Synthesis and some properties of 1,3-diaryl-2,2-dibromoaziridines

1,3-Aryl-2,2-dibromoaziridines have been synthesized and their hydrolytic cleavage in an aqueous medium has been performed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 84–85. January. 1974.     

Synthesis of 1,3-diaryl-4,7-phenanthrolines

A number of new 1,3-diaryl-4,7-phenanthrolines were synthesized by heterocyclization of arylidene-6-quinolylamines with acetophenones in the presence of an acidic catalyst. Intermediate amino ketones and side products, viz., N-(R¹-benzyl)-6-quinolylamines and ,-unsaturated ketones, were isolated. The IR, UV, PMR, and mass spectra of the synthesized compounds are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1398–1401, October, 1985.     

gem-Difluorination of 2,2-diaryl-1,3-dithiolanes by Selectfluor and pyridinium polyhydrogen fluoride

2,2-diaryl-1,3-dithiolanes, readily obtainable from diaryl ketones, were transformed into the corresponding gem-difluoro compounds using a novel reagent combination involving Selectfluor and pyridinium polyhydrogen fluoride (PPHF) under mild conditions in moderate to good yields.     

Synthesis of 1,3-diaryl-1H-benzo[g]indazoles

A facile three-step synthetic route toward 1,3-diaryl-1H-benzo[g]indazoles 1a–1n starting with 3,4-dimethoxy-2-allylbenzaldehyde (6) in modest total yield is described. The facile route was carried by aldol condensation of aldehyde 6 with aryl methyl ketones 5a–5d in alkaline MeOH at reflux, Knorr pyrazole synthesis of the resulting chalcones 4a–4d with aryl hydrazines 3a–3e in EtOH at reflux followed by DDQ-mediated aromatization in toluene at reflux, and oxidative cleavage annulation of olefins 2a–2n with the one-pot combination of OsO₄/NaIO₄/HOAc in the aqueous THF at reflux.     

Synthesis of 2,5-diaryl-1,3-oxazoles containing a carbamate group

Acetophenones containing a methoxycarbonylamino group in position 2, 3, or 4 of the aromatic ring reacted with phenylglycine in the presence of 2 equiv of iodine and 0.5 equiv of sulfanilic acid in DMSO at 100°C for 6 h to give methyl [2(3,4)-(2-phenyl-1,3-oxazol-5-yl)phenyl]carbamates. The reaction was presumed to involve intermediate formation of methyl [(iodoacetyl)phenyl]carbamate. This was confirmed by the isolation of methyl [2-(iodoacetyl)phenyl]carbamate in the reaction of methyl (2-acetylphenyl)carbamate with iodine in glacial acetic acid and its subsequent transformation to methyl [2-(2-phenyl-1,3-oxazol-5-yl)-phenyl]carbamate.     

Synthesis and fungicidal activities of 1-[(2,2-diaryl-1,3-dioxolan-4-yl)methyl]-1H-azoles

Ketalization of benzophenones with epichlorohydrin or 3-chloropropane-1,2-diol gave 2,2-diaryl-4-chloromethyl-1,3-dioxolanes, which were used to alkylate sodium salts of imid-azole or 1,2,4-triazole. The resulting 1-[(2,2-diaryl-1,3-dioxolan-4-yl)methyl]-1H-azoles exhibit high fungicidal activities. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 940–944, May, 2007.     

An Improved Synthesis of 2,2-Dialkyl-1,3-Indanediones

2,2-Dialkyl-1,3-indanediones are useful synthetic intermediates (^1,2) and are know to possess an anticonvulsive activity (³). These compounds are usually prepared by alkylation of 1,3-indanedione under drastic conditions and thus are obtained with low yields (20% to 40%). We describe here a convenient and high yield procedure for the synthesis of symmetrical and unsymmetrical 2,2-dialkyl-1,3-in-danediones based on alkylation of 1,3-indanediones in the presence of celite coated with potassium fluoride (KF-celite). This new reagent has been very recently used to carry out various alkylation reactions (³). We found that KF-celite promotes excellent C-dialkylation (⁴) of 1,3-indanedione la, giving rise to symmetrical 2,2-dialkylated compounds 2a. In the same way, unsymmetrical 2,2-dialkyl-1,3 indanediones 2b can be easily prepared from 2-methyl-1,3-indanedione Ib (⁵).     

Synthesis of 2,2-functionalized benzo[1,3]dioxoles

Highly functionalized catechol ketals exhibiting either a tert-butyl moiety or a spiro center in position 2 are synthesized by ketalization and functionalized in a sequence of subsequent transformations. By a specific ketalization protocol catechol ketals of enolizable β-keto esters can be prepared. With the succeeding steps these compounds incorporate moieties, which are not compatible and accessible by direct ketalization of catechol.     

Spectral-luminescence characteristics of 1,3-diaryl-4,7-phenanthrolines

The effect of the nature of the substituents and the solvent on the absorption and fluorescence spectra and the fluorescence quantum yields of 1,3-diaryl-4,7-phenanthrolines was studied. Electron-donor groups in the para position of the phenyl ring cause a bathochromic shift of the absorption and fluorescence spectra and an increase in the fluorescence quantum yields. A change in the polarity of the solvent leads to a significant shift of the fluorescence spectra of hydroxy and dialkylamino derivatives of 4,7-phenanthroline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1651–1654, December, 1987.     

