Synthesis of benzo[b]selenophene and its methyl homologs

A method for the synthesis of benzo[b]selenophenes was perfected. 3-Oxo-2,3-dihydrobenzo[b]selenophene and 2-methyl-3-oxo-2,3-dihydrobenzo[b]selenophene exist only in the keto form. 3-Methylbenzo[b]selenophene was obtained by the reaction of 3-oxo-2,3-dihydrobenzo[b]selenophene with methylmagnesium iodide. Metallation of benzo[b]selenophene with butyllithium proceeds at the 2 position of the selenophene ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1475–1480, November, 1970.     

Reactions de photoaddition de benzo[b]selenophenes avec l'acetylene dicarboxylate de methyle et avec le dichloro-1,2 ethylene

Photoirradiated in presence of acetophenone, benzo[b]selenophene and its 3-methyl derivative add to dimethyl acetylenedicarboxylate. In each ease, the primary reaction product is unstable and has not been isolated. Photoexeited in its triplet state (the energy of which is in the neighbourhood of 69 $\text{kcal}\text{mole}$) benzo[b]selenophene and its 2- and 3-methyl, 2,3 dimethyl, 3 acetoxy and 2-methyl-3-acetoxy derivatives add to 1,2 dichloroethylene leading to cyclobutanes. Neither cyclo-addition occurs in absence of photosensitiser. Single-crystal X-ray analysis gave the structures of the two adducts of 3-acetoxybenzo[b]selenophene with trans-1,2-dichloroethylene. In both compounds the chlorine atoms are trans.     

Synthesis of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene and some transformations based on it

A new method for the synthesis of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene was developed. The reaction of the latter with allyl isothiocyanate gave 2-(N-allylthioureido)-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene, which is cyclized to the potassium salt of 3-allyl-4-oxo-2-thio-3,4,5,6,7,8-hexahydrobenzo[b]selenopheno[2,3-d]pyrimidine on treatment with potassium hydroxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 326–328, March, 1973.     

Synthesis of 2-(β-Hetarylaminoethyl)-3,5,6-trichloro-1,4-benzoquinones

4,6,7-Trichloro-2-hetarylamino-5-hydroxy-2,3-dihydrobenzo[b]furans have been prepared from 4,6,7-trichloro-2,5-dihydroxy-2,3-dihydrobenzo[b]furan and hetarylamines. Reductive opening of the dihydrobenzofuran ring in these compounds gave 3,5,6-trichloro-2-(-hetarylaminoethyl)hydroquinones. The latter could be oxidised to the target 3,5,6-trichloro-2-(-hetarylaminoethyl)-1,4-benzoquinones which are novel 1,4-benzoquinone derivatives with intramolecular charge transfer.     

Synthesis of the precursors of bis(trichloro-1,4-benzoquinonyl)tetrathiafulvalenes

In reaction with potassium butylxanthate and sodium tert-butyltrithionate, 2,5-dihydroxy-3,4,6,7-tetrachloro-2,3-dihydrobenzo[b]furan forms the products from nucleophilic substitution of a chlorine atom, i.e., O-butyl S-(2,5-dihydroxy-4,6,7-trichloro-2,3-dihydrobenzo[b]furan-3-yl) xanthate and S-tert-butyl S-(2,5-dihydroxy-4,6,7-trichloro-2,3-dihydrobenzo[b]furan-3-yl) trithiocarbonate respectively. Recyclization of the xanthate in concentrated sulfuric acid gave 4-(2,5-dihydroxy-3,4,6-trichlorophenyl)-1,3-dithiol-2-one, which was oxidized by iron trichloride to the corresponding benzoquinone. Cyclization of the trithiocarbonate in the presence of trifluoroacetic and p-toluenesulfonic acid led to 7-hydroxy-5,6,8-trichloro-3a,8b-dithiolo[4,5-b]benzo[d]furan-2-thione.Dedicated to Prof. A. Katritzky in honor of his seventieth birthday.Riga Technical University, Riga LV-1048, Latvia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1055–1060, August, 1998.     

