Reaction of pyrrolo[2,1-a]isoquinoline-2,3-diones with carbon-centered nucleophiles

Knoevenagel condensations of 5,5-dimethyl-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-diones with malononitrile, ethyl cyanoacetate, indan-1,3-dione, and Drotaverine base involved the ketone carbonyl group in the former with formation of deeply colored dark blue substances. The lactam ring in the products can be opened by the action of nitrogen-centered nucleophiles, e.g., p-toluidine. The reaction of 5,5-dimethyl-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione with methyl magnesium iodide gave 2-hydroxy-2,5,5-trimethyl-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinolin-3-one.     

Condensed isoquinolines. Part 6. Synthesis of 5-aryl-7,12-dihydroisoquino[2,3-a]quinazolinium salts

2-(o-Aroyl)phenyl-1, 4-dihydroisoquinolin-3(2H)-imine hydrobromides have been synthesized by the reaction of o-bromomethylphenylacetonitrile with o-aminobenzophenones. The products were cyclized into 5-aryl-7,12-dihydroisoquino[2,3-a]quinazolinium perhclorates.T. G. Shevchenko University, Kiev 252017. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 664–666, May, 1995. Original article submitted April 15, 1995.     

Condensed isoquinolines 31. Reaction of 5-aryl-3-halo-12H-isoquino[2,3-a]quinazolines with electrophilic reagents

Treatment of 5-aryl-3-halo-12H-isoquino[2,3-a]quinazolines with electrophilic reagents readily forms their oxidation products. Acylation of the 3-chloro-5-phenyl-7,12-dihydroisoquino[2,3-a]quinazolinium perchlorate with Ac₂O in the presence of pyridine gave the product of electrophilic substitution at the C-7 atom 1-(3-chloro-5-phenyl-12H-isoquino[2,3-a]quinazolin-7-yl)-1-ethanone. By the same route phenacyl bromides react with the anhydro base 1 to give 5-aryl-7-(2-aryl-2-oxoethyl)-3-halo-isoquino[2,3-a]quinazolin-13-ium bromides. These salts readily react with nucleophilic reagents to form the products of addition at the C-12 atom. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1044–1052, July, 2008.     

Condensed isoquinolines. 9. Alkylation of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones

The alkylation of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-one proceeds at N₍₆₎ or C_(–) depending on the type of alkylating agent and reaction conditions. C_(–)-Alkylation occurs in the presence of base. The secondary alkylation of the 7-alkyl derivatives occurs at the same position under these conditions. Depending on the conditions, the reaction with o-xylylene dibromide leads to spiro[5H-isoquino[2,3-a]quinazolin-7(12H).2-indane]-5-one or 11-oxo-4b,5,10,16-tetrahydro-11H-10a-azonia-15b-azadibenz[a,e]pleiadene bromide, which are derivatives of new heterocyclic systems.Communication 8, see ref. [1].See also Letter to Editor [2].Taras Shevchenko Kiev University, 252017 Kiev, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 643–652, May, 2000.     

Condensed Isoquinolines. 10. Borohydride Reduction in the 5H-Isoquino[2,3-a]quinazolin-5-one Series

Borohydride reduction in a series of 7-benzyl- and newly synthesized 7-arylmethylene-7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones leads stereoselectively to erythro-7-benzyl-6,6a,7,12-tetrahydro-5H-isoquino[2,3-a]quinazolin-5-ones. 7,7-Disubstituted 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones are inert to the action of sodium borohydride, but spiro[5H-isoquino[2,3-a]quinazolin-7(12H),2'-indane]-5-one is reduced under rigid conditions to 6,6a-dihydrospiro[5H-isoquino[2,3-a]quinazolin-7(12H),2'-indan]-5-one. 7-Acetyl- and 7-benzoyl-6,11-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones are converted in an aqueous alcoholic solution of sodium borohydride to the previously described 6,6a,7,12-tetrahydro-5H-isoquino[2,3-a]quinazolin-5-one. The structure and special features of the conformational behavior of the reduction products obtained were demonstrated by ¹H NMR spectroscopy.!     

Condensed isoquinolines 29. Oxidation reactions of 5-aryl-7,12-dihydroisoquino[2,3-a]quinazolinium salts

5-Aryl-7,12-dihydroisoquino[2,3-a]quinazolinium perchlorates are readily oxidized by atmospheric oxygen to form the products of oxidative coupling 5,5′-bis(aryl)-3,3′-dihalo[7,7′]bi[isoquino-[2,3-a]quinazoline-13,13′-diylium perchlorates. Heating 3-chloro-5-phenyl-7,12-dihydroisoquino-[2,3-a]quinazolinium perchlorate in nitrobenzene gives the 3-chloro-5-phenylisoquino[2,3-a]quinazolin-13-ium perchlorate. The aromatic 5-arylisoquino[2,3-a]quinazoline derivatives obtained react with nucleophilic reagents to form addition products at the C-12 atom. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 428–439, March, 2008.     

