Ab initio and density functional theory studies on the mechanism of nucleophilic vinylic substitution of 4<Emphasis Type="Italic">H</Emphasis>-pyran-4-one and 2-methyl-4<Emphasis Type="Italic">H</Emphasis>-pyran-4-one with ammonia

 Nucleophilic vinylic substitutions of 4H-pyran-4-one and 2-methyl-4H-pyran-4-one with ammonia were calculated by the B3LYP method using the 6-31G(d,p) basis set. Bulk solvent effects of aqueous solution were estimated by the polarized continuum and Poisson–Boltzmann self-consistent reaction field models using the 6-311+G(d,p) basis set. In the gas phase different mechanisms were found for the two reaction systems calculated. The reaction of 4H-pyran-4-one proceeds through enol, whereas a feasible path for the less reactive 2-methyl-4H-pyran-4-one is the mechanism through a keto intermediate. Addition of ammonia in concert with proton transfer is the rate-determining step ofthe reaction. The mechanism proceeding either by a bimolecular nucleophilic substitution (S_N2) or by one involving a tetrahedral zwitterionic intermediate is shown to be unlikely in the gas phase or nonpolar solution. The effects of bulk solvent not only consist in a reduction of the various activation barriers by about 25–40 kJ mol⁻¹ but also in a change in the reaction mechanism. Received 26 May 2002 / Accepted 26 July 2002 / Published online: 14 February 2003     

Hetero-<Emphasis Type="Italic">Diels-Alder</Emphasis> reaction of propenenitriles with enol ethers: a convenient approach to functionalized 3,4-dihydro-2<Emphasis Type="Italic">H</Emphasis>-pyrans

The hetero-Diels-Alder reaction of 3-(N-acetyl-N-benzylamino)-2-formylprop-2-enenitrile with enol ethers yielded cis/trans diastereoisomers of 2-alkoxy-4-amino-3,4-dihydro-2H-pyran-5-carbonitriles in moderate yields. Acidic hydrolysis of cis-diastereoisomer in concentrated sulfuric acid gave 2-oxo-1,2-dihydropyrydine-3-carbaldehyde. The reaction of 2-benzoyl-3-heteroaromaticprop-2-enenitriles with enol ethers afforded diastereoisomeric cis/trans cycloadducts in good yields. The structure of the products is discussed in terms of configuration and preferred conformation. Correspondence: Aleksandra Pałasz, Department of Organic Chemistry, Jagiellonian University, Kraków, Poland.     

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.     

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.     

Reactions of 3-nitro-2-trihalomethyl-2<Emphasis Type="Italic">H</Emphasis>-chromenes with indole, <Emphasis Type="Italic">N</Emphasis>-methylindole,and <Emphasis Type="Italic">N</Emphasis>-methylpyrrole. Stereoselective synthesis of 4-azolyl-3-nitro-2-trihalomethylchromanes

Heating of 3-nitro-2-trifluoromethyl-and 3-nitro-2-trichloromethyl-2H-chromenes with indole, N-methylindole, and N-methylpyrrole under solvent-free conditions led with high stereoselectivity and in good yields to cis-trans-3-nitro-2-trifluoromethyl-or trans-cis-3-nitro-2-trichloromethylchromanes substituted by the indol-3-yl (pyrrol-2-yl) fragment in position 4. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1985–1990, October, 2007.     

Reaction sites of <Emphasis Type="Italic">N,N′</Emphasis>-substituted <Emphasis Type="Italic">p</Emphasis>-phenylenediamine antioxidants

The geometries of N,N′-diphenylbenzene-1,4-diamine (DPPD), N-phenyl-N′-(1-phenylethyl)benzene-1,4-diamine (SPPD), N-(4-methylpentan-2-yl)-N′-phenylbenzene-1,4-diamine (6PPD), N-propan-2-yl-N′-phenylbenzene-1,4-diamine (IPPD), N-(2-methoxybenzyl)-N′-phenylbenzene-1,4-diamine (MBPPD), and N-phenyl-N′-(2-phenylpropan-2-yl)benzene-1,4-diamine (CPPD) as well as of their dehydrogenation products were optimized by the semiempirical AM1 method. The results support the idea of stable N_B=C_X structures formation during the consecutive dehydrogenation of SPPD, 6PPD, IPPD, and MBPPD antioxidants. The biradicals formed during the second step of dehydrogenation of substituted phenylenediamines might be important for their antioxidant effectiveness. Dedicated to Professor Vladimír Kvasnička, DrSc., in honour of his 65th birthday     

