A simple synthesis of 4‐chloro‐5‐hydroxy‐1H‐benzo[g]indoles

The reaction of methyl 2‐(3‐chloro‐1,4‐dioxo‐1,4‐dihydronaphthalen‐2‐yl)propenoate ( 2a ) with primary amines gave 4‐chloro‐5‐hydroxy‐3‐methoxycarbonyl‐1H‐benzo[g]indoles 5a‐f as major compounds and 3‐methoxycarbonyl‐4,9‐dioxo‐2,3,4,9‐tetrahydro‐1H‐benzo[f]indoles 6a‐d as minor ones. Whereas the reaction of 3‐(3‐chloro‐1,4‐dioxo‐1,4‐dihydronaphthalen‐2‐yl)‐3‐buten‐2‐one ( 2b ) with primary amines afforded the corresponding 1H‐benzo[g]indoles 5g‐i as major products and 3‐acetyl‐4,9‐dihydro‐4,9‐dioxo‐1H‐benzo[f]indoles 7g, h as minor products.     

Synthesis,Characterization, and Cytotoxicity Evaluation of Some New Benzo[f]coumarin Derivatives

Interaction of 2‐(bromoacetyl)‐3H‐benzo[f]coumarin ( 1 ) with salicylaldehyde afforded 2‐(2‐oxo‐2‐(3H‐benzo[f]coumarin‐2‐yl)ethoxy)benzaldehyde ( 2 ) which underwent self‐condensation in refluxing dimethylformamide (DMF) to afford 2‐(2‐benzofuroyl)‐3H‐benzo[f]coumarin (3). Treatment of 1 with o‐aminothiophenol ( 4 ) gave 2‐(2‐((2‐aminophenyl)thio)acetyl)‐3H‐benzo[f]coumarin (5) . Refluxing of 5 in DMF led to formation of 2‐(4H‐[1,4]‐benzothiazin‐3‐yl)‐3H‐benzo[f]coumarin (6). Treatment of 1 with aryl amines 7a–d in boiling DMF gave 1‐aryl‐3‐hydroxybenzo[5,6]chromeno[4,3‐b]pyrrol‐4(1H)‐one ( 10a–d ) . Condensation of 11 with o‐phenylenediamine gave 2‐(2‐methyl‐2,3‐dihydro‐1H‐benzimidazol‐2‐yl)‐3H‐benzo[f]coumarin ( 12 ). Interaction of 2‐acetyl‐3H‐benzo[f]coumarin ( 11 ) with arylidene malonononitrile gave 4‐hydroxy‐2‐(3H‐benzo[f]coumarin‐2‐yl)‐5H‐dibenzo[c,f]chromen‐5‐one ( 16) . All reaction products were characterized by analytical and spectral data. Novel compounds bioactivity as antitumor were examined for in vitro cytotoxicity against HepG‐2 and MCF‐7.     

Selenium heterocycles. XLI . Syntheses of substituted thiazolo,selenazolo, 1,2,3-thiadiazolo and 1,2,3-selenadiazoloquinolines

The reaction of thionyl chloride with the semicarbazone 2 gave 4,5-dihydro[1,2,3]thiadiazolo[4,5-f]quinoline. Selenium dioxide oxidaion of compound 2 gave 4,5-dihydro[1,2,3]selenadiazolo[4,5-f]quinoline ( 4 ) and the aromatic analog 5 . Thermolysis of compound 5 yielded [1,4]diselenino[2,3-f:5,6-f′]diquinoline ( 6 ). Reaction of selenourea with α-bromoketone 7 gave 2-amino-4,5-dihydroselenazolo[4,5-f]quinoline ( 8 ). Compounds 9 and 10 were prepared from the reaction of selenobenzamide and thiobenzamide with compound 7 .     

