... European Journal of Medicinal Chemistry. ... b Leiden/Amsterdam Centre for Drug Research, Division of Medicinal Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The ... 1 H NMR (δ in ppm; DMSO-d 6 ): 14.3 (br*, 1H, NH); 8.45–8.35 (dd, 1H (6) ; J = 4.8, 1.6 ...