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The synthesis of 3-alkyl-5-trifluoromethyl-1H-pyrazole-1-carboxamides, 3-alkyl5-trifluoromethyl-1H-pyrazole-1-thiocarboxamides, and 2-(3-alkyl-5-trifluoromethyl-1H-pyrazol1-yl)-thiazoles derivatives are reported. [3 + 2] cyclocondensations for a series of long alkyl chain 1,1,1-trifluoro-4-methoxyalk-3-en-2-ones and semicarbazide or thiosemicarbazide were carried out in ethanol, an eco-friendly medium. The series of trifluoromethyl-1H-pyrazol-1-ylthiocarboxamide following a [3 + 2] cyclocondensation with 2-bromoacetophenone were converted into two series of 2-(3-alkyl-5-trifluoromethyl-1H-pyrazol-1-yl)-thiazoles. Good yields (69-96%) of the isolated products were obtained. The structures of the new long alkyl chain 1H-pyrazoles and 2-(1H-pyrazol-1-yl)thiazoles were characterized using 1 H, 13C, and 19F nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization tandem mass spectrometric (ESI MS/MS) data. Moreover, some of the products were evaluated for their antimicrobial activity against Gram-negative Escherichia coli American Type Culture Collection (ATCC) 35218, Salmonella enteritidis ATCC 13076, and Pseudomonas aeruginosa ATCC 15692; and Gram-positive Staphylococcus aureus ATCC 6538, methicillin resistant Staphylococcus aureus (MRSA clinical isolate), Streptococcus sp. (clinical isolate), and Candida albicans ATCC 14053 and Candida krusei ATCC 6258 fungi. All the tested 1H-pyrazoles exhibited antibacterial and antifungal activities at the tested concentrations. The compounds from series 4 were found to be powerful against MRSA.

A series of functionalized 1,1,1-trihalo-4-methoxy-3-alken-2-ones [CX3C(O)CR1=CROMe, where X = F or Cl; R = n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-tridecyl, (CH2)2CH=C(Me)2, (CH2)2Ph, (CH2)2-(4-HOC6H4), (CH2)2-(4-MeOC6H4), (CH2)2CO2Me, (CH2)3CO2Me, CH(SMe)CH3, CH2(2-MeOC6H4), and R1 = H, and R = H and R1 = n-decyl] were synthesized from respective alkyl methyl ketones or aldehyde via acetal acylation using trifluoroacetic anhydride and trichloroacetyl chloride. 1,1,1-Trihalo-4-methoxy-3-alken-2-ones with acid-compatible substituents were easily hydrolyzed to respective trihalomethyl-1,3-diketones. The 1,1,1-trihalo-4-methoxy-3-alken-2-ones and/or respective trihalomethyl-1,3-diketones were reacted regiospecifically with hydroxylamine hydrochloride, leading to isoxazole derivatives, and with hydrazines, leading to respective 1H-pyrazole derivatives. The structures of all compounds were assigned based on nuclear magnetic resonance (NMR) and mass spectrometric data. This method represents an efficient pathway for the regioselective trihaloacetylation of asymmetrically substituted alkyl methyl ketones and highly self-condensing aldehydes. Moreover, this approach allows the introduction of biologically recognizable moieties, such as those from levulinic acid, sulcatone (prenyl), benzylacetone, anisylacetone, and raspberry ketone, as synthetic molecular targets.

We develop an efficient method to synthesize novel propionyl-spaced bisheterocyclic compounds. It entails cyclocondensation of 3-(5-trifluoromethyl-1H-pyrazol-3-yl)propanoyl hydrazide obtained from levulinic acid, with 1,1,1-trifluoro-4-methoxy-3-alken-2-ones proceeding regiospecifically to 1-[(5-trifluoromethyl-5-hydroxy-3-substituted-4,5-dihydro-1H-pyrazol-1-yl)-3-(5-trifluoromethyl-1H-pyrazol-3-yl)propan-1-one derivatives.

The synthesis of 5-[2-(trifluoromethylheteroaryl)-ethyl]-1,3,4-oxadiazoles derived from levulinic acid is reported. Cyclocondensations [4 + 1] between four different 5-[2-(trifluoromethylheteroaryl)propionylhydrazides derived from methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate obtained from levulinic acid, and electrophilic orthoesters RC(OR1)3 (where R = H, Me, Ph) and CS2 were carried out in a mild medium. Good yields (69-96%) of isolated products were obtained. The structures of the new ethylene-spaced biheterocycles were characterized using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization coupled to tandem mass spectrometric (ESI MS/MS) data.