Targeting π‐Conjugated Multiple Donor–Acceptor Motifs Exemplified by Tetrathiafulvalene‐Linked Quinoxalines and Tetrabenz[bc,ef,hi,uv]ovalenes: Synthesis,Spectroscopic, Electrochemical,and Theoretical Characterization

An efficient synthetic approach to a symmetrically functionalized tetrathiafulvalene (TTF) derivative with two diamine moieties, 2‐[5,6‐diamino‐4,7‐bis(4‐pentylphenoxy)‐1,3‐benzodithiol‐2‐ylidene]‐4,7‐bis(4‐pentylphenoxy)‐1,3‐benzodithiole‐5,6‐diamine ( 2 ), is reported. The subsequent Schiff‐base reactions of 2 afford large π‐conjugated multiple donor–acceptor (D–A) arrays, for example, the triad 2‐[4,9‐bis(4‐pentylphenoxy)‐1,3‐dithiolo[4,5‐g]quinoxalin‐2‐ylidene]‐4,9‐bis(4‐pentylphenoxy)‐1,3‐dithiolo[4,5‐g]quinoxaline ( 8 ) and the corresponding tetrabenz[bc,ef,hi,uv]ovalene‐fused pentad 1 , in good yields and high purity. The novel redox‐active nanographene 1 is so far the largest known TTF‐functionalized polycyclic aromatic hydrocarbon (PAH) with a well‐resolved ¹H NMR spectrum. The electrochemically highly amphoteric pentad 1 and triad 8 exhibit various electronically excited charge‐transfer states in different oxidation states, thus leading to intense optical intramolecular charge‐transfer (ICT) absorbances over a wide spectral range. The chemical and electrochemical oxidations of 1 result in an unprecedented TTF^?+ radical cation dimerization, thereby leading to the formation of [ 1 ^?+]₂ at room temperature in solution due to the stabilizing effect, which arises from strong π–π interactions. Moreover, ICT fluorescence is observed with large solvent‐dependent Stokes shifts and quantum efficiencies of 0.05 for 1 and 0.035 for 8 in dichloromethane.     

Heteroatom chemistry of cyclic benzopolychalcogenides: Synthesis and characterization

Many benzopolychalcogenides, for example benzotrithioles, benzotetrathiins, and benzopentathiepins were synthesized from corresponding 1,2‐benzenedichalcogenols as starting compounds. The stability of the pentathiepin ring toward functional groups was confirmed by use of amino and sulfide groups as substituents in the molecule of benzopentathiepin. Furthermore, the intramolecular interaction between two polysulfide rings was also studied by synthesis of bisbenzotrithiole, 7,7′‐diethyl‐4,4′‐ethylenedioxybis (benzo[1,2‐d][1,2,3]trithiole). © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:419–423, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10069     

Arene imine derivatives of nitrogen heterocycles: 1a,9b-dihydrobenz[h]-azirino[f]quinoline, 1a,9b-dihydrobenz[f]azirino[h]quinoline and 1a,9b-dihydroazirino[f][1,10]phenanthroline

The syntheses of the K-imine derivatives of benzo[h]quinoline ( 1 ), benzo[f]quinoline ( 2 ) and 1,10-phenanthroline ( 3 ) are described. The parent nitrogen heterocycles were oxidized with sodium hypochlorite to the corresponding K-oxides, 4, 6 and 8 , which in turn were reacted with sodium azide. The resulting azido alcohols were then cyclized with triethyl phosphite to the title compounds 5, 7 and 9 . The oxirane ring cleavage in benzo[h]quinoline 5,6-oxide ( 4 ) and in benzo[f]quinoline 5,6-oxide ( 6 ) by sodium azide proceeded by the predicted regioselectivity: 4 gave trans-5-azido-5,6-dihydro-6-benzo[h]quinolinol ( 11 ) and trans-6-azido-5,6-dihydro-5-benzo[h]quinolinol ( 10 ) as the major and minor products respectively, and 6 yielded solely trans-6-azido-5,6-dihydro-5-benzo[f]quinolinol ( 12 ). The latter compound proved by X-ray analysis to crystallize as a hydrogen bonded dimer.     

Synthesis of 4-methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridine

4-Methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridine ( 3 ) was synthetized from 2-acetylfuro[3,2-f]benzo[b]furan ( 4 ) or from 2-acetyl-5,6-dihydrofuro[3,2-f]benzo[b]furan ( 10 ). The key step involves a rearrangement-cyclization of azides 6 and 12 to form 4-methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridin-1(2H) one ( 7 ) and 8,9-dihydro-4-methylfuro[3′,2′:5,6]benzofuro[3,2c]pyridin-1(2H)-one ( 13 ). Introduction of an aminoalkyl chain on carbon 1 was effected by substitution of 1-chloro-4-methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridine ( 8 ).     