Synthesis of 6-methyl-6H-indolo[3,2-c]isoquinoline and 6-methyl-6H-indolo[2,3-c]isoquinoline: two new unnatural isoquinoline isomers of the cryptolepine series

11H-indolo[3,2-c]isoquinoline has been synthesized in two steps starting from 4-bromoisoquinoline and 2-bromoaniline via a selective Buchwald-Hartwig reaction followed by a Pd-catalyzed intramolecular direct arylation involving C(sp²)-H activation. The synthesis of 7H-indolo[2,3-c]isoquinoline was achieved by a combination of a Suzuki reaction with an intramolecular nitrene insertion reaction starting from 4-bromoisoquinoline and {2-[(2,2-dimethylpropanoyl)amino]phenyl}boronic acid. Selective methylation of the tetracyclic skeletons yielded the title compounds 6-methyl-6H-indolo[3,2-c]isoquinoline and 6-methyl-6H-indolo[2,3-c]isoquinoline, which have never been described in the literature before.     

Reaction of 2,3-dioxopyrrolo[2,1-a]isoquinolines with naphthalene-2,3-diamine

Russian Journal of Organic Chemistry -     

2-Oxo-2,3-dihydroimidazo[2,1-a]isoquinoline and its transformations

2-Oxo-2,3-dihydroimidazo[2,1-a]isoquinoline (I) was synthesized by the action of -haloacetic acids on 1-aminoisoquinoline esters. The reactions of I with nitrous acid, acylating agents, aromatic aldehydes, p-nitrosodimethylaniline, and arenediazonium salts were studied. 3,3-Dihalo derivatives of this system with high reactivities of the halogen atoms were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1666–1671, December, 1976.     

Reaction of 5-chloroanthra[1,9-cd]-6-isoxazolone with oxygen-containing nucleophiles

Facile nucleophilic substitution of the chloride ion to give 5-alkoxy- or 5-aryloxy-anthra[1,9-cd]-6-isoxazolones occurs in the reaction of 5-chloroanthra[1,9-cd]-6-isoxazolone with alcohols and phenols. The possibility of conversion of the synthesized isoxazolones to 1-amino-4-alkoxyanthraquinones is demonstrated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1329–1331, October, 1983.     

Reaction of 2,3-dioxopyrrolo[2,1-a]isoquinolines with o-phenylenediamine

Reaction of 1,2,3,4-tetrahydroisoquinoline enaminoamides with oxalyl chloride gives 2,3-dioxpyrrolo[2,1-a]isoquinolines which react with o-phenylenediamine to give spiro benzimidazolines or condensed quinoxalines, depending on the conditions used.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 808–810, June, 1990.     

Cyclization of N-alkylazinium cations with bifunctional nucleophiles. 29. Synthesis of a novel 1,3,4-thiadiazolo-[2,3-a]quinoxalino[2,3-d]pyrrole heterocyclic system

1,4,4a,5,10,10a-Hexahydro-1,3,4-thiadiazino[5,6-b]quinoxalines react with acetylacetone and acetoacetate esters upon heating in ethanol to give derivatives of a novel heterocyclic system, hexahydro-1,3,4-thiadiazolo[2,3-a]quinoxalino[2,3-d]pyrrole.For Communication 28, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 697–702, May, 1990.     

Synthesis of indazolo[3,2-a]isoquinoline

Treatment of 1-(2′-nitrophenyl)isoquinoline with hot triethylphosphite afforded indazolo[3,2-a]isoquino-line.     

Synthesis of 5H-pyrido[2,3-a]phenoxazin-5-one and 5H-pyrido[3,2-a]phenoxazin-5-one derivatives

The 5H-pyrido[2,3-a]phenoxazin-5-one derivatives and 5H-pyrido[3,2-a]phenoxazin-5-one derivatives were prepared by the condensation of substituted 2-aminophenols with 6,7-dibromo-5,8-quinolinequinone followed by dehalogenation in the presence of sodium hydrosulfite dissolved in aqueous pyridine under a nitrogen atmosphere.     

Condensed 1,3,5-triazines: 1,3,4-Thiadiazolo[3,2-a]-1,3,5-triazines and isoxazolo[2,3-a]-1,3,5-triazines

A convenient route is reported for the synthesis of substituted 1,3,4-thiadiazolo[3,2-a]-1,3,5-triazine-5,7-diones and isoxazolo[2,3-a]-1,3,5-triazines. Condensation of the appropriately substituted 2-amino-1,3,4-thiadiazole and 3-aminoisoxazole with phenoxycarbonyl isocyanate provides the desired target compounds in fair yield.     

Synthesis of derivatives of the new heterocyclic systems benz[f] imidazo [2,1 -a ] isoquinoline and benz [f] pyrimido [2,1 -a] isoquinoline

The synthesis of several derivatives of benz [f] imidazo [2,1 -a] isoquinoline and benz [f] pyrimido-[2,l-a]isoquinoline, both new heterocyclic structures, is described.