Selective acylation of 5-nitro- and 5-ethoxycarbonyl-4,6-diaryl-3,4-dihydropyrimidin-2(1<Emphasis Type="Italic">H</Emphasis>)-ones

The acetylation and chloroacetylation of 5-nitro- and 5-ethoxycarbonyl-substituted 4,6-diaryl-3,4-dihydropyrimidin-2(1H)-ones proceeds regioselectively at the N³ atom of the heterocycle whereas the acetylation of the 5-aryloxy-substituted analog results in a mixture of N¹- and N³-acetylated regioisomers.     

4-Alkyl-6-amino-N 3,N 5-diaryl-2-thioxo-1,2,3,4-tetrahydropyridine-3,5-dicarboxamides: II. Synthesis and selected reactions

New 4-alkyl-6-amino-N ³,N ⁵-diaryl-2-thioxo-1,2,3,4-tetrahydropyridine-3,5-dicarboxamides have been prepared via enantioselective reaction of 3-amino-N-aryl-3-thioxopropanamides with N-aryl-2-cyanoacetamide and aliphatic aldehydes. The prepared products can be regioselectively alkylated at sulfur atom.     

The selective preparation of 1,4-diaryl-6-methyl- and 1,6-diaryl-4-methyl-2-(1H)pyrimidinones

N-Phenylurea reacted with benzoylacetone derivatives (I) to give 1,4-diaryl-6-methyl-2-(1H)pyrimidinones (II) in addition to low yields of 1,6-diaryl-4-methyl-2-(1H)pyrimidinones (IV), while N-phenylthiourea afforded only 1,6-diaryl-4-methyl-2-(1H)pyrimidinethiones (III) in good yields. Further 1,6-diaryl-4-methyl-2-(1H)- pyrimidinethiones (III) were successfully converted in satisfactory yields into the corresponding 2-(1H)-pyrimidinones (IV) by the treatment with methyl iodide in the presence of sodium methoxide in methanol at room temperature.     

Reaction of 3-oxo-3-R<Superscript>1</Superscript>-<Emphasis Type="Italic">N</Emphasis>-R<Superscript>2</Superscript>-propanethioamides with 2-amino-5-R-pyridines

Direction of a reaction between 3-oxo-3-R¹-N-R²-propanethioamides and 2-amino-5-R-pyridines in acetic acid depends on the structure of initial thioamides: at R¹ = Me, R² = Ar, Et 2-methyl-7-R-4H-pyrido[1,2-a]-pyrimidine-4-thiones are obtained, and at R¹ = Ar, R² = Me form 1-methyl-5-(N-methylaminothiocarbonyl)-4,6-diaryl-1,2-dihydropyridine-2-thiones.     

Cyclization of nitriles 41. Reaction of arylmethylenemalononitriles with malononitrile; crystal structure of 1-amino-3.5-diphenyl-2,4,4,6,6-pentacyano-1-Cyclohexene

1-Amino-3,5-diaryl-2,4,4,6,6-pentacyano-1-cyclohexenes are prepared by reaction of arylmethylenemalononitriles with malononitrile. The cyclohexene ring of (IVa) has a distorted N₂-C¹=C²-C⁷=N¹ fragment. Steric effects in (IVa) cause a substantial increase in C⁶-C¹ and C³-C⁴ bond length to 1.546(4) and 1.570(4) Å, respectively.For previous communication, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2771–2775, December, 1989.     

Synthesis of 4,<Emphasis Type="Italic">N</Emphasis>-diaryl-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxamides

Cyclohexane-1,3-dione reacted with substituted benzaldehydes and N-arylacetoacetamides in the presence of ammonium acetate under solvent-free conditions (150–160°C, 10–20 min) to give the corresponding 4,N-diaryl-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxamides. The product structure was determined by IR and ¹H NMR spectroscopy and mass spectrometry.     

4-alkyl-6-amino-4-N 3,N 5-diaryl-2-thioxo-1,2,3,4-tetrahydropyridine-3,5-dicarboxamides: I. Tandem synthesis and alkylation. Molecular and crystal structure of 6-allylsulfanyl-2-amino-4-isobutyl-N 3,N 5-di-m-tolyl-3,4-dihydropyridine-3,5-dicarboxamide

4-Alkyl-6-amino-4-N ³,N ⁵-diaryl-2-thioxo-1,2,3,4-tetrahydropyridine-3,5-dicarboxamides were obtained via tandem synthesis involving the Knoevenagel reaction, Michael reaction and intramolecular condensation. Alkylation of the obtained dicarboxamides proceeds regioselectively at the S atom to form the corresponding thioethers. Structure of 6-allylsulfanyl-2-amino-4-isobutyl-N ³,N ⁵-di-m-tolyl-3,4-dihydropyridine-3,5-dicarboxamide was uniquely determined by XRD analysis.     

Dithiophosphorylation of racemic and enantiomerically pure trimethyl-N-(1-phenylethyl)silanamine

Trimethylsilyl P-aryl-N-[(RS)-, (S)-(?)-, and (R)-(+)-(1-phenylethyl)]phosphonamidodithioates were synthesized by reactions of 2,4-diaryl-1,3,2λ⁵,4λ⁵-dithiadiphosphetane 2,4-disulfides with racemic and and enantiomerically pure trimethyl-N-(1-phenylethyl)silanamine.     