Synthesis and characterization of some new cobalt(II) and nickel(II) ternary complexes of <Emphasis Type="Italic">N</Emphasis>-acetyl, <Emphasis Type="Italic">N</Emphasis>-benzoyl and <Emphasis Type="Italic">N</Emphasis>-tosyl derivatives of amino acids

A series of some new cobalt(II) and nickel(II) ternary complexes of N-(acetyl)phenylalaninate (acphe), N-(acetyl)tyrosinate (actyr), N-(benzoyl)leucinate (bzleu), N-(benzoyl)phenylalaninate (bzphe), N-(tosyl)glutamic acid (tsglu), N-(tosyl)arginine (tsarg) with certain N-heterocyclic ligands such as imidazole (imi), methylimidazole (mimi), 2,2′-bipyridyl (bipy) 1,10-phenanthroline (phen) have been synthesized and characterized by elemental analyses, IR and electronic spectra. as well as thermogravimetry. The structure of the cobalt(II) N-phthaloylglycinate complex was also characterized by X-ray single crystal. It was found that the cobalt atom coordinates a 1,10-phenanthroline molecule and four water oxygen atoms, forming a distorted octahedral conformation. A molecule of N-phthaloylglycinate is connected by van der Waals contact and H-bonds.     

Synthesis and characterization of novel (<Emphasis Type="Italic">E</Emphasis>,<Emphasis Type="Italic">E</Emphasis>)-dioxime and its mono- and polynuclear metal complexes containing azacrown moieties

The novel (E,E)-dioxime,7,8-bis(hydroxyimino)-1,14-bis(monoaza[8]crown-6)-benzo[f]-4,11-dioxa-1,14-diazadecane[7,8-g]quinoxaline (H₂L), has been synthesized by the reaction of 6,7-diamino-1,12-bis(monoaza[18]crown-6)benzo[f]-4,9-dioxa-1,12-diazadecane (4) which has been prepared by the reduction of 6,7-dinitro-1,12-bis(mono-aza[18]crown-6)benzo[f]-4,9-dioxa-1,12-diazdecane (3) and cyanogendi-N-oxide. Mononuclear Ni^II and Cu^II complexes of H₂L have a metal:ligand ratio of 1:2 and the ligand coordinates through two hydroxyimino nitrogen atoms, as do most of the (E,E)-dioximes. The hydrogen-bridged Ni^II complex was converted into its BF ₂ ⁺ capped anologue by the reaction with BF₃ · Et₂O. The reaction of the Cu^II complex with 2,2′-dipyridyl as an end-cap ligand gave the homotrinuclear complex. Structures for the ligand and its complexes are proposed in accordance with elemental analysis, magnetic susceptibility measurements, ¹H, ¹³C-n.m.r, IR and MS spectral data.     

Reactions of <Emphasis Type="Italic">N</Emphasis>-and <Emphasis Type="Italic">C</Emphasis>-Alkenylanilines: VII. Synthesis of Indole Heterocycles from Products of Reaction between <Emphasis Type="Italic">N</Emphasis>-Mesyl-2-(1-alken-1-yl)anilines and Halogens

N-Mesyl-2-(1-methyl-1-butenyl)-6-methylaniline reacted with Br₂ to afford N-mesyl-2-(3-bromo-1-penten-2-yl)aniline that under treatment with NH₃ or amines underwent cyclization into N-mesyl-7-methyl-3-methylene-2-ethylindoline. The reaction of N-mesyl-2-(1-methyl-1-buten-1-yl)-4-methyl- and 2-(1-methyl-1-buten-1-yl)aniline with Br₂ gave rise to the corresponding N-mesyl-2-(2-bromo-1-methyl-1-buten-1-yl)anilines. Under the similar conditions N-tosyl-2-(1-cyclohexen-1-yl)aniline was converted into N-tosyl-2-(6-bromo-1-cyclohexen-1-yl)aniline that under treatment with NH₃ furnished N-tosyl-1,2,3,9a-tetrahydrocarbazole. The reaction of N-mesyl-1,2,3,9a-tetrahydrocarbazole with CuBr₂ in MeOH afforded N-mesyl-4-methoxy-1,2,3,4-tetrahydrocarbazole. N-Mesyl-6-methyl-2-(1-cyclopenten-1-yl)aniline in reaction with Br₂ in the presence of NaHCO₃ was oxidized into the corresponding cyclopentenone, and with NBS it gave N-mesyl-2-(2-bromo-1-cyclopenten-1-yl)aniline.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 730–737.Original Russian Text Copyright © 2005 by Gataullin, Sotnikov, Spirikhin, Abdrakhmanov.     

