Alkylation of aryl 3-oxopropanedithioate and 3-amino-1-aryl-3-thioxo-1-propanones as an effective tool for the construction of differently substituted thiophenes and annulated thiophenes

The alkylation of aryl 3-oxopropanedithioate with α-haloketones under different reaction conditions afforded substituted aryl[2-(methylsulfanyl)-4-phenyl-3-thienyl]methanones and [3-aryl-5-(methylsulfanyl)-2-thienyl](phenyl)methanones. The same strategy was extended to 3-amino-1-aryl-3-thioxo-1-propanones to afford aryl[2-amino-4-phenyl-3-thienyl]methanones and ethyl 3-phenyl-5-piperidino-2-thiophene carboxylate.     

Synthesis of some 5-aryl-2,2′-dipyrromethenes as analogs of prodigiosin

Three new dipyrromethenes have been synthesized as analogs of prodigiosin: 3-methoxy-5-phenyl-2,2′-dipyrromethene (10a) , 3-methoxy-4 -pentyl-5-phenyl-5′-methyl-2,2′-dipyrromethene (10b) , and 3-methoxy-4′-pentyl-5′-methyl-5-(2″-thienyl)-2,2′-dipyrromethene (10c). The Michael addition of ethyl glycinate to an appropriate arylidenemalonate, quenched with ethyl chloroformate and followed by a Dieckmann cyclization gave diethyl 1-ethoxycarbonyl-3-oxo-5-phenyl and thienylpyrrolidine-2,4-dicarboxylate, 2a and 2b. Methylation of the highly enolic keto-esters, followed by oxidation to N-ethoxycarbonylpyrroles led, after appropriate elaboration of the pyrrole nucleus, to 2-phenyl- and 2-thienyl-4-methoxypyrroles. The acid catalyzed condensation of these arylmethoxypyrroles with either pyrrole-2-carboxaldehyde or 5-methyl-4-pentylpyrrole-2-carboxaldehyde led to 10a, 10b and 10c.     

SYNTHESIS AND REACTIONS OF SOME NEW HETEROCYCLIC COMPOUNDS CONTAINING THE THIENYLTHIENO[2,3-B]PYRIDINE MOIETY

(4-Aryl-3-cyano-6-(2-thienyl)pyridin-2-ylthio)acethydrazides (5a–c), 3-amino-4-aryl-6-(2-thienyl)thieno[2,3-b]pyridine-2-carbohydrazides (6a–c) and 3-amino-4-phenyl-6-(2-thienyl)thieno[2,3-b]pyridine-2-carboxylic acid (30) were prepared and employed as key intermediates in the synthesis of the title compounds.     

Substituent position effect on the properties of new unsymmetrical isomeric diarylethenes having a chlorine atom

Three new unsymmetrical photochromic diarylethenes bearing a chlorine atom at para-, meta- and ortho-position of one terminal benzene ring, namely {1-(2-methyl-5-phenyl-3-thienyl)-2-[2-methyl-5-(4-chlorophenyl)-3-thienyl]}perfluorocyclopentene (para 1o), {1-(2-methyl-5-phenyl-3-thienyl)-2-[2-methyl-5-(3-chlorophenyl)-3-thienyl]}perfluorocyclopentene (meta 2o), and {1-(2-methyl-5-phenyl-3-thienyl)-2-[2-methyl-5-(2-chlorophenyl) -3-thienyl]}perfluorocyclopentene (ortho 3o), have been synthesized. The substituent position effect on their properties, including photochromism, fluorescence both in solution and in PMMA amorphous film and their electrochemical properties were investigated in detail. The results elucidated that the chlorine atom and its substituent position had a remarkable effect on the absorption characteristics, photochromic reactivity, fluorescence, as well as the electrochemical performances of these diarylethene compounds. For diarylethenes 1, 2 and 3, the cycloreversion quantum yields were gradually increased when the chlorine atom was attached to the para-, meta- and ortho-positions of the one terminal benzene rings; but their molar absorption coefficients both of their open-ring and closed-ring isomers were remarkably decreased. The fluorescent properties of para-substituted diarylethene embedded in poly(methyl methacylate) (PMMA) amorphous film showed good fluorescent switches (quenched to 28%). Furthermore, the cyclic voltammograms experiments elucidated that the electrochemical properties of these diarylethene derivatives were also remarkably dependent on the chlorine atom position effect, which may be attributed to the different electron-inducing ability and steric effect when the chlorine atom was substituted on the different position of the terminal benzene ring.     

