Iridium-catalyzed asymmetric ring-opening of oxabenzonorbornadienes with N-substituted piperazines was described. The reaction afforded the corresponding ring-opening products in high yields and moderate enantioselectivities in the presence of 2.5 mo...
We report a short synthetic route for synthesizing 2,3-substituted piperazine acetic acid esters. Optically pure amino acids were efficiently converted into 1,2-diamines that could be utilized to deliver the title 2,3-substituted piperazines in five...
The reaction of 3,5-dichloro-4H-1,2,6-thiadiazin-4-one with (R) and (S)-1,3-dimethylpiperazines (1 equiv), in THF, at ca. 20 °C gives (R) and (S)-3-chloro-5-(2,4-dimethylpiperazin-1-yl)-4H-1,2,6-thiadiazin-4-ones in 70% and 68% yields, respectively....
Tadalafil is a clinically approved phosphodiesterase-5 inhibitor for the treatment of erectile dysfunction and pulmonary arterial hypertension. It contains two chiral carbons, and the marketed isomer is the 6R, 12aR isomer with a methyl substituent o...
Five new diketopiperazine derivatives, (3Z,6E)-1-N-methyl-3-benzy lidene-6-(2S-methyl-3-hydroxypropylidene)piperazine-2,5-dione (1), (3Z,6E)-1-N-methyl-3-benzylidene-6-(2R-methyl-3-hydroxypropylidene)piperazine-2,5-dione (2), (3Z,6Z)-3- (4-hydroxyben...
Determination of psychoactive substances (PAS) and/or their metabolites in surface waters is crucial for environmental risk assessment, and disclosure of their enantiomeric fractions (EF) allows discrimination between consumption, direct disposal, an...
In order to better understand the chiral recognition mechanisms of positively charged cyclodextrin (CD) derivatives, the synthesis, the pKa determination by 1H nuclear magnetic resonance (NMR)-pH titration and a comparative chiral capillary electroph...
Reaction of NiCl2∙6H2O, d-camphoric acid (d-H2cam), and N,N′-bis(pyraz-2-yl)piperazine (bpzpip) in pure water at 150 °C afforded a novel nickel(II) coordination layer, [Ni4(d-cam)2(d-Hcam)4(bpzpip)4(H2O)2] (1), under hydro(solvo)thermal conditions. S...