New heterocyclic structures. [1,2,5]Thiadiazolo[3′,4′:4,5]pyrimido-[2,1-b][1,3]thiazine and thiazolo[3,2a][1,2,5]thiadiazolo[3,4-d]pyrimidine

Derivatives of two new molecular structures, namely, 7,8-dihydro-6H,10H-[1,2,5]thiadiazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazin-10-one and 6,7-dihydro-9H-thiazolo[3,2-a][1,2,5]thiadiazolo[3,4-d][pyrimidin-9-one, and derivatives of N-substituted sulfamic acid, namely, (8-amino-3,4-dihydro-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-on-7-yl)sulfamic acid and (7-amino-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidin-5-on-6-yl)sulfamic acid, were separated out as by-products in the reduction reaction of 8-amino-3,4-dihydro-7-nitroso-2H,6H-pyrimido[2,1- b][1,3]thiazin-6-one and 7-amino-2,3-dihydro-6-nitroso-5H-thiazolo[3,2-a]pyrimidin-5-one derivatives, respectively, with sodium hydrosulfite. A mechanism of reaction, which hypothesizes the action of sodium hydrosulfite in an asymmetic form, is proposed. The results of single-crystal X-ray investigation on 7,8-dihydro-6H,10H-[1,2,5]thiadiazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazin-10-one (R = 0.032 for 863 reflections) and (8-amino-3,4-dihydro-2H,6H-pyrimido[2,1-b]- [1,3]thiazin-6-on-7-yl)sulfamic acid, sodium salt (R = 0.028 for 3507 reflections) are reported.     

Heterocycles structurally influenced by a side chain. X. Effect of temperature and side chain on the imine-enamine tautomerism in the quinoxalinone and pyridopyrazinone systems

3-(1-Benzoyl)ethyl-1H-pyrido[2,3-b]pyrazin-2-one ( 7 ), 3-(1-ethoxycarbonyl)ethyl-1H-pyrido[2,3-b]-pyrazin-2-one ( 8 ), and 3-(1-benzoyl)ethyl-1H-quinoxalin-2-one ( 9 ) exist only in the imine form due to the steric effect of the methyl substituent. As regards the imine-enamine tautomerism, 3-(β-carbonylmethylene) derivatives of 1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one such as 12 and 15–18 gradually change from the enamine form to the imine form with elevated temperatures; however, 3-(carbonylmethylene) derivatives of 3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one such as 10, 19 and 20 show little temperature effect. 2-Phenacylidene-1,2-dihydro-4H-pyrido[3,4-b]pyrazin-3-one ( 21 ) and 3-phenacylidene-3,4-dihydro-1H-pyrido[3,4-b]pyrazin-2-one ( 22 ), which exist in the enamine form, show no temperature effect.     

Reaction of ketenes with N,N-disubstituted α-aminomethyleneketones VII. Synthesis of 2H,5H-[1]benzothiopyrano[4,3-b]pyran and 2H,5H-thiopyrano[4,3-b]pyran derivatives

The dipolar 1,4-cycloaddition of dichloroketerie to N,N-disubslituled 3-aminomethylene-2,3-dihydro-4-thiochromanones and 3-aminomethylenetelrahydro-4-thiopyranones gave N,N-disubstituted 4-amino-3,3-diehloro-3,4-dihydro-2H,5H-[1]benzolhiopyrano[4,3-b]pyran-2-ones and 4-amino-3,3-dichloro-3,4,7,8-tetrahydro-2H,5H-thiopyrano[4,3-b]pyran-2-ones, respectively, only in the ease of aromatic or strong hindering aliphatic N-substitution. The adducts gave N,N′-disubstituted 4-amino-3-chloro-2H,5H-[1]benzothiopyrano[4,3-b]pyran-2-ones and 4-amino-3-chloro-7,8-dihydro-2H,5H-thiopyrano[4,3-b]pyran-2-ones, respectively, by dehydro-chlorination with DBN. By chromatography on neutral alumina, 3-(2,2-dichloroethylidene)-2,3-dihydro-4-thiochromanone was isolated as an unstable liquid from the reaction between dichloroketerie and 3-diethylaminornethylene-2,3-dihydro-4-thiochromanone.     

Reaction of N-Heterocycles with Acetylenedicarboxylates in the Presence of N-Alkylisatins or Ninhydrin. Efficient Synthesis of Spiro Compounds

Summary. The 1,3-dipolar intermediates generated by addition of isoquinoline, to dialkyl acetylenedicaboxylates are trapped by N-alkylisatins to produce dialkyl 1,2-dihydro-2-oxo-1-alkylspiro[3H-indol-3,2′-[2H,11bH][1,3]oxazino[2,3-a]isoquinoline]-3′,4′-dicarboxylates in excellent yields. The reaction of isoquinoline, quinoline, or pyridine with dimethyl acetylenedicarboxylate in the presence of ninhydrin led to dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,2′-[2H,11bH][1,3]oxazino[2,3-a]isoquinoline]-3′,4′-dicarboxylate, dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,3′[3H,4aH][1,3]oxazino[3,2-a]quinoline]-1,2-dicarboxylate, or dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,2′-[2H,9aH]pyrido[2,1-b][1,3]oxazino]-3,4-dicarboxylate.     