Several new 1-(5-hydroxy-5-trifluoromethyl-1 H -pyrazol-1-yl)-3-(6-trifluoromethyl pyrimidin-4-yl)-propan-1-ones were prepared by cyclocondensation between two different 3-[6-trifluoromethyl-2-(substituted)pyrimidin-4-yl]propanoylhydrazides derived from levulinic acid and versatile 1,1,1-trifluoro-4-alkoxy-3-alken-2-ones. The structure of new propionyl-spaced bis trifluoromethylated biheterocycles was characterized based on 1 H and 13 C nuclear magnetic resonance spectroscopy and mass spectrometry data.

Efficient heterocyclization of methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate and methyl 7,7,7-trichloro-4-methoxy-6-oxo-4-heptenoate into isoxazole and pyrazole derivatives that represent a new type of glutamate-like 3-(trihalomethylated-1,2-azol-3-yl)propanoate is reported. Preparation of the key methyl 7,7,7-trihalo-4-methoxy-6-oxohept-4-enoate precursors from levulinic acid is also described. The synthetic potential of this synthetic protocol was indicated by the production of several methyl and ethyl 3-(isoxazol-3-yl)propanoates and 3-(1H-pyrazol-3-yl)propanoates, and the respective acid derivatives, in good (70–95%) yields. The crystal structure for ethyl 5-(3-ethoxy-3-oxopropyl)-1H-pyrazole-3-carboxylate (10c) has been determined by monocrystal X-ray diffraction analysis. The N–H…H intermolecular hydrogen bonds join the molecules into catamer.

Novel 1-aryl-4,4,4-trichloro-1,3-butanediones in good yields (80–97%) were synthesized in one pot through acetal acylation with trichloroacetyl chloride followed by acid hydrolysis. Structures of all compounds were elucidated by elemental analysis, mass spectrometry, and 1H/13C nuclear magnetic resonance (NMR) measurements. The 1H/13C NMR data showed that trichloromethyl-β-diketones 2a–k in solution are predominantly ketoenol. However, the spectroscopic data from 4,4,4-trichloro-2-methyl-1-phenyl-1,3-butabedione (2l) with methyl substituent between carbonyls showed a bias toward the diketo form in solution. X-ray diffraction of monocrystals from 2g and 2i showed that these compounds are cis-ketoenol tautomers. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communcations® to view the free supplemental file.

A new series of brominated 3,4-polymethylene-5-hydroxy-5-trichloromethyl-4,5-dihydroisoxazoles (2a–d) has been regiospecifically obtained from the reaction of ω-bromo-2-trichloroacetylcycloalkanones with hydroxylamine in 79–87% yield. Dehydration of the 5-hydroxydihydroisoxazoles 2a–d can be effected with concentrated sulfuric acid at 25 °C to give the regioisomeric brominated 3,4-polymethylene-5-trichloromethylisoxazoles (3a–d). In contrast, the dehydration of 5-hydroxydihydroisoxazoles with sulfuric acid in ethanol solution at 65 °C, for transformation of trichloromethyl to carboxyl group, was reproducible only with 9-bromo-3-trichloromethyl-3,3a,4,5,6,7,8,9-octahydrocycloocta[c]isoxazole-3-ol, 2d, leading to isoxazolecarboxylate 4d. The structural assignments of all isolated products are based on the analysis of their 1H and 13C NMR spectral data.

A green method was developed for the synthesis of chalcones using glycerin as solvent. Subsequently, the potential microbiology activity of these molecules was evaluated by testing them against the Gram-positive bacteria Staphylococcus aureus (S. aureus) ATCC 19095 and Enterococcus faecalis (E. faecalis) ATCC 4083, the Gram-negative bacteria Escherichia coli (E. coli) ATCC 29214 and Pseudomonas aeruginosa (P. aeruginosa) ATCC 9027, and the fungus Candida albicans (C. albicans), which includes ATCC 62342 and three clinical strains of C. albicans from human oral cavities. The results showed that some chalcones exhibited moderate inhibitory activity, the most prominent being those acting against the fluconazole-resistant strains of C. albicans.

A series of twelve novel 2-(pyrazol-1-yl)pyrimidine derivatives was easily obtained under ultrasonic conditions by the cyclocondensation reaction of 1-carboxamidino-pyrazoles with 4-methoxyvinyl-trifluoromethyl ketones using ethanol as an environment-friendly solvent in the presence of potassium hydroxide. Comparison of the ultrasound-promoted reaction with classical methodology shows that the former is faster and gives better yield. The products were isolated in excellent purity grades without purification by chromatography or recrystalization.

