Advances in Carbohydrate Chemistry, Vol. 13 by M. L. (editor) Wolfrom

Posted by

By M. L. (editor) Wolfrom

Show description

Read Online or Download Advances in Carbohydrate Chemistry, Vol. 13 PDF

Similar chemistry books

Making Crystals by Design. Methods, Techniques and Applns

A good review of the manifold features of contemporary crystal engineering. From layout and education to spectroscopy and functions, this guide either covers and evaluates all elements of crystal engineering. basically established, it presents an summary of the present prestige as noticeable from its quite a few angles in addition to a comparability of alternative thoughts and purposes.

In Memory of H.L. Meerwein

Content material: Brown, H. C. Meerwein and equilibrating carbocations. -- Olah, G. A. From boron trifluoride to antimony pentafluoride looking for strong carbocations. -- Hogeveen, H. and van Kruchten, E. M. G. A. Wagner-Meerwein rearrangements in long-lived polymethyl substituted bicyclo(3. 2. 0)heptadienyl cations.

Quantum Systems in Chemistry and Physics Volume 2: Advanced Problems and Complex Systems Granada, Spain, 1998

Those volumes gather forty-four chosen papers from the clinical contributions offered on the 3rd ecu Workshop on Quantum platforms in Chemistry and Physics, held in Granada (Spain), April 19–22, 1998. Ninety-nine scientists from Bulgaria, Columbia, Cuba, Denmark, Finland, France, Germany, Hungary, Israel, Italy, Mexico, Netherlands, Norway, Poland, Russia, Slovakia, Spain, Sweden, United Ki- dom, Uruguay and Venezuela attended the workshop, discussing the state-of-the-art, new traits, and destiny evolution of the tools and functions.

Extra resources for Advances in Carbohydrate Chemistry, Vol. 13

Example text

Irvine and Hynd116J1s noted t h i t the methyl glycoside of D-glucosamine (methyl 2-amino-2-deoxy-~-glucopyranoside) is 100 times more resistant to acid hydrolysis than methyl a-mglucopyrunoside and remains essentially unchanged on heating at 100" with 5 % hydrochloric acid. Subsequently, Moggridge and Neuberger117 showed that this compound has a true glycosidic structure (XXXII) and that t,he unusual resistance toward acid hydrolysis is caused by the presence of the positively charged, amino group (-NH3*) which decreases the concentration of hydronium ions in the immediate vicinity of the glycosidic group.

Vaughsn, J. Chem. ,3367 40 F. SHAFIZADEH acetal derivatives. It appears that methyl 3 ,G-anhydro-2,4-di-O-methyl-aD-mannopyranoside is for the same reason hydrolyzed more rapidly than is the corresponding f u r a n o ~ i d e . 133This reaction provides good evidence for the cleavage of the cyclized bond in preference to that of the glycosidic group. The formation of an acyclic intermediate during the process of mutarotation was long ago postulated by Lowry,134-137 and has recently been confirmed by isotopic138and p o l a r o g r a p h i ~ ~investigations ~~-~~~ of aqueous solutions, and by kinetic studies with non-aqueous s o l ~ e n t s .

J . Heidt and C. B. Purves, J . Am. Chem. ,66, 1385 (1944). (87) E. A. Moelwyn-Hughes, Trans. ,26, 503 (1929). (88) C . B. Purves and C. S. Hudson, J . A m . Chem. , 69, 1170 (1937). (89) C. B. Purves, J . Am. Chem. ,66, 1969 (1934). 9 2. 4 5. 1 9. 5 46. 98 X lo-' min-I). The numbers represent the position OII which the substituent is axial. In the terminology suggested by Reeves, the normal chair conformat,ion is denoted by CZ for D sugars and 1C for L sugars. d Indirectly obtained value. 0 1,3,4 A2,5 p anomer 3.

Download PDF sample

Rated 4.99 of 5 – based on 45 votes