Synthesis and properties of deoxypegan-1-one

Quinazolyl-2-propionic acid hydrochloride (5) was synthesized by reduction of N-(o-nitrobenzyl)succinimide with tin chloride. A pyrroloquinazolin-1-one {4, 3,9-dihydropyrrolo[2,1-b]quinazolin-1(2H)-one} was prepared in 68% yield by heating 5 in Ac₂O and subsequent treatment with Et₃N. Compound 4 was obtained in 71% yield in one step by reduction of N-(o-nitrobenzyl)succinimide with Fe in the presence of HCl. Compound 4 was protonated, alkylated, and acylated on the N₍₄₎ atom. Derivatives of quinazolyl-2-propionic acid and 1-(2-aminobenzyl)succinimide were prepared by reaction of derivatives of 4 with nucleophilic reagents. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 459–462, September–October, 2006.     

Synthesis and study of the mutagenic activity of di(indeno[2,1-b]indolyl)- and di(indeno[2,1-b]pyrrolyl)methanes and -dimethylsilanes

Dihetaryldimethylsilanes and dihetarylmethanes containing indeno[2,1-b]indolyl and indeno[2,1-b]pyrrolyl fragments were synthesized. Their mutagenic activity was tested according to Ames with standard test strains Salmonella typhimurium TA 1537, TA 98, and TA 100.     

Reaction of 6-methoxybenzo[b]furan-3(2H)-one and benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes as a convenient synthetic route to substituted 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans and 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans

The reactions of 6-methoxybenzo[b]furan-3(2H)-one with 2-aryl-1,1-dicyanoethylenes and malononitrile or with aromatic aldehyde and two moles of malononitrile afford 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans. The reactions of benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes or with aromatic aldehyde and one mole of malononitrile produce 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans.     

纳米TiO_2催化一锅法合成喹唑啉酮并酞嗪酮及3-酰胺基异吲哚酮并喹唑啉酮类化合物

以纳米TiO_2为催化剂,靛红酸酐、2-甲酰基苯甲酸、不同芳香肼或酰肼类化合物为原料,在乙醇/水溶液为溶剂的条件下一锅法合成,高产率得到6个喹唑啉酮并酞嗪酮类化合物及10个3-酰胺基取代的异吲哚酮并喹唑啉酮类化合物.该方法简洁高效,反应条件温和,为喹唑啉酮并杂环类化合物的合成提供了一条新途径.     

Condensed isoquinolines. 20. Characteristic features of thermal rearrangement of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-one to form 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one

We studied the dependence of the direction of conversions for salts of angular 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-one on temperature and the nature of the anion: heating in high-boiling solvents leads either to aromatization of the heterosystem or to the rearrangement product, the linear 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one. When its hydrobromide is heated in high-boiling solvents, along with dimerization of the linear isomers, processes of oxidation at the positions 6 and 11 of the heterosystem occur. The dimer obtained in the reaction with morpholine is readily cleaved, with formation of a 6-(4-morpholyl)-substituted linear compound. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 430–439, March, 2007.     

N-alkylation of 2,3-dihydroimidazo[2,1-b]quinazolin-1(10)H-5-one. On the cryptoanionic mechanism of N-substitution

Quantum chemical methods involving studies of transition states of the reaction showed that the main products of N-alkylation of prototropic 2,3-dihydroimidazo[2,1-b]quinazolin-1(10)H-5-one (1) in the gas phase and under neutral conditions in solution occurring via the S_N2 mechanism should be N(10)-alkyl-substituted derivatives formed from the 1H-tautomer. Minor N(1)-substituted derivatives in solution can be produced from both tautomers. For the alkylation of the free N-anion of compound 1, position 1 is attacked first. Validity of conclusions concerning the overall regioselectivity of the reaction was confirmed experimentally. In the absence of solvent, the alkylation proceeds abnormally with a sharp increase in the content of the 1-substituted isomers up to inversion of the regioselectivity of the reaction, which is explained by the participation in the process of the H-bonded dimer of the substrate (1a)₂, which undergoes alkylation via the cryptoanionic mechanism. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 876–887, May, 2006.     

Synthesis of 2-spiro-(1,2-dihydroperimid-2-yl)-5,5-dialkyl-2,3,5,6-tetrahydropyrrolo[2,1-a]-isoquinolin-3-ones

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. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1849–1854, December, 2008.     

