Reactions of <Emphasis Type="Italic">N</Emphasis>-alkyl- and <Emphasis Type="Italic">N</Emphasis>-aryltrihalogenoacetamides with phosphorus pentachloride

In the study of reactions of N-alkyl- and N-aryltrihalogenoacetamides with PCl₅, it was demonstrated for the first time that 3-alkyl(aryl)-2,2,2,4 tetrachloro-4-trihalomethyl-1,3,2-λ⁵-oxazaphosphetanes are intermediates in the synthesis of trihaloacetimidoyl chlorides. According to quantum-chemical calculations, acyclic N-tetrachlorophosphoranes, which are the primary products in the reactions of trihaloacetamides with PCl⁵, undergo rapid cyclization into the corresponding phosphorates and subsequent 1,3-chlorotropic migration gives rise to oxazaphosphetanes with the five-coordinate P atom.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 739-744, March, 2005.     

Reactions of <Emphasis Type="Italic">N</Emphasis>-acetyltrifluoroacetamide with chlorophosphites

Reactions of N-acetyltrifluoroacetamide with chlorophosphites give rise to O-phosphorylated N-trifluoroacetoacetylimidates, which transform into α-phosphorylated vinylamides of trifluroacetic acid as a result of vinylphosphite-vinylphosphonate rearrangement. On the basis of nonempirical calculations data the reaction protocol of N-acetyltrifluoroacetamide with chlorophosphites was suggested.     

Reactions of 1-bromo-1-nitro-3,3,3-trichloropropene with <Emphasis Type="Italic">O</Emphasis>- and <Emphasis Type="Italic">N</Emphasis>-nucleophiles

Reactions of 1-bromo-1-nitro-3,3,3-trichloropropene with alcohols, benzidine and o-, m-, and p-phenylenediamines was investigated and the reaction conditions were developed. The alkoxylation and amination products and an unusual nitrogen-containing bis-aziridine were obtained; their structures were characterized by the spectral (IR, ¹H, ¹³C NMR, HMQC, and HMBC) methods.     

Synthesis of new <Emphasis Type="Italic">N</Emphasis>-aminoglycosides based on halo-substituted <Emphasis Type="Italic">p</Emphasis>-phenylenediamines and <Emphasis Type="Italic">p</Emphasis>-aminophenols

Condensation of the monosaccharides D-glucose and D-galactose with synthesized halo-substituted p-phenylenediamines and 4-amino-2,6-dibromophenol was studied. It was found that glycosylation occurred only at the 4-amino group that was sterically unhindered by the halogen atom. The position of the aglycon in the glycoside was established by PMR spectroscopy.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-Arylsulfonyl-α-thienylglycines from <Emphasis Type="Italic">N</Emphasis>-(2,2,2-Trichloro-1-thienylethyl)arenesulfonamides

Reactions of N-(2,2,2-trichloroethylidene)arenesulfonamides with thiophene, 2-chlorothiophene, and 2,5-dichlorothiophene, as well as of N-(2,2,2-trichloro-1-hydroxyethyl)arenesulfonamides with 2-chlorothiophene, lead to formation of the corresponding N-(2,2,2-trichloro-1-thienylethyl)arenesulfonamides. Alkaline hydrolysis of the latter occurs selectively at the trichloromethyl group to give N-arylsulfonyl-α-thienylglycines.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 93–96.Original Russian Text Copyright © 2005 by Aizina, Rozentsveig, Ushakova, Levkovskaya, Mirskova.     

Reductive Acylamination of Pyridine <Emphasis Type="Italic">N</Emphasis>-Oxide with Aminopyridines and Their <Emphasis Type="Italic">N</Emphasis>-<Emphasis Type="Italic">p</Emphasis>-Tolylsulfonyl Derivatives

Pyridine N-oxide reacts with 2- and 3-aminopyridines and their N-p-tolylsulfonyl derivatives in alkaline medium in the presence of p-toluenesulfonyl chloride to give N-p-tolylsulfonyl-2,2′- and 2,3′-dipyridylamines, respectively, as a result of reductive acylamination. In the reactions with 4-aminopyridine and 4-p-tolylsulfonyl-aminopyridine, their N-p-tolylsulfonyl- and N,N-bis(p-tolylsulfonyl) derivatives are formed, while reductive acylamination does not occur.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 128–130.Original Russian Text Copyright © 2005 by Solekhova, Kurbatov.     