Some novel heterocyclic systems derived from 7-amino-2,3-dihydro-8-nitro-1H-pyrrolo[1,2-α]benzimidazole and the corresponding diamine

The preparation of 7-amino-2,3-dihydro-8-nitro-1H-pyrrolo[1,2-a]benzimidazole from 1,4-diacetamido-2,3-dinitrobenzene is described. Reaction of this compound with 2,5-dimethoxytetrahydrofuran produces 2,3-dihydro-8-nitro-7-N-pyrrolo-1H-pyrrolo[1,2-a]benzimidazole, which can be cyclised to produce two new heterocyclic ring systems, 9,10-dihydro-8H-pyrrolo[1,2-a]pyrrolo(1′,2′:1,2]imidazo[5,4-f]quinoxaline and 9,10-dihydro-8H-pyrrolo[2,1-c]pyrrolo[1′,2′:1,2]imidazo[4,5-h][1,2,4]benzotriazine. The corresponding diamine, 7,8-diamino-2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole undergoes a variety of condensation reactions to produce several new heterocyclic systems, for example, with formic acid, 1,7,8,9-tetrahydroimidazo-[4,5-e]pyrrolo[2,1-6]benzimidazole is formed and with diacetyl, 9,10-dihydro-2,3-dimethyl-8H-pyrrolo-[1′,2′:1,2]imidazo[5,4-y]quinoxaline is obtained.     

Unambiguously confirmed structure of 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one

To determine the structures of two isomeric products, 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (2) and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (3) obtained by condensation of 2,3-diaminopyridine (1) with ethyl benzoylpyruvate [1–3], these compounds were hydrolyzed to give 2-methyl-4H-pyrido[2,3-b]pyrazin-3-one (4) and 3-methyl-1H-pyrido[2,3-b]pyrazin-2-one (5) , respectively [4,5]. Both hydrolysates 4 and 5 were hydrogenated to afford 2-methyl-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (6) and 3-methyl-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (7) . The latter compound was identical with an unequivocally synthesized compound providing proof for the structures of all these compounds.     

Synthesis and structure elucidation of the condensation products between thiophene dicarbaldehydes and aromatic amines. Potential analgesic and anti-inflammatory agents

Thiophene-3,4-dicarbaldehyde 1 reacts in the presence of 2-mercaptoethanol to yield N-aryl-5,6-dihydro-4-oxo-4H-thieno[3,4-c]pyrroles 2 and N-aryl-4-arylimino-5,6-dihydro-4H-thieno[3,4-c]pyrroles 3 , while thiophene 2,3-dicarbaldehyde 4 reacts with aromatic amines to give N-aryl-5,6-dihydro-6-oxo-4H-thieno[2,3-c]pyrroles 5 in good yields. Labeling experiments and nmr spectral analysis give evidences for the possible reaction mechanism.     

Reaction of ketenes with N,N-disubstituted α-aminomethyleneketones. XVII. Synthesis of 2H-[1]benzothiepino[5,4-b]pyran derivatives

1,4-Cycloaddition of dichloroketene to a number of N,N-disubstituted (E)-4-amino methylene-3,4-dihydro-[1]benzothiepin-5(2H)-ones gave in excellent yield N,N-disubstituted 4-amino-3,3-dichloro-3,4,5,6-tetrahydro-2H-[1]benzothiepino[5,4-b]pyran-2-ones III, which are derivatives of the 2H-[1]benzothiepino[5,4-b]pyran system. Dehydrochlorination of III with DBN afforded N,N-disubstituted 4-amino-3-chloro-5,6-dihydro-2H-[1]-benzothiepino[5,4-b]pyran-2-ones, generally in excellent yield.     

Tetracyclic phenothiazines. III. . Intermolecular hydride transfer in acid induced disproportionation of 1,2-dihydro-3-hydroxy-3H-pyrido[3,2,1-kl] phenothiazines

1,2-Dihydro-3-hydroxy-3H-pyrido[3,2,1-kl]phenothiazines and 1H-pyrido[3,2,1-kl]phenothiazines undergo acid catalyzed disproportionation with intermolecular hydride transfer to form pyrido[3,2,1-kl]phenothiazinium salts and 1,2-dihydro-3H-pyrido[3,2,1-kl]phenothiazines. Sodium borohydride reduction of 3-alkyl- or 3-arylpyrido[3,2,1-kl]phenothiazinium salts gives 3-alkyl- or 3-aryl-1H-pyrido[3,2,1-kl]phenothiazines. In the presence of a proton source, borohydride reduction of pyrido[3,2,1-kl]phenothiazinium fluoroborate or 3-chloropyrido-[3,2,1-kl]phenothiazinium perchlorate gives 1,2-dihydro-3H-pyrido[3,2,1-kl]phenothiazine, while 1H-pyrido[3,2,1-kl]phenothiazine is formed in aprotic solvents with pyridine present.     