Twelve new 5-[(5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl)-1-propan-1-one-3-yl]-2-methyl-7-trifluoromethylpyrazolo[1,5-a]pyrimidines were prepared by cyclocondensation between 2-methyl-7-trifluoromethylpyrazolo[1,5-a]pyrimidine-5-propanoyl hydrazide derived from 2-methyl-5-(methylpropanoate-3-yl)-7-trifluoromethylpyrazolo[1,5-a]pyrimidine and a series of versatile 1,1,1-trifluoro-4-alkoxy-3-alken-2-ones [F3CC(O)C(R²)=C(R¹)OMe where R¹ = H, Me, (CH2)2CHCMe2, (CH2)2Ph, (CH2)2CO2Me, Ph, 4-MeC6H4, 4-MeOC6H4, EtO and R² = H; R¹, R² = -(CH2)4-, -(CH2)5-; R¹ = Ph and R² = Me]. The structures of new propionyl-spaced biheterocycles were derived from ¹H, 13C, and 19F nuclear magnetic resonance (NMR) spectroscopy and mass spectrometric (MS) data. Neste trabalho relatamos a ciclocondensação entre a 2-metil-7-trifluorometilpirazolo[1,5-a]pirimidino-5-propanoil hidrazida derivada da 2-metil-5-(metilpropanoato-3-il)-7-trifluorometilpirazolo[1,5-a]pyrimidina e doze versáteis 1,1,1-trifluoro-4-alcóxi-3-alquen-2-onas [F3CC(O)C(R²)=C(R¹)OMe onde R¹ = H, Me, (CH2)2CHCMe2, (CH2)2Ph, (CH2)2CO2Me, Ph, 4-MeC6H4, 4-MeOC6H4, EtO e R² = H; R¹, R² = -(CH2)4-, -(CH2)5-; R¹ = Ph e R² = Me]. A estrutura molecular dos produtos 5-[(5-trifluorometil-5-hidroxi-4,5-diidro-1H-pirazol-1-il)-1-propan-1-ona-3-il]-2-metil-7-trifluorometilpirazolo[1,5-a]pirimidinas, novos bihetererociclos contendo o espaçador propionil, foram atribuídas com base nos dados de ressonância magnética nuclear (NMR) de ¹H, 13C e 19F, e espectrometria de massas (MS).

The synthesis of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1 H -pyrrol-2(5 H )-ones 5, 6a – d from 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1 H -pyrrolidin-2-ones 3, 4a – d is reported. The 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1 H -pyrrolidin-2-ones 3, 4a – d were obtained from regiospecific bromination of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1 H -pyrrolidin-2-ones 1, 2a – d with molecular bromine. The NMR and X-ray diffraction data showed that 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1 H -pyrrolidin-2-ones were brominated at 4-position in the pyrrolidin-2-one ring.

The efficient synthesis of new fatty 1,1,1-trichloro-4-methoxy-3-alken-2-ones [Cl3CC(O)C(R²)=C(R¹)OMe, where R¹ = n-hexyl, heptyl, nonyl, undecyl, tridecyl and R² = H] and 1,1,1-trichloro-2,4-alkanediones [Cl3CC(O)CHR²C(O)R¹, where R¹ = n-pentyl and R² = Me, R¹ = Et and R² = n-butyl, R¹ = n-butyl and R² = n-propyl] in good yields (85-95%) from acetal acylation with trichloroacetyl chloride is reported. The fatty 1,1,1-trichloro-4-methoxy-3-alken-2-ones and 1,1,1-trichloro-2,4-alkanediones were reacted with hydrazine hydrochloride, leading to respective 1H-pyrazole-5-carboxylates, unusual class of fatty acid methyl (FAMEs) and ethyl (FAEEs) esters. Their structures were confirmed by elemental analysis and ¹H and 13C nuclear magnetic resonance (NMR). The fatty 1,1,1-trichloro-4-methoxy-3-alken-2-ones and 1H-pyrazole derivatives are new oleochemicals with potentially interesting and differential properties. A síntese eficiente de novas 1,1,1-tricloro-4-metoxi-3-alquen-2-onas graxas [Cl3CC(O)C(R²)=C(R¹)OMe, onde R¹ = n-hexil, heptil, nonil, undecil, tridecil e R² = H] e 1,1,1-tricloro-2,4-alkanediones [Cl3CC(O)CHR²C (O) R¹, onde R¹ = n-pentil e R² = Me, R¹ = Et e R² = n-butil, R¹ = n-butil e R² = n-propil] é apresentada, com bons rendimentos (85-95%) a partir da acilação dos respectivos acetais com cloreto de tricloroacetila. As 1,1,1-tricloro-4-metoxi-3-alquen-2-onas e 1,1,1-tricloro-2,4-alkanediones graxas reagem com cloridrato de hidrazina produzindo os respectivos 1H-pirazol-5-carboxilatos, uma classe de novos ésteres metílicos (FAMEs) e etílicos (FAEEs) graxos não comuns. As estruturas moleculares dos compostos sintetizados foram confirmadas por análise elementar e ressonância magnética nuclear (NMR) de ¹H e 13C. As 1,1,1-tricloro-4-metoxi-3-alquen-2-onas graxas e seus derivados 1H-pirazol-5-carboxilatos são novos oleoquímicos com propriedades diferenciadas e potencialmente interessantes.