One-Pot synthesis of N-heterocyclic compounds from cyclopropenethione derivatives

The one-pot reaction of 2-tert-butylthio-3-phenylcyclopropenethione (1a) and its 3-(2-thienyl) derivative (1b) with lithium pyrrolidinide at -70 degrees C, followed by methylation with methyl iodide, gives 6-methylthio-5-phenyl-2,3-dihydro-1H-pyrrolizine (2a) and its 5-(2-thienyl) derivative (2b), respectively. The reaction of 2-tert-butylthio-3-(pyrrolidin-1-yl)cyclopropenethione (1c) with phenyllithium gives also 2a in a high yield under similar conditions, and the reactions of 1a with N-lithium salts of 3-pyrroline, hexamethyleneimine, indoline, and carbazole, piperidine-potassium tert-butoxide mixture, and phenyllithium give 6-methylthio-5-phenyl-3H-pyrrolizine (3), 2-methylthio-3-phenyl-6,7, 8,9-tetrahydro-5H-pyrrolo[1,2-a]azepine (5), 6-tert-butylthio-5-methylthio-4-phenyl-1,2-dihydro-6H-pyrrolo[3,2, 1-ij]quinoline (6), 4-tert-butylthio-5-methylthio-6-phenyl-4H-pyrido[3,2,1-jk]carbazole (7), 2-methylthio-3-phenyl-5,6,7,8-tetrahydroindolizine (4), and 1-tert-butylthio-2-methylthio-3-phenylindene (9), respectively. The structures of 2a and 3 were determined by X-ray analyses of their tricarbonylchromium complexes.     

Full-color photochromism of a fused dithienylethene trimer

A diarylethene fused trimer, 1-(5-(2-(3,5-dimethyl-2-thienyl)hexafluorocyclopententen-1-yl)-2,4-dimethyl-3-thienyl)-2-(5-(2-(2,4-dimethyl-5-phenyl-3-thienyl)hexafluorocyclopentene-1-yl)-2,4-dimethyl-3-thienyl)hexafluorocyclopentene, was synthesized. The diarylethene derivative showed full-color photochromic performance by choosing appropriate wavelength of light.     

METHYLTHIODITHIOLYLIUM REACTIONS WITH 2-BUTENE NITRILES DERIVATIVES

Abstract

The 3-methylthio-1. 2-dithiolylium including at 5 position a donor substituent, in acetic acid in the presence of pyridine, the 2-methylthio-1. 3-dithiolylium ions in methylene chloride-triethylamine, react with the 2-butene nitrile derivatives and lead to the (A) and (B) corresponding 4-dithiolylidene-2-butene nitriles. In contrast ring opening reaction of the 1, 2-dithiole is observed when 2-cyano-3-phenyl-2-butene nitrile reacts with the 3-methylthio-4-aryl-1. 2-dithiolylium ions in 3 and 5 positions, in methylene chloride-triethylamine. The nucleophilic attack on the 5 position of the dithiolylium ion leads to a 2-cyano-3-phenyl-3 (4-aryl-5-methylthio-2-thienyl) propene nitrile (C), meanwhile the attack on the 3 position leads to a 2-cyano-3-phenyl-3-(4-aryl-3-mercapto-2-thienyl) propene nitrile (D). The proposed structures are established by means of physical methods (IR, NMR, and Mass Spectrometry) and by non ambiguous synthesis. The reactivities of the various sites are explained in function of the electronic and steric effects, furthermore the reaction conditions and the intermediary isolation allow to propose the mecanisms of these reactions.     

The synthesis of thienocycloheptenoindoles

A synthesis of the methylthieno[3,2-c]cyclohepteno[b]indole 7 from 2-methylthieno[3,2-b]cycloheptanone 3 is described. Unsuccessful attempts to prepare the isomeric thienocycloheptenoindole system present in formula 2 , from the dihydrobenzothiophenone 8 , and from derivatives of 5-(2-thienyl)-4-oxopentanoic acid, 17 and 18 , and from N-benzylcycloheptindol-1-one 22 were unsuccessful. The preparation of 4,5-dihydro-2-phenyl-1-thienylmethyl-3H-pyridazin-3-one 20 and of the 5-aminopyrazole 21 are reported.     

Synthesis of 3-substitued 5-(2-thienyl)isoxazoles

The reaction of 3,4,4-trichloro-1-(2-thienyl)but-3-en-1-one with hydroxylamine gave 3-hydroxyiminomethyl-5-(2-thienyl)isoxazole which was converted into 5-(2-thienyl)isoxazole-3-carbonitrile by the action of acetic anhydride in pyridine. 5-(2-Thienyl)isoxazole-3-carbonitrile reacted with hydroxylamine to produce the corresponding amide oxime. Heterocyclization of its O-acyl derivatives in acetic acid afforded 5-substituted 3-[5-(2-thienyl)isoxazol-3-yl]-1,2,4-oxadiazoles.     

