Muhammet Yıldırım

Synthesis and stereochemistry of some novel dihydropyrrolo[3,4-c]pyrazoles

Eleven novel dihydropyrrolo[3,4-c]pyrazole derivatives were obtained by the reaction of chiral (1R)-N-(1-phenylethyl)maleimide and C,N-aryl-substituted nitrilimines. The reaction afforded the cycloadducts as a regioisomeric mixture which can be separable in some cases. The structure and stereochemistry of cycloadducts were assigned on the basis of infrared (IR), 1H and 13C nuclear magnetic resonance (NMR), mass and X-ray spectra, optical rotation measurements, and CHN analyses.Graphical Abstract.

An efficient one-pot synthesis of 5-(substituted amino)-1,2,4-thia- and - oxa-diazoles

A general protocol for the synthesis of 5-(substituted amino)-1,2,4-thiadiazoles by the cyclocondensation reaction of amidoximes with N-substituted thioureas in the presence of KF/Al2O3, and of 5-(cyclohexylamino)-1,2,4-oxadiazoles with DCC in the presence of KF/Al2O3 and thiourea, is described. The structures of the new compounds were elucidated by spectroscopic and physical data, and the crystal structure determination by X-ray diffraction of three examples.

A rapid access to novel and diverse 3-oxothiazolo[3,2-c]pyrimidine-8-carboxylates using multicomponent Mannich cyclisation reactions.

An efficient synthesis of novel 3-oxotetrahyrothiazolo[3,2-

(3aR,6aR)-1-Phenyl-5-[(R)-1-phenyl­ethyl]-3-[4-(trifluoro­meth­yl)phen­yl]-1,6a-dihydro­pyrrolo[3,4-c]pyrazole-4,6(3aH,5H)-dione

c

Regioselective 1,3-dipolar cycloaddition of nitrilimines to 2-methyl-2-vinyl oxirane

c]pyrimidine-8-carboxylate derivatives was developed by reacting 4-oxothiazolidines with formaldehyde and amines under very mild conditions. A variety of novel thiazolopyrimidine carboxylates were attained rapidly by double Mannich/intramolecular cyclisation reactions in very good yields.

A rapid and efficient protocol for the synthesis of novel nitrothiazolo[3,2-c]pyrimidines via microwave-mediated Mannich cyclisation

In the title molecule, C27H23N3O4, the two central five-membered rings form a dihedral angle of 63.66 (4)°. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = −0.10 (7).

Base-promoted new C--C bond formation: an expedient route for the preparation of thiazolo- and imidazolo-pyridinones via Michael addition

In the title molecule, C26H20F3N3O2, the two central five-membered rings form a dihedral angle of 62.94 (8)°. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = −0.05 (11). Notable intra- and intermolecular contacts include C—H⋯O and C—H⋯π(arene) hydrogen bonds.

Synthesis, UV–Vis spectra, and Hammett correlation of some novel bis(dihydropyrrolo[3,4- c ]pyrazoles)

Abstract A simple and efficient protocol for one-pot three-component synthesis of structurally diverse dialkyl 2-amino-3-cyano-4H-chromen-4-ylphosphonates from the condensation of salicylaldehydes, malononitrile, and trialkyl phosphite using silver nanoparticles as catalyst in ethanol at reflux has been developed. Selected new compounds were evaluated for their antioxidant activity by free radical screening using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Among the compounds employed, 5a, 5 b, and 5 h showed promising DPPH radical scavenging activities compared to the experimental standards at low concentration (100 µg/mL) after 24 h incubation. Graphical Abstract