Studies on Different Hydrolysis Procedures for Drugs of Abuse in Hair

1.IntroductionDrugsofabusehavebecomeamajorprobleminoursocietyinrecentyearsandhaveresultedinwidespreadabuse.Thedetectionofdrugsofabuseinbiologicalsamplesisoneoftheprimaryfunctionsofaclinicalorforensictoxicologylaboratory.Particularlyincaseswheretheres...     

A new chemoenzymatic synthesis of d-cloprostenol

A new chemoenzymatic synthesis of d-cloprostenol based on the biocatalytical resolution of anti-2-oxotricyclo[2.2.1.0]heptan-7-carboxylic acid 1 has been developed. The resolution was attempted by different approaches: esterification or reduction of the acid and hydrolysis or reduction of the corresponding esters. The most efficient method proved to be the reduction of the propyl esters of 1 catalysed by the yeast Kluyveromyces marxianus, which allowed for the recovery of the enantiomerically pure ester of anti-2-oxotricyclo[2.2.1.0]heptan-(R)-7-carboxylic acid (R)-3 at 60% molar conversion of 3.0 g/l of racemic substrate acid under optimised conditions. anti-2-Oxotricyclo[2.2.1.0]heptan-(R)-7-carboxylic acid was obtained by alkaline hydrolysis and employed for the synthesis of d-cloprostenol.     

Typical conversion of lignocellulosic biomass into reducing sugars using dilute acid hydrolysis and alkaline pretreatment

The development and production of fossil fuel alternatives have become one of the main focal points in recent investigations. Lignocellulosic biomass is a renewable source of fermentable sugars for second-generation biofuels and chemicals via biotechnological pathways. However, the presence of lignin and hemicellulose in lignocellulosic biomass makes it difficult for the biomass to be hydrolyzed or digested during fermentation. Thus, effective biomass pretreatment is vital. The present review shows that chemical pretreatment is the current preferred method to obtain high sugar yields at low cost, with dilute acid and alkaline hydrolysis as the two most reported technologies. Dilute acid favours hydrolysis of the hemicelluloses whereas alkaline hydrolysis targets the lignin fraction. Both methods have merits and demerits, and have been combined with other treatments such as hydrothermal and enzymatic hydrolysis. Further investigation is required to improve the pretreatment processes and to ensure the economic viability of bioconversion.     

Structural investigation of lac resin—II

The three fractions of lac rein viz., hard resin I, hard resin II and soft resin have been cleaved with hydriodic acid followed by deiodination. The products were separated into fatty acids and terpene acids. The former have been studied by GLC and data on the nature and distribution of the chain lengths and their relative amounts were thus obtained. Cleavage of the different fractions of the resin with hydrogen chloride followed by alkaline hydrolysis gave the total aleuritic acid quantitatively. Based on the above results, the possibility of the presence of alkali stable linkages in lac resin and the amount of aleuritic acid liberated only by acid cleavage have been determined.     

Sequence Analysis of Polypeptides and Proteins by Combined Gas Chromatography-Mass Spectrometry

A new method for determining the amino acid sequence of polypeptides consists in initial partial hydrolysis to yield a complex mixture of oligopeptides. After derivatization to enhance its volatility, the mixture is analyzed by combined gas chromatography and mass spectrometry. The sequence of the polypeptide is established by a computer from the identified oligopeptides. So far polypeptides having up to 40 amino acids have been analyzed by this method. The advantages and disadvantages of the new method compared with the stepwise procedure of the Edman degradation are considered. Since the two methods are based on fundamentally different principles they may prove to be complementary.     

Electron beam combined with hydrothermal treatment for enhancing the enzymatic convertibility of sugarcane bagasse

The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors. A combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield. In this way, the present study reports on the enzymatic hydrolysis of SCB submitted to three kinds of pretreatment: electron beam processing (EBP), and EBP followed by hydrothermal (TH) and diluted acid (AH) treatment. SCB samples were irradiated using a radiation dynamics electron beam accelerator, and then submitted to thermal and acid (0.1% sulfuric acid) hydrolysis for 40 and 60 min at 180 °C. These samples were submitted to enzymatic hydrolysis (EH) using commercial preparations, including Celluclast 1.5 L and beta-glycosidase. The addition of diluted acid improved TH treatment allowing for a shorter application time. EBP with 50 kGy increased the enzymatic hydrolysis yield of cellulose by 20% after TH and 30% after AH.     