Synthesis of representative 10-aryl-, 10-aralkyl- and 10-heteraryl-9H-naphtho[1′,2′:4,5]thiazolo[3,2-b]- [1,2,4]triazin-9-ones as potential anti-HIV agents

To prepare the title compounds, cyclocondensation of 1-amino-2-iminonaphtho[1,2-d]thiazole ( 2 ) with some representative glyoxylic acid derivatives was investigated. Heating 2 with methyl phenylglyoxylate ( 3a ) in methanol afforded only the open chain intermediates 4a,b . However, when this reaction was performed in re-fluxing glacial acetic acid, the expected compound, 10-phenyl-9H-naphtho[1′,2′:4,5]thiazolo[3,2-b][1,2,4]- triazin-9-one ( 5a ) was produced in 27% yield. Similar treatment of 2 with benzyl-, 2-furyl- and 2-thienylgly-oxylic acids 3b-d gave the corresponding 10-benzyl-, 10-(2-furyl)- and 10-(2-thienyl)-9H-naphtho[1′,2′:4,5]thi-azolo[3,2-b][1,2,4]triazin-9-ones 5b-d in 48–67% yields. As by-products, 9-benzoyl- and 9-(2-thenoyl)naphtho-[1′,2′:4,5]thiazolo[3,2-b][1,2,4]triazoles 6a,d were also isolated. Compound 5a was selected for in vitro anti-HIV evaluation but found to be inactive.     

Synthesis of 1,4-Dihydropyrano[2,3-<Emphasis Type="Italic">c</Emphasis>]pyrazole Derivatives

In reaction of 2-(2-thienyl)- and 2-(2-furyl)acrylonitriles with 3-methyl-1-phenyl-5-pyrazolone in the presence of basic catalysts 4-thienyl- and 4-furyl derivatives of 3,5-dimethyl-1,7-diphenyl-4,8-dihydropyrano-[2,3-c, 5,6-c]dipyrazole were obtained.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 756–758.Original Russian Text Copyright © 2005 by Vasyun’kina, Bykova, Plotkin, Ramsh.     

Syntheses of various 5-(bromoaryl)-substituted uracils

The Suzuki Pd(0)-catalyzed coupling between arylboronic acids and aryl bromides or iodides in weakly alkaline medium, previously further developed by us, has been used for regioselective preparation of 5-(2′-bromo-5′-furyl)-, 5-(2′-bromo-4′-furyl)-, 5-(2′-bromo-5′-thienyl)-, 5-(2′-bromo-4′-thienyl)-, 5-(4′-bromo-2′-thiazolyl)-, 5-(3′-bromophenyl)-, 5-(6′-bromo-2′-pyridyl)- and 5-(4′-bromo-2′-pyrimidyl)-substituted 2,4-di-t-butoxypyrimidines. In the coupling between 2,4-di-t-butoxy-5-pyrimidineboronic acid and the nine different aryl dibromides that were tried as coupling partners, only the 2,4- and 2,5-dibromothiazoles did not give satisfactory yields, 15% and 0%, respectively. The other seven aryl dibromides gave the desired 5-(bromoaryl)-2,4-di-t-butoxypyrimidines in 58-89% yield. Attempts to synthesise 2,4-di-t-butoxy-5-(2′-bromo-4′-thienyl)pyrimidine from 2-bromo-4-iodothiophene failed. Dealkylation of the 5-(bromoaryl)-2,4-di-t-butoxypyrimidines in 2.5 M hydrochloric acid gave the corresponding 5-(bromoaryl)uracils in almost quantitative yields.     

Photochromism of metal complexes composed of diarylethene ligands and ZnCl2

Metal complexes composed of ZnCl(2) and bidentate 1,2-bis(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene (1a) and monodentate 1-(2-methyl-5-phenyl-3-thienyl)-2-(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene (2a) photochromic ligands were prepared. X-ray crystallographic analyses showed the formation of a coordination polymer and a discrete 2:1 complex for 1a.ZnCl(2) and 2a(2).ZnCl(2), respectively. While the 2a(2).ZnCl(2) crystal underwent photochromic reaction in the crystalline state by alternate irradiation with UV and visible light, the 1a.ZnCl(2) crystal did not show any photoreactivity. The difference in the photochromic behavior was explained by the difference in the conformation of the diarylethenes in the crystals.     

