Fluoro-containing Heterocycles: XIII. Fluoro-containing Derivatives of Thiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]-, Benzothiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]-, and Benzimidazo[3,2-<Emphasis Type="Italic">a</Emphasis>]quinazolinones

Reactions of 2-aminothiazole, derivatives of 2-aminobenzothiazole and 2-aminobenzoimidazole with polyfluorobenzoyl chlorides gave rise to acylation products that at heating in the diphenyl ether formed fluoro-containing derivatives of thiazolo[3,2-a]-, benzothiazolo[3,2-a]-, and benzimidazo[3,2-a]quinazolinone.     

Synthesis and X-ray study of 6<Emphasis Type="Italic">H</Emphasis>-chromeno[3,4-<Emphasis Type="Italic">e</Emphasis>][1,3,4]triazolo[2,3-<Emphasis Type="Italic">a</Emphasis>]pyrimidine

2-Dimethylamino methylenechromanone 1 reacted with 4H-1,2,4-triazol-3-amine in acetic acid to give only one isolated product which was identified by X-ray study as 6H-chromeno[3,4-e][1,3,4]triazolo[2,3-a]-pyrimidine. The molecular structure of 3, C₁₂H₈N₄O, was determined to be monoclinic, P2₁/c, a = 16.3875(5), b = 8.8378(3), c = 13.8392(5) Å, β = 101.190(1)°, V = 1966.22(11) ų, Z = 8.     

Synthesis of pyrazolo[4,3-<Emphasis Type="Italic">e</Emphasis>][1,2,4]triazolo[4,3-<Emphasis Type="Italic">c</Emphasis>]pyrimidines

Starting from 1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-ones, a synthesis pathway to the tricyclic pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidines is described. Reaction of 1,5-dihydro-4H-pyrazolo[3,4-d] pyrimidin-4-ones with phosphoryl chloride afforded the corresponding 4-chloro-1H-pyrazolo[3,4-d]pyrimidines. Treatment of these compounds with hydrazine hydrate at reflux temperature gave the hydrazino derivatives, which were subsequently cyclized to the titled compounds on heating with orthoesters in ethanol. Correspondence: Abolghasem Davoodnia, Department of Chemistry, School of Sciences, Islamic Azad University, Mashhad Branch, Mashhad 91735-413, Iran.     

Synthesis of azepino[1,2-<Emphasis Type="Italic">a</Emphasis>]benzimidazoles and imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]azepines

Fusion of 4-bromo-1,3-diphenyl-2-buten-1-ones (γ-bromodypnones) with 1,2-dimethyl-1H-benzimidazole and further treatment of the reaction product with a base (morpholine) gives 7,9-diaryl-5-methyl5,10-dihydroazepino[1,2-a]benzimidazol-11-ium bromides. The reaction of γ-bromodypnone with 1-alkyl-2-methyl-1H-imidazoles in benzene at 25 °C gives quaternary azolium salts. Upon heating their solutions in alcohol in the presence of K₂CO₃ the latter cyclize to 1-R-6,8-diaryl-1,5-dihydroimidazo[1,2-a]azepin-4-ium bromides or 1-R-6,8-diaryl-1H-imidazo[1,2-a]azepines depending on the nature of the substituent in the benzene rings and the substituent at the N(1) atom of the imidazole.     

Pyrazoles and Pyrazolo[4,3-<Emphasis Type="Italic">e</Emphasis>]pyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrazines,I. Synthesis and Antimicrobial Activity

Summary. The synthesis of the title compounds was achieved using 1-phenyl-5-(pyrrol-1-yl)-1H-pyrazole-3-carboxylic acid azide as starting material. The latter compound was allowed to react with alcohols and amines to afford the corresponding carbamates and urea derivatives. Alkaline hydrolysis of the carbamates gave the corresponding amine, which was acylated and/or aroylated to give amide derivatives. These and the urea derivatives were subjected to cyclodehydration to give the title compounds. Antibacterial and antifungal activities were observed for several derivatives.     

