Catalyzed liquid-phase oxidation of dialkylthiophenes

The oxidation of 3-methyl-2-ethylthiophene with molecular oxygen in glacial acetic acid in the presence of a cobalt-bromide catalyst was investigated. It was established that there is a dependence of the rate of oxidation of this compound on its concentration, on the catalyst (cobalt acetate) concentration, and on the initiator (NaBr) concentration. The principal oxidation products are 3-methyl-2-acetothienone (III) and 1-(3-methyl-2-thienyl) ethyl acetate, which were isolated and characterized. The reactivity of 3-methyl-2-ethylthiophene in the oxidation reaction is higher than that of 4-methyl-2-ethylthiophene.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 758–761, June, 1981.     

Reactions of 5-(6-Methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with Electrophiles

 Treatment of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with haloalkanes yielded oxadiazole S-alkyl derivatives, whereas its reaction with formaldehyde and amines resulted in formation of oxadiazole N(3)-aminomethyl derivatives. The alkylation of 2-alkylsulfanyl-5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles with methyl bromoacetate proceeded at the N(1)-position of pyrimidine to give 2-alkylsulfanyl-5-(1-methoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles, whereas aminomethylation, bromination, or nitration took place at position 5 of pyrimidine ring and afforded the corresponding 5-pyrimidine substituted derivatives.     

Synthesis of 5-(6-Methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-amino-1,2,4-triazole-3-thione and its Reactions with Polyfunctional Electrophiles

Summary.  In the reaction of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with hydrazine hydrate, 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-amino-1,2,4-triazole-3-thione was formed. The reactions of the latter with ethyl bromoacetate and chloroacetonitrile in the presence of triethylamine proceeded under formation of the corresponding S-alkylated derivatives, whereas from its reaction with ω-bromoacetophenone and ethyl 4-chloroacetoacetate triazolothiadiazines were obtained. Treatment of the title compound with ethyl 2-chloroacetoacetate led to the formation of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-N-acetylamino-(3-ethoxy-carbonylmethylthio)-1,2,4-triazole. Performing of the latter reaction without basic catalyst gave a triazolothiadiazine. Treatment of the S-alkylated derivatives with sodium methoxide resulted in triazolothiadiazines via a cyclocondensation reaction. Received November 20, 2000. Accepted January 15, 2001     

Dienol-Benzol-Umlagerung von Penta-2,4-dienyl-benzocyclohexadienolen

1-Hydroxy-2-methyl-2-(penta-2,4-dienyl)-1,2-dihydronaphthalene ( 2 ), on treatment with 0,75N H₂SO₄ in ether at 0°, underwent a [1s, 2s]-sigmatropic rearrangement to give 2-methyl-1-(penta-2,4-dienyl)-naphthalene ( 5 ), cf. scheme 2. 2-Hydroxy-1-methyl-1-(penta-2,4-dienyl)-1,2-dihydronaphthalene ( 4 ) under the same conditions gave 38% of the [1s, 2s]-product 1-methyl-2-(penta-2,4-dienyl)-naphthalene ( 6 ), together with 26% 1-methylnaphthalene, 21% 1-methyl-4-(penta-2,4-dienyl)-naphthalene ( 7 ) and 1% 1-methyl-5-(penta-2,4-dienyl)-naphthalene ( 8 ), cf. scheme 2. Most likely the latter two naphthalene derivatives at least are products of an intermolecular process.     

Reactions of 5-(6-Methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with Electrophiles

Summary.  Treatment of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with haloalkanes yielded oxadiazole S-alkyl derivatives, whereas its reaction with formaldehyde and amines resulted in formation of oxadiazole N(3)-aminomethyl derivatives. The alkylation of 2-alkylsulfanyl-5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles with methyl bromoacetate proceeded at the N(1)-position of pyrimidine to give 2-alkylsulfanyl-5-(1-methoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles, whereas aminomethylation, bromination, or nitration took place at position 5 of pyrimidine ring and afforded the corresponding 5-pyrimidine substituted derivatives. Received May 9, 2001. Accepted (revised) August 17, 2001     

Preparation and reactions of 1,3-diphosphacyclobutane-2,4-diyls that feature an amino substituent and/or a carbonyl group

