Syntheses and conformations of some cyclic hydroxamates. X-Ray crystal structure of 2-(p-nitrobenzoyl)tetrahydro-2H-1,2-oxazine

Alkylation of potassium p-nitrobenzohydroxamate with 1,4-dibromobutane gave 2-(p-nitrobenzoyl)tetrahydro-2H-1,2-oxazine (3). The X-ray crystal structure of 3 has been determined. The crystals are monoclinic, space group P2₁/n with a = 6.749(1), b = 7.644(1), c = 21.557(2)Å, β = 98.89(1), V = 1098.8(2)ų and Z = 4. The structure, which was refined to R = 0.039 using 1340 observed reflections, shows the oxazine and carbonyl oxygen atoms trans to each other. Alkylation of potassium benzohydroxamate with 1,3-dibromobutane gave a mixture of 3-methyl-2-benzoyloxazolidine (4) and 5-methyl-2-benzoyloxazolidine (5). The ¹H and ¹³C nmr spectra of the mixture of 4 and 5 indicates that these cyclic hydroxamates exist predominantly in the s-trans conformation.     

Synthesis of some 3-alkenyl-4-oxo-1-phenyl-5,6-dihydro-1H,4H, -pyrano[2,3-C]pyrazole derivatives

The title compounds were prepared from 3-alkenyl-1-phenyl-2-pyrazolin-5-one derivatives and α,β-unsaturated acyl chlorides as potential cardiotonic agents.     

Über 4-Alkylamino-bzw. 4-Arylamino-5,6-dihydro-2(1H)-pyridinthione

Heating 1-alkyl- or 1-aryldihydro-6-methyl-2(1H)-pyrimidinethiones5, 6 in an inert medium causes rearrangement to 4-alkylamino-(4-arylamino-)-5,6-dihydro-2(1H)-pyridinethiones11, 12, probably via the methylene form29, by thermal heterolysis of the N₁/C₂ bond and exchange of the alkylamino (arylamino) group 1 through the carbon atom of the methylene group 6. The aminodihydropyridinethiones11, which can be regarded as cyclic derivatives of 3-aminothiocrotonamide, react with bistrichlorophenylmalonate under diacylation, and with formaldehyde and primary amines to yield aminodialkylation products of the enamine system, tetrahydro-4-hydroxy-7,7-dimethyl-5-thioxopyrido[4,3-b]pyridine-2(1H)-ones13, 14 and hexahydro-7,7-dimethylpyrido[4,3-d]pyrimidine-5(6H)-thiones18, 19, 21 respectively. H₂O₂ converts11 to the corresponding 4-aminodihydro-2(1H)-pyridones22, which can be reconverted into11 with P₄S₁₀.11 reacts with alkyl halides to 2-alkylthiodihydropyridines23, 24, 25. The mechanism of the methylpyrimidine-pyridine rearrangement is discussed.     

Molecular and crystal structure of 2-phenyl-2-oxo-5,6 -benzo-1,3,2-dioxaphosphepine

The seven-membered heterocycle in the crystal structure of 2-phenyl-2-oxo-5,6-benzo-1,3,2-dioxaphosphepine has distorted (asymmetric) twist conformation and the plane of the phenyl substituent at the phosphorus atom does not coincide with the bisector of the plane of the OPO fragment of the heterocycle and is not perpendicular to it.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 214–217, January, 1991.     

5,6-Dihydropyridin-2(1H)-ones and 5,6-dihydropyridine-2(1H)-thiones (review)

Data on methods for the production of 5,6-dihydropyridin-2(1H)-ones and 5,6-dihydropyridine-2(H)-thiones and their biological activity are reviewed.Omsk State University, Omsk, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 147–167, February, 1999.     

Molecular and crystal structure of 1-methylmorpholinium 6-methyl-4-phenyl-3-cyano-5-ethoxycarbonyl-1,4-dihydro-2-pyridineselenolate

The structure of 1-methylmorpholinium 6-methyl-4-phenyl-3-cyano-5-ethoxycarbonyl-1,4-dihydro-2-pyridineselenolate was studied using x-ray diffraction analysis. It was found that the 1,4-dihydropyridine ring has a boat conformation, and the plane of the pseudoaxial phenyl substituent is perpendicular to the bottom of this boat. In the anion, the C–Se bond length, which is 1.882(2) Å, indicates that the negative charge is formally located on the Se atom. The anions and cations of the salt in the crystal are linked by intermolecular hydrogen bonds.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, Moscow 117813, Russia. T. G. Shevchenko Lugansk State Pedagogical Institute, Lugansk 348011, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 785–789, June, 1998.     