Synthesis of 2-aryl-5H-[1,3,4]-thiadiazolo[2,3-b]quinazolin-5-ones

3-Amino-2-thioxo-1,2,3,4-tetrahydroquinazolin-4-ones were converted into 2-aryl-5H-[1,3,4]thiadiazolo[2,3-b]quinazolin-5-ones on treatment with carboxylic acids and POCl₃. 3-Arylmethylidenamino-2-thioxo-1,2,3,4-tetrahydroquinazolin-4-ones also cyclized to 2-aryl-5H-[1,3,4]thiadiazolo[2,3-b]quinazolin-5-ones when oxidized with potassium chlorate in acetic acid, but on heating they were deaminated to give 2-thioxo-1,2,3,4-tetrahydroquinazolin-4-one and aryl nitriles. __________ Translated from Khimiya Geteotsiklicheskikh Soedinenii, No. 5, 787–791, May, 2006.     

A rapid and convenient synthesis of novel 1-imino-2,3-dihydro-1H-pyrazino[2,1,-b]quinazolin-5-ones

Exploring original approaches for the synthesis of therapeutic agents having a quinazoline part, we discovered that novel 3,4-dihydro-2H-pyrazino[2,1,-b]quinazolines (3) may be rapidly and easily obtained via the chemistry of 4,5-dichloro-1,2,3-dithiazolium chloride (1). Our synthetic approach of this reaction is described with the aim of obtaining a well-controlled access to this very rarely described pyrazino[2,1,-b]quinazoline skeleton.     

Synthesis and antimicrobial activity of some 2-alkyl-2H-1,4-benzothiazin-3(4H)-ones and 2-alkylbenzo[d]imidazolo[2,1-b]-thiazolidin-3-ones

Summary Sodium 2-aminothiophenoxide (1) reacts with ethyl 2-bromoalkanoates (2) under direct cyclization to form 2-alkyl-2H-1,4-benzothiazin-3(4H)-ones (3). Reaction of the sodium salt of 2-mercaptobenzimidazole (4) with2 or 2-bromoalkanoic acids (5) affords only S-alkylated products (6 or7, respectively). The cyclization products — 2-alkylbenzo[d]imidazolo[2,1-b]thiazolidin-3-ones (8) — can be obtained only from the corresponding 2-(2-benzimidazolylthio)alkanoic acids (7) by the action of acetic anhydride. Both compounds3 and8 exhibit only moderate antimicrobial activity against some gram-positive bacteria.

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Synthese und antimikrobielle Wirkung von einigen 2-Alkyl-2H-1,4-benzothiazin-3(4H)-onen und 2-Alkylbenzo[d]imidazolo[2,1-b]thiazolidin-3-onen

Zusammenfassung Bei der Reaktion von Natrium-2-aminothiophenolat mit 2-Bromoalkansäure-ethylestern (2) entstehen als Cyclisierungsprodukte 2-Alkyl-2H-1,4-benzothiazin-3(4H)-one (3). Die Umsetzung von Natriumbenzimidazol-2-thiolat mit2 oder mit 2-Bromoalkansäuren (5) liefert nur S-Alkylierungsprodukte (6 oder7). Die Cyclisierungsprodukte — 2-Alkylbenzo[d]imidazolo[2,1-b]thiazolidin-3-one (8) — sind nur durch Umsetzung von entsprechenden 2-(2-Benzimidazolylthio)-alkansäuren (7) mit Acetanhydrid erhältlich. Die Verbindungen3 und8 weisen nur mäßige antimikrobielle Wirkung gegen einige gram-positive Bakterien aus.

     

Condensed Isoquinolines. 17. Enamine Properties of Benzimidazo[1,2-b]isoquinolin-11(5H)-one in Alkylation Reactions

The alkylation of benzimidazo[1,2-b]isoquinolin-11(5H)-one has been studied. This occurs at N₍₅₎ or C₍₆₎ depending on the type of alkylating agent and the reaction conditions. It was shown that C₍₆₎ alkylation is effected in reactions with reactive alkyl halides. A repeat alkylation occurs preferentially at the same position. Interaction with o-xylylidene dibromide leads to spiro[benzimidazo[1,2-b]-isoquinolin-6,2'-indan]-11-one and 1,6-dihydro-11H-6a,11b-diazobenzo[b]benzo[5,6]cyclohepta[1,2,3-l,m]fluoren-11-one, which are derivatives of new heterocyclic systems.     