Halogenation of Imidazo[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one Derivatives

Chlorination and bromination of 2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one and its N-methyl-substituted derivatives in acetic acid at 90–95°C leads to formation of the corresponding 5,6-dichloro(dibromo)-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones. Iodination of the same substrates with ICl under analogous conditions yields 6-iodo derivatives. Chlorination of 6-iodo-1,3-dimethyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one is accompanied by replacement of the iodine atom by chlorine with formation of 5,6-dichloro-1,3-dimethyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one. Bromination of 6-bromo- and 6-chloro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones gives 5,6-dibromo- and 5-bromo-6-chloro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones, respectively.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 586–589.Original Russian Text Copyright © 2005 by Yutilov, Lopatinskaya, Smolyar, Gres’ko.     

Polycyclic N-hetero compounds. XXXV. Syntheses and anti-platelet aggregation activity of 5,6-Dihydro-4H-benzo[3,4]cyclohept[1,2-e]imidazo[1,2-c]pyrimidines with an oxygen function at the 1-position

Various 6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-d][pyrimidines bearing amino acid group at the 4-position of the skeleton were synthesized by the reaction of 4-chloro-6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-d]-pyrimidine with some amino acid, which were cyclized to 5,6-dihydro-4H-benzo[3,4]cyclohept[1,2-e]imidazo-[1,2-c]pyrimidines, corresponding to B-homo-11,13,15-triazasteroids. Their inhibitory activities against platelet aggregation induced by collagen were also investigated.     

Reaction of ketenes with N,N-disubstituted α-aminomethyleneketones. XIII. Synthesis of 2H-pyrano[3,2-d]-1-benzoxepin derivatives

Cycloaddition of dichloroketone to N,N-disubstituted (E)-4-aminomethylene-3,4-dihydro-1-benzoxepin-5(2H)-ones gave N,N-disubstituted 4-amino-3,3-dichloro-3,4,5,6-tetrahydro-2H-pyrano[3,2-d]-1-benzoxepin-2-ones II, which are derivatives of the new heterocyclic system 2H-pyrano[3,2-d]-1-benzoxepin. Dehydrochlorination with triethylamine of II afforded N,N-disubstituted 4-amino-3-chloro-5,6-dihydro-2H-pyrano-[3,2-d]-1-benzoxepin-2-ones III in good to moderate yields. In the triethylamine treatment of IIh (NR₂ = diphenylamino), 3-chloro-5,6-dihydro-2H-pyrano[3,2-d]-1-benzoxepin-2-one was isolated in low yield near to IIIh, whereas IIc (NR² = diisopropylamino) gave in low yield 4-diisopropylamino-5,6-dihydro-2H-pyrano(3,2-d)-1-benzoxepin-2-one.     

Annelated piperazinyl-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidines

Tricyclic analogs of piperazinylthiopyrano[3,2-d]pyrimidine hypoglycemic agents were prepared. The angular tricyclic systems, 8,9-dihydro-7H-thiopyrano[2,3-e][1,2,4]triazolo[4,3-a]pyrimidine and 8,9-dihydro-7H-tetrazolo[1,5-a]thiopyrano[2,3-e]pyrimidine derivatives were synthesized from 2,4-dichloro-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine in three step sequences. Derivatives of the linear tricyclic system, 5,6-dihydro-7H-thiopyrano[3,2-d][1,2,4]triazolo[2,3-a]pyrimidine, were prepared by condensation of 3-amino-1,2,4-triazole with ethyl 3-oxo-tetrahydropyran-2-carboxylate. The tricyclic heteroaryl-piperazines lacked significant hypoglycemic activity.     

Research on nitrogen heterocyclic compounds. XII. Synthesis of 5H-pyrrolo[1,2-b][2]benzazepine derivatives

Several routes to the synthesis of the unknown 5H-pyrrolo[1,2-b][2]benzazepine ring system have been explored. 1-(2-Cyanobenzyl)pyrrole was useful as starting material to obtain 1-(2-earboxymelhylbenzyl)pyrrole and 1-(2-chloromethylbenzyl)-2-pyrrolecarboxaldehyde. Poly-phosphoric acid catalyzed intramolecular cyclization of the former substance and treatment of the latter compound with potassium cyanide led to 11-oxo-10,11-dihydro-5H-pyrrolo[1,2-b]-[2]benzazepine and to 10-cyano-5H-pyrrolo[1,2-b][2]benzazepine, respectively. Starting from these materials the synthesis of the parent nucleus 5H-pyrrole[1,2-b][2]benzazepine and its 10,11-dihydro- and 1,2,3,10,11,11a-hexahydroderivatives has been realized.     