Synthesis of tricyclic and tetracyclic thieno[3,2-f]-1,4-thiazepines

Treatment of 5-methylthio-2,3-dihydrothieno[3,2-f]-1,4-thiazepine ( 9 ) with acylhydrazines gave 5,6-dihydrothieno[3,2-f]-1,2,4-triazolo[4,3-d][1,4]thiazepines 10, 11 , and that of 9 with ethyl anthranilate gave 5,6-dihydrothieno[3′,2′:6,7][1,4]thiazepino[5,4-b]quinazolin-8-one ( 14 ). Reaction of 9 with hydrazine hydrate or 4-chlorophenylhydrazine afforded 5-hydrazino compounds 12, 15 , which were subsequently cyclized to ethyl 5,6-dihydrothieno[3,2-f]-1,2,4-triazolo[4,3-d][1,4]thiazepine-3-carboxylate ( 13 ), 2-(4-chlorophenyl)-5,6-dihydrothieno[3,2-f]-1,2,4-triazolo[4,3-d][1,4]thiazepin-3(2H)-one ( 16 ) and 2-(4-chlorophenyl)-6,7-dihydro-2H-thieno[3,2-f][1,2,4]triazino[4,3-d][1,4]thiazepine-3,4-dione ( 17 ). New thieno-anellated heterocycles were prepared with the aim of studying their affinity for the benzodiazepine receptors.     

5,6-Dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetic acid diethyl ester,an useful synthon for the synthesis of new polycyclic nitrogen systems of pharmacological interest

This report describes the synthesis of derivatives of two nitrogen tetracyclic ring systems, respectively 9H,11H-pyrimido[4,3-c]pyrrolo[1,2-a][1,4]benzodiazepine and spiro[piperidine-4,4′-[4H]pyrrolo[1,2-a][1,4]-benzodiazepine], by the use of the diethyl ester of 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetic acid as a synthon. This compound was obtained by condensation of 1-(2-aminomethylphenyl)-1H-pyrrole with diethyl 1,3-acetonedicarboxylate in acid medium. Pyrimidopyrrolobenzodiazepine derivatives were obtained by treating either the pyrrolobenzodiazepine 4,4-diacetate or the related 4-methyl-4-acetate with phenylisocyanate in boiling diethyl ether in the presence of sodium metal. The structure of 12,13-dihydro-11,13-dioxo-12-phenyl-9H,11H-pyrimido[4,3-c]pyrrolo[1,2-a][1,4]benzodiazepine, a product formed by loss of an acetate unit when 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetate, sodium metal and phenyl-isocyanate reacted in boiling xylene, was proved by catalytic reduction to 11,13-dioxo-12-phenyl-12,13,14,14a-tetrahydro-9H,11H-pyrimido[4,3-c]pyrrolo[1,2-a][1,4]benzodiazepine, which was synthesized by unambiguous pathway via 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4-acetate. The 2,6-dioxospiro[piperidine-4,4′-[4H]pyrrolo[1,2-a][1,4]benzodiazepine] derivatives were synthesized from the N-BOC derivative of 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine-4,4-diacetic acid diethyl ester, by hydrolysis followed by treatment with 2 equivalents of 1,1′-carbonyldiimidazole (CDI) and then with aniline or benzylamine. Removal of BOC from the N-phenyl-2,6-dioxopiperidine derivative was obtained by heating the related spiroderivative in toluene in the presence of p-toluenesulphonic acid. Similar reaction failed when the N-benzyl-2,6-dioxopiperidine analog was used as substrate.     

Chemical Reactivity of 4,9‐Dimethoxy‐5‐oxo‐5H‐furo[3,2‐g]chromene‐6‐Carboxaldehyde Toward Some Nucleophilic Reagents

