An efficient sequential three-step reaction methodology for the synthesis of three new series-1-(prop-2-yn-1-yl)-1H-pyrroles, methyl 4-acetyl-1-((1H-1,2,3-triazol-4-yl)methyl)-1H-pyrrole-3-carboxylates and 6-((1H-1,2,3-triazol-4-yl)methyl)-2,6-dihydro-1H-pyrrolo[3,4-d]pyridazin-1-ones-is reported. The methodology comprises: (i) N-alkylation reactions of polyfunctionalized 1H-pyrroles-which were previously obtained from (E)-methyl 2-azido-3-arylacrylates-with propargyl bromide in order to obtain 1H-pyrroles; (ii) standard copper-catalyzed azide-alkyne cycloaddition (CuAAC) involving organic azides (benzyl-, 4-methoxybenzyl- and 4-chlorobenzyl, as well as n-octyl azide) and N-propargylated 1H-pyrroles to give triazolyl derivatives, as methyl 1H-pyrrole-3-carboxylates (click chemistry); and (iii) [4 + 2] cyclocondensation reactions of the ketoesters in the presence of hydrazine hydrochloride in order to furnish the desired series of pyrrolo[3,4-d]pyridazin-1-ones at total yields up to 54%.

This paper describes an efficient approach for the synthesis of a novel series of sixteen 2-(5-trifluoromethyl-1H-pyrazol-1-yl)-5-(5-trihalomethyl-1H-pyrazol-1-yl-1-carbonyl) pyridines, for the first time with non-identical substituents in both pyrazole rings, through the cyclocondensation reaction of 4-methoxy-4-alkyl(aryl/heteroaryl-1,1,1-trihaloalk-3-en-2-ones [CX3C(O)CH=CR1OCH3, in which R1 = CH3, C6H5, 4-CH3C6H4, 4-OCH3C6H4, 2-furyl and X = F, Cl] or acetylacetone with some 6-[3-alkyl(aryl)-5-trifluoromethyl-1H-pyrazol-1-yl]nicotinohydrazides. Optimized yields of 67-91% were obtained when the reactions were performed in ethanol (green solvent) at reflux for 16 h. Subsequent antioxidant and antimicrobial evaluation revealed promising 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibition percentage and exhibited fungiostatic and fungicidal activities against yeasts, dermatophytes and filamentous, especially for the pyridine systems, when the both pyrazole rings attached to a pyridine ring contain CX3 groups (X = H, F, Cl) of different kinds. It is also observed the trichloromethyl substituted compounds presented higher antioxidant activity in comparison to their fluorinated analogous.

Neste trabalho, 3-haloacetil-4-metilquinolinas foram sintetizadas a partir da reação de 4-alcóxi-3-alquen-2-onas [R¹C(O)CH=C(R²)OCH3, onde R¹ = CF3, CCl3, CHCl2, CF2Cl e CF2CF3 e R² = Me, Et, Pr, Bu, i-Bu e i-Pe] e 2-aminoacetofenona. A reação foi realizada em líquido iônico e ácido 4-toluenosolfônico sob irradiação de micro-ondas. Os resultados mostraram que o método catalítico foi efetivo e os produtos foram formados em tempos de reação curtos (10-20 min) e com bons rendimentos (70-91%).

In this work, 3-haloacetyl-4-methylquinolines were synthesized from the reaction of 4-alkoxy-3-alken-2-ones [R¹C(O)CH=C(R²)OCH3, where R¹ = CF3, CCl3, CHCl2, CF2Cl, CF2CF3 and R² = Me, Et, Pr, Bu, i-Bu and i-Pe] and 2-aminoacetophenone. The reaction was performed in ionic liquid and 4-toluene sulfonic acid under microwave irradiation. Results showed that the catalytic method was effective. Products were formed in a short time (10-20 min) and presented good yields (70-91%).

