An efficient synthesis of new polyfunctional hexahydro pyrido[1,2-a]pyrazin-1-ones

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Chelate synthesis of derivatives of 7-diaminomethylene-4,5,6,7-tetrahydro-2h-indazol-6-one

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 525–526, February, 1991.     

A new approach to the synthesis of 3-amino- and 3-benzoylamino-5-aminoalkyl-1,2,4-triazoles

Nickel(II) acetylacetonate for the first time was shown to efficiently catalyze the addition of Boc-protected amino acid hydrazides to the nitrile group of benzoylcyanamide with the formation of the corresponding 3-benzoylamino-substituted 1,2,4-triazoles with the Boc-aminoalkyl group at position 5. A further modification of the latter led, depending on the conditions, to mono- or dihydrochlorides of 1,2,4-triazole-derived amines.     

Boron-chelate assisted synthesis of new bipyrazole derivatives

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Shortened single-walled carbon nanotubes modification as design of nano-structural drug delivery system for pharmaceutical substances

The synthesis of drug delivery system for pharmaceutical substances, represented by modified shortened single-walled carbon nanotubes, was realized. The synthesis was carried out via covalent grafting of water soluble linker to the graphene surface of single-walled carbon nanotubes, and resulted in stabilization of synthesized substance in water suspension.

     

Synthesis of new 4-(pyrimidin-4-yl)pyrazol-3-one derivatives

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Synthesis of diaminomethylidene derivatives of tetronic acid

Methyl 4-chloro-3-oxobutanoate reacts with benzoylcyanamide in the presence of catalytic amounts of Ni(acac)₂ to give the corresponding ketene N-benzoylaminal, which is transformed in boiling AcOH into 3-[(amino)(benzoylamino)methylidene]tetrahydrofuran-2,4-dione. Debenzoylation of the latter in the presence of EtONa in EtOH yields a N,N-unsubstituted diaminomethylidene derivative of tetronic acid. Cyclization of the adduct of methyl 4-chloro-3-oxobutanoate with benzoylcyanamide in the presence of triethylamine follows a different pathway leading to methyl 2-amino-1-benzoyl-4-oxo-4,5-dihydro-1H-pyrrole-3-carboxylate.     

3-[Amino(methylthio)methylene]pentane-2,4-dione in the synthesis of functionalized pyridines

New syntheses of functionalized pyridines from 3-[amino(methylthio)methylene]-2,4-pentanedionevia its boron chelates were proposed. The products of condensation of dimethylformamide dimethylacetal with the latter chelates were converted into 3-acetyl-2-methylthio-4-hydroxypyridine by refluxing in BuOH and into 1-alkyl-3-cyano-2-methyl-4-pyridones by treatment with primary amines.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1118–1121, June, 1995.This study was financially supported by the International Science Foundation (Grant M5Q 000).