Synthesis of 1- and 5-Aryl-2,4-benzothiazepines. 25th Communication on Seven-membered Heterocycles

α-Aryl-o-xylyl dibromides 1 reacted with thioureas to give the mono-isothiouronium salts 2 , bis-isothiouronium salts 4 being formed as by-products in some cases. Compounds 2 , which readily reacted with water or alcohols to form 3 , were cyclized with Na₂CO₃ in anhydrous acetone to yield 5-aryl-2,4-benzothiazepines 5, 6 and 7 , but the 2′-chlorophenyl-derivative 21 exceptionally cyclized to the cyclobutene 20 . The 1-aryl-2,4-benzothiazepines 14, 15 and 16 were prepared unequivocally by acid-catalysed cyclizations of thioureas 13 and 19 .     

A novel palladium-catalyzed rearrangement of acetylenic ketones to furans

A novel rearrangement of 1-aryl-4-alkyl-2-butyn-1-one in the presence of Pd(dba)₂-PPh₃ catalyst gave 2,4-substituted furans in moderate yields.     

Facile TICl<Subscript>4</Subscript>-catalyzed synthesis of novel 1,2,4-triazoles appended to thiazoles

The reaction of sydnone-derived 3-aryl-5-methyl-1,3,4-oxadiazol-2(3H)-ones with thiourea and α-bromoacetophenone derivatives in the presence of a catalytic amount of TiCl₄ produces 2-aryl-4-(4-aryl-1,3-thiazol-2-yl)-5-methyl-2,4-dihydro-3H-1,2,4-triazol-3-ones. The title compounds were screened for their antibacterial and antifungal activity. The toxicity of the compounds was evaluated in terms of mutagenicity, tumorigenicity, and reproductive effects. The drug-relevant properties (ClogP, drug-likeness, and drug score) were calculated, and the structure–activity relationship was discussed.     

N,N′-Acylated 2,4-diazabicyclo[3.3.1]nonanes and 2,4-diazabicyclo [3.2.1]octanes from alicyglic bisazomethines

Conclusions Benzoylation of bisazomethine derivatives of 1,3-diaminocyclohexane and 1,3-diamino-cyclopentane has given 3-aryl-2,4-dibenzoyl-2,4-diazabicyclo₁3.3.1]-nonanes and 3-aryl-2,4-dibenzoyl-2,4-diazabicyclo[3.2.1]octanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 835–839, April, 1988.The authors thank V. V. Yakubënka for the gift of samples of cis- and trans-1,3-diaminocyclo-hexane.     

SYNTHESIS AND REACTIONS OF 2,3-DIHYDRO- 5-ARYL-5H,6H-THIAZOLO[3,2-b]-2,4-DIAZAFLUORENE-3,6-DIONES OF POTENTIAL BIOLOGICAL ACTIVITIES

Abstract

1,2,3,4-Tetrahydro-l-aryl-3,9-dioxo-2,4-diazafluorenes (2) and 1,2,3,4-tetrahydro-1-aryl-9-oxo-3-thi-oxo-2,4-diazafluorenes (3) were newly synthesized. Compounds 3 reacted with chloroacetic acid, α-bromopropanoic acid, or B-bromopropanoic acid in the presence of fused sodium acetate and acetic anhydride to give 2,3-dihydro-5-aryl-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (4), 2-methyl-2,3-dihydro-5-aryl-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (5) and 2,3-dihydro-6-aryl-6H,7H-thiazino[3,2-b]2,4-diazafluorene-4,7-diones (6), respectively.

2,3-Dihydro-2-arylmethylene-5-aryl-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (7) were prepared by the reaction of compounds (3) with chloroacetic acid and aromatic aldehydes in the presence of fused sodium acetate and acetic anhydride or by the reactions of (4) with aromatic aldehydes in the presence of acetic anhydride.

2-(Arylhydroazono)-5-aryl-2,3-dihydro-5H,6H-thiazolo[3,2-b]2,4-diazafluorene-3,6-diones (8) were synthesized by coupling (4) with aryldiazonium salts in the presence of pyridine.     

Aminomethylation of some 4-thiazolidinones

2-Arylaminomethylimino-3-aryl-4-oxothiazolidines were obtained by the Mannich reaction. The structure of the isolated products was confirmed by acid hydrolysis, the formation of monoacetyl derivatives, and the IR spectra.     

Efficient synthesis of 6-aryl-4-trifluoromethyl/ethoxycarbonyl-2H-pyran-2-ones through self-condensation of penta-2,4-dienenitriles

An efficient synthesis of two new series of 6-aryl-4-trifluoromethyl-2H-pyran-2-ones and 6-aryl-4-carboxyethyl-2H-pyran-2-ones, obtained through the self-condensation reaction of 5-aryl-5-methoxy-3-(trifluoromethyl)penta-2,4-dienenitriles 3 and ethyl 4-aryl-2-(cyanomethylene)-4-methoxybut-3-enoates 4 respectively, is reported. The self-condensation reaction of the enoates 4 was performed in water in the presence of hydrochloric acid whereas the self-condensation reaction of the penta-2,4-dienenitriles 3 required the use of zinc bromide and hydrochloric acid in order to give the respective 2H-pyran-2-ones. Products were obtained up to 97% yield.     

