... Heterocyclic Chem., 29, 1161 (1992 ... Chemical shifts are reported in ò (ppm) and measured relatively to the central peak of the solvent (deuter- iochloroform = 1385 Hz ... diethyl ether, mp 174-175°, 66% yield; "H nmr (deuteriochloroform): 4.0 (br s, IH, NH), 4.79 (d,2H,CH2,J = 1.8 Hz ...