The preparation and properties of a 1-amino-1,3-diphosphacyclobutane-2,4-diyl and a 1-benzoyl-1,3-diphosphacyclobutane-2,4-diyl, which can be regarded as functionalized cyclic biradical derivatives, were investigated. Hydrolysis of 1-diisopropylamino-3-methyl-2,4-bis(2,4,6-tri-tert-butylphenyl)-1,3-diphosphacyclobutane-2,4-diyl (7), which is formed by reaction of Mes*C[triple chemical bond]P (4; Mes*=2,4,6-tBu(3)C(6)H(2)) with lithium diisopropylamide and iodomethane, resulted in ring-opening of the 1,3-diphosphacyclobutane-2,4-diyl skeleton, as well as de-aromatization of one of the Mes* rings. 3-Oxo-1,3-diphosphapropene 8 and 7-phosphabicyclo[4.2.0]octa-1(8),2,4-triene 9 were the resultant products, and these were subsequently characterized. Isomerization and oxidation of 7 occurred in the presence of TEMPO (2,2,6,6-tetramethyl-1-piperidinoxy) to give the first example of a cyclic dimethylenephosphorane derivative, namely 3-oxo-1,3-diphospha-1,4-diene 10. 1-Benzoyl-3-tert-butyl-2,4-bis(2,4,6-tri-tert-butylphenyl)-1,3-diphosphacyclobutane-2,4-diyl (12) was isolated and characterized from the reaction of 4 with tert-butyllithium and benzoyl chloride. Compound 12 was subsequently heated and underwent rearrangement of the benzoyl group and ring-expansion to afford 1-oxo-1H-[1,3]diphosphole 13. Reaction of 4 with lithium diisopropylamide and benzoyl chloride afforded the 2H-[1,2,4]oxadiphosphinine 15, which was probably formed through the 1,3-diphosphacyclobutane-2,4-diyl intermediate 14. Thermolysis of 15 afforded 1-oxo-1H-[1,3]diphosphole 16 in an Arbuzov-type rearrangement.     

Synthesis of esters of polyfluoro-substituted 2-methyl- and 3-methyl-2,4-alkadienoic acids by Horner—Emmons olefination of polyfluoroalkanals

Ethyl 2- and 3-methyl-6,6,7,7-tetrafluoro-2,4-heptadienoates and ethyl 2-methyl-6, 6,7,7,8,8,9,9-octafluoro-2,4-nonadienoate were synthesized by condensing 2,2,3,3-tetrafluoropropanal or 2,2,3,3,4,4,5,5-octafluoropentanal with ethyl 2-methyl-4-diisopropoxyphosphono- and ethyl 3-methyl-4-diethoxyphosphono-2-butenoates under the conditions of the Horner—Emmons reaction.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2196–2198, November. 1995.     

Synthesis and Structure of 3-Aryl-2,4-dibenzoyl-5-hydroxy-5-methylcyclohexanones and 2-Benzoyl-5-hydroxy-5-methyl-3-phenylcyclohexanone

The reaction of benzoylacetone with aromatic aldehydes under basic catalysis conditions afforded 3-aryl-2,4-dibenzoyl-5-hydroxy-5-methylcyclohexanones. The reaction of benzoylacetone with benzalacetone led to the formation of 2-benzoyl-5-hydroxy-5-methyl-3-phenylcyclohexanone.     

Steric stabilization of a monomeric proalumatrane: experimental and theoretical studies

Treatment of tripodal tris(3-tert-butyl-2-hydroxy-5-methylbenzyl)amine (L) with 1 equiv of trimethylaluminum in toluene gave the stable proalumatrane (AlL) (1) [wherein L = tris(3-tert-butyl-5-methyl-2-oxidobenzyl)amine] featuring a distorted trigonal monopyramidal four-coordinate aluminum geometry. An analogous reaction uses the less sterically congested isomer of L, namely, tris(5-tert-butyl-2-hydroxy-3-methylbenzyl)amine provided dimeric (AlL')2 (2) [wherein L' = tris(5-tert-butyl-3-methyl-2-oxidobenzyl)amine], which contains two bridging alumatrane moieties possessing five-coordinate TBP aluminum geometries. Reaction of AlL with water provided the adduct H2O.AlL (3), a species that is representative of a coordinatively stabilized intermediate in the hydrolysis of an aluminum alkoxide. Theoretical calculations revealed that considerable stabilization energy is obtained by the coordination of a water molecule to the tetracoordinate aluminum in AlL and that this result is consistent with the postulate that the Lewis acidity of AlL exceeds that of boron trifluoride, despite the presence of the transannular N-->Al bond in AlL.     

