Synthesis of ethyl (2<Emphasis Type="Italic">E</Emphasis>,4<Emphasis Type="Italic">E</Emphasis>)- and (2<Emphasis Type="Italic">E</Emphasis>,4<Emphasis Type="Italic">Z</Emphasis>)-5-chloropenta-2,4-dienoates

An efficient synthetic approach to 2E,4E and 2E,4Z isomers of ethyl 5-chloropenta-2,4-dienoate has been developed on the basis of one-pot oxidation–olefination of readily accessible (E)- and (Z)-3-chloroprop-2-en-1-ols by the action of barium manganate and ethyl (triphenyl-λ⁵-phosphanylidene)acetate.     

Oxidative trifluoroacetamidation of (1<Emphasis Type="Italic">E</Emphasis>,3<Emphasis Type="Italic">E</Emphasis>)-1,4-diphenylbuta-1,3-diene and 1,1,4,4-tetraphenylbuta-1,3-diene

Reactions of trifluoroacetamide with (1E,3E)-1,4-diphenylbuta-1,3-diene and 1,1,4,4-tetraphenylbuta-1,3-diene in the oxidative system t-BuOCl–NaI have been studied. The reaction with (1E,3E)-1,4-diphenylbuta-1,3-diene afforded three products, N,N′-(phenylmethylene)bis(trifluoroacetamide), 3-chloro-4-iodo- 2,5-diphenyl-1-(trifluoroacetyl)pyrrolidine, and trifluoro-N-[(3E)-2-hydroxy-1,4-diphenylbut-3-en-1-yl]acetamide, with a high overall yield. 1,1,4,4-Tetraphenylbuta-1,3-diene failed to react with trifluoroacetamide.     

Reaction of ethyl 4-[(<Emphasis Type="Italic">E</Emphasis>)-1-chloro-3-oxoprop-1-en-1-yl]-3,5-dimethyl-1<Emphasis Type="Italic">H</Emphasis>-pyrrole-2-carboxylate with hydrazines

Ethyl 4-[(E)-1-chloro-3-oxoprop-1-en-1-yl]-3,5-dimethyl-1H-pyrrole-2-carboxylate reacted with substituted hydrazines in different solvents to give mixtures of regioisomeric 3- and 5-substituted pyrazoles. Conditions were found for selective formation of 1-aryl(alkyl)-5-(5-ethoxycarbonyl-2,4-dimethyl-1H-pyrrol-3-yl)-1H-pyrazoles.     

Preparation of stereochemically pure <Emphasis Type="Italic">E</Emphasis>- and <Emphasis Type="Italic">Z</Emphasis>-alkenoic acids and their methyl esters from bicyclo[<Emphasis Type="Italic">n</Emphasis>.1.0]alkan-1-ols. Application in the synthesis of insect pheromones

Oxidative cleavage of exo- and endo-alkyl- and hydroxyalkyl-substituted bicyclo[n.1.0]alkan-1-ols with (diacetoxy-λ³-iodanyl)benzene gave the corresponding methyl alkenoates exclusively with E or Z configuration of the double bond. This reaction was used as the key stage in the syntheses of stereoisomerically pure components of pest insect pheromones: (E)-dodec-9-en-1-yl acetate (European pine shoot moth Rhyacionia buoliana), (Z)-tetradec-11-en-1-yl acetate (European oak leafroller Tortrix viridana), and (3E,8Z,11Z)-tetradeca-3,8,11-trien-1-yl acetate (tomato leafminer Tuta absoluta).     

Oxidative Addition of <Emphasis Type="Italic">N</Emphasis>-Aminophthalimide to Alkenyl-4,5-dihydropyrazoles and Alkenylpyrazoles. Synthesis of Aziridinylpyrazoles

Oxidation of N-aminophthalimide with lead tetraacetate in the presence of 1,5-diaryl-3-[(E)-2-arylethenyl]-1H-pyrazoles, as well as of 1,3-diphenyl-5-[(E)-2-phenylethenyl]-1H-pyrazole, gives adducts at the exocyclic C=C bond, the corresponding phthalimidoaziridinylpyrazoles. From 1,5-diphenyl-3-[(1E,3E)-4-phenyl-1,3-butadienyl]-1H-pyrazole, only product of addition at both exocyclic C=C bonds was obtained. In the reaction with 1-phenyl-3-[(1E, 3E)-4-phenyl-1,3-butadienyl]-5-[(E)-2-phenylethenyl]-1H-pyrazole, the adduct at the styryl C=C bond was isolated. Analogous 4,5-dihydropyrazoles, 1,5-diphenyl-3-[(1E, 3E)-4-phenyl-1,3-butadienyl]-4,5-dihydro-1H-pyrazole and 1-phenyl-3-[(1E, 3E)-4-phenyl-1,3-butadienyl]-5-[(E)-2-phenylethenyl]-4,5-dihydro-1H-pyrazole, turned out to be inert in oxidative addition of N-aminophthalimide.     