The chemical reactivity of 4,9‐dimethoxy‐5‐oxo‐5H‐furo[3,2‐g ]chromene‐6‐carboxaldehyde (6‐formylkhellin) ( 1 ) was studied toward a diversity of nitrogen nucleophilic reagents. Reaction of carboxaldehyde 1 with some primary amines and heterocyclic amines afforded the corresponding Schiff bases. Also, the reactivity of carboxaldehyde 1 was studied toward some hydrazine derivatives, namely 7‐chloro‐4‐hydrazinoquinoline, 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine, N⁴‐phenylthiosemicarbazide, and S‐benzyldithiocarbazate. 6‐Formylkhellin ( 1 ) underwent ring transformation upon treatment with hydroxylamine hydrochloride producing 5‐hydroxy‐4,9‐dimethoxy‐7‐oxo‐7H‐furo[3,2‐g ]chromene‐6‐carbonitrile ( 22 ). Some pyrimidine, [1,2,4]triazolo[4,3‐a ]pyrimidine, tetrazolo[1,5‐a ]pyrimidine, and diazepine derivatives linked benzofuran were efficiently synthesized. Reaction of carboxaldehyde 1 with a variety of 1,4‐binucleophiles produced furochromone‐fused benzodiazepine, pyridotriazepine, benzoxazepine, and benzothiazepine derivatives. Some unsymmetrical thiocarbohydrazones were also synthesized. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data.     

2‐Triazolylpyrimido[1,2,3‐cd]purine‐8,10‐diones via 1,3‐dipolar cycloadditions to 2‐ethynylpyrimido[1,2,3‐cd]purine‐8,10‐dione

This paper presents the synthesis of a series of 5,6‐dihydro‐4H,8H‐pyrimido[1,2,3‐cd]purine‐8,10(9H)‐dione ring system derivatives with a [1,2,3]triazole ring bonded in position 2. The procedure is based on cycloaddition of substituted alkyl azides to the terminal triple bond of 5,6‐dihydro‐2‐ethynyl‐9‐methyl‐4H,8H‐pyrimido[1,2,3‐cd]purine‐8,10(9H)‐dione ( 4 ). This cycloaddition produced two regioisomers ?5,6‐dihydro‐9‐methyl‐2‐(1‐substituted‐1H‐[1,2,3]triazol‐5‐yl)‐4H,8H‐pyrimido[1,2,3‐cd]purine‐8,10(9H)‐dione ( 7 ) and 2‐(1‐substituted‐1H‐[1,2,3]triazol‐4‐yl) derivative 8 . The required 2‐ethynyl deriva tive 4 was obtained from the starting 2‐unsubstituted compound 1 by bromination to yield the 2‐bromo derivative 2 , which was converted by Sonogashira reaction to trimethylsilylethyne 3 and finally, the protective trimethylsilyl group was removed by hydrolysis.     

Hydrazonoyl Halides Precursors to Synthesis of New Thiazole,Thiadiazole, and Benzothiazepine Derivatives

New series of substituted thiazole and thiadiazoles were prepared starting from N ′‐(3,4‐dihydronaphthalen‐1(2H )‐ylidene)hydrazinecarbothiohydrazide by reacting with different types of hydrazonoyl chlorides. In addition, 7‐(4‐chlorophenyl)‐5,6,6a,7‐tetrahydrobenzo [b ]naphtha‐[1,2‐e ][1,4]thiazepine reacted with hydrazonoyl halides to afford a new derivatives of 7‐(4‐chlorophenyl)‐14‐phenyl‐5,6,6a,7‐tetrahydro‐16H‐benzo[b]naphtho[1,2‐e][1,2,4]triazolo[4,3‐d ][1,4]thiazepine. Structures of the newly synthesized compounds were elucidated on the basis of elemental analyses and spectral data.     

Synthesis and Antibacterial Activity of Some New 2,5‐Disubstituted‐1,3,4‐oxadiazole Derivatives

Synthesis of some new oxadiazole derivatives starting from 1,2,3-benzo[d]triazole-1-acetic hydrazide (1) is described. The target compounds 2-(N-substituted-aminocarbonylmethylthio)-5-(1,2,3-benzo[d]triazol-1-ylmethyl)- 1,3,4-oxadiazole (4a—4i) and 2-[2-(N-substituted-aminocarbonyl)ethylthio]-5-(1,2,3-benzo[d]triazol-1-ylmethyl)- 1,3,4-oxadiazole (5a—5i) were obtained in good yields via cyclisation of 1 and subjected to antibacterial activity test against pathogenic bacteria. The halogen containing mono- and di-substituted derivatives showed excellent antibacterial activity compared to other analogues.     

Vicinal acetylenic derivatives of 2-amino-1,4-naphthoquinone as key precursors of heterocyclic quinones

The Pd-catalyzed reaction between 3-acetylamino-2-bromo-1,4-naphthoquinones and Cu^I acetylides prepared in situ gave 3-acetylamino-2-alkynyl-1,4-naphthoquinones, which were transformed into benz[f]indole-4,9-dione and benzo[g]quinoline-5,10-dione derivatives.     