Heterocyclization of functionalized heterocumulenes with C,N-, C,O-, and C,S-Binucleophiles: XI. Synthesis of dialkyl 2-oxo-3,6-diaryl-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylates by cyclocondensation of 1-chlorobenzyl isocyanates with dialkyl anilinofumarates

1-Chlorobenzyl isocyanates react with N-arylfumarates with the formation of dialkyl 2-oxo-3,6-diaryl-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylates that on alkaline hydrolysis are converted into 6-alkoxycarbonyl-1,4-diaryl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acids. The condensation of 1-chloro-1-phenyl-2,2,2-trifluoroethyl isocyanate with N-arylfumarates results in dialkyl 6-oxo-2,3-diaryl-2-trifluoromethyl-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylates.     

Cascade Transformations of (2,2-Diaryl-3,3-dichloroaziridin-1-yl)acetates

Esters of (2,2-diaryl-3,3-dichloroaziridin-1-yl)acetic acid prepared from glycine derivatives under alkylation conditions afford esters of 2-[N-alkyl-N-(2,2-diaryl-1-cyanovinyl)amino]-3,3-diarylacrylic acid in 20-40% yield. The reaction resulting in these compounds proceeds through a cascade of 3-chloro-2-azadiene and ylide intermediates. 3-Chloro-2-azadienes originating from (2,2-diaryl-3,3-dichloroaziridin-1-yl)acetates react with primary and secondary amines at the carbon atom of imine group providing ketenimines which undergo ketenimine-nitrile rearrangement or fragmentation. The other bases (KOH, MeONa, DBU) effect dehydrochlorination of the mentioned 3-chloro-2-azadienes giving nitrile-ylides which are trapped by nucleophilic reagents. The 3-chloro-2-azadiene obtained from methyl (2,2-diaryl-3,3-dichloroaziridin-1-yl)acetate and DBU was relatively stable and was isolated as an individual compound. (2,2-diaryl-3,3-dichloroaziridin-1-yl)propionates behave as nonfunctionalized dichloroaziridines.     

Reactions of 1,1-diaryl-2-isopropylidene-3-methylenecyclopropanes with C,N-diarylnitrones and nitrile oxides

The reactions of unactivated bis(methylene)cyclopropanes with nitrones and nitrile oxides have been investigated. The 1,1-diaryl-2-isopropylidene-3-methylenecyclopropanes react with the C,N-diarylnitrones to give a mixture of 2,2-dimethyl-1,6-diaryl-3-(diarylmethylene)piperidin-4-ones and 5-methyl-1-aryl-1-(arylamino)-4-(diarylmethylene)hex-5-en-3-ones. 2,3-Dihydro-3-methylenepyridin-4(1H)-ones are obtained by reaction of 1,1-diaryl-2-isopropylidene-3-methylenecyclopropanes with nitrile oxides.     

Synthesis of 1,2-diaryl-2-imidazolines

Polyphosphoric acid and N-aryl-N′-benzoylethylenediamines in a type of Bischler-Napieralski reaction afforded 1,2-diaryl-2-imidazolines in good yields, rather than the 2,3-dihydro-1H-[1,4]-benzodiazepines. Blocking of the amino nitrogen by a methyl or ethyl group, to avoid imidazoline formation, gave starting material rather than the expected dihydrobenzodiazepine. When p-tosyl was the blocking group, imidazoline was again the only product isolated. Analytical and spectroscopic data of several unreported 1,2-diaryl-2-imidazolines are presented.     

A novel synthesis of 4,5-diaryl-6-arylamino-2,3-benzo-1,3a,6a-triazapentalenes

Treatment of N-alkyl- and N-aryl-imines of 2,3-diaryl- and 2-alkyl-3-aryl-3-(benzotriazol-1-yl)propenals with trifluoroacetic anhydride in THF at room temperature gave 5-alkyl-4-aryl-6-[N-alkyl (and aryl)-N-trifluoroacetyl]amino-2,3-benzo-1,3a,6a-triazapentalenes in moderate to good yields. On heating triazapentalenes having R²=aryl in MeOH at reflux, detrifluoroacetylation of triazapentalene occurred to give title compounds in good yields. However, the same treatment of triazapentalenes having R²=alkyl did not give the corresponding detrifluoroacetylation product. The title compounds and 5-alkyl-4-aryl-6-(N-alkyl-N-trifluoroacetyl)amino-2,3-benzo-1,3a,6a-triazapentalenes were found to be good precursors for the synthesis of 1-(o-aminophenyl)-3-arylamino-4-alkyl (and aryl)-5-arylpyrazoles and 1-(o-aminophenyl)-3-(N-alkyl-N-trifluoroacetyl)amino-4-alkyl (and aryl)-5-arylpyrazoles, respectively.     

