Synthesis of a 4H-anthra[1,2-b]pyran derivative and its antimicrobial activity

The five-step synthesis of the new 4H-anthra[1,2-b]pyran derivative 1 is reported. The key steps in this approach included a Marschalk alkylation of 1,4-dihydroxyanthraquinone followed by a Baker-Venkataraman reaction and then an acid-catalyzed cyclization of ring A to form the 4H-anthra[1,2-b]pyran system. Two compounds, the 4H-anthra[1,2-b]pyran 1 and the anthraquinone derivative 6 were evaluated for antimicrobial activity and showed moderate antialgal, antifungal, and antibacterial activities.     

The synthesis of dinaphthothiophenes

The synthesis of dinaphtho[1,2-b:2′,3′-d]thiophene ( 6 ), dinaphtho[2,1-b:2′,3′-d]thiophene ( 15 ), dinaphtho-[1,2-b:1′,2′-d]thiophene ( 20 ), dinaphtho[2,1-b:1′,2′-d]thiophene ( 26 ), dinaphtho[2,3-b:2′,3′-d]thiophene ( 37 ) and dinaphtho[1,2-b:2′,1′-d]thiophene ( 45 ) has been accomplished.     

The synthesis of polycyclic thiophenes derived from phenanthrene intermediates

The synthesis of benzo[b]triphenyleno[2,1-d]thiophene ( 9 ), benzo[b]triphenyleno[1,2-d]thiophene ( 13 ), 5-methylbenz[7,8]anthra[2,1-b]thiophene ( 17 ), l-methylchryseno[3,4-b]thiophene ( 18 ), triphenyleno[1,2-c]dibenzothiophene ( 22 ), triphenyleno[2,1-a]dibenzothiophene ( 26 ), triphenyleno[1,2-a]dibenzothiophene ( 29 ), and triphenyleno[2,1-b]dibenzothiophene ( 30 ) is described.     

A novel one-pot synthesis of some new interesting pyrrole derivatives

[reaction: see text] 11-(1H-Pyrrol-1-yl)-11H-indeno[1,2-b]quinoxaline and 3-(1H-pyrrol-1-yl)indolin-2-one derivatives have been synthesized in good yields in a novel, one-pot, and efficient process by condensation of 11H-indeno[1,2-b]quinoxalin-11-one or isatin derivatives with 4-hydroxyproline on solid-support montmorillonite K10 under microwave irradiation.     

Facile one-pot synthesis of photochromic pyrans

[reaction: see text]. Photochromic pyrans, including [3H]naphtho[2,1-b]pyrans, [2H]naphtho[1,2-b]pyrans, indeno-fused naphtho[1,2-b]pyrans, and heteroannulated pyrans, were synthesized in excellent yields through a facile one-pot procedure by reaction of propargyl alcohol and naphthol or phenol derivatives in the presence of 5 mol % PPTS and 2 equiv of (MeO)3CH. Symmetrical and nonsymmetrical bispyrans can also be prepared using the protocol.     

A facile and convenient synthesis of novel imidazo[1,2-b] isoxazoles and their Mannich bases as potential biodynamic agents

A series of novel imidazo[1,2-b]isoxazoles 3 and their Mannich bases 4–6 were synthesized via convenient reactions. The reaction of 3-aminoisoxazole 1 with substituted phenacyl bromides 2 in dry ethanol afforded the corresponding 6-methyl-3-aryl imidazo[1,2-b]isoxazoles 3 in good yields.Compounds 3 on treatment with 37% formaline and secondary amines furnished the corresponding novel Mannich bases viz., 6-methyl-3-aryl-2-(morpholine/pyrrolidin-1-yl/piperidin-1-yl)-methyl-imidazo[1,2-b]isoxazoles 4–6.     

Studies on the synthesis of trans-dihydrodiols of polycyclic aromatic thiaarenes as potential proximate carcinogenic metabolites: first synthesis of trans-10,11-dihydroxy-10,11-dihydroacenaphtho[1, 2-b]benzo[d]thiophene and 6,7-dihydroxy-6,7-dihydronaphtho[1, 2-b]thiophene

Polyaromatic thiophene compounds are found to occur concomitantly with numerous coal-derived products and shale oils and are suspected mutagens and/or carcinogens. The first synthesis of the two title compounds 9 and 16 has been achieved in five or four steps starting from 8,9-dihydroacenaphtho[1,2-b]benzo[d]thiophene (1) and 7-methoxynaphtho[1,2-b]thiophene (12), respectively. Compound 1 was converted to the cis-diol (11) (via treatment with OsO(4)/pyridine) or to trans-diol (3) [via Prevost reaction (PhCOOAg/I(2)) followed by hydrolysis] in 95-98% yield, respectively. Subsequent dehydration (PTS/benzene) of the diol followed by aromatization of the resulting ketone (5) produced the phenolic compound 6 in 97% yield. Oxidation of the phenol with phenyl iododiacetate followed by hydrolysis of the o-quinone monoketal 7 gave the o-quinone (8) in 86% yield. Stereoselective reduction of 8 with NaBH(4)/EtOH under oxygen afforded trans-10,11-dihydroxy-10,11-dihydroacenaphtho[1,2-b]benzo[d]thi oph ene(9) (orange yellow solid) in 55% yield. Compound 16 was obtained as a colorless solid, through the stereoselective reduction of the o-quinone 15 (with NaBH(4)), which in turn was prepared from 12 following the protocol of functional group transformation of methoxy --> phenol --> o-quinone monoketal --> o-quinone, as used in the previous case. The yields for all the steps are very good. The mutagenicity assay of compound 9 and 16 as well as their parent thiaarenes have been performed. The results showed that 9 may not be the proximate carcinogen of acenaphtho[1,2-b]benzo[d]thiophene, while it is likely that compound 16 is one of the possible proximate carcinogens for naphtho[1,2-b]thiophene.     

