The reaction of [4-g1utamic acidjdeamlnc-l-carba-oxytocin (lb) with diazoalkanes yielded the corresponding methyl ester Ie and ethyl ester ld. Alternatively, the methyl ester was prepared by means of carbodiimide or thionyl chloride, or by treating the caesium salt of compound Ib with methyl iodide. [2-0~Methyltyrosine, 4-glutamic acid methyl esterjdeamino-f-carba-oxytccin (liz) was also synthe...

background : vitiligo is an acquired disease of skin that presents with depigmented patches due to lack of melanocytes in the epidermis. accumulation of toxic free radicals like hydrogen peroxide in the epidermis may be responsible for melanocytes death. since ethyl vanillate (vanillic acid ethyl ester) is a strong hydrogen peroxide scavenger, it may be effective against vitiligo. this study wa...

Several commercial Lewis acids, including those of the Bronsted type, specifically HBF(4).OEt(2), are able to catalyze the reaction between aromatic aldehydes and ethyl diazoacetate to produce 3-hydroxy-2-arylacrylic acid ethyl esters and 3-oxo-3-arylpropanoic acid ethyl esters. Reactions catalyzed by the iron Lewis acid [(eta(5)-C(5)H(5))Fe(+)(CO)(2)(THF)]BF(4)(-) (i.e., 1) have the best yield...

Ultra-pure ethyl-eicosapentaenoic acid (ethyl-EPA), a semi-synthetic ethyl ester of eicosapentaenoic acid, is associated with clinical improvement in motor functioning in Huntington's disease. The aim was to determine the extent to which it might reduce the rate of progress of cerebral atrophy. High-resolution cerebral magnetic resonance imaging scans were acquired at baseline, 6 months and 1 y...

2-(Trimethylsilyl)ethyl 2,2,2-trichloroacetimidate is readily synthesized from 2-trimethylsilylethanol in high yield. This imidate an effective reagent for the formation of 2-trimethylsilylethyl esters without need exogenous promoter or catalyst, as carboxylic acid substrate acidic enough to promote ester additive. A deuterium labeling study indicated that a ?-silyl carbocation intermediate inv...

Thin-layer chromatography methods on the preparative and analytical scale are presented for the separation of porphyrin methyl esters according to the number of ester groups in each porphyrin. Complete and sharp separations are obtained on silica gel glass plates or aluminium cards run in benzene-ethyl acetate-methanol solvent systems. Dicarboxylic porphyrin esters from proto-, deuteroand hemat...

Substantial evidence suggests that oxidative stress in the lungs can affect the pathological events observed in asthma. We used a guinea pig model of asthma to assess whether the early asthmatic reaction is associated with decreased lung levels of glutathione, and whether a decrease in glutathione is implicated in the increased airway smooth muscle reactivity that is associated with exposure of...