Acid hydrolysis of carboxylic esters in a two-phase system in the presence of catalytic amounts of quaternary onium salts. Mild and selective cleavage of tert-butyl esters

1982 ◽  
Vol 47 (1) ◽  
pp. 154-156 ◽  
Author(s):  
Dario Landini ◽  
Franco Rolla
Keyword(s):  
Acid Hydrolysis ◽  
Phase System ◽  
Two Phase ◽  
Tert Butyl ◽  
Butyl Esters ◽  
Onium Salts ◽  
Carboxylic Esters ◽  
Hydrolysis Of

Hydrolysis of casein catalyzed by papain in n-propanol/NaCl two-phase system

2010 ◽  
Vol 46 (6) ◽  
pp. 438-443 ◽  
Author(s):  
Yan Zhang ◽  
Guqin Shi ◽  
Fengsheng Zhao
Keyword(s):  
Phase System ◽  
Two Phase ◽  
Hydrolysis Of

On the synthesis of 3,4-dihydroxyprolines. II. Synthesis, stereochemistry and reactivity of some 3,4-Epoxy-DL-proline derivatives

1975 ◽  
Vol 28 (11) ◽  
pp. 2479 ◽  
Author(s):  
CB Hudson ◽  
AV Robertson ◽  
WRJ Simpson
Keyword(s):  
Acid Hydrolysis ◽  
Methyl Esters ◽  
High Yield ◽  
Butyl Esters ◽  
Epoxy Acids ◽  
Trifluoroperacetic Acid ◽  
Catalytic Hydrogenolysis ◽  
Direct Separation ◽  
Proline Derivatives ◽  
Hydrolysis Of

N-Protected esters of 3,4-dehydro-DL-proline react with trifluoroperacetic acid to give, in high yield, approximately equal amounts of the corresponding stereoisomeric 3,4-epoxy-DL-proline derivatives, direct separation of which proved difficult. However individual members of the two families were obtained by discovery of selective transformations and fractionations. Relative configurations of the two 3,4-epoxy-N-tosylproline methyl esters were established by borohydride reduction to authentic 4-hydroxy-N-tosylprolinols. Epoxide reduction is regioselective. Extensive p.m.r. analyses then permitted stereochemical assignment of other derivatives. These epoxides are remarkably resistant to catalytic hydrogenolysis, and to hydration in acid or alkali. N-Substituted 3,4-epoxyproline methyl esters undergo ready β-elimination in alkali to yield the corresponding 4-hydroxy-2,3- dehydroproline esters and ultimately the N-substituted pyrrole-2- carboxylic acid or ester. Prolonged aqueous acid hydrolysis of 3,4- epoxy-N-tosylprolines, or of their methyl esters, gives mixtures of 3,4-dihydroxy-N-tosyl-DL-prolines in the 2,3-cis-3,4-trans and 2,3- trans-3,4-trans families. Their stereochemistry was allotted from p.m.r. of the diacetate methyl esters. During acid hydrolysis of 3,4- epoxy-N-tosylproline methyl esters, the ester of the trans stereoisomer hydrolyses selectively, and some epimerization of the cis stereoisomer occurs. Ester hydrolysis is much faster than epoxide hydration. Anhydrous acid cleavage of 3,4-epoxy-N-tosyl-DL-proline t-butyl esters to the epoxy acids is unusually slow.

Enzymic Hydrolysis of Starch in Agitated PEG-Dextran Aqueous Two-Phase System

1996 ◽  
Vol 48 (7-8) ◽  
pp. 291-294 ◽  
Author(s):  
M. Liakopoulou-Kyriakides ◽  
A. Karakatsanis ◽  
M. Stamatoudis
Keyword(s):  
Phase System ◽  
Enzymic Hydrolysis ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Hydrolysis Of

Enzymatic hydrolysis of soluble starch in a polyethylene glycol-dextran aqueous two-phase system

1990 ◽  
Vol 69 (4) ◽  
pp. 240-243 ◽  
Author(s):  
Kazuhiko Hayashida ◽  
Koji Kunimoto ◽  
Fumihide Shiraishi ◽  
Koei Kawakami ◽  
Yasuhiko Arai
Keyword(s):  
Polyethylene Glycol ◽  
Enzymatic Hydrolysis ◽  
Soluble Starch ◽  
Phase System ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Hydrolysis Of

Hydrolysis of isoflavone glycoside by immobilization of β-glucosidase on a chitosan-carbon in two-phase system

2013 ◽  
Vol 61 ◽  
pp. 465-470 ◽  
Author(s):  
Jie Chang ◽  
Yong-Suk Lee ◽  
Shu-Jun Fang ◽  
Dong-Ju Park ◽  
Yong-Lark Choi
Keyword(s):  
Phase System ◽  
Two Phase ◽  
Isoflavone Glycoside ◽  
Hydrolysis Of

Hydrolysis of Diazonium Salts Using a Two-Phase System (CPME and Water)

2015 ◽  
Vol 26 (6) ◽  
pp. 411-416 ◽  
Author(s):  
Toshihide Taniguchi ◽  
Mitsutaka Imoto ◽  
Motonori Takeda ◽  
Takeo Nakai ◽  
Masatoshi Mihara ◽  
...  
Keyword(s):  
Diazonium Salts ◽  
Phase System ◽  
Two Phase ◽  
Hydrolysis Of
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