Synthesis of naphtho[1,2-<Emphasis Type="Italic">e</Emphasis>]-pyrazolo[5,1-<Emphasis Type="Italic">b</Emphasis>][1,3]oxazines

The previously unknown heterocyclic system naphtho[1,2-e]pyrazolo[5,1-b][1,3]oxazine was synthesized by the condensation of 1-dimethylaminomethyl-2-naphthols with bromopyrazoles. It is proposed that the highly reactive o-methylenequinone of the naphthalene series is formed as an intermediate.     

Synthesis of new condensed derivatives of pyrano[4,3-<Emphasis Type="Italic">b</Emphasis>]thieno[3,2-<Emphasis Type="Italic">e</Emphasis>]pyridine and pyrido[3',2':4,5]thieno[3,2-<Emphasis Type="Italic">d</Emphasis>]pyrimidine

The reactions of 2-methyl (propyl) substituted 8,8-dimethyl-7,10-dihydro-4H,8H-pyrano[3",4":5',6']pyrido[3',2':4,5]thieno[3,2-d][1,3]oxazines with primary amines give 2-methyl (propyl) substituted 8,8-di- methyl-7,10-dihydro-8H-pyrano[3",4":5',6']pyrido[3',2':4,5]thieno[3,2-d][1,3]pyrimidin-4(3H)-ones or 3-acetyl-N-alkyl- and N-alkyl-3-butyrylamino-7,7-dimethyl-7,8-dihydro-5H-pyrano[4,3-b]thieno[3,2-e]- pyridine-2-carboxamides depending on steric hindrance in the amines.     

Regioselective Synthesis of Thieno[3,2-<Emphasis Type="Italic">c</Emphasis>][1]benzopyran-4-ones by Thio-<Emphasis Type="Italic">Claisen</Emphasis> Rearrangement

Summary. A number of thieno[3,2-c][1]benzopyran-4-ones, potential antiinflamatory, antipyretic, and antiallergic drugs, are synthesized in 65–80% yield by thermal thio-Claisen rearrangement of 4-allylthio[1]benzopyran-2-ones in refluxing quinoline for 0.5–8.0h. The 4-allylthio[1]benzopyran-2-ones are in turn prepared in 75–85% yield from 4-mercaptocoumarin and different allylic halides by phase-transfer-catalysed alkylation with TBAB or BTEAC catalyst in chloroform-aq. NaOH at room temperature.     

Synthesis and properties of cyanomethyl derivatives of imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridine,imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine,and imidazo[2,1-<Emphasis Type="Italic">b</Emphasis>]thiazole

2-Cyanomethyl derivatives were obtained of imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine, and imidazo[2,1-b]thiazole, and their reactivity was investigated by an example of imidazo[1,2-a]pyridine: It was subjected to nitration, bromination, azo coupling and nitrosation. Acylation of the methylene group effected by amino acids esters with a subsequent addition of the amino group to the cyano group resulted in the formation of 5-amino-4-imidazo[1,2-a]-pyridin-2-yl-1-phenyl-1,2-dihydro-3H-pyrrol-3-one and 2-amino-1-ethyl-3-imidazol[1,2-a]pyridin-2-yl-4(1H)-quinolinone.     

Formylation of pyrrolo-[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrazines

The formylation of pyrrolo[1,2-a]pyrazines containing alkyl, aryl, or hetaryl substituents in positions 1 and 6 of the heterocycle has been studied. It has been shown that formylation of 1-phenyl-and 1-(2 thienyl)pyrrolo[1,2-a]pyrazine occurs selectively at the α-position of the pyrrole ring. In all of the remaining examples the reaction course depends on substituent, reagent ratio, and reaction time. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 88–93, January, 2008.     

