The crystal structure of (4S)-5-(2-methoxy-2-oxoethylamino)-5-oxo-4-(3,4,5- trimethoxybenzamido) pentanoic acid 5 (C18H24N2O9, Mr = 412.39) has been determined by single- crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 27.665(9), b = 5.1444(16), c = 13.907(4) ?, β = 98.401(5)o, V = 1958.0(11) ?3, Z = 4, Dc = 1.399 g/cm3, μ = 0.113 mm-1, F(000) = 872, R = 0.0606 and wR = 0.1405 (I > 2σ(I)). The results con- firmed that 5 could be assigned to the tautomeric form. The intermolecular hydrogen bonds between O(5)–H(5)…O(7), N(2)–H(2)…O(6) and N(1)–H(1)…O(4) have been observed.
As an important intermediate to study cyclin-dependent kinase （CDK） inhibitors, 2-ary1-8-（piperidin-4-y1）-5,7-dimethoxy-4H- chromen-4-one derivatives were prepared using 13-diketone route with low yield. In our study, chalcone route has been investigated and the result suggested that the benzaldehydes substituted with electron-donating group give much better yield than β-diketone route. This new method will be an efficient way to start further research on new anticancer flavonoids.
An efficient way to coupling amine with the derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid was reported in this paper. We have found that the synthesis of derivatives is problematic with the commonly used DCC/HOBT method. As a substitute, the mixed anhydride method was adopted. A series of 6-（3-nitroguanidino）hexanamidopyrrolidine derivatives were prepared with this method.