Abiotic Hydrolysis of Poly[(R)-3-hydroxybutyrate] in Acidic and Alkaline Media

Poly[(R)-3-hydroxybutyrate)], P(3HB), is the most common member of polyhydroxyalkanoates, the natural biopolyesters of intrinsic biodegradability and biocompatibility. Abiotic hydrolysis of P(3HB) was investigated in acid and base media by monitoring the formation of two monomer products, 3-hydroxybutyric acid (3HB) and crotonic acid (CA), from three types of P(3HB) samples, amorphous granules, irregular precipitates and solvent cast films. The soluble monomeric products were not detected in acid solutions (0.1 to 4 N H⁺), but measured as the major hydrolytic products in base solutions (0.1 to 4 N OH⁻). Unlike the protons as catalyst in both hydrolysis and esterification, hydroxyl anions were consumed during formation of carboxylate anions. The amorphous granules of P(3HB) were decomposed 80- to 100-fold faster than the precipitates and solvent cast films. The latter two had around 71% crystallinity. The hydrolysis of amorphous grannules exhibited a quasi 0^th-order reaction rate and the activation energy of saponification was 82.2 kJ/mol, silimar to those of the biotic hydrolysis of P(3HB) by enzymes and living cells.     

Preparation and Anti-oxidative Effects of Corn Peptides

IntroductionBioactive peptides include the natural peptidesfrom organism itself and the active peptide fromhydrolysate of protein. In the pastfew years,someresearchers have found that small peptides derivedfrom the hydrolysates of food proteins play animportant role in regulating autonomic nervoussystem,activating the cellular immunity function,ameliorating the cardiovascular function,antioxidizing and antiaging,etc.[1— 7] . Smallpeptides prepared from food proteins becomenitrogenous source f…     

Reactivity of 3d transition metal cations in diethylene glycol solutions. Synthesis of transition metal ferrites with the structure of discrete nanoparticles complexed with long-chain carboxylate anions

Study of the reactivity of 3d transition metal cations in diethylene glycol solutions revealed several key features that made it possible to develop a new method for synthesis of the nanocrystalline transition metal ferrites. The 3-7 nm particles of [MFe2O4]n[O2CR]m, where M = Mn, Fe, Co, Ni, and Zn, ligated on their surface with long-chain carboxylate anions, have been obtained in an isolated yield of 75-90%. The key features are the following. Complexation of the first-row transition metal cations with diethylene glycol at a presence of alkaline hydroxide is sufficient to enable control over the rate of their hydrolysis. The reaction of hydrolysis leads to the formation of metal oxide nanocrystals in colloidal solution. The nanoparticles growth is terminated by an added long-chain carboxylic acid, which binds to their surface and acts as a capping ligand. The isolated nanocrystalline powders are stable against agglomeration and highly soluble in nonpolar organic solvents.     

Open-flask alkaline hydrolysis of amino acid phenylthiohydantoin derivatives.

It is suggested that the open-flask system for the acid hydrolysis of proteins described earlier can also be used to advantage for the alkaline hydrolysis of amino acid phenylthiohydantoin derivatives obtained in protein sequential analysis according to Edman. Results obtained under nitrogen and argon atmospheres are reported for the hydrolysis of 0.5 mumole of each phenylthiohydantoin derivative, which is the amount of protein that is usually employed in an automatic sequenator.     