Synthesis of imidazo[4,5-<Emphasis Type="Italic">a</Emphasis>]acridones and imidazo[4,5-<Emphasis Type="Italic">a</Emphasis>]acridines as potential antibacterial agents

Abstract  New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl₃. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug. Graphical abstract        

A facile one-pot synthesis of 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-<Emphasis Type="Italic">d</Emphasis>]-1,2,4-triazolo[4,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidin-5-ones

Abstract  The reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one or its 2-methylthio derivative with hydrazonoyl halides, in the presence of triethylamine, yielded 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The structure of the latter compounds was further confirmed by reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one with the appropriate active chloromethylenes followed by coupling of the products with benzenediazonium chloride to afford the non-isolable azo-coupling products which converted, in situ, to 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The reaction mechanism was proposed and the products were screened for their biological activity. Some of the newly synthesized compounds had a moderate effect against some bacterial and fungal species. Graphical abstract        

Synthesis of novel 2-phenoxybenzo[<Emphasis Type="Italic">g</Emphasis>][1,2,4]triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]quinazoline and its derivatives starting with diphenyl-<Emphasis Type="Italic">N</Emphasis>-cyanoimidocarbonate

Cyclocondensation reaction of 3-hydrazinyl-2-naphthoic acid with diphenyl-N-cyanoimidocarbonate furnished the target 2-phenoxy-benzo[g][1,2,4]triazolo[1,5-a]quinazolin-5(4H)-one (1) in high yield. Alkylation, thionation and chlorination of the lactam group in the compound 1 produced a variety of derivatives 2–17. Their structures were characterized by NMR and HREI-MS analyses.     

Atropisomeric <Emphasis Type="Italic">N</Emphasis>-acyl-<Emphasis Type="Italic">N</Emphasis>-(cyclopentenylphenyl)glycines in the synthesis of oxazolo[3,4-<Emphasis Type="Italic">a</Emphasis>]benzoxazocinones

Intramolecular [3+2]-cycloaddition was studied of munchnones generated at heating syn- and anti-atropisomers of N-acyl-N-[6-methyl-2-(cyclopent-2-en-1-yl)phenyl]glycines with acetic anhydride. By spectral and X-ray diffraction analysis syn-isomers of acids and tetrahydro-1,4,7-methanetriyl[1,3]oxazolo[3,4-a][1]- bensazocin-3(3aH)-ones were identified.     

A clean synthesis of oxazino[5,6-<Emphasis Type="Italic">f</Emphasis>]quinolinone and naphtho[1,2-<Emphasis Type="Italic">e</Emphasis>]oxazinone derivatives

A clean, simple, one-pot, and efficient synthesis of 1,2-dihydro-1-aryl[1,3]oxazino[5,6-f]quinolin-3-one and 1,2-dihydro-1-arylnaphtho[1,2-e]-[1,3]oxazine-3-one derivatives was accomplished in good yields via reaction between 6-quinolinol or 2-naphthol, aromatic aldehydes, and methyl carbamate in aqueous medium catalyzed by TEBA (triethylbenzylammonium chloride). Correspondence: Mohammad Hossein Mosslemin, Department of Chemistry, Islamic Azad University, Yazd 8916871967, Iran.     

Fluorinated [1,2,4]triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidines and [1,2,4]triazolo[5,1-<Emphasis Type="Italic">c</Emphasis>][1,2,4]triazines*

The reaction of 3-R-5-amino-1,2,4-triazoles with the ethyl ester of 2-fluoroacetoacetic acid gave 2-R-fluoro[1,2,4]triazolo[1,5-a]pyrimidin-7(4H)-ones. The reaction of a 3-R-1,2,4-triazolyl-5-diazonium salt with the ethyl ester of 2-fluoroacetoacetic acid and subsequent cyclization of the triazolylhydrazones lead to 7-R-3-fluoro[1,2,4]triazolo[5,1-c][1,2,4]triazin-4(1H)-ones.