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 3-methyl-3,4-dihydroisoquinolines based on myristicin

The reaction of a natural allylbenzene, myristicin, with nitriles afforded a series of 7,8-dihydro-[1,3]dioxolo[4,5-g]isoquinoline and 6,7-dihydro[1,3]dioxolo[4,5-h]isoquinoline derivatives.     

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 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.     

Synthesis of 3,3-Dialkyl-1-(3-coumarinyl)-3,4-dihydroisoquinolines

The reaction of dialkylbenzylcarbinols with 3-cyanocoumarin in the presence of sulfuric acid gave 3,3-dialkyl-1-(3-coumarinyl)-3,4-dihydroisoquinoline.     

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.     

Reaction of 1-methylthio-3,4-dihydroisoquinolines with amines

A study was carried out on the reaction of 1-methylthio-3,4-dihydroisoquinolines with aromatic and aliphatic amines, thiourea, semicarbazide, and thiosemicarbazide. The reactions with anthranilic acid and 2-amino-3-carboethoxy-4,5-dmeurylthiophene give 6,6-dmethyl-5,6-dihydro-8H-isoquino[1,2-blquinazolin-8-one and 6, 6, 9,10-tetramethyl-5,6-dihydro-8H-benzo[i]thieno[2,3-b]quinolizin-8-one, respectively. 1-Semicarbazido-and 1-thiosemicarbazido-3,4-dihydroisoquinolines were shown to undergo thermal elimination of ammonia to give substituted 1, 2, 4-triazolo [3, 4-a]isoquinolin-3-ones and 1, 2, 4-triazolo[3, 4-ajisoquinoline-3-thiones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 800-806, June, 1996. Original article submitted June 19, 1995; revision submitted March 14, 1996.     

Synthesis of polyimide and poly(imide-benzoxazole) in polyphosphoric acid

A polyimide made from 4,4′-diaminodiphenyl ether (ODA) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) was synthesized in polyphosphoric acid. Although the polymerization proceeded heterogeneously, a polyimide with an inherent viscosity of 0.90 was obtained, and a tough and flexible film was made from this polyimide. This polymerization was a one-step reaction including polycondensation and imidization; this was also confirmed by a model reaction between aniline and phthalic anhydride. Utilizing this polymerization method, 3,3′-dihydroxy-4,4′-diaminobiphenyl and 2 mol of 4-aminobenzoic acid were reacted in PPA, then BPDA was reacted to obtain an alternate copolymer containing imide and oxazole rings. This reaction gave a homogeneous solution of the poly(imide-benzoxazole). © 1993 John Wiley & Sons, Inc.     

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.     

Polyalkoxybenzenes from plant material 6. Synthesis of 3-methyl-3,4-dihydroisoquinolines from apiol

A number of dihydroisoquinolines were synthesized by the reaction of apiol, a natural allylbenzene, with nitriles. When methyl thiocyanate was used as the nitrile component, the formation of 2-azaspiro[4.5]deca-1,6,9-trien-8-one derivatives, the spiroheterocyclization product, was also observed.     

Reactions of 1,3,3-trimethyl-3,4-dihydroisoquinolines with polyhaloalkanonitriles

The reactions of 1,3,3-trimethyl-3,4-dihydroisoquinolines with halogenated nitriles afford -aminovinylimines, which undergo acid hydrolysis to form 1-(polyhaloacylmethylene)-3,3-dimethyl-3,4-dihydroisoquinolines.     

Thiocarbamoylation of 1,3,3-trimethyl-3,4-dihydroisoquinolines with benzoyl isothiocyanate

Russian Journal of Organic Chemistry -     

Synthesis and Photo-oxygenation of Some Substituted 1-Benzyl-3,4-dihydroisoquinolines. Mechanism of Enamine Photo-oxygenation

The synthesis of a series of substituted 1-benzyl-3,4-dihydroisoquinolines by Bischler-Napieralski cyclization is described. Competitive methylene blue sensitized photo-oxygenation experiments allowed the determination of relative rates of photo-oxygenation of 1-benzyl-3,4-dihydroisoquinolines, Substituents were shown to affect both the equilibrium concentration of the tautomeric enamine and the overall photo-oxygenation rate. After correcting for differences in enamine concentration, the relative rate data provided a diagnostic probe of the reaction mechanism, which involves transfer of charge in the rate-limiting step.     

Synthesis of quinolines involving electrophilic amination of arenes with sodium azide in polyphosphoric acid

Russian Chemical Bulletin -     

Reaction of β-aroylacrylic acids with 1-substituted 3,4-dihydroisoquinolines

The reactions of -aroylacrylic acids and their methyl esters with 1-methyl- and 1-benzyl-3,4-dihydroisoquinolines lead to the formation of -substituted -aroylpropionic acids and their esters, which undergo cyclization to benzopyrrocolinone derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 943–945, July, 1979.