13C NMR spectra of some 1,2-disubstitutedN-vinyl-1H-1,2,4-triazoles

¹³C NMR spectra (20 and 75 MHz, in DMSO-d₆) of a series of 1,3-diaryl-3-(1H-1,2,4-triazol-1-yl)- and 1,3-diaryl-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones were registered. It was shown that the chemical shifts of both the carbon atom of the alkene group and C(3) reflect regio- and stereoisomerism of these compounds. Taking this into account the isomeric structures of several 1,3-diaryl-3-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones were identified and the configurations relative to the double bond of a number of 1,3-diaryl-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones were determined.     

Synthesis of some sulfur-containing spiro-pyrimidinetriones,pyrazolidinediones, and isoxazolidinediones

Novel sulfur-containing spiro compounds such as 7,11-diaryl-9-thia-2,4-diazaspiro [5,5] undecane-1,3,5-trione 9,9-dioxides ( 2 ), 6,10-diaryl-8-thia-2,3-diazas-piro[4,5]decane-1,4-dione-8,8-dioxides ( 3 ) and 6,10-diaryl-2-oxo-8-thia-3-azaspiro [4,5] decane-1,4-dione-8,8-dioxides ( 5 ) have been prepared by the condensation of 4-dimethoxycarbonyl/diethoxycarbonyl-3,5-diaryl-1-thiane 1,1-dioxides ( 1 ) with urea, hydrazine hydrate, and hydroxylamine hydrochloride, respectively. The N-substituted derivatives ( 4 and 6 ) of 3 and 5 have also been prepared by acylation and nitrosation. The structures of 2, 3 , and 5 were established by IR, ¹H NMR, and ¹³C NMR spectral studies, respectively.     

Synthesis and characterization of 4,6-diaryl-4,5-dihydro-2H-indazol-3-ols and 4,6-diaryl-2-phenyl-4,5-dihydro-2H-indazol-3-ols — a new series of fused indazole derivatives

A novel class of 4,6-diaryl-4,5-dihydro-2H-indazol-3-ols and 4,6-diaryl-2-phenyl-4,5-dihydro-2H-indazol-3-ols is synthesized and characterized by melting point, elemental analysis, MS, FT-IR, ¹H and ¹³C NMR, D₂O exchanged ¹H NMR, and two-dimensional HSQC spectra. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1183–1188, August, 2008.     

Synthesis of some N,1- and N′,1-diaryl-1H-1,2,4-triazole-3,5-diamines

Two novel methods for the preparation of N, 1- and N′,1-diaryl-1H-1,2,4-lriazole-3,5-(Hamines are described.     

Three-component condensation of α-nitroacetophenone,aromatic aldehydes,and methylurea

The three-component condensation of aromatic aldehydes, methylurea, and α-nitroacetophenone affords both N(1)-and N(3)-methyl-substituted 4,6-diaryl-5-nitro-3,4-dihydropyrimidin-2(1H)-ones depending on the structure of aldehyde. Intermediate 4,6-diaryl-4-hydroxy-3-methyl-5-nitrohexahydropyrimidin-2-ones and trisubstituted urea, which is the transformation product of the 4-hydroxy-3-methyl derivative in an acidic medium (retro-Henry reaction), were identified in the reaction mixtures. Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1141–1145, June, 2007.     

Chemistry of 1,5-diketones: II. Specificity of transformations of polycyclic 1,5-diketones in acid media

2-(1,3-Diaryl-3-oxopropyl)cyclohexan-1-ones underwent carbo-and heterocyclization in a mixture of acetic acid with acetic anhydride in the presence of perchloric acid. The transformation of 2-(1,3-diaryl-3-oxopropyl)cyclohexan-1-ones into 2,4-diaryl-5,6,7,8-tetrahydrochromenylium salts was shown to involve intermediate 2,4-diarylbicyclo[3.3.1]non-2-en-9-ones. The structure of 2,4-diaryl-substituted bicyclo[3.3.1]non-2-en-9-ones and products of their reactions with halogens and hydroxylamine hydrochloride was confirmed by ¹H and ¹³C NMR spectroscopy.     

Effect of the aryl group substituent in the dimerization of 3-arylisoxazoles to syn 2,6-diaryl-3,7-diazatricyclo[4.2.0.0]octan-4,8-diones induced by LDA

3-Arylisoxazoles react with LDA in THF at 0 °C affording syn-2,6-diaryl-3,7-diazatricyclo[4.2.0.0^2,5]octan-4,8-diones (bis-azetidinones), via stereoselective dimerization of an azetinone anion intermediate. A fragmentation reaction affording arylnitriles may compete with electronic and steric effects of the substituent present in the aryl group being pivotal in determining the outcome of this reaction. An interesting behaviour with LDA of arylnitriles arising from the fragmentation reaction of some 3-arylisoxazoles was also observed. N,N-Diisopropylaminobenzonitriles were in fact formed (plausibly via a benzyne mechanism) from 3-(4-chlorophenyl)isoxazole and 3-(2-chlorophenyl)isoxazole, whereas 3-(2-methylphenyl)isoquinolin-1-amine was isolated starting from 3-(2-methylphenyl)isoxazole and LDA.