In connection with our studies on the synthesis of azole and pyrazine derivatives we were interested in developing general and convenient methods for the synthesis of biheterocyclic systems from methyl 7,7,7-trihalo-4-methoxy-6-oxo-3-heptenoates. Here we report the synthesis of 4-(2-(1,3,4-oxadiazol-2yl)ethyl)-6-trifluoromethylpyrimidines (6-10) from 3(6-trifluoromethylpyrimidin-4-yl)propanehydrazide and aromatic aldehydes.

The synthesis of hydrazides 3, 4 occurs by the reaction of pyrimidines and pyrazoles 1 and 2, previously synthesized, with hydrazine hydrate and methanol under reflux for 2 hours. After removing the solvent, the products were obtained in 68% yield and characterized by 1 H NMR spectroscopy, which evidenced the disappearance of the methoxy group for the two cases. To obtain biheterocycles 5-8, the hydrazides 3 and 4 were condensed with different βalkoxyvinyltrihalomethyl ketones – whose synthesis is well established in ours laboratories – by refluxing in ethanol for 24 hours (Scheme 1). The biheterocycle targets were obtained in good yields and high purity and their structures were elucidated by 1 H/ 13 C NMR spectroscopy and CG/MS data. All synthesized compounds are solids and, when necessary, were recrystallized in hot hexane. The pyrazole compounds synthesized are unpublished and demonstrate the versatility of βalkoxyvinyltrihalomethyl ketones produced in our laboratories. N N CF3

The cyclocondensation of methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate and methyl 7,7,7-trichloro-4-methoxy-6-oxo-4-heptenoate, derived from levulinic acid with amidines [NH2CONH2, NH2CR(NH) (R = H, Me, Ph, NH2, SMe and 1H-pyrazol-1-yl), 5-amino-3-methyl1H-pyrazol and 2-aminothiazole] into pyrimidine and pyrimidine-like derivatives as a new type of glutamate-like 3-(trihalomethylatedpyrimidinyl)propanoate is reported. Preparation of 3-(trihalomethylatedpyrimidinyl) propanohydrazides is also described. The synthetic potential of this straightforward protocol was established by the synthesis of fourteen new 3-(pyrimidinyl) propanoates in regular to good yields (38-92%). The structural assignments were based on the analysis of their ¹H and 13C nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS) data. Neste trabalho, a ciclocondensação dos precursores 7,7,7-trifluoro-4-metoxi-6-oxo-4 heptenoato de metila e 7,7,7-trichloro-4-metoxi-6-oxo-4-heptenoato de metila, a partir do ácido levulínico com amidinas [NH2CONH2, NH2CR(NH) (R = H, Me, Ph, NH2, SMe e 1H-pirazol-1-il), 5-amino-3-metil-1H-pirazol e 2-aminotiazol] para obtenção de 3-(6-trifluormetilpirimidina-4-il) propanoatos de metila com estrutura análoga a mediadores glutamatérgicos é relatada. A síntese de 3-(6-trifluormetilpirimidina-4-il)propanohidrazidas também é relatada. A versatilidade desse método foi demostrada através da síntese de quatorze 3(pirimidinil)propanoatos inéditos em rendimentos razoáveis a bons (38-92%). As estruturas moleculares dos produtos foram atribuídas com base nos dados de ressonância magnética nuclear (NMR) de ¹H e 13C e cromatografia de gases acoplada à espectrometria de massas (GC-MS).

A new series of brominated 3,4-polymethylene-5-hydroxy-5-trichloromethyl-4,5-dihydroisoxazoles (2a–d) has been regiospecifically obtained from the reaction of ω-bromo-2-trichloroacetylcycloalkanones with hydroxylamine in 79–87% yield. Dehydration of the 5-hydroxydihydroisoxazoles 2a–d can be effected with concentrated sulfuric acid at 25 °C to give the regioisomeric brominated 3,4-polymethylene-5-trichloromethylisoxazoles (3a–d). In contrast, the dehydration of 5-hydroxydihydroisoxazoles with sulfuric acid in ethanol solution at 65 °C, for transformation of trichloromethyl to carboxyl group, was reproducible only with 9-bromo-3-trichloromethyl-3,3a,4,5,6,7,8,9-octahydrocycloocta[c]isoxazole-3-ol, 2d, leading to isoxazolecarboxylate 4d. The structural assignments of all isolated products are based on the analysis of their 1H and 13C NMR spectral data.