Synthesis of pyrido[1,2-a]pyrimido[4,5-d]pyrimidin-5-ones. Cyclization reaction of 4-[(3-hydroxy-2-pyridyl)amino]-2-phenyl-5-pyrimidinecarboxylic acid with acetic anhydride

Treatment of 4-[(3-hydroxy-2-pyridyl)amino]-2-phenyl-5-pyrimidinecarboxylic acid (X) with acetic anhydride under refluxing conditions afforded 10-hydroxy-2-phenyl-5H-pyrido[1,2-a]-pyrimido[4,5-d]pyrimidin-5-one acetate (IX). The intermediate X was prepared from 4-chloro-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester (V). The reaction of V with the sodium salt of 2-amino-3-hydroxypyridine at room temperature gave 4-(2-amino-3-pyridyloxy)-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester (VI). Treatment of VI with a hot aqueous sodium hydroxide solution and subsequent acidification gave X. Involvement of 4-[(3-hydroxy-2-pyridyl)amino]-2-phenyl-5-pyrimidinecaroboxylic acid ethyl ester (VIII) (Smiles rearrangement product) as an intermediate in the above alkaline hydrolysis reaction of VI to X was demonstrated by the isolation of VIII and its subsequent conversion into X under alkaline hydrolysis conditions. Acetylation of VIII with acetic anhydride in pyridine solution gave 4-[(3-hydroxy-2-pyridyl)amino]-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester acetate (XI), which afforded IX on fusion at 220°. This alternative synthesis of IX from XI supported the structural assignment of IX. Fusion of VI gave 10-hydroxy-2-phenyl-5H-pyrido[1,2-a]pyrimido]4,5-d]pyrimidin-5-one (VII). The latter was also obtained when VIII was fused at 210°. Acetylation of VII with acetic anhydride afforded IX.     

Synthesis of thiazolotriazepinones

The synthesis of 4,5-dihydro-7-phenylthiazolo[2,3-c][1,2,4]triazepin-3(2H)-one ( 4 ) from 2-propenoic acid 2-(4-phenyl-2-thiazolyl)hydrazide ( 14 ), is reported. A synthesis of 4 which was reported earlier by Mahajan, Sondhi and Ralhan (9), from 3-chloropropanoic acid 2-(4-phenyl-2-thiazolyl)hydrazide ( 3 ), is erroneous. We were able to cyclize 3 to 1-(4-phenyl-2-thiazolyl)-3-pyrazolidinone ( 5 ). The cyclizations of 14 to 4 and 3 to 5 are consistent with the Baldwin Rules for Ring Closure.     

The reactions of 4-dicyanomethylene-2-phenyl-4H-1-benzopyran and some benzologs with nucleophiles

4-Dicyanomethylene-2-phenyl-4H-1-benzopyran (1) reacts with primary amines under mild conditions to give 4-imino-3-alkyl-5-alkylimino-2-phenyl-3,4-dihydro-5H-[1]benzopyrano[3,4-c]-pyridine derivatives which, in turn, are hydrolyzed with acid to 4-imino-3-alkyl-2-phenyl-3,4-dihydro-5H-[1]benzopyrano[3,4-c]pyridin-5-ones. When more vigorous conditions are employed for the reactions of 1 with primary amines, Dimroth rearrangements take place and the products are derivatives of 4-alkyl- (or aryl)amino-5-alkyl- (or aryl)imino-2-phenyl-5H-[1]benzopyrano-[3,4-c]pyridine. The latter compounds are hydrolyzed by acid to the corresponding 5-pyridone derivatives. The reaction of 1 with piperidine gives 2-phenyl-4-piperidyl-5H-[1]benzopyrano-[3,4-c]pyridin-5-one. Sodium methoxide reacts with 1 to give 3-cyano-2-methoxy-4-(2-hydroxyphenyl)-6-phenylpyridine. Two benzologs of 1 have been allowed to react with primary and secondary amines and the products are analogous to those obtained from 1 .     

Synthesis of 3H-pyrazol-3-one derivatives containing a 9H-thioxanthene ring

2,4-Dihydro-5-methyl-2-phenyl-4-(9H-thioxanthen-9-yl)-3H-pyrazol-3-one ( 3 ) was prepared by condensing 9H-thioxanthen-9-ol ( 1 ) with 2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one ( 2 ), or by cyclizing ethyl α-acetyl-9H-thioxanthene-9-acetate ( 4 ) with phenylhydrazine. 2,4-Dihydro-5-methyl-2-phenyl-4-(9H-thioxan- then-9-yl)-3H-pyrazol-3-one 10,10-dioxide ( 8 ) was prepared by cyclizing ethyl α-acetyl-9H-thioxanthene-9-acetate 10,10-dioxide ( 7 ) with phenylhydrazine. Compound 8 was also obtained by oxidizing 3 with hydrogen peroxide in acetic acid. 5-Amino-2,4-dihydro-2-phenyl-4(9H-thioxanthen-9-yl)-3H-pyrazol-3-one ( 10 ) was obtained by condensing 1 with 5-amino-2,4-dihydro-2-phenyl-3H-pyrazol-3-one ( 9 ).     

