R. I. Baichurin

Synthesis of pyrrole- and indole-containing nitropropanoates on the basis of β-heteryl-α-nitroacrylates

Synthetic approach to β-furyl- and β-thienyl-α-nitroacrylates was modified. It was established that these nitroethenes react with pyrrole, N-methylpyrrole, and substituted indole derivatives in the absence of catalyst to afford products of the alkylation of pyrrole C2 and indole C3 reaction sites. A possibility of this reaction to proceed under “dry reaction” condition on a silicagel surface was shown.

Synthesis and structure of β-aryl-α-nitroacrylates

The method for preparation of ethyl α-nitrocinnamates by nitroacetic acid ester alkenylation with aromatic aldehydes in the presence of acetic acid and β-alanine has been modified. Structures of the prepared compounds have been proved by electronic, IR, 1H, and 13C-{1H} NMR spectroscopy (including heteronuclear correlation experiments 1H-13C HMQC and 1H-13C HMBC). In solution these compounds exist in the form of Z-isomer; the Z⇄E isomerization is observed in the case of the compound containing strong electron-donor group [N(CH3)2] at benzene ring.

Aryl(hetaryl)-containing gem-cyanonitroethenes: Synthesis, structure, and reactions with 2,3-dimethyl-1,3-butadiene

Methods of aryl(hetaryl)-substituted gem-cyanonitroethenes preparation are summarized, and the products structure elucidation by means of 1H, 13C NMR, IR, and UV spectroscopy methods is discussed. E-Configuration of the compounds obtained has been proved. Reaction of the studied gem-cyanonitroethenes with 2,3-dimethyl-1,3-butadiene affords the diene synthesis adducts–6-aryl(hetaryl)-3,4-dimethyl-1-nitro-1-cyano- 3-cyclohexenes.

Geminal acylnitrostyrenes in the reaction with ortho-aminothiophenol

The synthesis of previously unknown 2,3- and 2,5-dihydro-1,5-benzothiazepines sontaining nitro group was performed by the easy sondensation of geminal acylnitrostyrenes with the o-aminothiophenol. The structure of the obtained sompounds was studied by physicochemical methods. By X-ray diffraction analysis the geometry and structural parameters of 4-methyl-3-nitro-2-phenyl-2,3-dihydro-1,5-benzothiazepine were determined.

3-(Nitromethyl)-3,4-dihydroquinoxalin-2(1H)-ones: synthesis and structure

Reactions of ethyl 3-nitroacrylate with o-phenylenediamine and its substituted derivatives were used for the synthesis of 3-(nitromethyl)-3,4-dihydroquinoxalin-2(1H)-ones, followed by structural characterization. These compounds were found to undergo elimination of nitromethane, leading to quinoxalin-2(1H)-ones.

Complexes of Ir(III) and Pt(II) with cyclometallated 2-phenylbenzothiazole and chelating diethyldithiocarbamate and O-ethyldithiocarbonate ions: Structures and optical and electrochemical properties

It is shown by X-ray diffraction analysis, IR spectroscopy, and 1Н, 13С{1H}, and 195Pt NMR spectroscopy that the Pt(II) and octahedral Ir(III) complexes with metallated 2-phenylbenzothiazole and chelating diethyldithiocarbamate and O-ethyldithiocarbonate ions have the square and cis-C,C structure, respectively. The highest occupied and lowest unoccupied molecular orbitals of the complexes determining their long-wavelength absorption, phosphorescence, and one-electron oxidation and reduction are assigned to those predominantly localized on the mixed p(S)/d(M) and π* orbitals of the metallated ligand. The cathodic shift of the oxidation voltammogram and the bathochromic phosphorescence shift of the Pt(II) complex with the О-ethyldithiocarbonate ion are attributed to the enhanced donor–acceptor interaction of the donor S atoms of the ligand with Pt(II). The structural data are deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC nos. 1058768 (Ia) and 1058767 (IIb)).

Reaction of α-nitroacrylates with acetylacetone

α-Nitrocinnamic acid esters I–III and their thiophene-containing analog IV successfully react with an equimolar amount of acetylacetone in anhydrous methanol in the presence of sodium methoxide at 0– 5°C to give addition products V–VIII. On heating in methanol in the presence of triethylamine (60°C, 2 h), adducts V and VII are converted into the corresponding tetrasubstituted dihydrofurans IX and X. Presumably, the latter are formed via intramolecular O-alkylation of the enol form of V–VIII with elimination of nitrous acid. Compound X was also synthesized in one-pot mode by heating α-nitroacrylate III with acetylacetone in acetonitrile in the presence of triethylamine (60°C, 2 h). The structure of adducts V–VIII was confirmed by their elemental compositions and IR and H NMR spectra. The IR spectra of V–VIII contained strong absorption bands due to stretching vibrations of the acetyl and ester carbonyl groups (1700– 1710, 1740–1755 cm) and unconjugated nitro group (1560–1565, 1360 cm). According to the H NMR data, compounds V–VIII were isolated as single diastereoisomers. In the H NMR spectrum of V in CDCl3, the HA, HB, and HX protons gave rise to an ABX spin system, and their signals were located at δ 5.47, 4.57, and 4.59 ppm, respectively. Signals at δ 1.24 (t) and 4.17 ppm (q) were assigned to the ester ethoxy group, and methyl protons in the acetyl fragments resonated at δ 1.86 and 2.25 ppm. Aromatic proton signals were observed at δ 7.25–7.30 ppm (m).

Alkyl 3-nitroacrylates: Synthesis and reactions with cyclohexane-1,3-diones and Meldrum’s acid

A modified procedure was proposed for the synthesis of alkyl 3-nitroacrylates by nitroiodination of alkyl acrylates and subsequent dehydroiodination of iodonitropropanoates with triethylamine. Alkyl 3-nitroacrylates reacted with cyclohexane-1,3-dione, dimedone, and Meldrum’s acid in the presence of N,N,N-tri-methylanilinium hydroxide (Rodionov’s catalyst) in anhydrous methanol to give the corresponding Michael adducts.

Geminally Activated Nitroethenes in Reactions with Sodium Azide. Synthesis of Functionalized 1,2,3-Triazoles

Reactions of geminally activated alkoxycarbonyl(acetyl, benzoyl, cyano)nitroethenes with sodium azide provided a series of functionally substituted 1,2,3-triazoles. Their structure was characterized by IR, 1H, and 13C–{1H} NMR spectroscopy.

Reactions of 1-Amino-2-nitroguanidine with 2-Aryl(hetaryl)-1-nitro-1-ethoxycarbonyl(benzoyl)ethenes

Reactions of 1-amino-2-nitroguanidine with 2-aryl(hetaryl)-1-nitro-1-ethoxycarbonyl(benzoyl)-ethenes proceed via initial formation the aza-Michael product, are accompanied by liberation of nitroacetic ester (or nitroacetophenone), and result in N-aryl(hetaryl)methylidene-N-(2-nitroguanidino)amines.