Cascade cyclization of 3(5)-aminopyrazoles with aromatic aldehydes and cyclohexanediones

Three-component condensation of 5(3)-amino-3(5)-methylpyrazole with aromatic aldehydes and 1,3-cyclohexanedione afforded mixtures of 3-methyl-4-aryl-2,4,6,7,8,9-hexa hydro-5H-pyrazolo[3,4-b]quinolin-5-ones and 2-methyl-9-aryl-5,6,7,9-tetrahydro pyrazolo[5,1-b]quinazolin-8(4H)-ones. The reaction of 3-aminopyrazolo-4-carbonitrile and ethyl 3-aminopyrazolo-4-carboxylate with aldehydes and cyclo hexanedione or dimedome is regioselective and leads to the formation of partially hydrogenated pyrazolo [5,1-b]quinazolin-8-one systems. In all compounds the dihydroazine ring exists in the enamine tautomeric form.     

Cascade cyclization reactions of 3,4,5-triamino-1,2,4-triazole with aromatic aldehydes and cycloalkanones

A three-component condensation of 3,4,5-triamino-1,2,4-triazole (1) with aromatic aldehydes 2a–f and dimedone (3) or cyclohexanone (8) afforded partially hydrogenated 9-aryl-[1,2,4]triazolo[5,1-b]quinazolin-8-ones. The structure of 2-amino-6,6-dimethyl-3-(4-nitrobenzylidene)amino-9-(4-nitrophenyl)-5,6,7,9-tetrahydro[1,2,4]triazolo[5,1-b]quinazolin-8-one (4e) was confirmed by X-ray diffraction data. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1178–1182, July, 2006.     

Fluorometric determination of aromatic aldehydes with 1,2-Diaminonaphthalene

A new fluorometric method for the determination of aldehydes is presented. 1,2-Diaminonaphthalene reacts with aldehyde in dilute sulphuric acid to give a compound which fluoresces intensely in alkaline medium. The fluorescences produced from aromatic aldehydes in this method are fairly characteristic of individual aldehydes and their intensities are generally higher than those of fluorescences from aliphatic aldehydes. The only interference is from 2-oxo acids. The method may be suitable for the determination of aldehyde in complex samples.     

Synthesis of 2, 6-diamino-8-arylpurines using aromatic aldehydes

2,6-Diamino-8-arylpurines were obtained by condensation of 2,4,5,6-tetraaminopyrimidine with aromatic aldehydes with nitrobenzene as the oxidizing agent in the presence of p-toluenesulfonic acid or divalent copper.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1430–1434, October, 1972.     

Fluorimetric determination of aromatic aldehydes with 4,5-dimethoxy-1,2-diaminobenzene

A sensitive fluorimetric method for the determination of aromatic aldehydes is described based on their reaction in dilute acid with 4,5-dimethoxy-1,2-diaminobenzene to give a compound which fluoresces intensely in alkaline solution. The fluorescence is stabilized by β-mercaptoethanol. The method is simple, selective for aromatic and arylaliphatic aldehydes, and sensitive; almost all the aldehydes can be determined at concentrations of 10^-8–10^-7 M.     

Nickel-catalyzed 1,2-addition of arylboroxines to aromatic aldehydes

Development of Ni-Et-Duphos-catalyzed 1,2-addition of arylboroxines to aromatic aldehydes is described. The dramatic effect of boron reagent and phosphine ligand is observed. This method with a phosphine ligand allows asymmetric arylation of aromatic aldehydes (up to 78% ee).     

The reaction of aromatic aldehydes with methyl-substituted 4H-pyrido [1,2-α] pyrimidin-4-ones

Sodium methoxide in methanol was the single effective reagent for the reactions between 2,8-dimethyl-, 3, 2,9-dimethyl-, 1 , and 2,3,9-trimethyl-4H-pyrido[1,2-α]pyrimidin-4-one, 2 , and either benzaldehyde or 3,4,5-trimethoxybenzaldehyde. The phenylethenyl derivatives that were formed had the trans-configuration. Although an excess of aldehyde and sodium methoxide as well as long heating periods were employed, with 1 and 2 reaction occurred only at the 2-methyl substituent; with 3 , however, a trace amount of the 2,8-bis-(phenylethenyl) derivative was also isolated.     

Interaction of esters of β-aroylacrylic acids with <Emphasis Type="Italic">o</Emphasis>-phenylenediamines and 1,2-diamino-4-phenylimidazole

3-Phenacylquinoxalin-2-ones were synthesized by the reaction of the ethyl esters of β-aroylacrylic acids with o-phenylenediamines, while interaction with 1,2-diamino-4-phenylimidazole gave ethyl 7-amino-2-aryl-5-phenyl-3,4-dihydroimidazolo[1,5-b]pyridazine-4-carboxylates. Their chemical properties have been investigated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1646–1654, November, 2007.     

Cyclocondensation reaction of 1,2-diamino-4-methylbenzene and p-substituted acetophenones

1,2-Diamino-4-methylbenzene 1 reacts in the presence of sulphuric acid with 4-substituted acetophenones 2a-e yielding 2,4-diaryl-2,3-dihydro-2,8-dimethyl-1H-1,5-benzodiazepines 3a-e and as minor component 2,4-diaryl-2,3-dihydro-2,7-dimethyl-1H-1,5-benzodiazepines 4a-e . The ratio 3:4 is in the range of 7:3. The structure determination of the regioisomers was performed by NOE measurements.     

