152093-83-9Relevant academic research and scientific papers
New Intramolecular α-Arylation Strategy of Ketones by the Reaction of Silyl Enol Ethers to Photosensitized Electron Transfer Generated Arene Radical Cations: Construction of Benzannulated and Benzospiroannulated Compounds
Pandey, Ganesh,Karthikeyan,Murugan
, p. 2867 - 2872 (2007/10/03)
Efficient intramolecular α-arylation of ketones is achieved by the reaction of silyl enol ethers to photosensitized electron transfer (PET) generated arene radical cations. The arene radical cations are generated by one-electron transfer from the excited state of the methoxy-substituted arenes to ground-state 1,4-dicyanonaphthalene (DCN). This arylation strategy has provided the unique opportunity of constructing five- (23), six- (18), seven- (25) and eight-membered (27) benzannulated as well as benzospiroannulated (34) compounds. The explanation for the formation of 27 has been advanced by considering the proximity between the arene radical cation and silyl enol ether due to the self-coiling in the aqueous environment.
2,4-Diaminothienopyrimidine Analogues of Trimetrexate and Piritrexim as Potential Inhibitors of Pneumocystis Carinii and Toxoplasma gondii Dihydrofolate Reductase
Rosowsky, Andre,Mota, Clara E.,Wright, Joel E.,Freisheim, James H.,Heusner, James J.,et al.
, p. 3103 - 3112 (2007/10/02)
A series of eight previously undescribed 2,4-diaminothienopyrimidine analogues of the potent dihydrofolate reductase (DHFR) inhibitors trimetrexate (TMQ) and piritrexim (PTX) were synthesized as potential drugs against Pneumocystis carinii and Toxoplasma gondii, which are major causes of severe opportunistic infections in AIDS patients. 2,4-Diamino-5-methyl-6-(aryl/aralkyl)thienopyrimidines with 3,4,5-trimethoxy or 2,5-dimethoxy substitution in the aryl/aralkyl moiety and 2,4-diamino-5-(aryl/aralkyl)thienopyrimidines with 2,5-dimethoxy substitution in the aryl/aralkyl moiety were obtained by reaction of the corresponding 2-amino-3-cyanothiophenes with chloroformamidine hydrochloride.The aryl group in the 5,6-disubstituted analogues was either attached directly to the hetero ring or was separated from it by one or two carbons, whereas the aryl group in the 5-monosubstituted analogues was separated from the hetero ring by two or three carbons. 2-Amino-3-cyano-5-methyl-6-(aryl/alkyl)thiophene intermediates for the preparation of the 5,6-disubstituted analogues were prepared from ω-aryl-2-alkylidenemalononitriles and sulfur in the presence of a secondary amine, and 2-amino-3-cyano-4-(aryl/aralkyl)thiophene intermediates for the preparation of the 5-monosubstituted analogues were obtained from ω-aryl-1-chloro-2-alkylidenemalononitriles and sodium hydrosulfide.Synthetic routes to the heterofore unknown ylidenemalononitriles, and the ketone precursors thereof, were developed.The final products were tested in vitro as inhibitors of DHFR from Pneumocystis carinii, Toxoplasma gondii, rat liver, beef liver, and Lactobacillus casei.A select number of previously known 2,4-diaminothienopyrimidines lacking the 3,4,5-trimethoxyphenyl and 2,5-dimethoxyphenyl substitution pattern of TMQ and PTX, respectively, were also tested for comparison.None of the compounds was as potent as TMQ or PTX, and while some of them showed some selectivity in their binding to Pneumocystis carinii and Toxoplasma gondii versus rat liver DHFR, this effect was not deemed large enough to warrant further preclinical evaluation.