Production of vegetable oil-based biofuels—Thermochemical behavior of fatty acid sodium salts during pyrolysis

To develop an advanced pyrolysis process for various biomass-derived feedstocks and improve product quality and yield, in-depth investigations into the reaction mechanisms are needed. This paper reports on pyrolysis experiments (Py-GC/MSD and FID) with model compounds including the sodium salts of stearic (C₁₈), oleic (C_18:1), and linoleic (C_18:2) acids principally obtained from alkaline hydrolysis of vegetable oils. Of the parameters studied – temperature (450–750 °C), time (20 s and 80 s), and the degree of unsaturation (i.e., saturated and mono- and dienoic C₁₈-hydrocarbon chains) – the latter had the most significant effect on the formation of volatile compounds detected in pyrolysates. The results indicated that in the case of sodium stearate, a homologous series of alkenes and alkanes was formed, whereas the pyrolysis of sodium oleate resulted mainly in aromatics, alkenes, and alkanes. In contrast, the most abundant liquefiable volatile products obtained from sodium linolate were aromatics and oxygen-containing compounds. In each case, an increase in temperature and time generally increased the quantity of products formed.     

Enzymatic and alkaline treatments of hardwood dissolving pulp

Dissolving pulp was solubilized in 9% NaOH, resulting in 32% solubilization of the pulp. Most of the pulp hemicelluloses were solubilized during this treatment. During the alkaline treatment the cellulose crystalline form was converted from cellulose I to cellulose II. The alkaline insoluble residue was further treated with cellulases in order to render it more alkaline soluble (two-step process). The cellulose II was readily hydrolysed by Trichoderma reesei endoglucanases. Considerably higher hydrolysis yields and lower viscosities were obtained in the hydrolysis of the alkaline insoluble residue as compared with the original pulp. Compared with direct enzymatic treatment with subsequent solubilization in alkali, the overall alkaline solubility of the two-step process was slightly higher at the same enzyme dosage. However, when compared at the same hydrolysis levels, slightly lower overall alkaline solubilities were obtained in the two-step method. 0969--0239 © 1998 Black ie Academic & Professional     

Studies of the forced hydrolysis degradation of copper complexes with different oligosaccharides

Bioactive copper complexes with oligosaccharides, pullulan or dextran, are the objective of the present study, because of their possible biomedical applications. The alkaline and acid hydrolysis of the Cu(II) complexes with reduced low-molar pullulan or dextran were carried out by conductometric method. The influence of ligand constitutions on the stability of the complexes was examined on the basis of ligand property. The complexes degradation during alkaline and acid hydrolysis were carried out in sodium hydroxide and hydrochloric acid solutions of 0.1, 0.5, and 1.0 mol dm⁻³, at different temperature (25, 40, and 60°C, respectively). According to the obtained results by the conductivity investigation during forced degradation studies, it could be concluded that the Cu(II) complexes show the small pharmaceutical stability to both hydrolysis.     

(R)-N-(β-三氯锗取代丙酰基)TTCA酯的合成及其倍半氧化物

β-三氯锗取代丙酰氯1a～1c与(R)TTCA酯反应, 得到光学活性的(R)-N-(β-三氯锗取代丙酰基)TTCA酯3a～3d([α]D^2^0-86.00～-94.35ⅲ)及光学活性的β-三氯锗取代丙酰氯2a～2d。化合物3a～3d经水解得到(R)-N-(β-取代丙酰基)TTCA酯基锗倍半氧化物4a～4d, [α]D^2^0-44.48～-77.00ⅲ。用半经验量子化学MNDO方法研究了反应物和产物最优构型的电子结构及反应的焓变。     

The Mechanism of Reaction between Poly(vinyl Alcohol) and Phosphorous Acid

The reaction mechanism of phosphorous acid and poly(vinyl alcohol) is presented. It has been found that there during this reaction mono- and diesters are formed in which most of the acid radicals are in the phosphonic form. To confirm the presence of this form in the product obtained, reactions with diethyleneamine and chloral have been carried out as characteristic tests for phosphonic groups. The occurrence of C—P bonds resistant to hydrolysis has been also found in the reaction product.     