Reactions of 3-hydroxy-1,2-dihydroquinazolin-4-ones with aldehydes

The reactions of 3-hydroxy-2-(2-hydroxyalkyl)- [or (2-hydroxyaryl)]-1,2-dihydro-quinazolin-4-ones with formaldehyde or acetaldehyde afford 1,3-oxazino[3,4-a]quinazolin-4-one derivatives. The reactions with other aldehydes RCHO and 3-hydroxy-2-R′-1,2-dihydroquinazolin-4-ones can give 3-hydroxy-2-R-1,2-dihydroquinazolin-4-ones, 2-substituted quinazolin-4-ones, or dianthranilide. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2523–2526, December, 1998.     

Stereoselective synthesis of substituted 2,5-diazabicyclo[2.2.1]heptanes by iodine-mediated cyclization of optically pure compounds containing the 4,5-diamino-1,7-octadiene and 1,2-diamino-4-alkene moieties

3,7-endo-Disubstituted 2,5-diazabicyclo[2.2.1]heptanes were obtained by iodo-cyclization of N,N′-di[(S)-1-phenylethyl]-(E,E)-4,5-diamino-1,8-diphenyl-1,7-octadiene and substituted N,N′-di[(S)-1-phenylethyl]-1,2-diamino-4-alkenes. Removal of only one N-substituent of the bridged piperazines was achieved by reduction with ammonium formate and Pd/C. Unexpected cleavage of the skeleton of vinyl-substituted bridged piperazines was observed using hydrogen, leading to substituted 3-aminopyrrolidines.     

Thermal cyclization of α -nit ros o-β-naphthol,o-nitronaphthols,and o-nitrophenols with aromatic aldehydes

The possibility of obtaining 2-aryl-substituted benzoxazoles and naphthoxazoles by heating o-nitrophenols, o-nitronaphthols, and -mtroso--naphthol with aromatic aldehydes in highboiling solvents with simultaneous removal of the water formed by distillation is demonstrated.Communication VI of the series Structure and Properties of Nitroso Compounds. See [1] for communication V.The preparation of XVI was carried out in mesitylene, while the other compounds were prepared in tetralin (10–20 ml of solvent per 0.03 mole of the hydroxy compound). In the preparation of III, VIII, XIII, and XVI-XVIII, 3 moles of aldehyde were introduced into the reaction per mole of hydroxy compound, while 5 moles of the aldehyde per mole of hydroxy compound were used in the remaining cases. Compounds XVI-XVIII were obtained from -nitroso--naphthol, XXI-XXIIwere obtained from -nitro--naphthol, and XIX-XX were obtained from -nitro--naphthol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 10–11, January, 1972.     

Stereoselective synthesis of 1,2-diamino-1,2-diarylethane derivatives

A procedure was developed for selective opening of the cis-2,4,5-triarylimidazoline ring to form erythro-1,2-diamino-1,2-diarylethane derivatives. These ring-opening products, erythro-ethylenediamine derivatives, can undergo quantitative isomerization to threo-ethylenediamine derivatives in the presence of strong bases in DMSO.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 206–209, January, 2005.     

Ruthenium (II)-catalyzed synthesis of phthalides via the cascade addition and cyclization of aromatic acids with aldehydes

The ruthenium-catalyzed intermolecular cascade cyclization of aromatic acids with aromatic aldehydes, which involves the direct insertion of C–H bond into a polar C=O bond and the successive intramolecular nucleophilic substitution, was developed for the synthesis of 3-substituted phthalides in good to excellent yields. This one-pot procedure characterizes in a short reaction time, the cheaper Ru(II) as a catalyst, readily available acids and aldehydes as starting materials, and water as the only theoretical by-product.These merits make the protocol an efficient and cost-effective route for the synthesis of 3-substituted phthalides.     

One-step synthesis of polysubstituted benzene derivatives by multi-component cyclization of alpha-bromoacetate, malononitrile and aromatic aldehydes

Polysubstituted benzene derivatives with an unprecedented substitution pattern are produced in a novel one-pot multi-component cyclization reaction from pyridine, ethyl alpha-bromoacetate, malononitrile and aromatic aldehyde in refluxing acetonitrile.     

Site-selective formation of N-arylmethylimidazoles and C-arylimines in the reaction of 4,5-diamino-2,1,3-benzothiadiazole with aromatic aldehydes

Regioselective formation of N-arylmethylimidazoles and C-arylimines was found in the reaction of 4,5-diamino-2,1,3-benzothiadiazole with selected aromatic aldehydes. The regiochemistry of the reaction products was confirmed by single crystal X-ray analysis. Gibbs free energy calculation using DFT method at the B3LYP/6-31G(d) level supports the regio-selectivity observed. The 4-imine obtained in the reaction of 4,5-diamino-2,1,3-benzothiadiazole with pyrene-1-carboxaldehyde showed an unusually low magnetic field shift of the imine proton that was reproduced by molecular calculations.     

Reaction of perfluoroisobutylene with aromatic aldehydes

Conclusions Depending on the nature of the catalyst, 1,1-bis(trifluoromethyl)-2-arylethylenes or products of the addition of the perfluoro-tert-butyl anion to the carbonyl group are formed in the reaction of perfluoroisobutylene with ArCHO under conditions of nucleophilic catalysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1367–1371, June, 1981.