3-Oxy-5-phenyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazole-4-carboxylic Acid. Synthesis,Structure, and Properties

The structure of 3-oxy-5-phenyl-1H-1,2,3-triazole-4-carboxylic acid was determined both experimentally (by the X-ray diffraction method) and by quantum-chemical calculations. Alkylation of 3-oxy-5-phenyl-1H-1,2,3-triazole-4-carboxylic acid (as crystal hydrate) with methyl iodide, depending on the reactant ratio, gives 1-methoxy-4-phenyl-1H-1,2,3-triazole-5-carboxylic acid and methyl 1-methoxy-4-phenyl-1H-1,2,3-triazole-5-carboxylate. Nitration of the title compound under mild conditions occurs at the 5-phenyl group with formation of meta-nitro derivative, while under more severe conditions 3,5-dinitrobenzoic acid is obtained. 3-Oxy-5-phenyl-1H-1,2,3-triazole-4-carboxylic acid was also converted into the corresponding acid chloride and substituted amide.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 601–608.Original Russian Text Copyright © 2005 by Shtabova, Shaposhnikov, Mel’nikova, Tselinskii, Nather, Traulsen, Friedrichsen.     

Photoinduzierte 1, 3-dipolare Cycloaddition von 3-Phenyl-2H-azirinen an Azodicarbonsäure-diäthylester. 32. Mitteilung über Photoreaktionen

Irradiation of 2, 2-dimethyl-3-phenyl- ( 1a ), 2, 3-diphenyl-2H-azirine ( 1b ) or the azirine-precursors 1-azido-1-phenyl-propene ( 2a ) and 1-azido-1-phenyl-ethylene ( 2b ), respectively, in benzene in the presence of azodicarboxylic acid diethylester, yields the corresponding 1, 2-carbethoxy-3-phenyl-Δ³-1, 2, 4-triazolines 4a–d (Scheme 1). Refluxing 4 ( a, c or d ) in 0, 2–0, 4M aqueous ethanolic potassium hydroxide leads to the formation of the 1-carbethoxy-3-phenyl-Δ²-1, 2, 4-triazolines 6 ( a, c or d ). Under the same conditions 4b is converted to 3, 5-diphenyl-1, 2, 4-triazole ( 7b , Scheme 2). In 10M aqueous potassium hydroxide solution heating of either 4 ( c or d ) or 6 ( c or d ) yields the 3-phenyl-1, 2, 4-triazoles 7 ( c or d ). Photolysis of 1-carbethoxy-5, 5-dimethyl-3-phenyl-Δ²-1, 2, 4-triazoline ( 6a ) in benzene in the presence of oxygen and trifluoroacetic acid methylester gives the 5-methoxy-2, 2-dimethyl-4-phenyl-5-trifluoromethyl-3-oxazoline ( 13 , Scheme 5). 5, 5-Dimethyl-3-phenyl-1, 2, 4-triazole seems to be the intermediate, which on losing nitrogen gives the benzonitrile-isopropylide ( 3a ).     

Photochromism of metal complexes composed of diarylethene ligands and Zn(II), Mn(II), and Cu(II) hexafluoroacetylacetonates

Metal complexes composed of bidentate 1,2-bis(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene (1a) and monodentate 1-(2-methyl-5-phenyl-3-thienyl)-2-(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene (2a) photochromic ligands and M(hfac)(2) (M = Zn(II), Mn(II), and Cu(II)) were prepared, and their photoinduced coordination structural changes were studied. X-ray crystallographic analyses showed the formation of coordination polymers and discrete 1:2 complexes for bidentate and monodentate ligands, respectively. The complexes underwent reversible photochromic reactions by alternate irradiation with UV and visible lights in solution as well as in the single-crystalline phase. Upon photoirradiation with UV and visible light, the ESR spectra of the copper complexes of 1a reversibly changed. While the open-ring isomer gave an axial-type spectrum, the photogenerated closed-ring isomer showed a rhombic-type spectrum. This indicates that the photoisomerization induced the change in the coordination structure.