Este trabalho relata interessantes resultados relativos a síntese convencional de uma nova série de 2,10-dialquil(aril)-4,8-bis (trifluorometil)-1,7-fenantrolinas, em rendimentos de 22-40%, a partir das reações de ciclização de N,N'-bis(oxotrifluoralquenil)-1,3-fenilenodiaminas [1,3-C6H4-(NHCR=CHC(O)CF3)2] em um meio fortemente ácido (PPA) e na ausência de solvente. A rota sintética também permitiu o isolamento simultâneo de uma nova série de 2-alquil(aril/heteroaril)-4-trifluormetil-7-aminoquinolinas, em 20-73% de rendimento. As enaminonas precursoras foram obtidas a partir da reação de 4-alcóxi-1,1,1-triflúor-3-alquen-2-onas [CF3C(O)CH=C(R)OR¹, onde R = H, Me, Ph, 4-MePh, 4-OMePh, 4-ClPh, 4-FPh, 4-BrPh, 4-NO2Ph, 2-furil e R¹ = Me, Et] com 1,3-fenilenodiamina em condições brandas, em rendimentos 47-91%.

This paper reports interesting results of the conventional synthesis of a new series of 2,10-dialkyl(aryl)-4,8-bis(trifluoromethyl)-1,7-phenanthrolines, in 22-40% yields, from cyclization reactions of N,N'-bis(oxotrifluoroalkenyl)-1,3-phenylenediamines [1,3-C6H4-(NHCR=CHC(O)CF3)2] in a strongly acidic medium (PPA) and absence of solvent. The synthetic route also allowed the isolation of a new series of 2-alkyl(aryl/heteroaryl)-4-trifluoromethyl-7-aminoquinolines, in 20-73% yields, simultaneously. The enaminone precursors were obtained from the reaction of 4-alkoxy-1,1,1-trifluoroalk-3-en-2-ones [CF3C(O)CH=C(R)OR¹, where R = H, Me, Ph, 4-MePh, 4-OMePh, 4-ClPh, 4-FPh, 4-BrPh, 4-NO2Ph, 2-furyl and R¹ = Me, Et] with 1,3-phenylenediamine under mild conditions, in 47-91% yields.

Este trabalho descreve a síntese de 1,4'-bipirazóis inéditos pela da reação de ciclocondensação de novas β-dimetilaminoenonas com as monoidrato de hidrazina, tert-butil hidrazina, fenil hidrazina, carboximetilhidrazina. Os produtos foram obtidos com alta regiosseletividade em rendimentos de bons a moderados (50-80%). A técnica de cristalografia de raios-X foi utilizada para a elucidação da regiosseletividade da formação dos produtos. 1,4'-Bipirazolilisoxazóis também foram descritos.

Novel 1,4'-bipyrazoles were synthesized via highly regioselective cyclocondensation reactions of β-dimethylaminoenones with hydrazine monohydrate, tert-butylhydrazine hydrochloride, phenylhydrazine hydrochloride or carboxymethylhydrazine. X-ray diffraction technique was used in the elucidation of the regiochemistry of the β-dimethylaminoenaminones and of the 1,4'-bipyrazoles. 1,4'-Bipyrazolylisoxazoles were also reported.

Este trabalho descreve a síntese de 4,5-diidro-1H-pirazóis pela reação de ciclocondensação de hidrazinas [NH2NH-R², onde R² = CO2Me, Ph, CH2CH2OH] com 4-alcóxi-1,1,1-trifluor-3-alquen-2-onas [CF3C(O)CH=C(R¹)OR, onde R/R¹ = Et/H, Me/Me and Me/Ph] sob irradiação de micro-ondas utilizando um equipamento de micro-ondas para síntese e em condição livre de solvente. Algumas reações foram realizadas na presença de metanol. Os resultados obtidos utilizando micro-ondas para síntese foram comparados com aqueles obtidos quando a reação foi feita pelo método convencional e no forno de micro-ondas doméstico. Os produtos foram obtidos com bons rendimentos em um intervalo de tempo pequeno. Além disso, foi demonstrado que a temperatura da reação alterou a formação dos produtos para cada hidrazina mostrando que o equipamento de micro-ondas para síntese é eficiente para as reações de hidrazinas com 4-alcóxi-1,1,1-trifluor-3-alquen-2-onas levando à formação dos produtos 4,5-diidro-1H-pirazóis e pirazóis.

