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A simple and efficient arylamination reaction of 5-nitroisoquinoline based on the oxidative nucleophilic substitution of hydrogen was demonstrated under metal-catalyst-free conditions. This reaction can be used as a method for the synthesis of isoquinoline-based diarylamines containing a nitroso group in the ortho position, which are compounds with high synthetic potential. The oxidation of the latter leads to the formation of 6-arylamino-5-nitroisoquinoline N-oxides. The absence of the need to introduce leaving groups and a good overall yield are features of this reaction. [ABSTRACT FROM AUTHOR]

The possibility of expanding a hydrated imidazoline fragment in 2,3-dihydro-9H-dibenzo[b,f]imidazo[2,1-d][1,5]oxazocines was demonstrated for the first time, which granted access to 6,11-dihydro-12H-dibenzo[b,f][1,5]oxazocin-12-one derivatives, previously undescribed compounds with medium-sized rings. In addition, it was shown that imidazooxazocines underwent expansion reactions more readily than their seven-membered analogs. [ABSTRACT FROM AUTHOR]

The review systematizes literature data on methods for constructing imidazo[2,1-b]thiazines and their hydrogenated analogs. The synthetic approaches are grouped by the degree of research done on the imidazothiazine scaffold, from more to less studied. The bibliography of the review includes 80 sources from the last two decades. [ABSTRACT FROM AUTHOR]

A study of cobalt-catalyzed C–H functionalization of phenylglycine derivatives with alkynes is described. During the optimization studies, a range of cobalt catalysts, oxidants, base additives, and reaction solvents were evaluated. Product yield dependence on phenylglycine ester substituent was evaluated. Conditions for 1,2-dihydroisoquinoline synthesis with acceptable yield were found. [ABSTRACT FROM AUTHOR]

Synthesis of novel indeno[1,2-c]isoquinoline derivatives, functionalized at the D ring and bearing 1,2,3-triazole unit, has been reported. These hybrid compounds display cytotoxic activity against two human cancer cell lines – KB and HepG2 with half maximal inhibitory concentration (IC50) values in a range of 20–40 μM. [ABSTRACT FROM AUTHOR]

A convenient method was developed for the synthesis of novel isoquinolin-1(2H)-ones, 1-chloroisoquinolines, and 1-aminoisoquinolines with a heterocyclic substituent in position 3 via a recyclization of 3-hetarylisocoumarins with (NH4)2CO3. 1-Aminoisoquinolines were efficiently obtained from corresponding 1-chloro-3-hetarylisoquinolines (obtained by interaction of isoquinolin-1(2H)-ones with POCl3) and cyclic secondary amines (morpholine or 1-methylpiperazine). Literature data and preliminary results of biological assays allow to consider 1-amino-3-hetarylisoquinolines a promising family of anticancer compounds. [ABSTRACT FROM AUTHOR]

Synthetic approach toward pyridone-substituted furan-2(5H)-ones has been described. Intramolecular cyclization of these compounds leads to novel 7-substituted furo[3,4-f]isoquinolines in moderate to high yields. [ABSTRACT FROM AUTHOR]

Transformations of 2-methyl-1-phenylethynyl-1,2,3,4-tetrahydroisoquinoline resulting from the action of activated alkynes in trifluoroethanol and hexafluoroisopropanol were studied. In reactions with dimethyl acetylenedicarboxylate, 6-phenylethynyl-substituted benzazocines were prepared, while methyl 4-benzyl-5-(2-ethenylphenyl)-1-methyl-1H-pyrrole-3-carboxylate and benzo[d][3]-azacyclodeca[4,6,7]triene with the allene fragment, respectively, were isolated in reactions with methyl propiolate and acetylacetylene in addition to the corresponding benzazocines. As a rule, in hexafluoroisopropanol, the yields of azocines are higher. In reaction with acetylacetylene in dichloromethane, 1-(2-acetylvinyl)-1-phenylethynyltetrahydroisoquinoline is formed in high yield. [ABSTRACT FROM AUTHOR]