Chemistry of benzo[b]furan. V.. Synthesis of substituted thia-analogs and oxa-analogs of dihydrorutecarpine and evodiamine

Cycloaddition of 3,4-dihydrobenzo[b]thieno[2,3-c]pyridine ( 6 ) with the sulfinamide anhydride 9 (R = H) afforded the thia-analog of dihydrorutecarpine ( 2a ). Condensation of the imine 6 with the sulfinamide anhydride 9 (R = CH₃) gave the thia-analog of evodiamine ( 2b ). Starting from 1-methyl-3,4-dihydrobenzo[b]thieno[2,3-c]pyridine ( 12 ) and 1-methyl-3,4-dihydrobenzo[b]furo[2,3-c]pyridine ( 14 ), a series of 3-methyl derivatives of thia-analogs of dihydrorutecarpine and evodiamine ( 2c-2i ) and oxa-analogs of dihydrorutecarpine and evodiamine ( 1a-1g ) were similarly prepared.     

Reaction of propiolic acid esters with dithiols and β-mercaptoethanol

2-Alkoxycarbonylmethyl-1,3-oxathiolane and -dithiolane, 3-methyloxycarbonylmethyl-7,8-dimethyl-1,5-dihydrobenzo[e]-1,3-dithiepine, and 2-methoxycarbonylmethyl-1,3-dithiolo[4,5-b]quinoxaline were synthesized on the basis of the reaction of esters of propiolic acid with -mercaptoethanol, 1,2-dimercaptoethanol, 1,2-dimethyl-4,5-di(mercaptomethyl)benzene, and 2,3-dimercaptoquinoxaline in chloroform medium in the presence of K₂CO₃ or in DMSO medium.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 8, pp. 1062–1065, August, 1984.     

Synthesis of [b]-Fused Benzo[d]furano Heterocycles

In the reactions of 3,4,6,7-tetrachloro-2,5-dihydroxy-2,3-dihydrobenzo[b]furan with 4-methyl and 4-phenyl thiosemicarbazides, dithizone and sodium N,N-diethyldithiocarbamate the [b]fused benzo[d]furano heterocycles have been synthesized.     

Chemistry of benzo[b]selenophene

The bromination of benzo[b]selenophene with an equimolecular amount of bromine and its acetylation with acetic anhydride in the presence of boron trichloride etherate proceed to form a mixture of isomeric 2- and 3-substituted derivatives; 2,3-dibromobenzo[b]selenophene is formed on bromination with two equivalents of bromine. Benzo[b]selenophene-2-carboxylic acid, its acid chloride and methyl ester, as well as 2-acetylbenzo[b]selenophene, were synthesized from the lithium derivative of benzo[b]selenophene.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 15–19, January, 1972.     

Synthesis and some reactions of selenopheno[2,3-c]pyrylium salts

The catalytic acylation and subsequent heterocyclization of -acetonyl derivatives of selenophene have been investigated. Methods have been proposed for the synthesis of new heteroaromatic systems: salts of the selenopheno[2,3-c]pyrylium cation and of selenopheno[2,3-c]pyridine. Methods have been developed for the synthesis of selenophene-3-carbaldehydes and 3-acetonylselenophenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 918–922, July, 1973.     

Synthesis of trichloro-1,4-benzoquinonyl-substituted 2,2′-bithiazoles

2,2-Bi[5-(2,5-dihydroxy-3,4,6-trichlorophenyl)thiazole] and 6-(2,5-dihydroxy-3,4,6-trichlorophenyl)-2-imino-3,4-dihydro-4H-1,4-thiazin-3-thione are synthesized from 2,5-dihydroxy-3,4,6,7-tetrachloro-2,3-dihydrobenzo[b]furan and dithiooxalyldiamide. The products are oxidized by FeCl₃ to the corresponding trichloro-1,4-benzoquinonyl-substituted sulfur-containing heterocycles. N-Methylation of 2,2-bithiazole by dimethyl sulfate gives 2,2-bi[5-(2,5-dihydroxy-3,4,6-trichlorophenyl)-3-methylthiazolium] bismonomethyl sulfate. The last compound is readily transformed to 2,2-bi[5-(2-hydroxy-5-oxido-3,4,6-trichlorophenyl)-3-methylthiazolium] bisbetaine.Riga Technical University, Riga LV-1048, Latvia, Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 988–992, July, 1999.     