Thermolysis of benzannulated enyne-carbodiimides. Application in the synthesis of pyrido[1',2':1,2]pyrimido[4,5-b]indoles and related heteroaromatic compounds

Several derivatives of the pyrido[1',2':1,2]pyrimido[4,5-b]indoles 4 and the pyrazino[1',2':1,2]pyrimido[4,5-b]indoles 14 were synthesized by treatment of the benzannulated enyne-isocyanates 8 with the iminophosphoranes 9 and 13, respectively, for the aza-Wittig reaction followed by thermolysis. The reaction presumably proceeds through an initial formation of the corresponding benzannulated enyne-carbodiimides, such as 10, followed by a formal intramolecular hetero Diels-Alder reaction. Surprisingly, when the iminophosphorane 17 was used for condensation with 8, the expected pyrimido[1',6':1,2]pyrimido[4,5-b]indoles 16 were not obtained. Instead, the isomeric pyrimido[6',1':2,3]pyrimido[4,5-b]indoles 21 were isolated. Presumably, an alternative reaction pathway involving an initial [2 + 2] cycloaddition reaction to form 19 followed by ring opening could lead to 20 and, after an intramolecular radical-radical coupling, 21. Treatment of the urea derivatives 24 with dibromotriphenylphosphorane also produced in situ the benzannulated enyne-carbodiimides 25, which on thermolysis gave the isoquinolino[2',1':1,2]pyrimido[4,5-b]indoles 26. Methylation of 4a, 14a, and 26a with methyl iodide occurred exclusively at the site of the indolo nitrogen. The planar geometry of those novel heteroaromatic compounds, resembling many DNA-binding agents, makes them potential candidates as DNA intercalators.     

Structural effects on the electronic properties of extended fused-ring thieno[3,4-b]pyrazine analogues

The synthesis and characterization of the extended thieno[3,4-b]pyrazine analogues acenaphtho[1,2-b]thieno[3,4-e]pyrazine (3a), 3,4-dibromoacenaphtho[1,2-b]thieno[3,4-e]pyrazine (3b), 3-octylacenaphtho[1,2-b]thieno[3,4-e]pyrazine (3c), dibenzo[f,h]thieno[3,4-b]quinoxaline (4), and thieno[3',4':5,6]pyrazino[2,3-f][1,10]phenanthroline (5) are reported. Comparison of structural, electrochemical, and photophysical properties to those of simple thieno[3,4-b]pyrazines are provided in order to provide structure-function relationships within this series of compounds.     

3-炔基咪唑并[1,2-b]哒嗪的简便合成

以咪唑并[1,2-b]哒嗪为原料,与N-碘代丁二酰亚胺在三氟乙酸/二氯甲烷中于室温进行碘代反应制得3-碘咪唑并[1,2-b]哒嗪(3);3与三甲基硅基乙炔在Pd(OAc)_2催化下经Sonogashira偶联反应制得3-三甲基硅基乙炔基咪唑并[1,2-b]哒嗪(4);4在碳酸钾作用下脱除三甲基硅基合成了3-炔基咪唑并[1,2-b]哒嗪,总收率61.2%,其结构经~1H NMR和HR-MS确证。     

Facile and convenient synthesis of new thieno[2,3-b]-thiophene derivatives

A facile and convenient synthesis of bis(2-(1H-benzo[d]imidazol-2(3H)-ylidene)-3-oxopropanenitrile), bis((3-amino-5-(methylthio)-1H-pyrazol-4-yl)methanone) and bis(2-thioxo-1,2-dihydropyrimidine-5-carbonitrile) derivatives incorporating a thieno- [2,3-b]thiophene moiety via versatile, readily accessible diethyl 3,4-dimethylthieno-[2,3-b]thiophene-2,5-dicarboxylate is described.     

The Pictet-Spengler reaction in the synthesis of condensed benzodiazepines 1. synthesis of 6,11,12,14-tetrahydrobenzo-[4,5][1,2]diazepino[7,1-b]quinazolin-14-ones

A new strategy is proposed for the synthesis of the seven-membered heterocyclic skeleton of tetrahydro[4,5][1,2]diazepino[7,1-b]quinazolin-14-ones based on the Pictet-Spengler reaction of 3-amino-2-(3,4-dimethoxybenzyl)quinazolin-4(3H)-one with aromatic aldehydes and paraform in acid media.     