An improved procedure for the preparation of benzo[4, 5]imidazo[2,1- a]isoquinolines using PdCl-PPh as catalyst was developed, featuring simple, sequential workup, good selectivity, and compatibility with a wide range of functional groups. Various ( Z)-2-bromovinylimidazoles and 2-chlorophenylboronic acids containing either electron-withdrawing or electron-donating groups were shown to smoothly undergo this sequence of reactions to generate the respective benzo[4, 5]imidazo[2,1- a]isoquinolines in 62-77% yields. [ABSTRACT FROM AUTHOR]

This review considers new methods for the synthesis of N, N ʹ- and C, N-cyclic azomethine imines, as well as the most characteristic of their transformations - (3+2)-dipolar cycloaddition reactions. Particular attention was focused on the issues of regio- and stereoselectivity, the effects of the structure of starting materials, solvents, and catalysts on the reaction direction and yields of cycloadducts. The review covers literature data about the chemistry of cyclic azomethine imines published over the previous 10 years. There are 71 references given. [ABSTRACT FROM AUTHOR]

Transformations of N-cyanomethyl-substituted 1-methyl- and 1-phenylisoquinolinium salts were studied in the presence of various o-hydroxybenzaldehydes, leading to the formation of substituted chromeno[2',3':4,5]imidazo[2,1- a]isoquinolines. 1,8-Diazabicyclo- [5.4.0]undec-7-ene was shown to be a superior base in this reaction compared to sodium carbonate. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] Linear and angular 1-substituted derivatives of 3,3-di- and 3,3,4,4-tetramethyl-3,4-dihydrobenzofuroisoquinoline were obtained under Ritter reaction conditions, and the stereochemical features of these compounds were analyzed. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] New derivatives of partially hydrogenated isoquinolines were obtained by condensation of 2,4-diacetyl-3-aryl(hetaryl)-5-hydroxy-5-methylcyclohexanones with malononitrile and its dimer, 2-amino-1,1,3-tricyano-1-propene, and alkylation reactions of the obtained compounds were studied. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which discusses the synthesis of 3-cyano-1-(2-pyridyl)isoquinolines based on the 5-cyano-3-(2-pyridyl)-1,2,4-triazines by using a method for the synthesis of various pyridine derivatives.

Condensed 3-cyanopyridin-2(1 H)-ones have been synthesized via an intramolecular nucleophilic substitution (Smiles rearrangement). The X-ray structural analysis revealed the existence of intermolecular hydrogen bonding. [ABSTRACT FROM AUTHOR]

2-(3,3-Dimethyl-3,4-dihydro-2H-isoquinolin-1-ylidene)acetonitrile containing an enamine fragment has been acylated using acetyl or benzoyl chlorides to give the corresponding enamino ketones. The acylation using oxalyl chloride gives 5,5-dimethyl-2,3-dioxo-2,3,5,6-tetrahydropyrrolo[2,1- a]-isoquinoline-1-carbonitrile. Reaction of the latter with guanidine carbonate or o-phenylenediamine is accompanied by opening of the pyrrole ring and heterocyclization to give the corresponding 2-amino-4-imidazolone and 2-quinoxalone derivatives. Linear amines were formed in similar reactions with m-toluidine, 1-aminoadamantane, o-aminophenol, and 2-amino-3-hydroxypyridine. [ABSTRACT FROM AUTHOR]

We examined the tandem alkylation/[2+4] cycloaddition of 1-(2-furyl)-3,4-dihydroisoquinolines by various allyl halides. It was found that the process occurred through the intermediate formation of 2-allyl-1-furyl-3,4-dihydroisoquinolinium salts with a subsequent intramolecular exo addition of the allyl fragment to the furan ring. The adducts obtained were structural analogs of the isoindolo-[1,2- a]isoquinoline alkaloids jamtine and hirsutine. [ABSTRACT FROM AUTHOR]

New derivatives of the benzo[de]isoquinoline-1,3-dione system containing an amino group were synthesized by the reaction of 2-benzyl-6-bromobenzo[de]isoquinoline-1,3-dione with ethylenediamine and hydrazine. Further functionalization of the free amino groups leads to imines, amines, thioureas, and hydrazones. Some compounds exhibit high chemosensor selectivity in the determination of anions. [ABSTRACT FROM AUTHOR]

