scholarly journals Pseudomonas aeruginosaarylsulfatase: a purified enzyme for the mild hydrolysis of steroid sulfates

2015 ◽  
Vol 7 (10) ◽  
pp. 903-911 ◽  
Author(s):  
Bradley J. Stevenson ◽  
Christopher C. Waller ◽  
Paul Ma ◽  
Kunkun Li ◽  
Adam T. Cawley ◽  
...  
Keyword(s):  
Mild Hydrolysis ◽  
Hydrolysis Of

A synthesis and some reactions of 7-Oxabicyclo[2.2.1]heptan-2-one

1983 ◽  
Vol 36 (12) ◽  
pp. 2473 ◽  
Author(s):  
J Moursounidis ◽  
D Wege
Keyword(s):  
Thermal Decomposition ◽  
Alder Reaction ◽  
Diels Alder ◽  
Acid Mixture ◽  
Diels Alder Reaction ◽  
Reaction Proceeds ◽  
Atom Migration ◽  
Acyl Azide ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Diels-Alder reaction between furan and α-chloroacrylonitrile gives a mixture of exo-2-chloro-and endo-2-chloro-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile (4) and (5). Mild hydrolysis affords the corresponding α-chloro acid mixture, from which the endo carboxylic acid may be removed through iodo lactone formation. Catalytic hydrogenation of (4) and (5) followed by hydrolysis, acyl azide formation, Curtius rearrangement, and hydrolysis of the resulting mixture of a-chloro isocyanates yields 7-oxabicyclo[2.2.l]heptan-2-one (1) in preparatively useful amounts. Reduction of (1) gives only endo alcohol, and Baeyer-Villiger reaction proceeds with exclusive bridgehead atom migration. Thermal decomposition of the sodium salt of the p-toluenesulfonylhydrazone of (1) affords 7-oxatricyclo[2.2.1 .02,6]heptane.

Mild hydrolysis of nitriles by the immobilized nitrilase from Aspergillus niger K10

2006 ◽  
Vol 39 (1-4) ◽  
pp. 55-58 ◽  
Author(s):  
Vojtěch Vejvoda ◽  
Ondřej Kaplan ◽  
Karel Bezouška ◽  
Ludmila Martínková
Keyword(s):  
Aspergillus Niger ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Electrochemical, Spectroscopic, and Structural Evidence for the Mild Hydrolysis of Tetracyanoethylene, TCNE, To Form the 2,3,3-Tricyanoacrylamidate Ligand:  Isolation of an Unexpected Quadruply-Bonded Polymeric Material [Mo2(O2CCMe3)3((NC)2CC(CN)CONH)]∞

2004 ◽  
Vol 43 (12) ◽  
pp. 3673-3681 ◽  
Author(s):  
Françoise Conan ◽  
Benoît Le Gall ◽  
Jean-Michel Kerbaol ◽  
Sylvie Le Stang ◽  
Jean Sala-Pala ◽  
...  
Keyword(s):  
Polymeric Material ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Mild hydrolysis of 2-trifluoromethylphenol: Kinetics, mechanism and environmental relevance

Chemosphere ◽  
2006 ◽  
Vol 65 (2) ◽  
pp. 318-323 ◽  
Author(s):  
Uwe M. Reinscheid ◽  
Jacques Vervoort ◽  
Han Zuilhof
Keyword(s):  
Mild Hydrolysis ◽  
Hydrolysis Of ◽  
Environmental Relevance

scholarly journals Pd/C-CATALISED HYDROGENIZATION OF METHYL PYRROLE-3-CARBOXYLATES IN THE DIASTEREOSELECTIVE SYNTHESIS OF α-SUBSTITUTED β-PROLINES

