Arci Dirceu Wastowski

Haloacetylated enol ethers: 12 [18]. Regiospecific synthesis and structural determination of stable 5-hydroxy-1H-pyrazolines

Abstract The regiospecific synthesis and structural elucidation by NMR spectroscopy, AM1 semiempirical MO calculations and X-ray diffraction of a novel series of twelve 3-aryl[alkyl]-5-hydroxy-5-trichloromethyl-4, 5-dihydro-1H-pyrazole-1-carboxyamides and analogous 1-thiocarboxy-amides, is reported.

Haloacetylated enol ethers 10. Condensation of β-alkoxyvinyl trifluoromethyl ketones with thiosemicarbazide. Synthesis of new trifluoromethyl 4,5-dihydro-1H-1-pyrazolethiocarboxyamides

The synthesis of 3-aryl[alkyl]-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-pyrazolethiocarboxyamides (2a‐g) from the direct cyclocondensation reaction of b-alkoxyvinyl trifluoromethyl ketones (1a‐g) with thiosemicarbazide in methanol, under mild conditions, is reported. Similarly, the 1H-1-pyrazolethiocarboxyamide derivatives (2a‐g) were easily dehydrated and the thiocarboxyamide group hydrolyzed in a one-step reaction by stirring with concentrated sulfuric acid to give the 3-aryl[alkyl]-5-trifluoromethyl-1H-pyrazoles (3a‐g) in good yields. Specific syntheses and physical properties of 3-aryl[alkyl]-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-pyrazolethiocarboxyamides are reported here for the first time. # 1998 Elsevier Science S.A. All rights reserved.

A convenient method for the synthesis of 2-trichloromethyl-4-p-substituted-phenyl-3H-1,5-benzodiazepines

Abstract A convenient method to obtain a new series of 2-trichloromethyl-4-aryl-3H-1,5-benzodiazepines from the reaction of β-methoxyvinyl trichloromethyl ketones derived from acetals and o-phenylenediamine is reported.

β-Alkoxyvinyl trichloromethyl ketones as N-heterocyclic acylating agent. A new access to 5H-thiazolo[3,2-a]pyrimidin-5-ones

Abstract Using trichloromethyl substituent as convenient leaving group for the synthesis of interesting bi-heterocyclic compounds, a series of 6-methyl- and 7-alkyl(aryl)-5 H -thiazolo[3,2- a ]pyrimidin-5-ones, where alkyl=methyl, n -propyl, isopropyl, isobutyl, n -hexyl, isopentyl and aryl=phenyl, 4-toluyl, 4-chlorophenyl, 4-bromophenyl, 4-methoxyphenyl was obtained from a simple and regiospecific reaction of 4-alkoxy-1,1,1-trichloro-3-alken-2-ones with 2-aminothiazole in good yield (45–89%).

A Convenient Method to Obtain 4,5-Dihydro-1H-Methylpyrazoles by A Ring Transformation Reaction

Abstract A convenient method for the synthesis of alkyl[aryl]-substituted 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-methylpyrazole (2) from a new ring transformation reaction of alkyl[aryl]-substituted-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-pyrazolethiocarboxyamide (1) with methylhydrazine in THF, and the thermal dehydration of 2, are reported.

Dissimilaridade genética e análise de trilha de cultivares de soja avaliada por meio de descritores quantitativos

Alem das avaliacoes entre genotipos, a utilizacao de tecnicas multivariadas possibilita restringirem-se os erros, principalmente quanto a diversidade genetica, podendo-se, assim, prever combinacoes com maior efeito heterotico, alem da maior possibilidade de recuperacao dos genotipos superiores. Objetivou-se, com este trabalho, avaliar a divergencia genetica entre 18 cultivares de soja, por meio de seis caracteres morfoagronomicos. Foi realizada a analise de trilha, para averiguar as contribuicoes direta e indireta desses caracteres sobre o rendimento de graos. A distância generalizada de Mahalanobis fundamentou as tecnicas de agrupamentos, tanto a de Tocher, bem como a do dendrograma por ligacao simples. Observaram-se cinco grupos divergentes, sendo nove genotipos considerados similares entre si, enquanto os cultivares CEP 59, Netuno e Urano foram formadores de grupos isolados pelos dois metodos de agrupamento. Quanto a analise de trilha, observou-se que os caracteres indiretos pouco influenciaram o rendimento de graos, tendo relacao direta significativa com massa de 100 graos, tendo-se destacado os cultivares Tertulha e CEP 53, com produtividade de graos acima de 3,7 t ha-π. Palavras-chave: agrupamento, Glycine max (L.) Merr., divergencia genetica.

