 128.1 (2-, 6-, 2′-, 6′-C), 129.4 (3″-, 5″-C), 130.4, 130.6 (3-, 5-, 3′-, 5′-C), 133.5 (4′-C), 136.9, 138.0 (1-, 1″-C), 141.3 (4-C), 144.4 (1″-C), 156.1 (N(H)C(O)NH), 196.3 (Ar2C(O)) ppm; max 3431 (N—Hstr), 1724 ((R(H)N)2C═Ostr), 1658 (Ar2C═Ostr) cm−1; m/z 375 [M+H]+ (5%), 397 [M+Na]+ (10%), 433 [M+MeCN+NH4]+ (100%); found 375.1703, C23H23N2O3 requires 375.1709.