2020 ◽  
Vol 86 (2) ◽  
pp. 100-110
Author(s):  
Sergiy Kemskiy ◽  
Alina Grozav ◽  
Sergiy Sujkov ◽  
Oleksandr Yurchenko ◽  
Mykhailo Vovk
Keyword(s):  
Catalytic Reduction ◽  
Water Solution ◽  
Dichloromethane Solution ◽  
Methods Of Synthesis ◽  
Noesy Experiment ◽  
Intermolecular Reactions ◽  
Substituted Pyrroles ◽  
Cis And Trans ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

The analysis of synthetic and biological importance of α-substituted β-prolines was conducted. Methods of synthesis of β-prolines and their esters, based on both intra- and intermolecular reactions of formation of functionalized pyrrolidinic cycle, as well as catalytic reduction of corresponding 2,3-substituted pyrroles and their dihydro derivatives, were systematized. The necessity of the hydrogenation process improvement of 2,3-di-substituted pyrroles using cheap catalysts was justified. The approach to α-substituted β-prolines (2-substituted pyrrolidine-3-carboxylic acids) was pro-posed, the first stage of which is N-Boc-protection of 2-substituted pyrrolidine-3-carboxylates with di-tert-butyl dicarbonate (Boc-anhydride) in the dichloromethane solution at the room temperature in presence of catalytic amounts of N,N-dime-thylaminopyridine. Obtained derivatives were subjected to hydrogenation in the autoclave at 45 atm. at 40 oC for 20 hours in presence of 10 % Pd/C catalyst. It was found, that reaction at such conditions proceeds with the full conversion of starting compounds and demonstrates high stereoselec-tivity and leads to the mixture of diastereomeric N-Boc-protected pyrrolidine-3-carboxylates of cis- and trans-configurations with corresponding contents of 84–87 % and 13–16 % according to NMR 1Н and chromato-mass spectra. The mild hydrolysis of isolated reaction mixtures in the water solution of lithium hydroxide followed by neutrali-zation and N-Boc-deprotection with 15 % hydrochloric acid allows isolating pure major diaste-reomers of α-substituted β-prolines with 69–74 % yields. Their trans-configuration was reliably confirmed by NMR 1Н spectroscopy using the NOESY experiment.

URINARY EXCRETION OF DEHYDROEPIANDROSTERONE IN NORMAL AND ABNORMAL LATE PREGNANCY AND IN NON-PREGNANT WOMEN

1972 ◽  
Vol 71 (1) ◽  
pp. 205-208 ◽  
Author(s):  
C.-G. Dässler
Keyword(s):  
Standard Deviation ◽  
Urinary Excretion ◽  
Pregnant Women ◽  
Silica Gel ◽  
Late Pregnancy ◽  
Chronic Hypertension ◽  
Colorimetric Determination ◽  
Foetal Death ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

ABSTRACT The urinary excretion of dehydroepiandrosterone (DHA) in 10 healthy women during the last month of pregnancy (mean m = 0.43 mg/24 h; standard deviation sd = ±0.13) was found to be as high as that in 7 patients with chronic hypertension or with toxaemia of pregnancy (m = 0.40 mg/24 h; sd = ±0.13). The values were significantly (P < 0.01) decreased in 6 women in late pregnancy with intrauterine foetal death (m = 0.20 mg/24 h; sd = ±0.10), in two cases of pregnancy with anencephalic foetuses (0.30 and 0.25 mg/24 h, resp.) and in 11 healthy non-pregnant women (m = 0.26 mg/24 h, sd = ±0.10). The method used involved separation of free non-conjugated Zimmermann chromogens from the urine by extraction with benzene, mild hydrolysis of the urine, column chromatography on silica gel and colorimetric determination as Zimmermann chromogen. It is assumed that the increased excretion of DHA in the two groups of late pregnant women with intact pregnancy as compared with non-pregnant women may be caused by the biosynthesis of DHA in the foetal adrenals. The unchanged values of DHA in the two groups of women during late pregnancy with intrauterine foetal death or with anencephalics may reflect the interrupted biosynthesis of DHA.

A Mild Hydrolysis of Esters Mediated by Lithium Salts.