This paper presents a study of solvent-free reaction conditions using microwave irradiation (MW) to obtain 4,5-dihydro-1H-pyrazoles and dehydrated pyrazoles by the cyclocondensation reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF3C(O)CH=C(R¹)OR, where R/R¹ = Et/H, Me/Me and Me/Ph] with hydrazines [NH2NH-R², where R² = CO2Me, Ph, CH2CH2OH]. Some reactions were performed under the same reaction conditions using methanol as solvent. The results obtained using MW equipment for synthesis under solvent-free conditions were also compared with those described in literature for conventional thermal heating and heating with a domestic MW oven. In general, the products furnished by reaction in MW equipment for synthesis presented better yields and shorter reaction times. In addition, it was demonstrated that the reaction temperature altered the formation of products for each hydrazine showing that MW equipment for synthesis is efficient for reacting hydrazines and 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones to procedure the products 4,5-dihydro-1H-pyrazoles and dehydrated pyrazoles.

Este trabalho apresenta a síntese regiosseletiva de séries de bis-2-pirazolinas e bis-1H-pirazóis succinil intercalados inéditas, denominadas 1,4-bis[5-(trifluormetil)-5-hidróxi-4,5-diidro-1H-pirazol-1-il]butano-1,4-dionas (46-88%), o respectivo sistema desidratado (60-78%), 1-[5-(trifluormetil)-5-hidróxi-4,5-diidro-1H-pirazol-1-il]-4-oxabutano hidrazidas (52-81%) e 2-pyrazolinas derivadas não simétricas, como 1-[5-(trifluormetil)-5-hidróxi-4,5-diidro-1H-pirazol-1-il)-4-(5-(triclorometil)-5-hidróxi-4,5-diidro-1H-pirazol-1-il]butano-1,4-dionas (75-91%). Todos os bis-pirazóis succinil substituídos foram obtidos a partir de reações de ciclocondensação de 4-alcóxi-1,1,1-trialo-3-alquen-2-onas 4-substituídas (4-substituinte = H, Me, fenil, 4-FC6H4, 4-ClC6H4, 4-OMeC6H4, 4-NO2C6H4, 1-naftil and 2-furil), com dihidrazida succínica, em etanol como solvente, sob condições reacionais convencionais controladas.

This paper describes the conventional regioselective synthesis of a series of new succinyl spacer bis-(3,5-substituted 2-pyrazolines and 1H-pyrazoles), namely; 1,4-bis[5-(trifluoromethyl)-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl]butane-1,4-diones (46-88%) and the respective dehydrated system (60-78%), new 1-[5-(trifluoromethyl)-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl]-4-oxobutane hydrazides (52-81%) and the non-symmetrical 2-pyrazolines derivatives thereof as 1-[5-(trifluoromethyl)-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl)-4-(5-(trichloromethyl)-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl]butane-1,4-diones (75-91%). All succinyl substituted bispyrazoles were obtained from the cyclocondensation reactions of 4-substituted 4-alkoxy-1,1,1-trihaloalk-3-en-2-ones, where the 4-substituents are H, Me, Ph, 4-FC6H4, 4-ClC6H4, 4-OMeC6H4, 4-NO2C6H4, 1-naphthyl and 2-furyl, with succinic acid dihydrazide in ethanol as solvent under controlled reaction conditions.

Este trabalho descreve a síntese de dois novos trifluoracetilceteno O,N-acetais [CF3C(O) CH=C(OEt)(NS(O)R2), onde R = CH3, Ph], obtidos da reação de 4,4-dietóxi-1,1,1-trifluorbut-3- en-2-ona [CF3C(O)CH=C(OEt)2] com S,S-dimetil- e S-metil-S-fenil-sulfoximida [HN=S(O)R2], na presença de trietilamina, com rendimentos de 60-72%, e suas aplicações na obtenção de pirazóis, isoxazóis e pirimidinas S,S-dimetilsulfoximido substituídos, em 55-89% de rendimento, a partir de reações de 4-etóxi-4-(S,S-dimetilsulfoximido)-1,1,1-trifluorbut-3-en-2-ona com hidrazinas, hidrazidas, cloridrato de hidroxilamina e acetilguanidina.

Two new trifluoroacetylketene O,N-acetals [CF3C(O)CH=C(OEt)(NS(O)R2), where R = CH3, Ph] derived from the reaction of 4,4-diethoxy-1,1,1-trifluorobut-3-en-2-one [CF3C(O)CH=C(OEt)2] with S,S-dimethyl- and S-methyl-S-phenyl-sulfoximide [HN=S(O)R2], in the presence of triethylamine, have been obtained, in 60-72% yields, and applied in the synthesis of S,S-dimethylsulfoximido-substituted pyrazoles, isoxazoles and pyrimidines, in 55-89% yields, from the reactions of 4-ethoxy-4-(S,S-dimethylsulfoximido)-1,1,1-trifluorobut-3-en-2-one with hydrazines, hydroxylamine hydrochloride and acetylguanidine.