Synthesis of new pyridazino[4′,3′:4,5]-thieno[3,2-d]-1,2,3-triazine and pyrimido[4′,5′:4,5]thieno[2,3-c]pyridazine derivatives

Summary 8,9-Diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-one (2), 3-substituted 8,9-diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-ones (3a–c), 3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8(7H)-one (4), 8-chloro-3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazine (5), 8-substituted 3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazines (6a–h) and 7-substituted 3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8(7H)-ones(7a–c) were synthesized from 5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxamide (1).

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Synthese neuer Pyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-und Pyrimido[4,5:4,5]thieno[2,3-c]pyridazin-Derivate

Zusammenfassung Folgende Verbindungen wurden ausgehend von 5-Amino-3,4-diphenylthieno[2,3-c]pyridazin-6-carboxamid (1) synthetisiert: 8,9-Diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-on (2), 3-substituierte 8,9-Diphenylpyridazino[4,3:4,5]thieno[3,2-d]-1,2,3-triazin-4(3H)-one (3a–c), 3,4-Diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8[7H]-on (4), 8-Chlor-3,4-diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin (5), 8-substituierte 3,4-Diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazine (6a–h) und 7-substituierte 3,4-Diphenylpyrimido[4,5:4,5]thieno[2,3-c]pyridazin-8(7H)-one (7a–c).

     

Synthesis and properties of novel dibenz[b,f]azocines

5-Acetyl- and 5-trifluoroacetyl-12-hydroxy-11-cyano-5,6-dihydrodibenz[b,f]azocines have been synthesized by intramolecular cyclocondensation of ethyl N-acetyl and N-trifluoroacetyl-N-[1-(cyanomethyl)benzyl]-anthranilates. Spectral data show that the hydroxyl group in 5-acetyl-12-hydroxy-11-cyano-5,6-dihydrodibenz[b,f]azocine takes part in transannular hydrogen bond formation with the acetamide group carbonyl oxygen. A study of the chemical properties of this compound has shown that its alkylation by p, -dibromoacetophenone is accompanied by a Thorpe reaction to form 11-amino-5-acetyl-12-(p-bromo-bemoyl)-5,6-dihydro[b,f]dibenzofuro[2,3-d]azocine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 109–113, January, 1991.     

艾托拉嗪的合成

自从色洛托宁(Serotonin)在1948年作为神经传导素被发现以后,它就与中枢神经系统(CNS)的活动联系在一起.经过科学家们的多年努力,芳基哌嗪作为种类繁多的5-HT1A受体中的一类得到了迅速发展,像布斯哌隆(Buspirone)和伊沙匹隆((Ipsapirone)很早就作为有效的抗焦虑和抗抑郁症药物得到广泛的应用.     

The Synthesis and Bioactivity of Dimethyl (2,3- Dihydrobenzo[b][1,4]Dioxin-6-Yl)(Aryl Amino)Methylphosphonates

Abstract

A new series of α-aminophosphonates have been synthesized by a one-pot three-component reaction of 2,3-dihydrobenzo[b][1,4]dioxine-6-carbaldehyde, various amines, and dimethyl phosphite by using nano-TiO₂ as a catalyst under solvent-free conditions at 50°C. The major advantages of the present method are high yields, short reaction times, recyclable catalyst, and solvent-free reaction conditions. Among these new structurally diversified set of α-aminophosphonates, dimethyl (2,3-dihydrobenzo[b][1,4]dioxin-6-yl)(3-nitrophenylamino) methylphosphonate and dimethyl (2,3-dihydrobenzo[b][1,4]dioxin-6-yl)(4-fluoro-3-nitro-phenyl-amino) methylphosphonate have shown higher antioxidant activity in diphenyl picryl hydrazyl (DPPH) scavenging, reducing power assay, and lipid peroxidation methods.     

Synthesis of methyl-substituted benzofuro-, benzothieno-, and benzoselenopheno[2,3-b]pyridines

Three-ring systems with benzo[b]furan, benzo[b]selenophene, and benzo[b]thiophene rings condensed with the pyridine ring and with a methyl group in the position of the pyridine ring were synthesized by the reaction of 2-chloro-3-nitro-6-methylpyridine with sodium phenoxide, sodium thiophenoxide, or sodium selenophenoxide, reduction of the resulting 2-phenoxy-, 2-phenylthio-, and 2-phenylseleno-3-nitro-6-methylpyridines with stannous chloride in concentrated hydrochloric acid, diazotization of the substituted 3-aminopyridines, and heating of the diazonium compounds in 25% sulfuric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1541–1543, November, 1972.     

