The Synthesis of Trisubstituted Enol Ethers and of Methyl Ketones from Ketones

1973 ◽  
Vol 51 (6) ◽  
pp. 981-983 ◽  
Author(s):  
Gilles Caron ◽  
Jean Lessard
Keyword(s):  
Acid Hydrolysis ◽  
Hydroxy Acid ◽  
Reliable Method ◽  
Acid Salt ◽  
Methyl Ketones ◽  
Enol Ether ◽  
Mild Acid Hydrolysis ◽  
Enol Ethers ◽  
Hydrolysis Of ◽  
Mild Acid

A reliable method for the synthesis of trisubstituted enol ethers (and of the corresponding methyl ketones) is described involving the condensation of the α-lithiated 2-methoxypropionic acid salt with a ketone to give a β-hydroxy acid, the cyclization to a β-lactone which is then decarboxylated (and mild acid hydrolysis of the enol ether).

Alkylation of enolate anions with dimethyl 3-bromo-2-ethoxypropenylphosphonate. A convergent cyclopentenone annulation method

1982 ◽  
Vol 60 (9) ◽  
pp. 1114-1121 ◽  
Author(s):  
Edward Piers ◽  
Brian Abeysekera
Keyword(s):  
Acid Hydrolysis ◽  
Ferric Chloride ◽  
Sodium Hydride ◽  
Enol Ether ◽  
Mild Acid Hydrolysis ◽  
Chloride Hexahydrate ◽  
Ferric Chloride Hexahydrate ◽  
Allylic Bromide ◽  
Hydrolysis Of ◽  
Mild Acid

A new, convergent synthesis of 2-cyclopenten-1 -ones is reported. Treatment of dimethyl 2-oxopropylphosphonate (21) with excess triethyl orthoformate in the presence of ferric chloride hexahydrate provides the enol ether 22, which upon allylic bromination with N-bromosuccinimide yields the allylic bromide 19. Alkylation of the ketones 24–28 with 19, followed by mild acid hydrolysis of the resultant products 29–33, affords the diketo phosphonates 34–38. When the latter substances are treated with sodium hydride in dimethoxyethane, the corresponding 2-cyclopenten-1 -ones 40–44 are formed in good yields.

Sequential Enzymatic and Mild-Acid Hydrolysis of By-Product of Carrageenan Process from Kappaphycus alvarezii

2019 ◽  
Vol 12 (2) ◽  
pp. 419-432 ◽  
Author(s):  
Fernando Roberto Paz-Cedeno ◽  
Eddyn Gabriel Solórzano-Chávez ◽  
Levi Ezequiel de Oliveira ◽  
Valéria Cress Gelli ◽  
Rubens Monti ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Kappaphycus Alvarezii ◽  
Mild Acid Hydrolysis ◽  
Hydrolysis Of ◽  
Mild Acid

scholarly journals IMMUNOCHEMICAL STUDIES ON BLOOD GROUPS

1971 ◽  
Vol 133 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Ten Feizi ◽  
Elvin A. Kabat ◽  
Giuseppe Vicari ◽  
Byron Anderson ◽  
W. Laurence Marsh
Keyword(s):  
Acid Hydrolysis ◽  
Blood Group ◽  
Ovarian Cyst ◽  
Periodate Oxidation ◽  
Human Saliva ◽  
Mild Acid Hydrolysis ◽  
Group B ◽  
Hydrolysis Of ◽  
Substantial Heterogeneity ◽  
Mild Acid

A partially purified blood group-like substance obtained from milk showed I activity with 2 of 21 anti-I sera. With these antisera, certain human ovarian cyst substances considered to be precursors of the A, B, H, Lea, and Leb substances also showed I activity comparable to the milk material. Strong I activity could be produced by one-stage periodate oxidation and Smith degradation of human ovarian cyst A and B substances, or of hog mucin A + H substance, or by mild acid hydrolysis of human saliva or ovarian cyst blood group B substance. The two sera indicate that I specificity appears at intermediate stages in the biosynthesis of the A, B, H, Lea, and Lea substances. Anti-I sera differ strikingly in their specificities, indicating substantial heterogeneity of the I determinants.

THE WATER-SOLUBLE POLYSACCHARIDES OF DERMATOPHYTES: III. A GALACTOMANNAN FROM TRICHOPHYTON INTERDIGITALE

1964 ◽  
Vol 42 (12) ◽  
pp. 2862-2871 ◽  
Author(s):  
F. Blank ◽  
M. B. Perry
Keyword(s):  
Formic Acid ◽  
Acid Hydrolysis ◽  
Copper Complex ◽  
Periodate Oxidation ◽  
Water Soluble ◽  
Mild Acid Hydrolysis ◽  
Trichophyton Interdigitale ◽  
Soluble Polysaccharide ◽  
Hydrolysis Of ◽  
Mild Acid

The water-soluble polysaccharide preparation from Trichophytoninterdigitale was fractionated to give two distinct galactomannans and a glucan. A galactomannan isolated via its insoluble copper complex had [α]D +75° (water) and was composed of D-galactose (12%) and D-mannose (88%). On periodate oxidation, the galactomannan consumed 1.73 mole periodate and released 0.67 mole formic acid and 0.12 mole formaldehyde per anhydrohexose unit. Hydrolysis of the methylated galactomannan gave 2,3,5,6-tetra-O-methyl-D-galactose (1 part), 2,3,4,6-tetra-O-methyl-D-mannose (1 part), 2,3,4-tri-O-methyl-D-mannose (4 parts), and3,4-di-O-methyl-D-mannose (2 parts). Mild acid hydrolysis of the galactomannan removed all the galactose residues, leaving a mannan having [α]D +84° (water) whose structure was analyzed by periodate oxidation and methylation techniques.

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