Synthesis of 2-(3-coumarinyl)pyrrolo[2,1-<Emphasis Type="Italic">a</Emphasis>]isoquinoline derivatives by the chichibabin reaction

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.     

Synthesis and characterization of 1H-benz[f]indole-4,9-dione and the related dihydroxy derivative

Dehydrogenation and contemporaneous demethylation of the parent 4,9-dimethoxy-5,6,7,8-tetrahydro-1H-benz[f]indole ( 2 ) yielded the expected aromatization products 4 and 5 (1H-benz[f]indole-4,9-dione and 4,9-di-hydroxy-1H-benz[f]indole, respectively).     

Pyridyl-substituted [1,3]Dithiolo-[4,5-<Emphasis Type="Italic">b</Emphasis>][1,4]dithiine-2-thiones

We have obtained 5-(2-pyridyl)[1,3]dithiolo[4,5-b][1,4]dithiine-2-thione for the first time by cycloaddition of 2-ethynylpyridine to 4,5-dihydro-1,3-dithioltrithione (isotrithionedithiol). We have studied this thione, 5-(2-pyridyl)- and 5-(4-pyridyl)-5,6-dihydro[1,3]dithiolo[4,5-b][1,4]dithiine-2-thiones by mass spectroscopy and also IR, UV, ¹H and ¹³C NMR spectra. We have determined the crystal and molecular structure of 5-(2-pyridyl)-5,6-dihydro[1,3]dithiolo[4,5-b][1,4]dithiine-2-thione.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 429–434, March, 2005.     

Synthesis of pyrimidinones by action of benzamidine on a benzocycloheptenic β‐keto ester

The synthesis of a polycyclic heterocyclic ring system compound, ethyl 7‐hydroxy‐4‐oxo‐2‐phenyl‐4,5‐dihydro‐3H‐benzo[6,7]cyclohepta[1,2‐d]pyrimidine‐6‐carboxylate was carried out by condensation of benzamidine on diethyl 5,9‐dihydroxy‐7H‐benzo[a]cycloheptene‐6,8‐dicarboxylate, after opening and then closure of the seven membered ring.     

Study of reaction between activated acetylenes and N,N′‐diethyl‐2‐thiobarbituric acid in the presence of isocyanides or triphenylphosphine

In a series of separate experiments reaction between N,N′‐diethyl‐2‐thiobarbituric acid and acetylenic diesters in the presence of isocyanides or triphenylphosphine led to highly functionalized 4H‐pyrano[2,3‐d]thiopyrimidine or 1,4‐di‐ionic organophosphorus derivatives. The ¹H NMR spectra of diethyl‐7‐(2,6‐dimethylphenylamino)‐4‐oxo‐2‐thio‐ 1,3‐diethyl‐4H‐pyrano[2,3‐d]pyrimidine‐5,6‐dicarboxylate showed dynamic NMR effect that was attributed to restricted rotation around the aryl‐nitrogen single bond. Activation free energy (ΔG^≠) for this process is about 54.85 ± 2 kJ mol⁻¹. Betaines as 1,4‐diionic organophosphorus compounds in this reaction are possessed of two vicinal stereogenic centers and exist in the solution as a mixture of two diastereoisomers. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:228–235, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20601     

Selenium heterocycles XLIV. Syntheses of 8,9‐dihydro‐1,2,3‐thiadiazolo[4,5‐a]‐4,7‐dihydroxynaphthalene and 1,2,3‐selenadiazolo[4,5‐a]‐4,7‐dimethoxynaphthalene

The reaction of thionyl chloride with the semicarbazone 2 gave 4,5‐dihydro‐6,9‐dihydroxynaphtho‐[1,2‐d][1,2,3]thiadiazole ( 3 ) instead of 4,5‐dihydro‐6,9‐dimethyoxynaphtho[1,2‐d][1,2,3]thiadiazole ( 4 ). Selenium dioxide oxidation of compound 2 gave 4,5‐dihydro‐6,9‐dimethyoxynaphtho[1,2‐d][1,2,3]selenadiazole ( 5 ). Oxidation of compound 5 with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone afforded 6,9‐dimethyoxynaphtho[1,2‐d][1,2,3]selenadiazole ( 6 ).