A synthesis of spirofuran-indenoquinoxalines via isocyanid-based one-pot four-component reaction

A simple and versatile procedure for the combinatorial synthesis of (Z)-dialkyl-5-(alkylimino)-5Hspiro[ furan-2,11'-indeno[1,2-b]quinoxaline]-3,4-dicarboxylates via the catalyst-free one-pot fourcomponent reaction of ninhydrin, benzene-1,2-diamines, dialkyl acetylenedicarboxylates and isocyanides is described.     

Iodine catalyzed synthesis of the chromene derivatives in one-pot

Iodine catalyzed one-pot reactions of salicylaldehyde and dimolecular 1 H-indene-1,3(2H)-dione,barbituric acids,4-hydroxycoumarin, or 4-hydroxy-6-methylpyran-2-one were performed and provided a rapid,convenient and general approach to synthesize the chromene derivatives.2-(11-Oxo-10,11-dihydroindeno[l,2-b]chromen-10-yl)-1H-indene-1,3(2H)-diones P1-P4 and 10-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-methylpyrano[4,3-6]chromen-1(10H)-ones P8-P9 were unprecedentedly prepared and structurally identified by NMR and Mass.The confirmation of structure by single crystal X-ray crystallography is reported for P3.     

Parham-type cycliacylation with Weinreb amides. Application to the synthesis of fused indolizinone systems

[reaction: see text] Weinreb amides behave as efficient internal electrophiles in Parham-type cycliacylation reactions. Thus, aryl- and heteroaryllithiums generated by lithium-halogen exchange undergo intramolecular cyclization to give fused indolizinone systems as pyrrolo[1,2-b]isoquinolines, thieno[2,3-f]indolizinones, and pyrrolo[1,2-b]acridinones in high yields.     

A new route to benzo[4,5]cyclohepta[1,2-b]naphthalenes: synthesis of radermachol

[formula: see text] Condensation of 3-phenylsulfonyl-1,3-isobenzofuranone (3) with benzocyclohept-6,7-en-5-ones such as 4 and 15 provides a straightforward, general method for synthesis of functionalized benzo[4,5]cyclohepta[1,2-b]naphthalenes (e.g., 5 and 16). This finding was used to achieve a brief and efficient preparation of 6,7-benzo-3,4-(1,4-dimethoxy-2,3-naphtho)-1,5-dioxosuberane (2), an established intermediate to the naturally occurring red pigment radermachol (1).     

Solvent-free,sonochemical, one-pot,four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones catalyzed by Fe3O4@SiO2-imid-PMAn magnetic nanoparticles

Research on Chemical Intermediates - A practical and green method for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones using Fe3O4@SiO2-imid-PMAn...     

Heterocycles containing nitrogen and sulfur. Part 49. Synthesis of derivatives of new heterocyclic systems: 1,2-Dioxocyclopenta(hexa)[g]oxazolidino-[3,2-f] pyrimido[4,5-b][1,4]thiazine, 1,2-dioxocyclopenta(hexa)-[g] imidazolidino[3,2-f]pyrimido[4,5-b][1,4]thiazine, and 1,2-oxazino[5,4-g]pyrimidino[4,5-b][1,4]thiazine

The reaction of 4-methoxy-5-amino-6-mercaptopyrimidine with 2-oxo-1-chlorocyclopentyl(hexyl)glyoxalate esters gave derivatives of the previously unknown tetracyclic systems 1,2-dioxocyclopenta (hexa)[g]oxazolidino[3,2-f]pyrimido[4,5-b][1,4]thiazines, which are transformed by ammonium acetate into derivatives of 1,2-dioxocyclopenta(hexa) [g]imidazolidino[3,2-f]pyrimido[4,5-b]-[1,4] thiazines. Derivatives of the new tricyclic 1-oxazino [5,4-g]pyrimido[4,5-b][1,4]thiazine system were obrtained by reaction of 6-carbethoxy-7-acetylpyrimido [4,5-b] [1,4] thiazines with hydroxylamine.     

Condensed isoquinolines. 36*. Cyclization of N-alkyl-3-(2-benzoylbenzyl)azolium salts. A novel method of preparing azolo[<Emphasis Type="Italic">b</Emphasis>]isoquinolines

A 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 Ac₂O to give the corresponding quasi-aromatic azolo[b]isoquinolinium salts.     

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides in the synthesis of 2,3-dihydronaphtho- and naphtho[1,2-b]thiophenes

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides, obtained by thermolysis of alkyl 1-naphthyl sulfoxides, are reduced by lithium aluminum hydride to 2,3-dihydronaphtho [1,2-b]thiophenes, whereas under the influence of acetic and trifluoroacetic anhydrides they form naphtho[1,2-b]thiophenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1629–1633, December, 1989.