ChemInform ◽  
2007 ◽  
Vol 38 (28) ◽  
Author(s):  
Sara Mattsson ◽  
Mikael Dahlstroem ◽  
Staffan Karlsson
Keyword(s):  
Lithium Salts ◽  
Hydrolysis Of Esters ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Some reactions of 2-ethenyl-4,4-Ethylenedioxy-1-methylcyclohex-1-ene prepared by pyrolysis of 5,5-Ethylenedioxy-7a-methyl-4,5,6,7-tetrahydro-2H-inden-1(7aH)-one

1984 ◽  
Vol 37 (11) ◽  
pp. 2295 ◽  
Author(s):  
RFC Brown ◽  
GL Burge ◽  
DJ Collins
Keyword(s):  
High Pressures ◽  
Preparative Thin Layer Chromatography ◽  
Major Product ◽  
Diels Alder ◽  
Lewis Acid Catalysts ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Layer Chromatography ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Flash vacuum pyrolysis of 5,5-ethylenedioxy-7a-methyl-4,5,6,7-tetrahydro-2H-inden-1(7aH)-one (2) at 630� gave a good yield of 2-ethenyl-4,4-ethylenedioxy-1-methylcyclohex-1-ene (6), but at 740� p-cresol was the major product. The diene acetal (6) was also obtained by pyrolysis of 5,5-ethylene- dioxy-lβ-hydroxy-7a-methyl-1,2,5,6,7,7a-hexahydro-4H-indene-1α-carbonitrile (3) at 600�. Pyrolytic reactions of 7a-methyl-2,3,7,7a-tetrahydro-1H-indene-1,5(6H)-dione (1), 5,5-ethylenedithio-7a- methyl-2,3,5,6,7,7a-hexahydro-1H-inden-1-one (7) and of 1,1-ethylenedioxy-3,5,5-trimethylcyclohex- 3-ene (8) are also described. Mild hydrolysis of the diene acetal (6) afforded 3-ethenyl-4-methylcyclohex-3-en-1-one (9) which upon brief treatment with dry hydrogen chloride in chloroform at 0� gave, after preparative thin-layer chromatography, a low yield of pure 3-ethenyl-4-methylcyclohex-2-en-1-one (11). The diene acetal (6) failed to undergo Diels-Alder reactions, even at high pressures with Lewis acid catalysts, and it reacted anomalously with two molecules of 4-phenyl-1,2,4-triazoline-3,5-dione; the isomeric diene acetal 1-ethenyl-3,3-ethylenedioxy-6-methylcyclohex-1-ene (18) gave the expected Diels-Alder adduct with this reagent.

scholarly journals Preparation of pH-Responsive Poly(aspartic acid) Nanogels in Inverse Emulsion

2016 ◽  
Vol 61 (1) ◽  
pp. 19 ◽  
Author(s):  
Enikő Krisch ◽  
Benjámin Gyarmati ◽  
András Szilágyi
Keyword(s):  
Aspartic Acid ◽  
Gelation Time ◽  
Compression Tests ◽  
Inverse Emulsion ◽  
Precursor Polymer ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Poly(aspartic acid) (PASP) hydrogels were prepared by cross-linking polysuccinimide (PSI) with diaminobutane followed by the mild hydrolysis of the resultant PSI gels to PASP hydrogels. The composition dependence of the gelation time and the stiffness of bulk PASP hydrogels were determined by rheometry and compression tests, respectively. The composition of the prepared PASP nanogels was chosen based on the results on bulk PASP hydrogels. Prior to nanogel preparation stability of DMSO-in-oil (inverse) emulsions was tested as a function of the chemical quality of apolar phase, the concentration of the precursor polymer and the concentration of the surfactant. PASP nanogels in the size of a few hundred nanometers were prepared by the hydrolysis of PSI nanogels synthesized in inverse emulsion. PASP nanogels showed pH-dependent swelling and strongly negative surface charge at physiological pH values, thus they can be further developed to meet the specific criteria of different bio-related applications.

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