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.     

Ionic Liquid Promoted One-Pot Synthesis of Furo[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidine-2,4(1<Emphasis Type="Italic">H</Emphasis>,3<Emphasis Type="Italic">H</Emphasis>)-diones

Summary. The three-component condensation of aldehyde, N,N′-dimethylbarbituric acid and alkyl or aryl isocyanide afforded the corresponding furo[2,3-d]pyrimidine-2,4(1H,3H)-diones in 1-butyl-3-methylimidazolium bromide as an ionic liquid in high yields at room temperature within several minutes.     

Synthesis of 1-{4a,6-dimethyl-4a,9a-dihydropyrano-[3,4-<Emphasis Type="Italic">b</Emphasis>]indol-9(1<Emphasis Type="Italic">H</Emphasis>)-yl}ethanone

Heating of the bromination product of 4-methyl-3,6-dihydro-2H-pyran with 4-toluidine or 2-bromo-4-methylamiline in triethylamine gave 4-methyl-N-(4-methylphenyl)- and N-(2-bromo-4-methylphenyl)-4-methyl-3,6-dihydro-2H-pyran-3-amines which were converted into the corresponding amides by reaction with bromo- or chloroacetyl chloride. 1-{4a,6-Dimethyl-4a,9a-dihydropyrano[3,4-b]indol-9(1H)-yl} ethanone was synthesized in good yield by heating N-(2-bromo-4-methylphenyl)-N-(4-methyl-3,6-dihydro-2Hpyran-3-yl)acetamide in boiling toluene in the presence of palladium(II) acetate, triphenylphosphine, copper(II) acetate, triethylamine, and potassium carbonate.     

Contribution to the Protonation of a Calix[4]arene: DFT Calculated Structure of Protonated <Emphasis Type="Italic">p-tert</Emphasis>-Butylcalix[4]arenetetrakis(<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-diethylacetamide)

Summary. By using DFT calculations, the most probable structure of the p-tert-butylcalix[4]arenetetrakis(N,N-diethylacetamide) · H₃O⁺ complex species was derived. In this complex, the hydroxonium ion H₃O⁺ is predominantly bound by strong hydrogen bonds to three phenoxy oxygens of the ligand and partly to the remaining phenoxy oxygen atom by two somewhat weaker hydrogen bonds. Besides, the H₃O⁺ cation is also bound to two carbonyl oxygens of the mentioned ligand by further two weaker hydrogen bonds.     

Transformations of 3-nitropyridin-4(1<Emphasis Type="Italic">H</Emphasis>)-one and 1-Methyl-3-nitropyridin-4(1<Emphasis Type="Italic">H</Emphasis>)-one in reaction with hydrazine

Hydrazinolysis of 3-nitropyridin-4(1H)-one and its N-methyl derivative leads to the formation of 1-(1H-pyrazol-3-yl)ethanone hydrazone whose structure was confirmed by independent synthesis from authentic 3-acetyl-1H-pyrazole and comparison of the IR and ¹H NMR spectra. Oxidation of 1-(1H-pyrazol-3- yl)ethanone hydrazone with potassium permanganate gave 1H-pyrazole-3-carboxylic acid.     

Reaction of <Emphasis Type="Italic">N</Emphasis>-Sulfinyltrifluoromethanesulfonamide CF<Subscript>3</Subscript>SO<Subscript>2</Subscript>N=S=O with Carbonyl Compounds

N-Sulfinyltrifluoromethanesulfonamide CF₃SO₂N=S=O reacts with salicylaldehyde, 2-furaldehyde, 2-thiophenecarbaldehyde, 3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde, and 2-phenyl-2H-1,2,3-triazole-4-carbaldehyde to afford the corresponding N-aryl(hetaryl)methylidenetrifluoromethanesulfonamides in high yields. Reactions of the latter with aniline give no adducts at the C=N bond but transamination products. The reaction of trifluoromethanesulfonamide with phenyl isocyanate led to formation of N,N′-diphenylurea instead of expected N-phenyl-N′-(trifluoromethylsulfonyl)urea.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005, pp. 1006–1010.Original Russian Text Copyright © 2005 by Shainyan, Tolstikova.     