Aminovinyl derivatives of quinoline-5,8-dione and isoquinoline-5,8-dione were obtained. The structure of ( E)-6-chloro-7-[2-( N, N-diethylamino)vinyl]quinoline-5,8-dione was confirmed by X-ray structural analysis. [ABSTRACT FROM AUTHOR]

The alkylation of derivatives of 3-aminoisoquinolin-1(2H)-one in the presence of NaH may proceed in three directions: 1) at the carbonyl group oxygen atom, 2) at the nitrogen atom N-2, and 3) at the 3-amino group. The reaction of equivalent amounts of the reagents gives predominantly products of substitution at the 3-amino group. Repeated alkylation proceeds at the lactam fragment to give a mixture of O-alkyl and N-alkyl derivatives. Acylation of 3-dialkylamino- and 3-alkylanilinoisoquinolin- 1(2H)-ones in the presence of NaH gave derivatives of 3-amino-1-isoquinolinyl 4-ethoxybenzoate. [ABSTRACT FROM AUTHOR]

The reaction of 3-NHR-isoquinolin-1(2H)-ones (R = Ar) with aromatic aldehydes in the presence of Me3SiCl or in acetic acid leads to the formation of derivatives of dibenzo[b,f][1, 8]naphthyridin-5(6H)- one and benzo[f]isoquino[3,4-b][1, 8]naphthyridine-5,9(6H,7H)-dione. The reaction for R = Het in the presence of Me3SiCl gives derivatives of 5H-pyrido[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, benzo[f]isoquinoline[3,4-b][1,8]naphthyridine-5,9[6H,7H]-dione, and derivatives of new heterocyclic systems, 5H-pyrazino[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, 5H-[1,3]thiazolo[3',2':1,2]pyrimido- [4,5-c]isoquinolin-5-one, 5-H-benzo[f]pyrazolo[3,4-b][1,8]naphthyridin-5-one, and isoquino[3,4-b]- [1,5]naphthyridin-5(6H)-one. The effect of the structure of substituent R and nature of the substituent in the benzaldehydes on the structure of the reaction products was studied. [ABSTRACT FROM AUTHOR]

2-(3-Coumarinyl)-5,5-dimethyl-5,6-dihydropyrrolo[2,1- a]isoquinolines were synthesized by the Chichibabin reaction of 3,3-dimethyl-1,2,3,4-tetrahydroisoquinoline with 3-bromoacetylcoumarin. Derivatives of benzo[ f]isoquinoline and benzo[ f]coumarin were obtained similarly. [ABSTRACT FROM AUTHOR]

The reactions of 1-substituted isoquinolinium salts have been studied in the cases of the 1-isopropyl-2-methyl- and 2-methyl-1-cyclohexylisoquinolinium iodides using an alcoholic solution of sodium hydroxide. The possibility of preparing a wide range of spirocyclic ketones, alcohols, amino alcohols, and isochroman-3-ones has been demonstrated. [ABSTRACT FROM AUTHOR]

The reaction of 2,2-dimethyl-1,2-dihydrobenzo[ f]isoquinoline with malonic acid gave (2,2-dimethyl-1,2,3,4-tetrahydrobenzo[ f]isoquinolin-4-yl)acetic acid, the acid chloride of which readily forms esters with alcohols and phenols. Reaction of the same azomethine with thioglycolic acid leads to (2,2-di-methyl-1,2,3,4-tetrahydro-benzo[ f]isoquinolin-4-yl)thioacetic acid. Activation of the initial azomethine by iodomethylation enables reaction with 1,3-indanedione to be carried out. The obtained substances display antifungal action. [ABSTRACT FROM AUTHOR]