Este trabalho descreve a reação de ciclocondensação de 3-amino-5-metil-1H-pirazol com 1,1,1-tricloro-4-alcóxi-3-alquen-2-onas [CCl3C(O)CH=C(R¹)OR, onde R¹/R = H/Me, Me/Et, Et/Me, Pr/Et, Bu/Me, iso-Bu/Me] e β-dimetilaminovinil cetonas [R²C(O)CH=CHNMe2, onde R² = Ph, Ph-4-Me, Ph-4-F, Ph-4-Cl, Ph-4-Br, Ph-4-NO2, fur-2-il, tien-2-il, pirrol-2-il, pyrid-2-il], em refluxo de ácido acético para a obtenção de uma série de catorze pirazolo[1,5-a]pirimidinas. Os produtos foram obtidos em bons rendimentos (65-98%). Este trabalho apresenta ainda uma metodologia simples e seletiva para a obtenção de 3-bromo-pirazolo[1,5-a]pirimidinas, com rendimentos de 70-98%.

The reaction of 3-amino-5-methyl-1H-pyrazole with 1,1,1-trichloro-4-alkoxy-3-alken-2-ones [CCl3C(O)CH=C(R¹)OR, where R¹/R = H/Me, Me/Et, Et/Me, Pr/Et, Bu/Me, iso-Bu/Me] or β-dimethylaminovinyl ketones [R²C(O)CH=CHNMe2, where R² = Ph, Ph-4-Me, Ph-4-F, Ph-4-Cl, Ph-4-Br, Ph-4-NO2, fur-2-yl, thien-2-yl, pyrrol-2-yl, pyrid-2-yl], in acetic acid under reflux for 16 hours, furnished highly regioselective the halomethylated pyrazolo[1,5-a]pyrimidines and aryl[heteroaryl]pyrazolo[1,5-a]pyrimidines, respectively. A protocol for the bromination reaction at the 3-position pyrazolo[1,5-a]pyrimidines also was investigated.

Este trabalho apresenta a síntese de uma nova série de 2-[3-alquil (aril/heteroaril)-5-trialometil-5-hidróxi-4,5-diidro-1H-pirazol-1-il]-5-[3-alquil(aril/heteroaril)-5-trialometil-5-hidróxi-4,5-diidro-1H-pirazol-1-il-1-carbonil]piridinas, obtida a partir de reações de ciclocondensação de 4-alcóxi-4-alquil(aril/heteroaril)-1,1,1-trialo-3-alquen-2-onas [CX3C(O)CH=CR¹OR, onde R = Me, Et; R¹ = H, Me, Ph, 4-MeOPh, 4-NO2Ph, 4,4'-Bifenil, 1-Naftil, Fur-2-il e Tien-2-il e X = F, Cl] com hidrato de hidrazida 6-hidrazino-nicotínica. Os melhores rendimentos foram obtidos quando as reações foram executadas em etanol como solvente a 78 ºC por 4 horas (67-97%). Em sequência, são descritas as reações de desidratação de 2-(1H-pirazol-1-il)-5-(1H-pirazol- 1-il-1-carbonil)piridinas. Estas reações foram realizadas em meio piridina / benzeno, na presença de cloreto de tionila e levaram ao isolamento de uma série de 2-[3-alquil(aril/heteroaril)-5-trifluormetil-1H-pirazol-1-il]-5-[3-alquil(aril/heteroaril)-5-trifluormetil-1H-pirazol-1-il-1-carbonil]piridinas, com rendimentos de 64 a 86%.