Hydrogen bonding of 2,4-pentanediol and related molecules studied by infrared and 1H-NMR spectroscopy

Intermolecular self-associations of 2,4-pentanediol, 2-methyl-2,4-pentanediol and 1,3-butanediol in carbon tetrachloride solution have been studied by i.r. and ¹H-NMR spectroscopy. The spectrophotometric data have been analyzed by the least squares method to obtain the association constants and thermodynamic parameters. It turned out that 2,4-pentanediol, 2-methyl-2,4-pentanediol and 1,3-butanediol all take a cyclic trimer structure through hydrogen bonding. The association constants for trimerization were obtained as 330 and 810 mol⁻² dm⁶ at 30°C, and the enthalpy changes were −34 and −38 kJ mol⁻¹ and entropy changes were −62 and −68 J K⁻¹ mol⁻¹, for 2,4-pentanediol and 2-methyl-2,4-pentanediol, respectively.     

Transformations of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one under various conditions of cyclopropyldiazonium generation

Cyclopropyldiazonium generated by basic decomposition of N-cyclopropyl-N-nitrosourea easily entered into an azo coupling reaction with 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (2) to give the corresponding cyclopropylhydrazone in up to 90% yield. Competitive processes occurring under the conditions of cyclopropyldiazonium generation by nitrosation of cyclopropylamine with butyl nitrite mainly include nitrosation of the starting pyrazolone 2. Subsequent transformations of the resulting heterocyclic 3-methyl-1-phenyl-1H-pyrazole-4,5-dione 4-oxime yield 4-[cyclopropyl(oxido)imino]-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2151–2155, December, 2006.     

2,4-dihydroxyquinoline derivatives

Instead of the expected 2,4-dihydroxy-3-quinolyl-3-butanol, the product of its cyclization in the form of the angular isomer-2-methyl-5-hydroxypyrano[3,2-c]quinoline — is obtained in the reduction of 2,4-dihydroxy-3-quinolyl-3-butanone with aluminum, isopropoxide. Some transformations of 2,4-dihydroxy-3-(3-chlorocrotyl)quinoline were investigated.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 836–838, June, 1973.     

Synthesis of divinyl derivatives of 5-substituted l,2,4-triazole-3-thiones

Conclusions The reaction of 5-methyl-, 5-phenyl- and 5--furyl-l,2,4-triazole-3-thiones with acetylene gave their N 1, S- and N 2, S-divinyl derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1674–1676, July, 1986.     

Reactivity of Organolithium Reagents to 2,3,4,5-Tetraphenylcyclopentadienone and Crystal Structures of Addition Products

The conjugate addition reactions of four organolithium reagents to 2,3,4,5-tetraphenylcyclopentadienone (tetracyclone) were investigated to reveal the reactivity of organolithium reagents to tetracyclone. The results show that 1,2-addition products 2,3,4,5-tetraphenyl-1-(2-thienyl)-2,4-cyclopentadien-1-ol(1), 1-n-butyl-2,3,4,5-tetraphenyl-2,4-cyclopentadien-1-ol(2) and 1,2,3,4,5-pentaphenyl-2,4-cyclopentadien-1-ol(3) were synthesized in excellent yields while tetracyclone reacted with 2-thienyllithium, n-butyllithium and phenyllithium, respectively. Interestingly, three 1,2-, 1,4- and 1,6-addition isomers 1-tert-butyl-2,3,4,5-tetraphenyl-2,4-cyclopentadien-1-ol(4), 4-tert-butyl-2,3,4,5-tetraphenyl-2-cyclopenten-l-one(5) and 2-tert-butyl-2,3,4,5-tetraphenyl-3-cyclopenten-l-one(6), were simultaneously obtained by the conjugate addition reaction of tert-butyllithium with larger steric hindrance to tetracyclone. Compounds 1-6 were characterized by ¹H and ¹³C NMR spectra, Fourier transform infrared(FTIR) spectra and mass spectra(MS). The crystal and molecular structures of compounds 1, 2 and isomers 5, 6 were determined by X-ray single crystal diffraction technique. The results imply that the steric hindrance of tert-butyllithium probably play a key role in controlling the conjugate addition reaction. The conjugate addition mechanism of organolithium reagents to tetracyclone was proposed.     

Decyclization of 5-Aryl-4-methyl-2,3-dihydrofuran-2,3-diones by the Action of Nucleophiles

Ring cleavage in 4-methyl-5-phenyl-2,3-dihydrofuran-2,3-dione by the action of methanol and in 5-aryl-4-methyl-2,3-dihydrofuran-2,3-diones by the action of aniline and N-methylaniline results in formation of, respectively, methyl 3-methyl-4-phenyl-2,4-dioxobutanoate and 4-aryl-3-methyl-2,4-dioxobutananilides. The reaction mechanism was studied by ¹H NMR spectroscopy.     