novel method is proposed for the preparation of azolo[b]isoquinolines based on the alkylation of N-alkyl-1,3-diazoles or 1,3-thiazole derivatives using [2-(bromomethyl)phenyl](phenyl)methanone with subsequent cyclization of the quaternary azolium salts in the presence of base. The 10(11)-hydroxy derivatives of the 5,10-dihydro-1H-imidazo[1,2-b]isoquinolinium, 6,11-dihydro-5H-benzimidazo-[1,2-b]isoquinolinium, 5,10-dihydro-1H-[1, 2, 4]triazolo[4,3-b]isoquinolinium, or 5,10-dihydro[1, 3]-thiazolo[3,2-b]isoquinolinium bromides obtained in this way readily lose a molecule of water upon heating with HBr or AcO to give the corresponding quasi-aromatic azolo[b]isoquinolinium salts. [ABSTRACT FROM AUTHOR]

Derivatives of the previously unknown tetracyclic system 4H-thieno[3′,4′:5,6]pyrimido[1,2-b]iso-quinoline-4,11(5H)-dione have been synthesized. A comparison of the spectral characteristics and the biological activities of these compounds has been carried out, and also of their positional isomers and benzene isosteres. The differences, associated with the position of the sulfur atom, are most reflected in their electronic spectra. [ABSTRACT FROM AUTHOR]

ylation of 3-amino-1(2H)-isoquinolinone may proceed at three points - at the oxygen atom of the carbonyl group, at the nitrogen atom of the 3-amino group, and at the carbon atom in position 4 of the isoquinolinone fragment. Factors influencing the results of the reactions have been determined, and conditions have been found for the synthesis of three types of products - 4-(acyl)-3-(R-amino)-1(2H)-isoquinolinones, N-(1-oxo-1,2-dihydro-3-isoquinolinyl)-R-amides, and esters of 3-(R-amino)-1-iso-quinolinol. [ABSTRACT FROM AUTHOR]

The reaction of 2-(cyanomethyl)benzoic acid with amines RNH (R = Ar, Het, CHAr, CHHet) leads to the formation of the corresponding 3-NHR-isoquinolin-1(2H)-ones. When R = CHAr and CHHet, there is a side reaction involving hydrolysis of the hydrolytically-unstable intermediates, derivatives of 2-(2-amino-2-iminoethyl)benzoic acid, leading to 2-R-isoquinoline-1,3(2H,4H)-diones. [ABSTRACT FROM AUTHOR]

It has been shown that the reaction of the methyl ester of 3-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-idene)pyruvic acid with thiosemicarbazide in glacial acetic acid leads to heterocyclization with the formation of 3,3-dimethyl-1-(5-thioxo-1,5-dihydro-1,2,4-triazol-3-ylmethylidenecarbonyl)-1,2,3,4-tetra-hydroisoquinoline, but the interaction with semicarbazide under the same conditions leads to annelation of the pyrrole ring. On condensation of the enamino keto ester with malonodinitrile, the nitrile of 2-cyano-4-dicyanomethylidene-5-(3,3-dimethyl-1,2,3.4-tetrahydroisoquinolin-1-idene)-3-oxo-pentanoic acid is formed. [ABSTRACT FROM AUTHOR]

Interaction of (4 Z)-2,2-dimethyl-4-(2-oxo-2-pyrrolidin-1-ylethylidene)-1,2,3,4-tetrahydrobenz[ f]isoquinoline with ninhydrin leads to annulation of an indeno[1,2- b]pyrrole ring. An analogous product is formed by replacing of the pyrrolidine ring with the piperidine ring. Further heating of the obtained glycol in the presence of AcOH leads to rearrangement with the formation of benz[ f]isochromeno-[4',3':4,5]pyrrolo[2,1- a]isoquinoline hexacyclic system. [ABSTRACT FROM AUTHOR]

7-(4-Piperidyl)[1,6]napththiridin-5-one was synthesized on the basis of 2-methylnicotinic acid. 3-(4-Piperidyl)isoquinolin-1-one was synthesized from the diethylamide of o-toluic acid and Weinreb's amide of N-Boc-isonipecotic acid. [ABSTRACT FROM AUTHOR]