This paper describes the synthesis of a new series of 2-[3-alkyl(aryl/heteroaryl)- 5-trifluoro(chloro)methyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl]-5-[3-alkyl(aryl/heteroaryl)-5-trifluoro(chloro)methyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl-1-carbonyl]pyridines by the cyclocondensation reaction of 4-alkoxy-4-alkyl(aryl/heteroaryl)-1,1,1-trifluoro(chloro)-3-alken- 2-ones [CX3C(O)CH=CR¹OR, where R = Me, Et; R¹ = H, Me, Ph, 4-MeOPh, 4-NO2Ph, 4,4'-Biphenyl, 1-Naphthyl, Fur-2-yl, Thien-2-yl and X = F, Cl] with 6-hydrazinonicotinic hydrazide hydrate. Yields of 62 to 97% were obtained when the reactions were performed in ethanol as solvent at 78 ºC for 4 hours. In a subsequent step, the dehydration reactions of 2-(5-hydroxy-1H-pyrazol-1-yl)-5-(5-hydroxy-1H-pyrazol-1-yl-1-carbonyl)pyridines were carried out in pyridine/benzene in the presence of thionyl chloride and led to the isolation of a series of 2- [3-alkyl(aryl/heteroaryl)-5-trifluoro(chloro)methyl-1H-pyrazol-1-yl]-5-[3-alkyl(aryl/heteroaryl)-5-trifluoro(chloro)methyl-1H-pyrazol-1-yl-1-carbonyl]pyridines, in 64 to 86% yields.

Este trabalho apresenta a síntese de uma série de treze 1-cianoacetil-5-hidroxi-5-halometil-1H-4,5-diidropirazóis a partir da reação de condensação entre cianoacetohidrazida e 4-alcoxi-3-alquen-2-onas [R³C(O)C(R²)=C(R¹)(OR), onde R³ = CF3, CCl3, CHCl2, CO2Et; R² = H, Me; R¹ = H, Me, Et, Pr, Pentil, c-Hexil, Ph, e R = Me, Et]. Reações de desidratação e derivatização destes compostos também são apresentadas com o objetivo de demonstrar a versatilidade de pirazóis 1-cianoacetil-substituídos como blocos precursores em síntese orgânica.

The synthesis of thirteen 1-cyanoacetyl-5-hydroxy-5-halomethyl-1H-4,5-dihydropyrazoles from the reaction of 4-alkoxy-3-alken-2-ones [R³C(O)C(R²)=C(R¹)(OR), where R³ = CF3, CCl3, CHCl2, CO2Et; R² = H, Me; R¹ = H, Me, Et, Pr, Pentyl, c-Hexyl, Ph, and R = Me, Et] with cyanoacetohydrazide is reported. In order to show the versatility of using the 1-cyanoacetyl-substituted pyrazoles as important building blocks in organic synthesis, some attempts to obtain pyrazole derivatives also are described.

Uma nova série de nove 3-fosfato-(4,4,4-trifluor-butil)-carbamatos de etila (compostos fosfato-carbamato), foram obtidos através da reação de (4,4,4-trifluor-3-hidroxibut-1-il)-etil carbamatos com oxicloreto de fósforo seguido de adição de álcoois. Os produtos foram caracterizados por espectroscopia de RMN de ¹H, 13C, 31P e 19F, CG-EM e análise elementar. Todos os compostos sintetizados foram testados para a inibição da enzima acetilcolinesterase (AChE) usando o método de Ellman. Todos os compostos analisados contendo os grupos carbamato e fosfato em sua estrutura, mostraram inibição enzimática, sendo que o composto contendo o grupo dietóxi (2b) apresentou a maior atividade inibitória. Estudos de modelagem molecular foram realizados para obter informações detalhadas entre o sítio ativo da enzima acetilcolinesterase e os compostos candidatos a inibição, obtendo-se valiosas informações estruturais com relação à inibição de enzima acetilcolinesterase.

A series of nine new [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters (phosphate-carbamate compounds) was obtained through the reaction of (4,4,4-trifluoro-3-hydroxybut-1-yl)-carbamic acid ethyl esters with phosphorus oxychloride followed by the addition of alcohols. The products were characterized by ¹H, 13C, 31P, and 19F NMR spectroscopy, GC-MS, and elemental analysis. All the synthesized compounds were screened for acetylcholinesterase (AChE) inhibitory activity using the Ellman method. All compounds containing phosphate and carbamate pharmacophores in their structures showed enzyme inhibition, being the compound bearing the diethoxy phosphate group (2b) the most active compound. Molecular modeling studies were performed to investigate the detailed interactions between AChE active site and small-molecule inhibitor candidates, providing valuable structural insights into AChE inhibition.