Microwave assisted synthesis of substituted (<Emphasis Type="Italic">Z</Emphasis>)-2-{[1-phenyl-3-(thiophen-2-yl)-1<Emphasis Type="Italic">H</Emphasis>-pyrazol- 4-yl]methylene}benzofuran-3(2<Emphasis Type="Italic">H</Emphasis>)-ones and their antimicrobial activity

Aurones, pyrazole and thiophene scaffolds are known for their potential antimicrobial activity. Herein, we have synthesized hybrid compounds containing three substituted (Z)-2-{[1-phenyl-3-(thiophen-2-yl)- 1H-pyrazol-4-yl]methylene}benzofuran-3(2H)-ones that had been produced from substituted (E)-1-(2-hydroxyphenyl)- 3-[1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-4-yl]prop-2-en-1-ones in high yields. All synthesized compounds were tested in vitro for their antimicrobial activity. Several of those demonstrated promising activity against some fungal and bacterial strains.     

Iron-Catalyzed Synthesis of 2-[(2<Emphasis Type="Italic">E</Emphasis>)-Hex-2-en-1-yl]cyclopentanone

An efficient synthesis of a widely used fragrance, 2-[(2E)-hex-2-en-1-yl]cyclopentan-1-one, has been developed on the basis of iron-catalyzed cross-coupling of 2-[(2E)-3-chloroprop-2-en-1-yl]cyclopentan-1- one with propylmagnesium bromide.     

Microwave-assisted synthesis of 1-{2-[(1-benzyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl)methoxy]phenyl}-3-(3-aryl-1-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-4-yl)prop-2-en-1-ones and their antimicrobial activity

A series of new (E)-1-{2-[(1-benzyl-1H-1,2,3-triazol-4-yl)methoxy]phenyl}-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones (3a–3i) has been synthesized via copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition reaction (CuAAC) of benzyl azide with substituted (E)-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-1-[2-(prop-2-ynyloxy)phenyl]prop-2-en-1-ones (2a–2i). The synthesized compounds have been characterized by their IR, ^lH, ¹³C NMR spectra, and mass spectroscopy data. All the compounds have been screened for antimicrobial activity.     

Cyclopropanation of methyl (2<Emphasis Type="Italic">E</Emphasis>)-3-[(1<Emphasis Type="Italic">R</Emphasis>,6<Emphasis Type="Italic">S</Emphasis>)-7,7-dimethyl-2-oxo-3-oxabicyclo[4.1.0]hept-4-en-4-yl]prop-2-enoate with dichlorocarbene and diazomethane

Cyclopropanation of methyl (2E)-3-[(1R,6S)-7,7-dimethyl-2-oxo-3-oxabicyclo[4.1.0]hept-4-en-4-yl]prop-2-enoate with dichlorocarbene occurred at the endocyclic double bond, while its reaction with diazomethane in the presence of Pd(acac)₂ involved the exocyclic double bond. The resulting lactones reacted with sodium methoxide in methanol via opening of one cyclopropane fragment.     

Halocyclization of 3-{[2-methyl(bromo)prop-2-en-1-yl]-sulfanyl}-5<Emphasis Type="Italic">H</Emphasis>-[1,2,4]triazino[5,6-<Emphasis Type="Italic">b</Emphasis>]indoles

Reactions of 3-[(2-bromoprop-2-en-1-yl)sulfanyl]-5H-[1,2,4]triazino[5,6-b]indole with bromine and of 3-[(2-methylprop-2-en-1-yl)sulfanyl]-5H-[1,2,4]triazino[5,6-b]indole with iodine and bromine afforded 3-halomethyl-10H-[1,3]thiazolo[3′,2′: 2,3][1,2,4]triazino[5,6-b]indol-4-ium halides whose structures were determined by ¹H NMR and X-ray analysis.     