Derivate des 3-Phenyl-benzo[b]thiophens

Zusammenfassung 2-Methylthio-benzophenon reagierte mit Chloressigsäure zu 3-Phenyl-benzo[b]thiophen-2-carbonsäure und mit -Chlorphenylessigsäure zu 2,3-Diphenyl-benzo[b]thiophen. 3-Phenyl-5-methoxy-benzo[b]thiophen-2-carbonsäure wurde aus 3-Phenyl-5-amino-benzo[b]thiophen-2-carbonsäure durch Verkochen des Diazoniumsalzes und Methylierung erhalten; ihr N-Methylpiperazid sowie 3 basisch substituierte Ester wurden dargestellt.

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Derivatives of 3-phenylbenzo[b]thiophene

2-Methylthio-benzophenone reacted with chloroacetic acid to 3-phenyl-benzo[b]thiophene-2-carboxylic acid and with -chloro-phenylacetic acid to 2,3-diphenyl-benzo[b]thiophene. 3-Phenyl-5-methoxy-benzo[b]thiophene-2-carboxylic acid was prepared by diazotation of 3-phenyl-5-amino-benzo[b]thiophene-2-carboxylic acid and hydrolysis to the hydroxy compound followed by methylation; its N-methylpiperazide and three esters with basic substituents were synthesized.

     

Synthesis of 3-(2-Oxo-2,3-dihydrobenzo[<Emphasis Type="Italic">b</Emphasis>]furan-3-ylidenehydrazono)-2,3-dihydrobenzo[<Emphasis Type="Italic">b</Emphasis>]furan-2-one

Reactions of benzophenone and fluoren-9-one hydrazones with (2-hydroxyphenyl)oxoacetic acid gave [carboxy(2-hydroxyphenyl)methylidenehydrazono](2-hydroxyphenyl)acetic acid which underwent intramolecular cyclization with formation of 3-(2-oxo-2,3-dihydrobenzo[bfuran-3-ylidenehydrazono)-2,3-dihydrobenzo[b]furan-2-one. The symmetric azine was also obtained by reactions of (2-hydroxyphenyl)oxoacetic acid with triphenylphosphoranylidenehydrazones derived from benzophenones, fluoren-9-one, and 1-methyl-2,3-dihydro-1H-indole-2,3-dione.     

The synthesis of benzofuroquinolines. I. Some benzofuro[2,3-b]quinoline and benzofuro[3,2-c]quinoline derivatives

Benzofuro[2,3-b]quinoline ( Ia ) and its 11-methyl derivative ( Ib ) were synthesized by demethylcyclization of 3-(o-methoxyphenyl)-1,2-dihydroquinolin-2-ones (VIa,b). Benzofuro[2,3-b]quinoline-11-carboxylic acid (Id) was synthesized by chlorination followed by the action of potassium hydroxide of a lactone (IX) prepared by demethyl-cyclization of 3-(o-methoxyphenyl)-2-oxo-1,2-dihydroquinoline-4-carboxylic acid (VIII). Isomeric benzofuro[3,2-c]quinoline (Ha) and its 6-methyl derivative (IIb) were synthesized by demethyl-cyclization of 3-(o-methoxyphenyl)-1,4-dihydroquinolin-4-ones (XIa,b). Both the methyl derivatives (Ib and IIb) were converted to the carboxylic acids (Id and IId) through condensation with benzaldehyde followed by oxidation. The benzofuroquinolines (Ia,b,d and IIa,b) thus obtained were oxidized to the corresponding N-oxides (IIIa,b,d and IVa,b).     

Thiényl- et séléniénylthiocyanates et sélénocyanates. 4. Synthèses de thiéno[2,3-d]thiazoles,de thiéno[2,3-e]thiazines et de quelques analogues sélénophéniques

Nucleophilic aromatic substitution of 3-bromo-2nitrothiophene and selenophene by thiocyanate and selenocyanate ions in dimethylsulfoxide yields 3-thienyl-and 3-selenienylthicoyanates and selenocyanates. After reduction of the nitro group, the amino derivatives undergo cyclizatrion to thieno[2,3-d]thiazoles and seleno [2,3-d]thiazoles. Also, 4H-2,3-dihydro-3-oxothieno[2,3-e]1,4-thiazine and its selenophene analog have been obtained.