7-(3-Piperidyl)- and 7-(4-piperidyl)[1,6]naphthyridines have been synthesized from 2-methylpyridine-3-carbaldehyde cyclohexylimine and the methylmethoxycarboxamides (Weinreb amides) of N-Boc- substituted nipecotic and isonipecotic acids. [ABSTRACT FROM AUTHOR]

3-(3-Piperidyl)isoquinoline and 3-(4-piperidyl)isoquinoline have been synthesized from o-tolylaldehyde aldimines and the methylmethoxycarboxamides (Weinreb amides) of N-Boc-substituted nipecotic and isonipecotic acids. [ABSTRACT FROM AUTHOR]

The nitration of 1'-alkyl-1',4'-dihydro-2,3'-biquinolin-4'-ones and 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones has been investigated. It was shown that the regioselectivity of nitration of the first depends on the acidity of the medium and the order of adding reactants. In strongly acidic medium 1'-alkyl-5,6'-dinitro-1',4'-dihydro-2,3'-biquinolin-4'-ones or mixtures of them with 1'-alkyl-5-nitro-1',4'-dihydro-2,3'-biquinolin-4'-ones are formed. In less acidic media 1'-alkyl-6'-nitro-1',4'-dihydro-2,3'-biquinolin-4'-ones and then 1'-alkyl-6,6'-dinitro-1',4'-dihydro-2,3'-biquinolin-4'-ones are formed. Nitration of 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones leads to 1'-alkyl-6'-nitro-1',2'-dihydro-2,3'-biquinolin-2'-one and then 1'-alkyl-6,6',8'-trinitro-1',2'-dihydro-2,3'-biquinolin-2'-one. [ABSTRACT FROM AUTHOR]

2,3-Dioxpyrrolo[2,1- a]isoquinolines react with 1,8-naphthalenediamine in 2-propanol in the presence of p-toluenesulfonic acid to give 2-spiro-(1,2-dihydroperimid-2-yl)-5,5-dialkyl-2,3,5,6-tetrahydro-pyrrolo[2,1- a]isoquinolin-3-ones whose structure was confirmed by X-ray analysis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The thermal opening of the diaziridine ring in 1-methyl-and 1,3,3-trimethyl-1,3,4,8b-tetra-hydro[1,2]diazirino[3,1-a]isoquinolines in the presence of N-arylmaleimides leads to the predominant or exclusive formation of the trans isomers of the products of 1,3-dipolar cycloaddition. In the absence of dipolarophile, the conversion of the starting diaziridines is incomplete over the same time period, while the thermolysis products are N-[3,4-dihydro-2(1H)-isoquinolyl]-and N-[3,3-dimethyl-3,4-di-hydro-2(1H)-isoquinolyl]-N-methyleneamines formed as the result of isomerization of intermediate labile azomethineimines. [ABSTRACT FROM AUTHOR]

Treatment of 2-(4-oxo-3,4-dihydrothieno[2,3-d]-and-[3,2-d]pyrimidin-2-ylmethyl)benzoic acids and 2-(4-oxo-3,4-dihydro-2-quinazolinylmethyl)benzoic acid with acetic anhydride gave thieno[3′,2′:5,6]-and-[2′,3′:5,6]pyrimido[1,2-b]isoquinoline-4,11-diones and isoquino[2,3-a]quinazoline-5,12-dione respectively. NMR spectroscopy showed that an intramolecular acylation of the above acids occurs at the atom N-1 of the pyrimidinone part of the bicycle. [ABSTRACT FROM AUTHOR]

Treatment of quinazoline-2,4-dione and its symmetrical 1,3-dialkyl derivatives with chlorosulfonic acid gave the corresponding 6-chlorosulfonylquinazoline-2,4-diones. Reaction of the compounds obtained with nucleophilic agents (water, ammonia, aliphatic and cyclic amines) gave the corresponding free 2,4-dioxoquinazoline-6-sulfonic acids, 6-sulfamidoquinazoline-2,4-diones, and 2,4-dioxoquinazoline-6-sulfonic acid amides. [ABSTRACT FROM AUTHOR]