Synthesis and reactions of 3-(3-ethoxycarbonyl-1-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-4-yl)propenic acid

The reaction of ethyl 4-formyl-1-phenyl-1H-pyrazole-3-carboxylate with the malonic acid led to the formation (2E)-3-(3-ethoxycarbonyl-1-phenyl-1H-pyrazol-4-yl)propenic acid. In reactions of this acid chloride with 4-amino-5-aryl(hetaryl)-4H-1,2,4-triazole-3-thiols were obtained ethyl 4-[(E)-2-{3-aryl(hetaryl)[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-6-yl}ethenyl]-1-phenyl-1H-pyrazoe-3-carboxylates, with 5-aryltetrazoles, ethyl 4-[(E)-2-(5-aryl-1,3,4-oxadiazol-2-yl)-ethenyl]-1-phenyl-1H-pyrazole-3-carboxylates, with 1-(2-hydroxy-3,5-dimethylphenyl) followed by the Baker-Venkataraman rearrangement and the cyclization, ethyl 4-[(E)-2-(6,8-dimethyl-4-oxo-4Hchromen-2-yl)ethenyl]-1-phenyl-1H-pyrazole-3-carboxylate.     

Chemistry of iminofurans: IX. Synthesis and cyclization of (2<Emphasis Type="Italic">Z</Emphasis>)-2-{(2<Emphasis Type="Italic">Z</Emphasis>)-2-[2-(3-R-adamantan-1-yl)-2-oxoethylidene]hydrazinyl}-4-(het)aryl-4-oxobut-2-enoic acids

1-(3-R-adamantan-1-yl)-2-[(triphenyl-λ⁵-phosphanylidene)hydrazinylidene]ethanone reacted with 4-aryl(hetaryl)-2,4-dioxobutanoic acids to give 2-{2-[2-(3-R-adamantan-1-yl)-2-oxoethylidene]hydrazinyl}-4-aryl(hetaryl)-4-oxobut-2-enoic acids which were shown to exist in solution as mixtures of Z- and E-isomeric enehydrazine tautomers. The products underwent cyclization to 3-{[2-(3-R-adamantan-1-yl)-2-oxoethylidene]- hydrazinylidene}-5-aryl(hetaryl)furan-2(3H)-ones.     

Molecular structure of (4Z)-{[(1<Emphasis Type="Italic">R</Emphasis>,6<Emphasis Type="Italic">S</Emphasis>)-7,7-dimethyl-2-oxo-3-oxabicyclo [4.1.0] hept-4-en-4-yl]methylene}-2-phenyl-l,3-oxazol-5(4H)-one

The (4Z)- {[(1R, 6S)-7,7-dimethyl-2-oxo-3-oxabicyclo[4.1.0]hept-4-en-4-yl]methylene}-2-phenyl-1,3-oxazol-5(4H)-one compound is synthesized and its molecular structure is determined.     

Synthesis of 2-(halomethyl)-3,4-dihydro-2<Emphasis Type="Italic">H</Emphasis>-pyrido[2,1-<Emphasis Type="Italic">b</Emphasis>][1,3]oxazinium halides

Alkylation of pyridin-2(1H)-one and 5-nitropyridin-2(1H)-one with 4-bromobut-1-ene afforded a mixture of N- and O-butenyl derivatives. 1-(But-3-en-1yl)pyridin-2(1H)-one and 1-(but-3-en-1-yl)-5-nitropyridin- 2(1H)-one reacted with bromine and iodine to give 2-(halomethyl)-3,4-dihydro-2H-pyrido[2,1-b][1,3]-oxazinium halides.     

Electrophilic cyclization of <Emphasis Type="Italic">N</Emphasis>-allyl(propargyl)-5-amino-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-4-carboxamides. Synthesis of 4-[(dihydro)oxazol-2-yl]-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-5-amines

N-Allyl-5-amino-1H-pyrazole-4-carboxamides in reactions with polyphosphoric acid, with N-halosuccinimides in chloroform, and with (chlorosulfanyl)benzenes in nitromethane in the presence of lithium perchlorate underwent cyclization involving the N-allylamide fragment to give 4-[5-methyl(halomethyl)-4,5-dihydrooxazol-2-yl]-1H-pyrazol-5-amines and 2-(5-amino-1H-pyrazol-4-yl)-5-[(arylsulfanyl)methyl]-4,5-dihydro-1,3-oxazolium perchlorates, respectively. Analogous reactions of N-propargyl-5-amino-1H-pyrazole-4-carboxamides with polyphosphoric acid afforded 4-(5-methyloxazol-2-yl)-1H-pyrazol-5-amines, and with (chlorosulfanyl) benzenes, 2-(5-amino-1H-pyrazol-4-yl)-5-[(arylsulfanyl)methylidene]-4,5-dihydro-1,3-oxazolium perchlorates.     