Substitution effects in <Emphasis Type="Italic">N</Emphasis>-pyrazole and <Emphasis Type="Italic">N</Emphasis>-imidazole derivatives along the periodic table

A theoretical study of the monosubstitution effects of all the atoms of the second and third row of the periodic table on the pyrazole and imidazole rings has been carried out by means of B3LYP/6-31+G(d,p) DFT calculations. The geometric and electronic properties, calculated using the atoms in molecules methodology, electrostatic potential, and frontier orbitals have been analyzed. Some of the results have been rationalized based on the electronegativity of the substituents. In addition, the different parameters obtained have been compared with aromaticity indexes (HOMA and NICS). A comparison with the results obtained for the corresponding N-pyrrole derivatives has been carried out.     

<Emphasis Type="Italic">N</Emphasis>-arylsulfinyl-1,4-benzoquinonimines

Stable N-arylsulfinyl-1,4-benzoquinonimines were synthesized by acylation of the corresponding 1,4-benzoquinone monooximes with arenesulfenyl chlorides. The process involves transformation of sulfur(II) into sulfur(IV).Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 9, 2004, pp. 1340–1343.Original Russian Text Copyright © 2004 by Avdeenko, Pirozhenko, Stanovskii, Konovalova, Yusina.This study was performed under financial support by the ES INTAS program (grant no. 00 157–1999) and by the Ministry of Education and Science of Ukraine.     

Structure and photochromism of 2-(<Emphasis Type="Italic">N</Emphasis>-acyl-<Emphasis Type="Italic">N</Emphasis>-arylaminomethylene)benzo[<Emphasis Type="Italic">b</Emphasis>]thiophen-3(2<Emphasis Type="Italic">H</Emphasis>)-ones

It was shown by electron absorption spectroscopy and X-ray diffraction analysis that steric strains in photochromic 2-(N-acyl-N-arylaminomethylene) benzo[b]thiophen-3(2H)-one molecules ortho-substituted in the N-phenyl ring increase the quantum yield of the N→O photoinduced rearrangement in accord with an increase in the steric constant of the ortho-substituent.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2151–2155, October, 2004.     

Regioselective <Emphasis Type="Italic">N</Emphasis>-alkylation of (2-chloroquinolin-3-yl) methanol with <Emphasis Type="Italic">N</Emphasis>-heterocyclic compounds using the Mitsunobu reagent

The Mitsunobu reaction is a well-established fundamental reaction and has been widely applied in organic synthesis. In this paper, under Mitsunobu conditions dehydration proceeds between (2-chloroquinolin-3-yl)methanol and nitrogen heterocyclic compounds such as quinazolinone, pyrimidone, 2-oxoquinoline in dry THF in the presence of triethylamine, triphenylphosphane and diethyl azodicarboxylate to give the corresponding products. As part of our recent research, we attempted to couple two N-heterocyclic compounds under Mitsunobu reaction conditions to provide efficient building blocks for natural product synthesis.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-and <Emphasis Type="Italic">C</Emphasis>-trimethylsilyl-substituded anililes

N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and ¹H, ¹³C, and ²⁹Si NMR spectroscopy.     

Kinetic characterisation of arylamine <Emphasis Type="Italic">N</Emphasis>-acetyltransferase from <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>

Background  

Arylamine N-acetyltransferases (NATs) are important drug- and carcinogen-metabolising enzymes that catalyse the transfer of an acetyl group from a donor, such as acetyl coenzyme A, to an aromatic or heterocyclic amine, hydrazine, hydrazide or N-hydroxylamine acceptor substrate. NATs are found in eukaryotes and prokaryotes, and they may also have an endogenous function in addition to drug metabolism. For example, NAT from Mycobacterium tuberculosis has been proposed to have a role in cell wall lipid biosynthesis, and is therefore of interest as a potential drug target. To date there have been no studies investigating the kinetic mechanism of a bacterial NAT enzyme.     

Synthesis of isomeric 2-oxazolidinones from (1<Emphasis Type="Italic">R</Emphasis>,2<Emphasis Type="Italic">R</Emphasis>)-and (1<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-2-amino-1-(4-nitrophenyl)-1,3-propanediols

A synthesis is reported for (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones and (1′R,4R)-and (1′S,4S)-4-[hydroxy(4-nitrophenyl)methyl]oxazolidin-2-ones from (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols. The effect of the experimental conditions on the formation of these compounds was studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1562–1570, October, 2007.     

Reaction of dialkylphosphites with <Emphasis Type="Italic">N</Emphasis>-alkyl-2-chloraldimines

Reactions of some dialkylphosphorous acids with the N-substituted 2-chloroimines were studied. It was shown that the nature of substituents at the nitrogen and phosphorus atoms in the starting materials affected the structure of the reaction products.