Synthesis and alkylation of cyclic azomethines—3-spiro-and 3,3-dimethyl-3,4-dihydroisoquinolines

The cyclic imines 3,3-dimethyl-, 3-spiro-3,4-dihydro-, and benzo[f]isoquinolines were synthesized, and their quaternary salts were obtained. Institute of Technical Chemistry, Urals Branch, Russian Academy of Sciences, Perm 614600, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 236–240, February, 1998.     

1-R-3,3-dialkyl-6,7-ethylenedioxy-3,4-dihydroisoquinolines

A three component “one-pot” condensation of 1,2-ethylenedioxybenzene and RCN nitriles with isobutylene oxide, isobutyraldehyde, or cyclohexanecarboxaldehyde in the presence of conc. H₂SO₄ gives 1-R-3,3-dialkyl-6,7-ethylenedioxy-3,4-dihydroisoquinolines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1198–1203, August, 2005.     

Reduction of enamines of the 3,3-dialkyl-3,4-dihydroisoquinoline series

Lithium aluminum hydride reduced enamines of the 3,3-dialkyl-3,4-dihydroisoquinoline series to the corresponding tetrahydroisoquinolines. In the presence of a hydrogen atom at the -carbon atom of the enamino ester the action of lithium aluminum hydride and alkylmagnesium bromide leads to the products from the condensation of two molecules of the initial compound.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1089–1091, August, 1987.     

Synthesis and tautomerism of 1-substituted 3,3-dialkyl-3,4-dihydroisoquinolines

A number of ethyl esters of 3,3-dialkyl-3,4-dihydroisoquinoline-^1(2H), -- alkylacetic acids have been synthesized. The effect of replacement of -hydrogen by alkyl radicals on the azomethine-enamine tautomeric equilibrium was shown.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 794–797, June, 1985.     

Synthesis of substituted bis(3,3-dialkyl-3,4-dihydro-1-isoquinolyl)methanes

Symmetrical and non-symmetrical substituted bis(3,4-dihydro-1-isoquinolyl)methanes were synthesized by fusion of substituted 1-methylthio-3,4-dihydroisoquinolines with 1-methyl-3,4-dihydroisoquinolines and by the Ritter reaction of 1,1-dialkyl-2-arylethanols with 1-cyanomethylidene-1,2,3,4-tetrahydroisoquinoline or malononitrile.     

Synthesis of 3,3-dialkyl-1-(3-pyridyl)-3,4-dihydroisoquinolines

It has been shown that the reaction of dialkylbenzylcarbinols with 3-cyano-2-pyridones and 2-chloro-3-cyanopyridines gives the corresponding 3,3-dialkyl-1-(3-pyridyl)-3,4-dihydroisoquinolines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1208–1212, August, 2007.     

Themolysis of 3,4-dialkyl-1,2-dioxetames: Effect of cyclic substituents

In 3,4-dialkyl-1,2-dioxetanes, the effect of ring size of cyclic substituents on E_a was found to be 5 ? 7 < 8 < 6 while little or no effect was observed on ΔS^≠.     

Synthesis and structures of 1,1"-dialkyl-3,3"-bidiaziridines

First representatives of 3,3"-bidiaziridines, viz., 1,1"-dialkyl-3,3"-bidiaziridines, were synthesized and isolated as mixtures of two diastereomers. In the case of Alk = Me, the diastereomers were separated. It was demonstrated by nuclear Overhauser effect experiments and X-ray diffraction analysis that the diastereomers are the racemate (rac-1R*,2R*,3S*,1"R*,2"R*,3"S*) and the meso-form (1S*,2S*,3R*,1"R*,2"R*,3"S*).     

Oxiranes in the Ritter Reaction. Synthesis of 6,7- and 5,8-Dimethoxy-3,3-dialkyl-3,4-dihydroisoquinolines by a Tandem Alkylation-Cyclization Reaction

The interaction of 1,2- or 1,4-dimethoxybenzene with isobutylene oxide and nitriles RCN leads to 1-R-6,7- or 1-R-5,8-dimethoxy-3,3-dimethyl-3,4-dihydroisoquinolines. In the case of 1,2-dimethoxybenzene and cyclohexene oxide the similar reaction is accompanied by rearrangement and 1-R-3,3-tetramethylene-3,4-dihydroisoquinolines are formed in low yield. On using cyanoacetic acid ester and any oxide derivatives of tetrahydroisoquinolylideneacetic acid are formed.     

Regioselective reaction of 5,6-dialkyl-2-halopyridine-3,4-dicarbonitriles with ammonia

The reaction of 5,6-dialkyl-2-halopyridine-3,4-dicarbonitriles with alcoholic ammonia under elevated pressure gave 5,6-dialkyl-2-aminopyridine-3,4-dicarbonitriles as a result of nucleophilic replacement of the halogen atom by amino group. 6,7-Dialkyl-4-halo-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diimines were formed in analogous reaction at room temperature in the presence of potassium carbonate.     

