A Facile Approach to Bis(isoxazoles), Promising Ligands of the AMPA Receptor

A convenient synthetic approach to novel functionalized bis(isoxazoles), the promising bivalent ligands of the AMPA receptor, was elaborated. It was based on the heterocyclization reactions of readily available electrophilic alkenes with the tetranitromethane-triethylamine complex. The structural diversity of the synthesized compounds was demonstrated. In the electrophysiological experiments using the patch clamp technique on Purkinje neurons, the compound 1,4-phenylenedi(methylene)bis(5-aminoisoxazole-3-carboxylate) was shown to be highly potent positive modulator of the AMPA receptor, potentiating kainate-induced currents up to 70% at 10−11 M.

A convenient synthetic approach to obtain meso-Uracil-BODIPY

An effective and convenient protocol for the synthesis of 1-Substituted-6-formyl-uracil derivatives has been developed. A three-step sequence has allowed obtaining new 6-Formyl uracil with various substituents at N-1, in large quantity using low-cost precursors. Uracil molecules containing an aldehyde group have been used as useful precursors for the preparation of meso-(1’-Substituted-6’-uracil)-BODIPY derivatives. In this way, regioselectively functionalized BODIPYs directly connected to a nucleobase were prepared in yields from 30 to 45%. MALDI-TOF mass spectrometry, NMR, UV-vis absorption, steady-state and time-resolved fluorescence spectroscopies have been used to characterize the structures and the spectroscopic/photophysical properties of the obtained dyes.

α-(Imino)pyridyldifluoroethyl Phosphonates: Novel Promising Building Blocks in Synthesis of Biorelevant Aminophosphonic Acids Derivatives

A convenient synthetic approach to previously unknown NH-iminophosphonates bearing 2-, 3-, and 4-pyridyldifluoromethyl groups at the imine carbon atom was developed. The synthetic potential of these novel building blocks was demonstrated by their conversion into highly functionalized acyclic and heterocyclic aminophosphonates and phosphonic acids combining in their structure biorelevant aminophosphonic fragment, difluoromethyl group, and pyridyl, piperidyl, thiazolidin-4-one, or thiazidinan-4-one heterocyclic moieties in a single molecular platform.

Synthesis and Photochromic Properties of a Novel Chromene Derivative

A convenient synthetic approach to a novel 2,2-diphenyl-2H-chromene derivative is developed starting from vanillin or acetovanillone. The photochromic properties of the resulting chromene are studied. The kinetic characteristics of this compound show its potential for the design of new efficient DNA intercalators.

The preparative synthetic approach to 4-(trifluoromethoxy)piperidine and 4-(trifluoromethoxymethyl)piperidine

Aim. To develop a convenient synthetic approach for the preparation of multigram amounts of 4-(trifluoromethoxy)-piperidine and 4-(trifluoromethoxymethyl)piperidine – promising building blocks for medicinal chemistry.Results and discussion. 4-(Trifluoromethoxy)piperidine (8.4 g) and 4-(trifluoromethoxymethyl)piperidine (12.9 g) were synthesized in 5 stages starting from 4-hydroxypiperidine (the overall yield 40 %) and 4-(hydroxymethyl)piperidine (the overall yield 13.5 %), respectively.Experimental part. The first stage of the synthetic strategy was acylation of 4-hydroxypiperidine with benzoyl chloride. N-benzoyl-4-hydroxypiperidine obtained was transformed to N-benzoyl-4-(trifluoromethoxy)piperidine in two stages using the Hiyama method (the synthesis of the corresponding S-methyl xanthate with the subsequent desulfurization/fluorination using N-bromosuccinimide and Olah’s reagent). Then the N-benzoyl group was reduced to benzyl one, which was removed using 1-chloroethyl chloroformate. The similar approach was applied to the synthesis of 4-(trifluoromethoxymethyl)piperidine starting from 4-(hydroxymethyl)piperidine. The structure and composition of the compounds synthesized were confrmed by 1Н, 13C and 19F NMR spectroscopy,mass-spectrometry and elemental analysis.Conclusions. The synthetic approach developed is a convenient method for the multigram preparation of4-(trifluoromethoxy)piperidine and 4-(trifluoromethoxymethyl)piperidine and can be used for the synthesis of other secondary amines containing the CF3O-group.Key words: fluorination; trifluoromethoxy group; xanthate; piperidine; protection group

Conversion of N-acyl amidines to amidoximes: a convenient synthetic approach to molnupiravir (EIDD-2801) from ribose

A method for the preparation of molnupiravir (EIDD-2801) via regioselective conversion of an N-acyl-nucleoside intermediate, generated through stereoselective glycosylation of protected ribose and N4-acetyl cytosine, to an amidoxime.

Synthesis of meso-2,2’-bipyridyl-substituted calix[4]arenes and their response to metal cations

A convenient synthetic approach to meso-substituted with 2,2’-bipyridine and 1-(pyridin-2-yl)isoquinoline residues calix[4]arenes is reported. This approach involves the reaction of generated in situ 2-lithio-calix[4]arene with 1,2,4-triazine precursor with the following aromatization of the obtained adduct, and the aza-Diels-Alder reaction of the 1,2,4-triazinyl-substituted calix[4]arene with 2,5-norbornadien or in-situ generated 1,2-dehydrobenzene. The UV/fluorescence response of thus obtained meso-pyridyl-substituted calix[4]arenes to metal cations is studied.

A convenient synthetic approach to 5-(het)arylhydrazine substituted 1,2,4-triazines

A convenient synthesis of 1,2,4-triazines bearing the moieties of (hetero)arylhydrazines at the position of C5 of the 1,2,4-triazine core is reported.