Electronic effects in the reaction of 1,3-diaryl-1,3-diketones with hydrazinopyridines

The regioselectivity of the condensation of electronically unsymmetrical 1,3-diaryl-1,3-diketones with 2-hydrazinopyridine and 2,6-bis-hydrazinopyridine to form N-(2-pyridyl)-3,5-diarylpyrazoles was studied. Significant electronic effects on regioselectivities were observed, and regioselectivities were opposite to those exhibited by perfluoroalkyl/alkyl 1,3-diketones. The electronic effects correlate well to the difference between the Hammett σ⁺ coefficients of the para substituents on the aryl rings.     

The Synthesis of 3-Acyl-2,3-dihydro-2,2-dimethyl-1,3-thiazoles

Acylation of 2,5-dihydro-2,2-dimethyl-1,3-thiazoles leads to 3-acyl-2,3-dihydro-2,2-dimethyl-1,3-thiazoles as potential starting materials for the total synthesis of racemic cephalosporins.     

Synthesis of Dialkoxydimethylsilanes and 2,2-Dimethyl-1,3-dioxa- 1-Silacyclo Compounds

In the presence of iodine, magnesium reacts with alcohols to give magnesium alkoxides, which are treated with octamethylcyclotetrasiloxane to produce dialkoxydimethylsilanes. Similarly, magnesium reacts with 1,3, 1,4 and 1,5 diols and then with octamethylcyclotetrasiloxane, producing 2, 2-dimethyl-1, 3-dioxa-2-silacyclo compounds.     

Synthesis of 2,2′-(adamantylene-1,3)-diethanoic acids

Via direct oxidative addition of 1,1-dichloroethylene to adamantane or 1,3-dimethyladamantane one obtains diethanoic acids of the adamantane series, which are useful in themselves or for preparation of other functional derivatives. Optimal reaction conditions were found by mathematical modeling.A. V. Topchiev Institute of Petrochemical Synthesis, Volgograd Polytechnic Institute, Russian Academy of Sciences, 117912 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1612–1615, July, 1992.     

Facile Synthesis of Selectively Monoprotected Unsymmetrical 1,3-Diketones from 2,2-Dimethoxyethyl Esters

Selectively monoprotected unsymmetrical 1,3-diketones were obtained by the reaction of 2,2-dimethoxyethyl esters with enamines in the presence of dichlorobis(trifiuoro-methanesulfonato)titanium.     

Synthesis and reactions of 3-alkylsulfanyl-1,3-dihydro-2,1-benzisothiazole 2,2-dioxides

Alkyl- and arylsulfanylation of 1,3-dihydro-2,1-benzisothiazole 2,2-dioxides (benzosultams) 1a-c and pyridosultam 1d with dialkyl and diaryl disulfides provides dithioacetals of 2-aminobenzaldehydes 6-13. 1,3-Dimethylbenzosultam 19 with disulfides forms 3-alkyl(aryl)sulfanyl-1,3-dimethylbenzosultams 20-22 that undergo thermal extrusion of SO₂ followed by a [1,5] sigmatropic hydrogen shift in the intermediate aza-ortho-xylylene leading to 1-arylvinyl sulfides 24-26. Tandem alkylation-sulfanylation of benzo- and pyridosultams 1a-d with 4-bromobutyl thiocyanate gives tetrahydrothiopyrano-spiro-benzosultams 27-30 that, after extrusion of SO₂ and [1,5] hydrogen shift, form 2-aryl-5,6-dihydro-4H-thiopyrans 32-35. Alkylation of pyridosultam 1d with 3-chloropropyl thiocyanate leads directly to 2-pyrido-3,4-dihydrothiophene derivative 37.     

Synthesis of derivatives of 1,3-dihydrospiro[2h-indole-2,2′-pyrrolidine]

Derivatives of 1,3-dihydrospiro[2H-indole-2,2-pyrrolidine] were synthesized by the reaction of 2-methylene-2,3-dihydro-1H-indoles with -iodoacetamide. Treatment of the products with alkyl iodides in the presence of potassium hydroxide gave 1-substituted spiroindole-2,2-pyrrolidines. The 1,3-dihydrospiro[2H-indole-2,2-pyrrolidines] were converted by the action of perchloric acid into 2-(2-carbamoylethyl)-3H-indolium perchlorates.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 57–59, January, 1989.     

A novel method for the synthesis of 2,2-diaryl-1,1-difluoroethenes

β,β-Difluoro-α-phenylvinylstannane 3 was prepared in 60% yield from the reaction of β,β-difluoro-α-phenylvinylsulfone 2 with tributyltin hydride in refluxing benzene for 5 h. The cross-coupling reaction of 3 with aryl iodides bearing substituents such as proton, fluoro, chloro, bromo, methoxy, methyl, trifluoromethyl, and nitro on ortho, meta, para positions of the benzene ring in the presence of 10 mol % Pd(PPh₃)₄/10 mol % CuI afforded the corresponding 2,2-diaryl-1,1-difluoroethenes 4 in 22-82% yields.     

Efficient synthesis of 2,2-diaryl-1,1-difluoroethenes via consecutive cross-coupling reactions of 2,2-difluoro-1-tributylstannylethenyl p-toluenesulfonate

2,2-Difluoro-1-tributylstannylethenyl p-toluenesulfonate (2) was reacted with aryl iodides in the presence of 10 mol % of Pd(PPh(3))(4) and 10 mol % of CuI in DMF at 80 °C for 10-20 h to give the cross-coupled products 3 in 35-97% yields. Further coupling reaction of 3 with arylstannanes in the presence of 5 mol % of Pd(PPh(3))(4) and 3 equiv of LiBr in DMF at 100 °C for 2-24 h afforded the desired products 5 in 25-78% yields.