Francisco C. Biaggio

Síntese de padrões cromatográficos e estabelecimento de método para dosagem da composição de ésteres de ácidos graxos presentes no biodiesel a partir do óleo de babaçu

Several alkyl esters were synthesized, purified, characterized by 1H NMR and employed as standards for establishing chromatographic methods to monitor their formation in the synthesis of biodiesel. The efficiency of the chromatographic methods was confirmed with the products of enzymatic transesterification of babassu oil with different alcohols (C2 to C4), using Lipozyme as catalyst.

Screening of lipases for the synthesis of xylitol monoesters by chemoenzymatic esterification and the potential of microwave and ultrasound irradiations to enhance the reaction rate.

Lipases from different sources, Pseudomonas fluorescens (AK lipase), Burkholderia cepacia (PS lipase), Penicillium camembertii (lipase G) and Porcine pancreas lipase (PPL), previously immobilized on epoxy SiO(2)-PVA, were screened for the synthesis of xylitol monoesters by esterification of the protected xylitol using oleic acid as acyl donor group. Among all immobilized derivatives, the highest esterification yield was achieved by P. camembertii lipase, showing to be attractive alternative to bulk chemical routes to satisfy increasing commercial demands. Further experiments were performed to determine the influence of fatty acids chain size on the reaction yield and the feasibility of using non-conventional heating systems (microwave and ultrasound irradiations) to enhance the reaction rate.

Sulfenylation of β-keto sulfoxides. III. Diastereoselectivity induced by a chiral phase transfer catalyst

Abstract The asymmetric induction in the sulfenylation of several β-keto sulfoxides under phase transfer catalytic conditions in the presence of the chiral catalyst N-benzylquininium chloride was investigated. It is concluded that the diastereoselectivity is not accompanied by enantiomeric resolution.

α-Phosphoryl sulfoxides. XI. Sulfenylation of α-phosphoryl sulfoxides and a general synthesis of optically active ketene dithioacetal mono-S-oxides

Abstract Sulfenylation and selenenylation of α-phosphoryl sulfoxides 1 with S-methyl methanethiosulfonate and phenylselenenyl bromide, respectively, affording α-methylsulfenyl- and α-phenylselenenyl-α-phosphoryl sulfoxides 8 and 9 are described. Sulfenylation of (+)-(S)-dimethoxyphosphorylmethyl p-tolyl sulfoxide 2 gave a mixture of optically active diastereoisomers of the sulfoxide 8a which is a key substrate in the Horner-Wittig synthesis of enantiomeric ketene dithioacetal mono-S-oxides 10. The E Z ratio of geometrical isomers of 10 was determined and briefly discussed. The crystal and molecular structure of E-1-p-tolylsulfinyl-1-methylsulfenyl-2-phenyl-ethene 10a is reported.

PTC SULFANYLATION OF SOME CARBOXYLIC ACIDS DERIVATIVES ACTIVATed BY α-SULFONYL OR α-SULFINYL GROUP, In SOLID-LIQUID SYSTEM

Abstract The sulfanylation of α-sulfonyl substituted lactone and thioesters and α-sulfinyl-substituted esters and thioesters, employing solid K2CO3, S-methyl methanethiosulfonate and TEBA, is reported. The results are compared with those in the homogeneous phase and in the non-catalytic two-phase system.

Synthesis of a novel prostaglandin containing heteroatoms in the ring cyclopentane

A novel prostaglandin analogue, n-heptyl-4-(3-hydroxy-trans-1-octenyl)-1,3-thiazolidin-2-thione, containing heteroatoms in the ring has been synthesized. The key step in the synthesis was the preparation of the five-membered ring starting from of l-cysteine ethyl ester hydrochloride.

A potent larvicidal agent against Aedes aegypti mosquito from cardanol

Cardanol is a constituent of Cashew Nut Shell Liquid that presents larvicidal activity against Aedes aegypti. The isolation of cardanol is somewhat troublesome, however, in this work we describe an efficient and inexpensive method to obtain it as a pure material. The compound was used as starting material to make chemical transformation leading to saturated cardanol, epoxides and, halohydrins. These derivatives were tested for toxicity against Aedes aegypti larvae. The results showed that iodohydrins are very promising compounds for making commercial products to combat the vector mosquito larvae presenting a LC50 of 0.0023 ppm after 72 h of exposure.

Two new spiro lactam-lactones

In 3-methyl-2-oxa-6-azaspiro[4.5]decane-1,7-dione, (1) (C 9 H 13 NO 3 ), and 3-methyl-2-oxa-6-azaspiro[4.6]undecane-1,7-dione, (2) (C 10 H 15 NO 3 ), the lactone rings are in an envelope conformation. The lactam rings are in a distorted half-chair conformation in compound (1) and in a chair conformation in (2). Molecules are joined through hydrogen bonds in both compounds.

Sulfenylation Reaction of Some α-Phosphoryl Sulfoxides

Abstract Some α-methylsulfanyl phosphorylsulfoxides were obtained by sulfenylation reaction in homogeneous phase.

Síntese enzimática do caprilato de isopentila utilizando óleo fúsel como matéria-prima

Four commercial lipase preparations immobilized by covalent attachment on epoxy-polysiloxane-β-cyclodextrin were tested as potential biocatalysts to mediate the esterification reaction of isopentanol with caprylic acid in solvent-free medium. Among them, the immobilized lipase from Rhizopus oryzae was the most active biocatalyst, attained ester conversion higher than 80% in 24 h, being selected for subsequent tests using fusel oil as source of isopentanol. An experimental design was performed and the analysis of the results revealed that the formation of the isopentyl caprylate was strongly influenced by the variable molar ratio at 95% of confidence level. The proposed mathematical model allowed predicting that the excess of caprylic acid (molar ratio fusel oil to acid of 1:1.5) and reaction temperature of 45 oC favor the reaction to attain high ester conversion. Sensory evaluation of the flavors profile in relation to all the components involved in the reaction (caprylic acid, fusel oil and esters) showed that the formed esters had distinct aromas from the starting materials, confirming that the changes in flavors occurred before and after esterification reactions.