Reaction of synthetic equivalents of arylideneimines, <Emphasis Type="Italic">viz.</Emphasis>, 1-aryl- <Emphasis Type="Italic">N,N’</Emphasis>-bis(arylidene)methanediamines,with 2,3-diphenylcyclopropenone

N,N’-Bis(arylidene)methanediamines regiospecifically react with 2,3-diphenylcyclo- propenone to form stable adducts of both the mono- and the diaddition. Ammonium acetate serves as the catalyst of the process. During hydrolysis of these adducts, an oxidative coupling of 1,2-dihydro-3H-pyrrol-3-ones occurs with the formation of 2,2’,4,4’,5,5’-hexaaryl-l,1’,2,2’- tetrahydro-H,3’-2,2’-bipyrrole-3,3’-diones.     

<Emphasis Type="Italic">N</Emphasis>-benzyl derivatives of valine esters

The reactions of methyl and ethyl esters of valine with m-bromobenzaldehyde and p-chlorobenzaldehyde in absolute methanol in the presence of magnesium sulfate yielded the corresponding azomethines (CH₃)₂CHCH(COOR¹)N=CHR² (R¹ = CH₃, C₂H₅; R² = 3-BrC₆H₄, 4-ClC₆H₄); their reduction with sodium borohydride gave N-benzyl derivatives of valine esters, (CH₃)₂CHCH(COOR¹)NHCH₂R².Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1855–1857.Original Russian Text Copyright © 2004 by Yakubovich, Zhavnerko, Shirokii, Knizhnikov.This revised version was published online in April 2005 with a corrected cover date.     

Reaction of the Reformatskii reagent obtained from bromotetrahydrofuran-2-one with 2-oxochromene-3-carboxylic or 3-oxo-3<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">f</Emphasis>]chromene-2-carboxylic acid derivatives

The Reformatskii reagent obtained from 3-bromotetrahydrofuran-2-one reacts with alkyl esters of 6-bromo- and 6,8-dibromo-2-oxochromene-3-carboxylic acid or alkyl esters and N-benzylamide of 3-oxo-3H-benzo[f]chromene-2-carboxylic acid to form alkyl esters of 6-bromo- and 6,8-dibromo-2-oxo-4-(2-oxotetrahydrofuran-3-yl)chroman-3-carboxylic acid or alkyl esters and N-benzylamide of 2,3- dihydro-3-oxo-1-(2-oxotetrahdrofuran-3-yl)-1H-benzo[f]chromene-2-carboxylic acid as a mixture of two diastereomers.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1513–1515.Original Russian Text Copyright © 2004 by Shchepin, Fotin, Shurov.This revised version was published online in April 2005 with a corrected cover date.     

Ultrasound-accelerated one-pot synthesis of <Emphasis Type="Italic">N</Emphasis>-acetyl-2-aryl-1,2-dihydro-4<Emphasis Type="Italic">H</Emphasis>-3,1-benzoxazin-4-ones

The one-pot synthesis of N-acetyl-2-aryl-1,2-dihydro-4H-3,1-benzoxazin-4-one derivatives from the condensation reaction of anthranilic acids with heteroaromatic aldehydes in the presence of excess amount of acetic anhydride has been explored. The reactions proceed smoothly under ultrasound irradiation and without catalyst at 35 − 40 °C to afford the title products in high yields.     

Synthesis of <Emphasis Type="Italic">N</Emphasis><Superscript>2</Superscript>-Arylisocytidines and <Emphasis Type="Italic">N</Emphasis><Superscript>2</Superscript>-Aryl-2′-deoxyisocytidines

Summary. 2-(Arylamino)pyrimidin-4-ones were synthesized, silylated, and condensed with l,2,3,5-tetra-O-acetyl-β- d-ribofuranoside to afford the corresponding N ²-aryl protected isocytidines. Deprotection of the acetylated isocytidines using saturated NH₃ in MeOH solution gave 1-(β-d-ribofuranosyl)-2-(arylamino)-4-pyrimidinones. Methyl 2-deoxy-3,5-di-O-toluyl-α/β-d-ribofuranoside was prepared and condensed with the previously silylated bases to afford the anomeric mixture of protected nucleosides. The pure β-anomers were synthesized with better yield by treating the sodium salts of N ²-arylisocytosine derivatives with 2-deoxy-3,5-di-O-toluyl-α-d-ribofuranosyl chloride. Deprotection of the latter anomers afforded the corresponding free hydroxyl derivatives. The synthesized free nucleosides are under antiviral and oligonucleotide investigations.