L. S. Vasil'ev

Chelate synthesis of 3-ethoxycarbonyl-4-hydroxy-2-trifluoromethylpyridine from ethyl acetoacetate and trifluoroacetonitrile

Ethyl 2-acetyl-3-amino-4,4,4-trifluoro-2-butenoate was synthesized by treatment of ethyl acetoacetate with CF3CN in the presence of Ni(acac)2. Condensation of the diphenylboron chelate of the former with dimethylformamide dimethylacetal followed by refluxing in ethanol yielded 3-ethoxycarbonyl-4-hydroxy-2-trifluoromethylpyridine.

Boron chelates with 5,5,5-trifluoro- and 5,5,5-trichloro-4-aminopent-3-en-2-ones

Boron chelates were obtained by the reaction of butoxy(butylthio)diphenylborane with 5,5,5-trifluoro(trichloro)-4-aminopent-3-en-2-one, and their reactions with primary amines were investigated. β-Diiminate complexes of boron with trifluoro- and trichloromethyl groups were synthesized.

CHELATE SYNTHESIS OF FUNCTIONALLY SUBSTITUTED 2-TRICHLOROMETHYLPYRIDINES

We are proposig new schemes for the synthesis of 2-trichloromethylpyridines via chelate-type boron compounds. We found that the diphenylboron chelate (2) prepared from 4-amino-5,5,5-trichloro-3-penten-2-one (1) reacts with dimethylformamide dimethylacetal to give the condensation product, viz, complex (3). Boiling the latter in BuOH results in its cyclization to pyridine (4) (Scheme 1). Unexpectedly, it turned out that, when treated with Ph2BOMe , the C-acetyl derivative of enaminone 1, 4-amino3-acetyl-5,5,5-trichloro3-penten2-one (5), behaves as a 13-diketone-type chelating ligand, rather than an enaminone-type ligand, and affords complex (6), according to the 1H and 13C N M R spectra. The latter reacts with Me2NCH(OMe)2 at -20 ~ to yield the condensation product (7), which is smoothly converted to pyridine (8) when boiled in MeOH (Scheme 2). The structures of chelates 3, 6, and 7 and pyridines 4 and 8 were confirmed by IH and t3C N M R and IR spectroscopy and mass spectrometry. The elemental analysis data correspond to the calculated values. The 4-pyridone ~ 4-hydroxypyridine equilibria for compounds 4 and 8 are shifted to hydroxypyridines, which is indicated by the signal at -110 ppm in the 170 N M R spectrum.

Synthesis of functional derivatives of trifluoromethylpyrimidines from acetylacetone, trifluoroacetonitrile, and aryl isocyanates

Abstract1, 1,1-Trifluoro-2-amino-3-acetyl-2-penten-4-one was obtained by the addition of acetylacetone to trifluoroacetonitrile in the presence of catalytic amounts of nickel acetylacetonate. The reaction of 1,1,1-trifluoro-2-amino-3-acetyl-2-penten-4-one with aryl isocyanates gave 1-aryl-5-acetyl-6-methyl-4-trifluoromethyl-1H-pyrimidin-2-ones.

Various approaches to the use of 3-acetyl-2-amino-4-hydroxy-1,3-pentadienecarbonitrile in heterocyclic synthesis

Two approaches to the use of 3-acetyl-2-amino-4-hydroxy-1,3-pentadienecarbonitrile (1) in heterocyclic synthesis are considered. A method for preparing 3-acetyl-4-amino-5-cyano-2-methylpyridine directly from1 andN,N-dimethylformamide dimethylacetal (DMF DMA) was proposed, together with a synthetic route to 2-(2-amino-3-cyano-6-hydroxy-phenyl)-8-cyano-5-hydroxy-4-methylquinoline based on the transformation of hydroxyvinyl ketone1 into its diphenylboron chelate and condensation of the latter with DMF DMA.

Synthesis of 4-hydroxy- and 3-aryl-4-amino- 2-trifluoromethylpyridines

Schemes for synthesizing 3-acyl-4-amino(hydroxy)-2-trifluoromethylpyridines from 3-acyl 4-amino-5,5,5-trifluoro-3-penten-2-ones via their diphenylboron chelate complexes have been suggested.

CHELATE SYNTHESIS OF 2,2'-BIPYRIDIN-4-ONE

A method for the synthesis of 2,2′-bipyridin-4-one from 4-amino-4-(2-pyridyl)-but-3-en-2-onevia its diphenylboron, chelates was proposed.

Boron chelate complexes with some enaminones and diketones containing the pyridine fragment and their mutual transformations in solutions

The interaction of Ph2BOBu with 4-amino-4-(2-pyridyl)-3-buten-2-one, 3-amino-1-(2-pyridyl)-2-buten-I-one, and 1-(2-pyridyl)butan-1,3-dione was investigated. The 5- or 6-membered chelates withN,O- orN,N-coordination of boron are formed depending on the pyridine-containing ligand structure. These complexes are capable of mutual transformation in solutions.

3-Acetyl-2-amino-4-hydroxy-1,3-pentadienecarbonitrile:E,Z-isomerism and the ability to form chelates

The Ni acetylacetonate-catalyzed addition of acetylacetone to malononitrile was shown to afford 3-acetyl-2-amino-4-hydroxy-1,3-pentadienecarbonitrile. The diphenyl boron chelate of the latter with a β-diketone-type structure was obtained.E,Z-isomerism of the chelate and the free ligand were investigated. TheZ-isomers were found to dominate in low polarity solvents.