3-芳胺甲叉-6-苯基-5,6-二氢-2H-吡喃-2,4-二酮类新化合物的设计与合成

交链孢酸;杀菌剂;双键顺反异构;3-芳胺甲叉-6-苯基-5;6-二氢-2H-吡喃-2;4-二酮类新化合物的设计与合成     

Interaction of 5-aryl-4-quinoxalinyl-2,3-dihydro-2,3-furandiones with mesitylamine and methyl(phenyl)hydrazine. Synthesis and crystal and molecular structure of 2-(1-mesityl-4,5-dioxo-2-phenyl-4,5-dihydro-3-pyrollyl)-3-phenylquinoxaline

The interaction of 5-aryl-4-quinoxaline-2,3-dihydro-2,3-furandiones with mesitylamine and methyl(phenyl) hydrazine results in the formation of 1-substituted 5-aryl-4-quinoxalinyl-2,3-dihydro-2,3-pyrrolediones. The crystal and molecular structure of the 1-mesityl-5-phenyl derivative was investigated by X-ray diffraction.Original Russian Text Copyright © 2004 by Z. G. Aliev, N. Yu. Lisovenko, L. O. Atovmyan, and A. N. MaslivetzTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 553–557, May–June 2004.     

New heterocyclic compounds derived from 1,4-dihydro-3(2H)-cinnolinone. Cyclic hydrazides. Note I

The question concerning the synthesis of the 1,4-dihydro-3(2H)cinnolinone was solved and some new tetracyclic derivatives are described. The structure and the synthesis of the two isomers 2-(2-carbomethoxymethylphenyl)phthalazine-1(2H),4(3H)dione and 1-(2-carbomethoxybenzoyl)-1,2-dihydrocinnolin-3(4H)one are discussed.     

Über N1- und N2-substituierte 2-Amino-5,6-dihydro-4(1H)-pyrimidinone

The reactions of the monosubstituted guanidines2 b-h with methyl acrylate in dimethylformamide or ethanol as solvent preferentially afford 1-substituted 2-amino-5,6-dihydro-4(1H)-pyrimidinones6 b-h. The structures of 1-hexyl- and 1-benzyl-4-pyrimidinones6 c, e and of the picrate of 1-phenylpyrimidinone6 g were proved by comparison with authentic samples, which were prepared from N-substituted ethyl 3-amino-propionates14 c, e andg and cyanamide. Accordingly,6 g is not identical with authentic 2-phenylaminopyrimidinone7 g (prepared from 2-methylthio-4-pyrimidinone10 and 2-thioxo-4-pyrimidinone12 respectively, compare¹⁰).N,N-Disubstituted guanidines2 i-m react with methyl acrylate in dimethylformamide as solvent to afford N²,N²-disubstituted 2-amino-5,6-dihydro-4-(1H)-pyrimidinones7 i-m. Action of morpholine-4-carboxamidine (21) on methyl acrylate in ethanol yields 2-morpholinopyrimidinone71 as byproduct and 3-ethoxy-N-[morpholino(amino)methylene]propionamide (91) as mainproduct.

Herrn Prof. Dr.Robert Ott mit den besten Wünschen zum 60. Geburtstag gewidmet.     

Synthesis of 3-S-hetaryl-substituted pyridin-2(1H)-ones and 5,6-dihydropyridin-2(1H)-ones*

A method has been developed for the synthesis of 3-S-hetaryl-substituted pyridin-2(1H)-ones and 5,6-dihydropyridin-2(1H)-ones based on the base catalyzed cyclization of N-(3-oxoalkyl)- and N-(3-oxoalkenyl)amides which contain a divalent sulfur atom in an α-position to a carbamoyl group and bound to the heterocycle.     

Synthesis,characterization, crystal structure and electrochemical behavior of a nickel(II) complex of 5,6-dihydro-2H-pyran-3-aldehyde thiosemicarbazone

A new Ni^II complex of 5,6-dihydro-2H-pyran-3-aldehyde thiosemicarbazone (HDPTSC) has been synthesized and characterized by microanalyses, magnetic susceptibility, molar conductance measurements and by spectral methods (i.r., u.v.–vis., ¹H-n.m.r.). The structure of [Ni(DPTSC)₂] · B DMF has been solved using X-ray diffraction and found to be highly symmetrical with a trans -arrangement of the two bidentate ligands. The thiosemicarbazone coordinates as an anionic ligand via the thiosemicarbazone moietys azomethine nitrogen and thiolate sulfur [on loss of the N2 hydrogen]. The electrochemical behavior of the ligand and its Ni^II complex, determined by cyclic voltammetry, shows that the redox process of the ligand was highly irreversible, whereas the redox process of the Ni^II complex was observed as a one electron transfer process in a quasi-reversible and diffusion-controlled reaction.