A novel synthesis of 2-substituted 2H-imidazo[1,5-b]isoquinoline-1,5-diones by reductive desulfurization of a variety of 2-substituted 3-thioxo-2H-imidazo[1,5-b]isoquinoline-1,5-diones is reported with nickel boride in dry methanol at ambient temperature. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The reaction of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones with o-xylidene dibromide leads to 11-oxo-4bH,5H,10H,11H,16H-10a-aza-15b-azoniadibenzo[a,e]pleiadene bromides, which are converted to 11-oxo-10H,11H,16H-10a-aza-15b-azoniadibenzo[a,e]pleiadene salts upon oxidation using nitrobenzene. The reaction of these salts with benzylamine leads to 6-{2-[(benzylimino)methyl]phenyl}-7,12-dihydroisoquino[3,2-b][2]benzazepin-14(6H)-ones, which recyclize to 11-oxo-5H,10H,11H-10a-aza-15b-azoniadibenzo[a,e]pleiadene perchlorates upon the action of perchloric acid. The reactions of the 10a,15b-diazadibenzo[a,e]pleiadene salts obtained with NaBH4 were studied and the structures of the reduction products were determined by spectral methods. [ABSTRACT FROM AUTHOR]

The reaction of 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one with carbonyl compounds occurs at the C(6) and/or N(5) atoms depending on the nature of the reagent and the conditions. Condensation with aldehydes gives 6-arylidene-6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-ones. Acylation using acid anhydrides or acid chlorides gave 5-acyl-, 6-acyl-, and 5,6-diacyl-5,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-ones depending again on the reaction conditions. Acylation using chloroacetyl chloride is accompanied by an intramolecular alkylation to give 7H,8H-2a, 7a-diaza-cyclopenta[f,g]naphthacene-1,7(2H)-dione. Phenyl isocyanate gave the derivative containing a CONHPh group at position 6. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The direction of the reaction of anthranilic acids with o-bromomethylphenylacetonitrile upon fusion depends on the temperature and nature of the substituent in the anthranilic acid. The reaction may lead to three types of products: Derivatives of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones below 150°C and to 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one or derivatives of 6H,12H,17H-dibenzo[3,4:6,7][1,8]naphthyridino[1,8-ab]quinazoline-6,17-diones above 150°C depending on the nature of the substituent in the anthranilic acid. A study was carried out on the mechanism for the formation of 6H,12H,17H-dibenzo[3,4:6,7][1,8]naphthyridino[1,8-ab]quinazoline-6,17-diones, which permitted the preparation of 6-(4-methylphenyl)-6,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-one. [ABSTRACT FROM AUTHOR]

It has been shown that the Chichibabin reaction of enamines of the 1,2,3,4-tetrahydroisoquinoline series and 1,2,3,4-tetrahydrobenzo[f]isoquinoline series with p-bromophenacyl bromide leads to pyrrolo[2,1-a]isoquinoline derivatives. The same heterocyclic system is obtained on interaction of 1-alkyl-3,4-dihydroisoquinolines or their benzo[f]-analogs with oxalyl chloride. The obtained dioxopyrrolines form derivatives of benzo[g]quinoxalino[2,3-b]indolizine on condensation with o-phenylenediamine. [ABSTRACT FROM AUTHOR]

The reaction of 3-haloanthranilic acids with o-bromomethylphenylacetonitrile gave 2-(2-carboxy-6-halophenyl)-1,4-dihydro-3(2H)-isoquinolinium bromides. 2-Chlorophenylisoquinolinium bromides are readily converted into 4-R-6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-ones by heating >145°C, but 2,4-dibromophenylisoquinolinium bromide only on fusing with anthranilic acid. The effect of the nature and position of substituents in the quinazoline fragment of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones on the rate of the rearrangement into 6,11-dihydro-13H-isoquino[3,2-b]quinazol-13-ones has been studied. The oxidation and borohydride reduction of 6,11-dihydro-13H-isoquino[3,2-b]quinazol-13-ones has been studied. [ABSTRACT FROM AUTHOR]