Synthesis of Cyclopropane Derivatives of Aspartic Acid by Thermal Decomposition of Substituted Pyrazolines

Thermal decomposition of substituted ¹- and ²-pyrazolines was used to obtain cyclopropane derivatives of aspartic and adipic acids.     

Synthesis and structure of nitrocyclohexenylcarboxylates

The diene condensation of 3-nitro- and 3-bromo-3-nitroacrylates with 2,3-dimethyl-1,3-butadiene and isoprene obtained under the reaction condition from 3-methyl-3-thiolene-1,1-dioxide was investigated. The formed 6-nitro-3-cyclohexenylcarboxylates were subjected to the intramolecular transformation (dehydration and dehydrohalogenation) to give the corresponding nitrocyclohexadienyl- and arylcarboxylates. The structure of the obtained compounds was established from the IR, ¹H NMR spectra and independent synthesis.     

Specific Features of the Reaction of 2-Nitro- and 2-Bromo-2-Nitroethenylphosphonates with Furan

Investigation of the reactions of phosphorylated 2-nitro- and 2-bromo-2-nitroethenes with furan showed that bis(2-chloroethyl) 2-nitroethenylphosphonate reacts with this heterocycle according to the pathway of diene condensation, while in the case of 2-bromo-2-nitroethenylphosphonate by two pathways, the complete diene synthesis accompanied by aromatization, and the electrophilic substitution at C²-atom of the furan with the subsequent partial dehydrohalogenation.     

3-nitro- and 3-bromo-3-nitroacrylates in reactions with phenyl azide

1,3-Dipolar cycloaddition of alkyl 3-nitro-and 3-bromo-3-nitroacrylates to phenyl azide gives regioisomeric alkyl 5(4)-nitro-1-phenyl-4,5-dihydro-1H-1,2,3-triazole-4(5)-carboxylates, the corresponding triazoles both with and without nitro group, and alkyl 3-nitro-1-phenylaziridine-2-carboxylates. Nitrotriazolecarboxylates were found to lose the ester moiety during chromatographic separation of the products on aluminum oxide. The structure of the products was determined on the basis of IR, ¹H NMR, and X-ray diffraction data.     

α-Nitro chalcones: Structure and reaction with pyrrole

According to the ¹H NMR, IR, and electronic absorption spectra and X-ray diffraction data, 2-aryl-1-benzoyl-1-nitroethenes have E configuration with predominant s-cis conformation, where the nitro group lies in the plane of the double carbon-carbon bond, while the carbonyl group deviates from that plane. Reactions of 2-aryl-1-benzoyl-1-nitroethenes with pyrrole and N-methylpyrrole gave the corresponding alkylation products at the C² atom in the heteroring.     

Reaction of bis(2-chloroethyl)-2-nitroethynylphosphonate with diazoacetic ester

Reactions of 1,3-dipolar cycloaddition of bis(2-chloroethyl)-2-nitroethenylphosphonate to methyl and ethyl diazoacetates proceed with the formation of a mixture of regioisomers of phosphorylated nitropyrazoline carboxylates that under the reaction conditions undergo isomeric transformations and denitration and afford a mixture of Δ¹- and Δ²-pyrazoline- and pyrazolecarboxylates. Structures of the synthesized substances are studied by the methods of IR and ¹H, ³¹P NMR spectroscopy and partially by X-ray structural analysis.