3-methylthio-1,2-dithiolylium salts : Reaction with 4-hydroxy-6-methyl-2H-pyran-2-one and 4-hydroxycoumarin

The reaction of 4- and 5-aryl-3-methylthio-1,2-dithiolylium iodides with 4-hydroxy-6-methyl-2$\text{H}$-pyran-2-one and 4-hydroxycoumarin has been studied. 4-Substituted salts yielded 3-aryl-7-methyl-2-thioxo-2$\text{H}$,5$\text{H}$-pyrano [3,2-c]pyran-5-ones and 3-aryl-2-thioxo-2H,5H-pyrano[3,2-c]benzo[e]pyran-5-ones, respectively, whereas 5-substituted salts gave rise to 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-6-methyl-2$\text{H}$-pyran-2,4-diones and 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-2$\text{H}$-benzo [b]-pyran-2,4-diones.     

Ru(II)-Catalyzed rearrangement of 2-aryl-2-(phenylthio)penta-3,4-dienyl 2,2,2-trichloroacetimidates

[RuCl₂(p-cymene)]₂ efficiently catalyzes the rearrangement of 2-aryl-2-(phenylthio)penta-3,4-dienyl 2,2,2-trichloroacetimidate to afford (Z)-2,2,2-trichloro-N-(4-aryl-1-(phenylthio)penta-2,4-dien-2-yl)acetamide. Ru carbene is assumed as the reactive intermediate in this rearrangement.     

Reactions of Sodium Enolates Derived from 6-Aryl-3,5,5-trimethyl-2,3,5,6-tetrahydropyrane-2,4-diones with Substituted Benzenesulfonyl Chlorides and Arenediazonium Salts

Sodium enolates derived from 6-aryl-3,5,5-trimethyl-2,3,5,6-tetrahydropyrane-2,4-diones react with substituted benzenesulfonyl chlorides to give the corresponding O-sulfonation products, 6-aryl-4-(4-R-phenylsulfonyloxy)-3,5,5-trimethyl-5,6-dihydropyrane-2-ones. Reactions of the title compounds with arenediazonium tetrafluoroborates afford 6-aryl-3-arylazo-3,5,5-trimethyl-2,3,5,6-tetrahydropyran-2,4-diones as mixtures of syn and anti isomers.     

Carbon-13 NMR Studies of 3-Aryl-4-(5-aryl-Δ 2-1,2,4-oxadiazolin-3-yl)sydnones and 3-Aryl-4-(5-aryl-1,2,4-oxadiazol-3-yl)sydnones

The ¹³C NMR spectra of twelve 3-aryl-4-(5-aryl-Δ²-l,2,4-oxadiazolin-3-yl)sydnones and twelve 3-aryl-4-(5-aryl-l,2,4-oxadiazol-3-yl)sydnones have been measured and assigned by means of proton-noise decoupling and DEPT-experiments. The coupling constants were determined by means of gated decoupling, and NOE effects were observed by comparison of proton-decoupled and inverse-gated decoupled spectra. Differences shown by the oxadiazoline and the oxadiazole rings and the substitution effects are discussed.     

Extension of β-chloroenals to ethyl 5-chloro-2,4-pentadienoates using Wadsworth-Emmons reactions: subsequent conversions to 5-aryl-5-chloro-2,4-pentadienoic acids and 5-aryl-2-penten-4-ynoic acids

Convenient routes from (Z)-3-aryl-3-chloroenals to (2E,4Z)-5-aryl-5-chloro-2,4-pentadienoates and (2E)-5-aryl-2-penten-4-ynoates are described. The stereochemical assignments are based on NMR spectral data.     

2-Aryl-6-Polyfluoroalkyl-4-Pyrones as Promising RF-Building-Blocks: Synthesis and Application for Construction of Fluorinated Azaheterocycles

A convenient and general method for the direct synthesis of 2-aryl-6-(trifluoromethyl)-4-pyrones and 2-aryl-5-bromo-6-(trifluoromethyl)-4-pyrones has been developed on the basis of one-pot oxidative cyclization of (E)-6-aryl-1,1,1-trifluorohex-5-ene-2,4-diones via a bromination/dehydrobromination approach. This strategy was also applied for the preparation of 2-phenyl-6-polyfluoroalkyl-4-pyrones and their 5-bromo derivatives. Conditions of chemoselective enediones bromination were found and the key intermediates of the cyclization of bromo-derivatives to 4-pyrones were characterized. Synthetic application of the prepared 4-pyrones has been demonstrated for the construction of biologically important CF₃-bearing azaheterocycles, such as pyrazoles, pyridones, and triazoles.     

