same solvent was measured by the conductometric method. The rates of both O- and C-ethylations of the enolate ion were measured. The pKa of the corresponding β-ketoesters were measured in DMF. The reactivity of the enolates investigated was found to be proportional to their basicity.
Copper(II) Triflate Catalyzed Amination and Aziridination of 2-Alkyl Substituted 1,3-Dicarbonyl Compounds
作者:Thi My Uyen Ton、Ciputra Tejo、Diane Ling Ying Tiong、Philip Wai Hong Chan
DOI:10.1021/ja301415k
日期:2012.5.2
A method to prepare alpha-acyl-beta-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu(OTf)(2) + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhI=NTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic C-H bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the beta-aminatecl adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2-3 equiv was discovered to result in preferential formal aziridination of the C-C bond of the 2-alkyl substituent of the starting material and formation of the aziridine product.
Design, Synthesis, and Pharmacological Evaluation of Monocyclic Pyrimidinones as Novel Inhibitors of PDE5
Cyclic nucleotide phosphodiesterase type 5 (PDES) is a prime drug target for treating the diseases associated with a lower level of the cyclic guanosine monophosphate (cGMP), which is a specific substrate for PDE5 hydrolysis. Here we report a series of novel PDE5 inhibitors with the new scaffold of the monocyclic pyrimidin-4(3H)-one ring developed using the structure-based discovery strategy. In total, 37 derivatives of the pyrimidin-4(3H)-ones, were designed, synthesized, and evaluated for their inhibitory activities to PDES, resulting in 25 compounds with IC50 ranging from 1 to 100 nM and 11 compounds with IC50 ranging from 1 to 10 nM. Compound 5, 5,6-diethyl-2[2-n-propoxy-5-(4-methyl-1-piperazinylsulfonyl)phenyl]pyrimid-4(3H)-one, the most potent compound, has an excellent IC50 (1.6 nM) in vitro and a good efficacy in a rat model of erection. It thus provides a potential candidate for the further development into a new drug targeting PDE5.