New Method of Preparation of Brassinosteroids

1994 ◽  
Vol 59 (2) ◽  
pp. 457-460 ◽  
Author(s):  
Ladislav Kohout
Keyword(s):  
New Method ◽  
Hydroxyl Groups

Brassinosteroids with lactone B-ring (II and IV) were prepared by oxidation of the corresponding 6-keto derivatives I and III without protection of the hydroxyl groups against the action of the oxidation reagent.

ChemInform Abstract: A New Method for Selective Protection of Two Hydroxyl Groups in Carbohydrates, Glycals in Particular.

ChemInform ◽  
2010 ◽  
Vol 23 (4) ◽  
pp. no-no
Author(s):  
C. W. HOLZAPFEL ◽  
J. J. HUYSER ◽  
T. L. VAN DER MERWE ◽  
F. R. VAN HEERDEN
Keyword(s):  
New Method ◽  
Hydroxyl Groups ◽  
Selective Protection

A New Method for Selective Protection of Two Hydroxyl Groups in Carbohydorates, Glycals in Particular

Heterocycles ◽  
1991 ◽  
Vol 32 (8) ◽  
pp. 1445 ◽  
Author(s):  
Cedric W. Holzapfel ◽  
Johan J. Huyser ◽  
Thilo L. van der Merwe ◽  
Fanie R. van Heerden
Keyword(s):  
New Method ◽  
Hydroxyl Groups ◽  
Selective Protection

Solvent-free and selective tosylation of alcohols and phenols with p-toluenesulfonyl chloride by heteropolyacids as highly efficient catalysts

2006 ◽  
Vol 84 (5) ◽  
pp. 812-818 ◽  
Author(s):  
Razieh Fazaeli ◽  
Shahram Tangestaninejad ◽  
Hamid Aliyan
Keyword(s):  
Aliphatic Alcohols ◽  
Solvent Free ◽  
New Method ◽  
Heteropoly Acids ◽  
Hydroxyl Groups ◽  
Secondary Alcohols ◽  
Highly Efficient ◽  
Keggin Type ◽  
Primary Hydroxyl ◽  
Solvent Free Reaction

Tosylation of some alcohols and phenols has been directly carried out with p-toluenesulfonyl chloride using heterodoxy acids (H3PW12O40, H3PMo12O40, AlPW12O40, and AlPMo12O40) as catalysts in the absence of solvent. We found that heteropoly acids AlPW12O40 and AlPMo12O40 were effective catalysts for the tosylation of alcohols and phenols. In the case of aliphatic alcohols, secondary alcohols undergo tosylation chemoselectively in the presence of primary hydroxyl groups. This new method consistently has the advantage of excellent yields and short reaction time.Key words: tosylation, p-TsCl, Keggin-type polyoxometalate, solvent-free reaction.

A new method of quaternizing amines and its use in amino acid and peptide chemistry

1976 ◽  
Vol 54 (20) ◽  
pp. 3310-3311 ◽  
Author(s):  
Francis C. M. Chen ◽  
N. Leo Benoiton
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Methyl Iodide ◽  
New Method ◽  
Hydroxyl Groups ◽  
Amino Groups ◽  
Small Peptides ◽  
Peptide Chemistry ◽  
Selective Reagent ◽  
Derivatives Of

Methyl iodide and potassium bicarbonate in methanol is presented as a mild, efficient, and selective reagent for the quaternization of amino groups. It does not attack hydroxyl groups. Its use with amino acids, derivatives of lysine, and small peptides is described.

ChemInform Abstract: NEW METHOD OF BENZYLATION OF HINDERED GLUCOSIDIC HYDROXYL GROUPS

1977 ◽  
Vol 8 (2) ◽  
pp. no-no
Author(s):  
S. CZERNECKI ◽  
C. GEORGOULIS ◽  
C. PROVELENGHIOU
Keyword(s):  
New Method ◽  
Hydroxyl Groups
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