Synthesis of 6-hetaryl-5,5-dialkyl-3,3-dimethyl-tetrahydropyran-2,4-diones by Reformatsky Reaction

Zinc enolates derived from ethyl 4-bromo-2,2,4-trimethyl-3-oxopentanoate and 4-bromo-4- ethyl-2,2-dimethyl-3-oxohexanoate react with 2-furan-, 2-thiophene-, 1-(3-nitrophenyl)-2-pyrrole-, 1-acyl-3-indole-, and 2-pyridinecarbaldehydes to give the corresponding 6-hetaryl-5,5-dialkyl-3,3-dimethyltetrahydropyran-2,4-diones.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1549–1551.Original Russian Text Copyright © 2004 by Shchepin, Korzun, Sazhneva.     

Reaction of 3,3-dialkyl-6-trifluoromethyl-2,3-dihydro-4-pyrones with hydrazine hydrate

3,3-Dialkyl-2,3-dihydro-6-trifluoromethyl-4-pyrones react with hydrazine hydrate to give 2-hydrazino-2-trifluoromethyl-4-tetrahydropyrone hydrazones. When heated, the latter are transformed into 3(5)-(2-hydroxyethyl)-5(3)-trifluoromethylpyrazoles, while their treatment with HCl in ether leads to 3,3-dialkyl-2,3-dihydro-6-trifluoromethyl-4-pyrone azines.     

New aspects in the reaction of azomethines with cyclic CH-acidic compounds

Summary Treatment of substituted benzylidene anilines1 a – df with cyclic CH-acidic compounds2a–m in ethanol at room temperature yields in additon/elimination reactions the corresponding arylidene derivatives4 and the 2:1 adducts5. The addition products3, which are formed as intermediates, could not be isolated in any case. The donor/acceptor effect of the substituents on the benzylidene moiety influences to a significant extent the reactivity towards the azomethine carbon.

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Neue Aspekte der Reaktion von Azomethinen mit cyclischen CH-aciden Verbindungen

Zusammenfassung Bei der Umsetzung der substituierten Benzylidenaniline1 a – f mit den cyclischen CH-aciden Verbindungen2 a – m in Ethanol bei Raumtemperatur erhält man in Additions/Eliminierungsreaktionen die Arylidenderivate4 und die 2:1-Addukte5. Die als Intermediat gebildeten Additionsprodukte3 konnten in keinem Fall isoliert werden. Die Donor-bzw. Acceptorwirkung der Substituenten am Benzylidenrest beeinflußt maßgebend die Reaktivität am Azomethinkohlenstoff.

     

Synthesis of 1-substituted-3,3-dimethyl-3,4-dihydroisoquinolines

The Ritter reaction between -substituted propionitriles and dimethylbenzylcarbinols gives 3,3-dimethyl-3,4-dihydroisoquinolines containing substituents in the 1-position corresponding to those in the starting nitrile.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 657–659, May, 1991.     

Synthesis of methylene-bis(1-oxy-3,3-dialkyl-1-triazene 2-oxides) and their analogs

Synthetic procedures towards methylene-bis(1-oxy-3,3-dialkyl-1-triazene 2-oxides), the first representatives of a new class of promising exogenous nitric oxide (NO) donors, which can release NO in living organisms, were developed. Synthesis involves the reactions of salts of 1-hydroxy-3,3-dialkyl-1-triazene 2-oxides with either dibromomethane or 1-chloromethoxy-3,3-dialkyl-1-triazene 2-oxides.     

Synthesis of pyrazolo[3,4-c]isoquinoline and pyrazolo[3,4-b]pyridine derivatives from azomethines and CH-acidic compounds

Summary Donor substituted arylidene aminopyrazoles1a–c and CH-acidic 1,3-dicarbonyl compounds2a–e give in ethanol in an addition/cyclization reaction pyrazolo[3,4-c]isoquinolines4a–i and pyrazolo[3,4-b]pyridine derivatives5a,b, respectively. Using ethyl cyanoacetate as CH-acidic component, cinnamate6 and the cyano substituted pyrazolo[3,4-b]pyridine7 are formed.

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Synthese von Pyrazolo[3,4-c]isochinolin- und Pyrazolo[3,4-b]pyridin-Derivaten aus Azomethinen und CH-aciden Verbindungen

Zusammenfassung Die Reaktion der donorsubstituierten Aryliden-aminopyrazole1a–c mit den CH-aciden 1,3-Dicarbonylverbindungen2a–e führt in einer Additions/Cyclisierungsreaktion zu den Pyrazolo[3,4-c]isochinolin-4a–i bzw. Pyrazolo[3,4-b]pyridin-Derivaten5a,b. Verwendet man Cyanessigester als CH-acide Komponente, werden der Zimtsäureester6 und das cyanosubstituierte Pyrazolo[3,4-b]pyridin7 gebildet.

     

Oxidation of 1-hydrazino-3,3-dimethyl-3,4-dihydroisoquinoline. X-ray,spectroscopic, and quantum-chemical study of the structure of 3,3-dimethyl-3,4-dihydroisocarbostyryl azine

3,3-Dimethyl-3,4-dihydroisocarbostyryl azine (2) has been synthesized by oxidation of l-hydrazino-3,3-dimethyl-3,4-dihydroisoquinoline (1). The crystal and molecular structures of compound 2 were determined. It has been established that in the solid state, compound2 exists as an azine tautomer. The IR, electronic, and NMR spectral data indicate that in solution the tautomeric form of2 does not change. A possible mechanism of the oxidation of1 to2 is suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2468–2474, December, 1995.The authors are grateful to Professor V. F. Zakharov (Russian University of People's Friendship) for recording the¹H NMR spectra.