Caracterização dos níveis de elementos químicos em solo, submetido a diferentes sistemas de uso e manejo, utilizando espectrometria de fluorescência de raios-x por energia dispersiva (EDXRF)

This study aimed to evaluate the chemical elements levels in soil, submitted to different management systems and use by the Energy Dispersive X-Ray Fluorescence Spectrometry - EDXRF. The systems were T1 - agro forestry (SAF), T2 - Native Field (CN), T3 - Native Forest (NM), T4 - Tillage Forest (PF); T5 - conventional tillage system (SPC) and T6 - System tillage (NT). Samples were collected at 0-10 and 10-20 cm, dried and ground for analysis in EDX-720. The soil showed no difference in the average concentrations of chemical elements analyzed in the profiles, but the systems presented different concentrations of metal elements, and T3 had the highest K, Ca and Zn at 0-10 cm and higher contents of K, Ca, Cu, Zn and Mn in the layer of 10-20 cm.

Evaluation of QuEChERS Sample Preparation and Gas Chromatography Coupled to Mass Spectrometry for the Determination of Pesticide Residues in Grapes

An effective analytical method for pesticides multiresidue determination in grape samples was developed and validated. A modified quick, easy, cheap, effective, robust and safe (QuEChERS) method was used to extract the target compounds. Several sorbent materials were tested for the clean-up step using dispersive solid phase extraction (d-SPE) and Florisil® was selected. Samples extracts were evaporated before injection in the gas chromatography with mass spectrometry (GC-MS) system in order to improve detectability. Recoveries from blank samples spiked at 0.04, 0.3 and 1.0 mg kg−1 ranged from 95 to 102% with relative standard deviation (RSD) from 1.3 to 19.7%. Method limits of detection (LODm) and quantification (LOQm) ranged from 0.006 to 0.012 and 0.02 to 0.04 mg kg−1, respectively. The positive matrix effect caused an increase in the peak areas of all compounds and matrix matched calibration curve linearity (coefficient of determination, r2) was higher than 0.98 for all target analytes. The validated method was successfully applied for the determination of 19 pesticides in grape samples.

Comparison of the analytical performance of EDXRF and FAAS techniques in the determination of metal species concentrations using protocol 3050B (USEPA)

ABSTRACT Sediments are active environmental compartments capable of interchanging the chemical species with the water column, degrading their quality and influencing the toxicity of the matrix. The average concentrations of sediment-associated metallic species have been used to evaluate the extent of their contamination. The approaches used have progressed considerably over the last few decades and different instrumental techniques have been employed in quali-quantification of metal compounds associated with sediments. This study aimed to evaluate the accuracy of the technique of Energy Dispersive X-Ray Fluorescence Spectrometry (EDXRF) performed on the equipment Shimadzu (model Rany, Series EDX-720) in the validation process, adopting as reference the technique of Flame Atomic Absorption Spectroscopy (FAAS), appliance GBC (model Avanta) to quantify the species: Zn, Fe, Ni, Cu, Pb and Cr in solution, in chemically available fraction (3050B Protocol-United States Environmental Protection Agency), extracted from sediments of the River Barigüi, metropolitan region of Curitiba, southern Brazil. The samples were collected according to the clean techniques protocols. The analytical figures of precision, accuracy and determination limit of the method were evaluated using the two techniques separately and on the same samples. Statistically significant differences were observed between the two methods.

Cyclocondensation reaction of 4-aryl-4-methoxy-1,1,1-trifluoro-3-buten-2-ones with urea

The synthesis of a novel series of eleven 6-aryl(5-methyl)-4-trifluoromethyl-2(1H)-pyrimidinones, where aryl ¼ Ph, 4-CH3Ph, 4-FPh, 4ClPh, 4-BrPh, 4-OCH3Ph and alkyl ¼ H, CH3, from the reaction of 4-aryl-4-methoxy-1,1,1-trifluoro-3-buten-2-ones with urea in the presence of hydrochloric acid, is reported. Trifluoroacetylation of acetophenone- and propiophenone-dimethylacetals derived from phenones, was employed to obtain the precursors. # 2002 Elsevier Science B.V. All rights reserved.