Copper-catalyzed cross-coupling of (<Emphasis Type="Italic">Z</Emphasis>)-allyl phenyl ethers with Grignard compounds in the synthesis of insect pheromones

(8Z)-Dodec-8-en-1-yl acetate (pheromone of oriental fruit moth Grapholita molesta) and (9Z)-dodec-9-en-1-yl acetate (pheromone of grape berry moth Paralobesia viteana) containing impurities of isomeric structures were synthesized via copper-catalyzed cross-coupling of (Z)-1-phenoxyhex-2-ene and (Z)-1-phenoxypent-2-ene, respectively, with Grignard compounds in the key stage.     

Synthesis and Anticholinesterase Activity of [(4<Emphasis Type="Italic">Z</Emphasis>)-2-Aryl-4-(arylmethylidene)-5-oxo-4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-imidazol-1-yl]alkanoic Acids

ω-[(4Z)-2-Aryl-4-arylmethylidene-5-oxo-4,5-dihydro-1H-imidazol-1-yl]alkanoic acids were synthesized by reaction of N-substituted α,β-dehydropeptides with chloro(trimethyl)silane or 1,1,1,3,3,3-hexamethyldisilazane. Both initial peptides and (4H)-imidazol-5-one derivatives based thereon were tested for anticholinesterase activity.     

Synthesis and biotests of 2-aryl-5-arylmethylidene-substituted 1,3-oxazol-5(4<Emphasis Type="Italic">H</Emphasis>)-ones and <Emphasis Type="Italic">N</Emphasis>-methyl-3,5-dihydro-4<Emphasis Type="Italic">H</Emphasis>-imidazol-4-ones as combretastatin A-4 analogs

A series of 2-aryl-5-arylmethylidene-1,3-oxazol-5(4H)-ones and 2-aryl-5-arylmethylidene-N-methyl-3,5-dihydro-4H-imidazol-4-ones was synthesized as structural analogs of combret- astatin A-4 (a compound possessing antitumor activity). (5Z)-5-[(4-Methoxyphenyl)methyl-idene]-3-methyl-2-(4-methylphenyl)-3,5-dihydro-4H-imidazol-4-one was found to exhibit the highest cytotoxicity against cells of human A549 lung carcinoma line (EC₅₀ = 6±0.8 μmol L^?1).     

Microwave assisted selective synthesis of (<Emphasis Type="Italic">E</Emphasis>)-1-(4-Chloro-7-hydroxy-2-aryl-2<Emphasis Type="Italic">H</Emphasis>-chromen-6-yl)-3-arylprop-2-en-1-ones and their antimicrobial activity

A series of new (E)-1-(4-chloro-7-hydroxy-2-aryl-2H-chromen-6-yl)-3-arylprop-2-en-1-ones (2a–2f) have been synthesized by selective mono cyclization of 4,6-dicinnamoyl resorcinols (1a–1f) using Vilsmeier–Haack reagent under conventional heating and microwave irradiation. The structures of the synthesized compounds have been elucidated by elemental analysis, IR, ¹H NMR, ¹³C NMR and Mass spectral data. The synthesized compounds were tested in vitro for antimicrobial activity.     

Polyfunctional imidazoles: XIII.<Superscript>1</Superscript> Addition and cyclization reactions of 1-aryl-4-chloro-5-(2-nitroethenyl)-1<Emphasis Type="Italic">H</Emphasis>-imidazoles with sulfur and nitrogen nucleophiles

1-Aryl-4-chloro-5-(2-nitroethenyl)-1H-imidazoles reacted with thiols and aromatic amines via Michael addition to give 5-[(1-arylsulfanyl)-2-nitroethyl)]-4-chloro-1H-imidazoles and N-[1-(1-aryl-4-chloro-1H-imidazol-5-yl)-2-nitroethyl]anilines, respectively. [2 + 3]-Cycloaddition of the title compounds to sodium azide afforded 4-(4-chloro-1H-imidazol-5-yl)-1H-1,2,3-triazoles.