Remarkable substituent effects found in the base-catalyzed reaction of 5-methyl-2-(4′-substituted-phenyl)-2,4-dihydro-3H-pyrazol-3-ones

Remarkable substituent effects found in the base-catalyzed reaction of 5-methyl-4-(1-methylethylidene)-2-(4′-substituted-phenyl)-2,4-dihydro-3H-pyrazol-3-ones ( 2 ) with acetone at reflux are described.     

New Dimethyl(Methylenoxyaryl)Phosphine Oxides

Abstract

In the poster presentation is reported the preparation of the new dimethyl(methylenoxyaryl)phosphine oxides via ZVilliamson reaction from dimethyl-chloromethyl-phoaphine oxide and sodium solts of the coresponding phenols: l-di-methylphosphinylmethylenoxy-4-methyl-2,6-bis(l,l -dimethylethyl)benzene; 1,3-bis(dimethylphosphinylmethylenOxy)benzene; 1,4-bis(dimethylphosphinylmethylenoxy)ben-zene; 1,3,5-tris(dimethylphosphinylmethylenoxy)benzene; 1,2,3-tris(dimethylphosphinylmethylenoxy～benzene; 2,2′-methylene-bia(6-tert-butyl-4-methyl-l-dimethyl-phosphinylmethylenoxybenzene); 2,2′-rnethylene-bis-(6-tert-butyl-4-ethyl-l-dimethylphosphinylmethyleno～-benzene) and 1,1,3-tris(5-tert-butyl-4-dimethylphoa-phinylmethylenoxy-2-methyl-phenyl)butan.     

PASE facile and efficient multicomponent approach to the new type of 5-C-substituted 2,4-diamino-5H-chromeno[2,3-b]pyridine scaffold

The new multicomponent reaction comprises the triethylamine catalyzed assembling of salicylaldehydes, 2-aminoprop- 1-ene-1,1,3-tricarbonitrile and 3-methyl-2-pyrazolin-5-one in small amount of propanol, which affords substituted 2,4-diamino-5-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-5Hchromeno[2,3-b]pyridine-3-carbonitriles in 63–98% yields. This process is in agreement with PASE principles and opens the way to new chromeno[2,3-b]pyridine scaffold containing 3-methyl-2-pyrazolin-5-one fragment, which is promising for various biomedical applications.     

Synthesis of 2,4-diphenyl-1H-pyrrol-1-amine derivatives

The direction of the reaction of 4-bromo-1,3-diphenyl-2-buten-1-one (γ-bromodypnone) with hydrazines depends on the nature of the substituent they contain. Reaction with 1-methylhydrazinium hydrosulfate gives 1-methyl-3,5-diphenylpyridazin-1-ium bromide but carboxylic acid hydrazides give N-(2,4-diphenyl-1H-pyrrol-1-yl)carboxylic acid amides. γ-Bromodypnone and phenylhydrazine give both 1,3,5-triphenyl-1,4-dihydropyridazine and N,2,4-triphenyl-1H-pyrrol-1-amine (15%). 1-(2,4-Dinitrophenyl)hydrazine gives the 2,4-dinitrophenylhydrazone of (Z)-4-bromo-1,3-diphenyl-2-buten-1-one. Condensation of 2,4-diphenyl-1H-pyrrol-1-amine with aromatic aldehydes readily leads to N-(arylmethylidene)-2,4-diphenyl-1H-pyrrol-1-amines and alkylation with methyl iodide gives N,N-dimethyl-2,4-diphenyl-1H-pyrrol-1-amine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 404–414, March, 2009.     

Pyrimidine derivatives and related compounds. 38. Synthesis of 1,3-oxazine-2,4-diones and their reaction with nucleophiles. Ring transformation of 1,3-oxazines to pyrimidines

5,6-Unsubstituted 1,3-oxazine-2,4-diones ( 3 ) and 6-unsubstituted 5-methyl-1,3-oxazine-2,4-diones ( 4 ) were prepared by reduction of the corresponding 6-chloro derivatives ( 1 and 2 ). Treatment of 6-chloro-3-methyl-1,3-oxazine-2,4-dione ( 1a ) with sodium azide, sodium cyanide, secondary amines and aniline gave the corresponding 6-substituted compounds ( 7, 9, 10 and 11 ) while the reaction of 1a and 2a,b with primary aliphatic amines such as methylamine and ethylamine caused a ring transformation to pyrimidine ring system giving barbituric acids ( 13a-d ).