Este trabalho mostra a síntese, em bons rendimentos (57-95%), de duas séries de 1-alquil(aril)amino-2-oxo-5-(2-oxo-3,3,3-trialopropiliden)-pirrolidinas 5 e 6, a partir dos intermediários 4-[alquil(aril)amino]-6-oxo-7,7,7-trialo-4-hepteno-atos de metila 3 e 4 obtidos por substituição da metoxila-beta nos precursores 4-metoxi-6-oxo-7,7,7-trialo-4-heptenoatos de metila 1 e 2, pela série de aminas primárias RNH2, onde R = PhCH2, PhCH2CH2, Ph, 4-MeC6H4, 4-MeOC6H4, 4-ClC6H4, 4-BrC6H4, 2-piridnil, 5-metil-3-isoxazolil, 4-NH2C6H4. A estrutura molecular dos produtos inéditos foi atribuída a partir dos dados de RMN ¹H, 13C e espectrometria de massas. A configuração geométrica dos compostos 3d e 5b foi confirmada pelos dados de difração de raios-X em monocristal.

Reactions of methyl 4-methoxy-6-oxo-7,7,7-trihalo-4-heptenoates 1 and 2 with primary amines RNH2, where R = PhCH2, PhCH2CH2, Ph, 4-MeC6H4, 4-MeOC6H4, 4-ClC6H4, 4-BrC6H4, 2-pyridyl, 5-methyl-3-isoxazolyl, 4-NH2C6H4 affording methyl 4-[alkyl(aryl)amino]-6-oxo-7,7,7-trihalo-4-heptenoates 3, 4, in good yields (57-95%), which suffer quantitative intramolecular cyclocondensation to produce 1-alkyl(aryl)-5-(2-oxo-3,3,3-trihalopropylidene)pyrrolidin-2-ones 5, 6, are reported. The structures of the isolated new products were assigned by means of ¹H,13C NMR measurements and mass spectrometry. The Z and E configuration of compounds 3d and 5b respectively were established from X-ray crystallography.

Este trabalho apresenta uma metodologia, ambientalmente adequada e mais econômica em relação àquelas descritas na literatura, para a obtenção de uma série de vinte e seis 4-amino-1,1,1-trialo-3-alquen-2-onas [CX3C(O)CH=C(R¹)NR² R³, com X = F, Cl, R¹ = H, Me, e R²/R³ = H/Ph, H/4-F-Ph, H/Bn, H/(CH2)2OH, Me/Ph, Me/Bu, Et/Et, -(CH2)4-], a partir da reação de 1,1,1-trialo-4-alcóxi-3-alquen-2-onas com aminas primárias e secundárias, na ausência de solvente, a temperatura ambiente e em cinco minutos (rendimentos de 73-99%).

An efficient green procedure to prepare a series of twenty-six 4-amino-1,1,1-trihalo-3-alken-2-ones [CX3C(O)CH=C(R¹)NR² R³, where X = F, Cl, R¹ = H, Me, and R²/R³ = H/Ph, H/4-F-Ph, H/Bn, H/(CH2)2OH, Me/Ph, Me/Bu, Et/Et, -(CH2)4-] from the solvent-free reaction of 1,1,1-trihalo-4-alkoxy-3-alken-2-ones with primary and secondary amines at room temperature for five minutes is reported (yields of 73-99%).

A preparação, com bons rendimentos (70-98%), de doze novos ésteres etílicos de 5-triclorometil-4,5-diidro-1H-1-pirazóis, usando-se ambientalmente boas técnicas induzidas por microondas, é descrita. Estes compostos foram sintetizados a partir da reação de ciclocondensação de 1,1,1-tricloro-4-alcoxi-3-alquen-2-onas [CCl3C(O)C(R²)=C(R¹ )OR, onde R, R² = H, alquila; R¹ = H, alquila e arila] com metil carboxilato hidrazina. As vantagens obtidas pelo uso de irradiações de microondas na ausência de solventes, em relação ao método convencional foram demonstradas.

Twelve novel 5-trichloromethyl-4,5-dihydro-1H-1-pyrazole ethyl esters have been synthesized in good yields (70-98%) by using environmentally benign microwave induced techniques. The compounds were synthesized from the cyclocondensation of 1,1,1-trichloro-4-alkoxy-3-alken-2-ones [CCl3C(O)C(R²)=C(R¹ )OR, where R, R² = H, alkyl; R¹ = H, alkyl and aryl] with hydrazine methyl carboxylate. The advantages obtained by the using of microwave irradiation under solvent-free conditions, rather than a conventional method, were demonstrated.