Stereocontrolled synthesis of (3Z,5E)-6-aryl-3-methylhexa-3,5-dien-1-ols,intermediates in the synthesis of strobilurin antibiotics

(2E,4E)-5-Aryl-2-(2-benzyloxyethyl)penta-2,4-dien-1-als (aryl is phenyl and 4-methox-yphenyl) were reduced with NaBH₄ quantitatively and stereospecifically to the corresponding penta-2(E),4(E)-dien-1-ols. The hydroxymethyl group in the latter was transformed into a methyl one with a stereoselectivity of 92–97%. Debenzylation of the resulting (1E,3Z)-1-aryl-6-benzyloxy-4-methylhexa-1,3-dienes with AlCl₃ in the presence of PhNMe₂ afforded the target (3Z,5E)-6-aryl-3-methylhexa-3,5-dien-1-ols; the configuration of the C=C bonds in the conjugated aryl diene systems was retained at 95%.     

Five-Membered 2,3-Dioxo Heterocycles: XLV. Thermolysis of 5-Aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the Absence of Other Partners and in the Presence of Carbonyl Compounds

Aroyl(phenyl)ketenes generated by thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones undergo [4+2]-cyclodimerization to 3-aroyl-6-aryl-3,5-diphenyl-3,4-dihydro-2H-pyran-2,4-diones. Heating of the latter leads to rearrangement with formation of 4-aroyloxy-6-aryl-3,5-diphenyl-2H-pyran-2-ones. Thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the presence of carbonyl compounds yields 6-aryl-5-phenyl-4H-1,3-dioxin-4-ones.     

The triflic acid-mediated cyclisation of N-benzylcinnamanilides

N-Benzylcinnamanilides cyclise with triflic acid to form 1-benzyl-4-aryl-2,4-dihydro-1H-quinolin-2-ones and 2,5-diaryl-benzazepin-3-ones. The product ratio is determined by the preferred orientation of the amide and by the electronics of the substituents. With ortho-substituted anilides, N-debenzylation also occurs to give 4-aryl-2,4-dihydro-1H-quinoline-2-ones.     

The route of action of sodium methoxide on 5-Arylmethylene-2-Disubstituted amino-4-oxo-2-thiazolines

5-Arylmethylene-2-disubstituted amino-4-oxo-2-thiazolines 1a-d reacted with six and two moles of sodium methoxide to give the 2-mercaptocinnamic acid esters 6 and mixtures of 2,2 -dimethoxy-4-oxothiazolidines 4 and 2,4-dioxothiazolidines 5 , respectively. The intermediate mixture of the sodium salt of 5-aryImethylene-2,2-dimethoxy-4-oxothiazolidines 3 in the above mentioned transofrmations was established. The structures of 3, 4, 5 and 6 were based on analytical and spectral evidence. The route of conversion of 1 into 3, 4,5 and 6 was presented and discussed.     

Synthesis and Intramolecular Cyclization of N-Substituted 2-Amino-4-aryl-4-oxo-2-butenoic Acids

Treating 4-aryl-2,4-dioxobutanoic acids with aromatic amines, 4-aminoantipyrine, and benzophenone hydrazone furnished N-substituted 2-amino-4-aryl-4-oxo-2-butenoic acids that existed in solutions in enaminoketone and iminoketone forms. The acids obtained underwent in the presence of acetic anhydride cyclization into N-substituted 5-aryl-3-imino-3H-furan-2-ones.     

Gold(I)-Catalyzed [8+2]-Cycloaddition of 8-Aryl-8-azaheptafulvenes with Allenamides and Ynamides: Regioselective Synthesis of Dihydrocycloheptapyrrole Derivatives

Gold(I)-catalyzed higher-order [8+2] cycloadditions of 8-aryl-8-azaheptafulvenes 1 with allenamides 2 and ynamides 3 were studied. 1,8-Dihydrocycloheptapyrroles 4 were achieved by a regioselective [8+2] cycloaddition of azaheptafulvenes 1 and allenamides 2 in the presence of (2,4-ditBuC₆H₃O)₃PAuNTf₂ as catalyst. Besides, ynamides 3 and 8-aryl-8-azaheptafulvenes 1 , undergo a regioselective [8+2] cycloaddition, to give 2-amido-1,4-dihydrocycloheptapyrroles 7 in the presence of JohnPhosAuNTf₂ as catalyst. Both reactions take place with good yields and with a variety of substituents. A plausible mechanism hypothesis suggests a nucleophilic attack of the 8-azaheptafulvene to the gold activated electron rich allene or alkyne moieties of the allenamide and ynamide, respectively.     

Synthesis and photophysical properties of oligoarylenes with a pyrrolo[2,3-d]pyrimidine core

The palladium-catalyzed Suzuki-Miyaura reaction of 2,4-dichloropyrrolo[2,3-d]pyrimidine with aryl boronic acids has been studied. Pd(OAc)₂/dicyclohexyl(2-biphenyl)phosphine/K₃PO₄ was found to be an efficient catalyst system to prepare 4-aryl-2-chloro- and 2,4-diarylpyrrolo[2,3-d]pyrimidines. Novel non-linear molecules consisting of a pyrrolo[2,3-d]pyrimidine core and aryl branches have been elucidated as blue light-emitters with fluorescence quantum yields ranging from 4% to 67% in THF solution. The impact of an electron-withdrawing t-BuOCO group attached to the pyrrole ring of pyrrolopyrimidine derivatives on optical properties is discussed.