Condensed isoquinolines 26. Oxidation reactions of 6,11-dihydro-13H-isoquino-[3,2-<Emphasis Type="Italic">b</Emphasis>]quinazolin-13-one derivatives

Oxidation of the hydrobromide of 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one with dimethyl sulfoxide leads to 11-hydroxy-11H-isoquino[3,2-b]quinazoline-6,13-dione, and with hydrogen peroxide to the hydrobromide of 2-[(4-oxo-3,4-dihydro-2-quinazolinyl)carbonyl]benzoic acid. Salts of 5-and 6-alkyl-substituted isoquino[3,2-b]quinazolines are readily oxidized on boiling in nitrobenzene, which leads to aromatization of the isoquino[3,2-b]quinazoline system to 5-methyl-13-oxo-5H,13H-isoquino[ 3,2-b]quinazolinium perchlorate and 6-benzyl-13H-isoquino[3,2-b]quinazolin-13-one. The structures of the dehydrogenation products were established from ¹H NMR and UV spectra. The interaction of the obtained compounds with NaBH₄ has been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1833–1840, December, 2007.     

Synthesis of 2-Aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones and 7-Aryl-2,3,6,7-tetrahydro-5H-imidazo[2,1-b]-1,3-thiazin-5-ones

The reaction of 2-mercaptobenzimidazole, 5-ethoxy-2-mercaptobenzimidazole, and 2-mercaptoimidazoline with cinnamoyl chloride, its derivatives, and heteroanalogs was studied. Convenient methods were found for the synthesis of 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones and 7-aryl-2,3,6,7-tetrahydro-5H-imidazo[2,1-b]-1,3-thiazin-5-ones.     

Microwave-assisted Hantzsch thiazole synthesis of N-phenyl-4-(6-phenylimidazo[2,1-b]thiazol-5-yl)thiazol-2-amines from the reaction of 2-chloro-1-(6-phenylimidazo[2,1-b]thiazol-5-yl)ethanones and thioureas

N-Phenyl-4-(6-phenylimidazo[2,1-b]thiazol-5-yl)thiazol-2-amines (6a-q) have been synthesized by the Hantzsch thiazole reaction of 2-chloro-1-(6-phenylimidazo[2,1-b]thiazol-5-yl)ethanones (4a-e) with suitably substituted thioureas using microwave heating. The ethanones (4a-e) were prepared by the reaction of 6-phenylimidazo[2,1-b]thiazoles (3a-e) with chloroacetylchloride in refluxing 1,4-dioxane whereas the thiazoles (3a-e) were synthesized by the reaction of 2-bromo-1-phenylethanones (2a-e) with thiazol-2-amine in refluxing acetone.     

One-pot synthesis of 3-(2-cyanophenyl)quinazolin-4(3H)-one

Anthranilonitrile reacting with formic acid at room temperature for three days gave 64% of 3-(2-cyanophenyl)quinazolin-4(3H)-one. Under similar conditions anthranilic acid. 4-nitroaniline, and 2,5-dichloroaniline were N-formylated in good yields.Institute of Organic Chemistry and Technology, Silesian Technical University, Krzywoustego, 4, 44–100 Gliwice, Poland; e-mail: wojtex@zeus.polsl.gliwice.pl. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 922–924, July, 2000.     

Synthesis and transformations of 3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridines

Reactions of 2,5-dimethoxytetrahydrofuran with 3-aminothieno[2,3-b]pyridines afford a number of substituted 3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridines. The possibility of the reaction and the yield of the product are determined by the character of a substituent in position 2 of thieno[2,3-b]pyridine. The Curtius rearrangement of 2-acylazido-3(1H-pyrrol-1-yl)thieno[2,3-b]pyridines yields 4,5-dihydropyrido[3",2":4,5]thieno[2,3-e]pyrrolo[1,2-a]pyrazin-4-ones. The molecular and crystal structures of ethyl 4-methoxymethyl-6-methyl-3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridine-2-carboxylate were determined by X-ray diffraction analysis.     

A new method for the synthesis of [1,4]diazepino[6,5-b]indole derivatives

Reactions of 3-[(N-aryl-N-chloroacetyl)amino]-2-formylindoles with substituted anilines gave 1,4-diaryl-2-oxo-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indol-4-ium chlorides and those with 4-aminopyridine yielded 4-amino-1-(1-aryl-2-oxo-2,5-dihydro-1H-pyrido[3,2-b]indol-3-yl)pyridinium chlorides. Reduction of 1,2,3,6-tetrahydrodiazepinoindol-4-ium chlorides afforded the corresponding hexahydro derivatives. An alternative synthesis of 1-(4-nitrophenyl)-3-oxo-4-phenyl-1,2,3,4,5,6-hexahydro[1,4]diazepino[6,5-b]indole from 3-[N-(4-nitrophenyl)amino]-2-[(phenylimino)methyl]indole was developed. The method involves the following sequence of transformations: reduction, chloroacetylation, and intramolecular alkylation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2193–2199, December, 2006.