Synthesis of Benzofuro[3,2-e][1,4]diazepines

A synthesis of 4-N-oxides and of 3-hydroxy derivatives of 1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-ones and of 2,3-dihydro-1H-benzofuro[3,2-e][1,4]diazepines is described. Condensation of 2-acetyl- and 2-benzoyl-3-ethoxycarbonylaminobenzofurans with acrylonitrile gave derivatives of 1,2-dihydro- and of 1,2,3,4-tetrahydrobenzofuro[3,2-b]pyridine.     

Azaindoles. V. Pyrido(4,3-b]indoles (γ-carbolines) fonctionnalisés sur leur sommet 4: Synthèse en une seule étape

In boiling diphenylether phenylhydrazine reacts with 1,2-dihydro-2-oxo-4-hydroxypyridines to give 3,4-dihydro-4-oxo(9H)-pyrido[4,3-b]indoles (γ-carbolines) in one step. Nucleophilic displacement of their 4-chloro derivatives by secondary amines affords both 3,4-disubstituted γ-carbolines and chlorination of 2,3-dimethyl-4-oxo(9H)pyrido[4,3-b]indoles, as well as methylation of 2-methyl-4-chloro-(9H)pyrido[4,3-b]indole leads to derivatives in the (3H)4-substituted pyrido[4,3-b] indole series.     

A reinvestigation of the synthesis of 3H-[1,2]diazepino[5,6-b]indoles. The synthesis of pyrido[4,3-b]indoles

Recently reported [1] syntheses of 6-methyl-1,2,4,5-tetrahydro-1,4-dioxo-3H[1,2]diazepino[5,6-b]indole ( 5 ) and 4-hydroxy-6-methyl-3H[1,2]diazepino[5,6-b]indole ( 12 ) were reinvestigated and shown to be in error. The correct assignments for these respective structures are 3-amino-1,9-dihydro-9-methyl-2H-pyrido[4,3-b]indol-2,4(3H)-dione ( 6 ) and 3-amino-3,9-dihydro-9-methyl-2H-pyrido[4,3-b]indol-2-one ( 13 ). Condensation of 6 and 13 with p-nitrobenzaldehyde produced benzylidene derivatives, which confirmed the presence of the amino groups.     

2,3,4,9-Tetrahydro-1H-pyrido[3,4-b]indoles. II. Reversible transformation of 1-alkyl-2-(4,9-dihydro-3H-pyrido[3,4-b]indol-1-yl)cyclohexanol into 1-alkylidene-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indoles

Treatment of 2-(4,9-dihydro-3H-pyrido[3,4-b]indol-1-yl)-1-methylcyclohexanol ( 2a ) with acetic anhydride or methyl isocyanate gave 2-acetyl-2,3,4,9-tetrahydro-1-(6-oxoheptylidene)-1H-pyrido[3,4-b]indole ( 3 ) or 1,3,4,9-tetrahydro-N-methyl-1-(6-oxoheptylidene)-2H-pyrido[3,4-b]indole-2-carboxamide ( 4 ), respectively. Simpler analogues, 1-alkyl-4,9-dihydro-3H-pyrido[3,4-b]indoles, 7 , subjected to identical reaction conditions, gave 2-acetyl-1-alkylidene-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indoles 8 and 1,3,4,9-tetrahydro-N-methyl-1-alkyli-dene-2H-pyrido[3,4-b]indole-2-carboxamides 9 , respectively. A limited lanthanide shift reagent study to determine stereochemical assignments was also performed.     

Synthesis of pyrroloazepines. Facile synthesis of 2-substituted pyrrole derivatives by the phosgene method

A highly convenient method for the synthesis of 2-substituted pyrrole derivatives 7a-c from pyrrole using phosgene was developed. Successively, 7-methyl-6,7-dihydro-1H,5H-pyrrolo[2,3-c]azepine-4,8-dione 1a and 6,7-dihydro-1H,5H-pyrrolo[2,3-c]azepine-4,8-dione 1b (aldisin) were synthesized by phosphorus pentoxide/methanesulfonate and polyphosphoric acid cyclization.     

New heterocyclic structures. [1,3]Thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d][1,3]thiazino[3,2-a]pyrimidine

Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d]-[1,3]thiazino[3,2-a]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4-dihydro-7,8-diamino-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6-diamino-2,3-dihydro-2-thioxo-4(lH)-pyrimidi-none with 1,3- or 1,2-dibromoalkane, respectively.