The kinetics and mechanism of aqueous cleavage of imide bond in 5, 5-diethyl barbituric acid (5, 5-diethyl-2,4,6-(1H, 3H) pyrimidinetrione) in a highly alkaline medium

The kinetic study of alkaline hydrolysis of 5, 5-diethyl barbituric acid has been carried out at various [O H] and different temperatures ranging from 85–95°C. The reaction follows an irreversible first-order consecutive reaction path of the type \documentclass{article}\pagestyle{empty}\begin{document}${\rm A}\buildrel{{k1{\rm obs}}}\over\longrightarrow{\rm B}\buildrel{{k2{\rm obs}}}\over\longrightarrow$\end{document} X under pseudo-first-order kinetic conditions. A, B, and X represent for 5, 5-diethyl barbituric acid, diethyl malonuric acid, and ammonia, respectively. The pH-rate profiles obtained at three different temperatures reveal distinct phases which are attributed to a change in rate-determining step with change in [O H]. On the basis of the observed data, a possible mechanism has been discussed.     

A new approach to characterization of insulin derived from different species using 1H-NMR coupled with multivariate analysis

Most of the active components of polypeptides have a complex molecular structure, large molecular size. Such components may also be structurally heterogeneous. Therefore, development of a method that can confirm the consistency of polypeptides amino-acid sequences for product characterization is desirable. In general, it is extremely difficult to distinguish differences of a few amino acid residues in the 1H-NMR spectrum of polypeptides with molecular weights greater than several thousand. However, we have been able to distinguish between three insulin species differing in one to three amino acid residues using a combination of multivariate statistics and 1H-NMR spectra. These results demonstrate that this methodology could be useful for characterization of polypeptides.     

Thermokinetics of the ethyl acetate acid and alkaline hydrolysis by differential scanning calorimetry

The kinetic investigation of thermoanalytical curves for the ethyl acetate and alkaline hydrolysis, requires tedious calculations of several mathematical expressions, to establish the correlation between the thermochemical and kinetic parameters. Using the DSC measured data for the heat flow-temperature dependence of the studied reactions, we have obtained the kinetic bulk parameters and the dependencek=k(T) for the basic and acid hydrolysis of ethyl acetate.     

New Triterpenoid Fatty Acid Esters from the Small Twigs of Viburnum Odoratissimum

α‐Amyrin margarate ( 1 ), moretenyl margarate ( 2 ) and moretenyl palmitate ( 3 ), three triterpenoid fatty acid esters, have been isolated from the acetone extract of the small twigs of Viburnum odoratissimum in addition to the three known compounds, α‐amyrin palmitate ( 4 ), ursolic acid ( 7 ) and vibsanin‐K ( 8 ). The structures of compounds 1–3 were elucidated based on extensive spectroscopic analysis and alkaline hydrolysis. Preliminary pharmacological studies revealed that vibsanin‐K and ursolic acid exhibited significant cytotoxicity against human gastric (NUGC) and oral epidermoid (HONE‐1) tumor cells at a concentration of 50 μg/mL while compounds 1–3 were inactive.     

Controlled-potential electrosynthesis of glucosaminic acid from glucosamine at a gold electrode

The electrocatalytic oxidation of d-glucosamine (2-amino-2-deoxy-d-glucose) in alkaline and neutral solutions was examined using a carbon felt electrode modified with 2 nm core sized gold nanoparticles (Au_2 nm nanoparticles) and a gold plate electrode. The electrocatalytic voltammetric oxidation curves of d-glucosamine were obtained in both solutions. The voltammetric responses for the electrocatalytic oxidation at a Au_2 nm nanoparticle-modified electrode in both alkaline and neutral solutions were almost the same to those at a gold plate electrode. The oxidized product was identified to be d-glucosaminic acid (2-amino-2-deoxy- d-gluconic acid) generated by the 2-electron oxidation product of d-glucosamine by electrospray ionization time-of-flight mass spectra (ESI TOF-MS). The HPLC results also indicated that the oxidation product was d-glucosaminic acid.The controlled-potential electrolysis of d-glucosamine was performed at the Au_2 nm nanoparticle-modified carbon felt electrodes in both alkaline and neutral solutions. In the alkaline solution, at a potential of −0.2 V, d-glucosaminic acid was formed with a current efficiency of 100%. In the neutral solution, electrolysis at 0.4 V on d-glucosaminic acid was obtained with current efficiencies of 70%.