Heterocyclic Compounds Carbohydrates Nucleosides Nucleotides and Polynucleotides Monocyclic and Bicyclic Aglycon Isotopically Labelled Compounds Reagents, Intermediates and Miscellaneous Compounds Instrumental or Analytical Techniques and Applications.

Several of the polysaccharides in the examples have less-ordered structures.In the structural formulas given for these, the main sugar components and linkages are given, but not their proportions.

The conformations of eight acylated 1,1-bis(acylamido)-1-deoxypentitols in solution have been studied by pulse, Fourier-transform, p.m.r. spectroscopy at 90 Mhz. The arabino and lyxo derivatives adopt the zigzag conformation, whereas the ribo and xylo derivatives favor different sickle conformations. The validity of the conformational assignments of these derivatives by the p.m.r. method is discussed. The relative merits and accuracy of the continuous-wave and pulse-Fourier p.m.r. spectroscopic methods in the conformational analysis of carbohydrates are appraised, and the applicability of the exponential-filtering technique to enhancement of either the sensitivity or the resolution of their spectra is demonstrated.

For the preparation of pure D-psicose (5a) via oxidation of 1,2:4,5-di-O-isopropylidene-β-D-fructopyranose (2a), the latter must be free from its 2,3:4,5 isomer (6a), which is oxidized to the corresponding aldosulose acetal. Pure 1,2:4,5-di-O-isopropylidene-β-D-erythro-2,3-hexodiulo-2,6-pyranose (3) undergoes stereospecific reduction with sodium borohydride to give only 1,2:4,5-di-O-isopropylidene-β-D-ribo-hexulopyranose (4a), which exists as two different crystal modifications. Compounds 3 and 4a have been characterized, and discrepancies in the literature have been explained.

Chemischer Informationsdienst. Organische ChemieVolume 2, Issue 33 Organic Dyes ChemInform Abstract: CYCLISCHE ACETALE VON KETOSEN 4. MITT. NOCHMALIGE UNTERSUCHUNG DER OX. DER 1,2/4,5-DI-O-ISOPROPYLIDEN-BETA-D-FRUCTOPYRANOSE MIT METHYLSULFOXID-ACETANHYDRID R. S. TIPSON, R. S. TIPSONSearch for more papers by this authorR. F. BRADY, R. F. BRADYSearch for more papers by this authorB. F. WEST, B. F. WESTSearch for more papers by this author R. S. TIPSON, R. S. TIPSONSearch for more papers by this authorR. F. BRADY, R. F. BRADYSearch for more papers by this authorB. F. WEST, B. F. WESTSearch for more papers by this author First published: August 17, 1971 https://doi.org/10.1002/chin.197133347Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume2, Issue33August 17, 1971 RelatedInformation

The syrupy mixture of eight pentoses obtained by boiling a solution of either d-xylose (1) or d-arabinose (2) in pyridine for 4.5 h was freed of the four d-aldopentoses. The resulting mixture of four d-pentuloses was resolved by condensation with acetone, followed by partition between solvents or by distillation; in this way, crystalline 2,3-O-isopropylidene-β-d-O-isopropylidene-d-erythro-pentulofuranose (14) from 2. Each of the isomerizations yielded a small proportion of the epimeric d-2-pentulose, but the proportions of the d-3-pentuloses were much lower. The diacetal 14 was partially hydrolyzed, with dilute acid, to 3,4-O-isopropylidene-d-erythro-pentulofuranose (17), the α-d anomer of which was obtained in crystalline form. The structure of 17 was proved by oxidation with periodate, to give the known, crystalline 2,3-O-isopropylidene-d-erythrono-1,4-lactone. The anomers of the 1,3,4-triacetate and 1,3,4-tribenzoate of methyl d-erythro-pentulofuranoside were prepared, and characterized by specific optical rotation and n.m.r. spectroscopic evidence.

The syrupy mixture of eight pentoses obtained by boiling a solution of either d -xylose ( 1 ) or d -arabinose ( 2 ) in pyridine for 4.5 h was freed of the four d -aldopentoses. The resulting mixture of four d -pentuloses was resolved by condensation with acetone, followed by partition between solvents or by distillation; in this way, crystalline 2,3- O -isopropylidene-β- d - O -isopropylidene- d - erythro -pentulofuranose ( 14 ) from 2 . Each of the isomerizations yielded a small proportion of the epimeric d -2-pentulose, but the proportions of the d -3-pentuloses were much lower. The diacetal 14 was partially hydrolyzed, with dilute acid, to 3,4- O -isopropylidene- d - erythro -pentulofuranose ( 17 ), the α- d anomer of which was obtained in crystalline form. The structure of 17 was proved by oxidation with periodate, to give the known, crystalline 2,3- O -isopropylidene- d -erythrono-1,4-lactone. The anomers of the 1,3,4-triacetate and 1,3,4-tribenzoate of methyl d - erythro -pentulofuranoside were prepared, and characterized by specific optical rotation and n.m.r. spectroscopic evidence.

Report presenting of survey of the literature on the infrared spectroscopy of carbohydrates in order to assemble and systematize information in this field. Discusses principles and instrumentation, sampling techniques, comparison of samples, and the interpretation of the spectra. In addition, examples are discussed of the use of infrared spectra for qualitative and quantitative purposes and in the determination of structure. Special techniques are briefly described.

The infrared absorption spectra of two glycofuranosylacetamides and their perbenzoates, and of eleven glycopyranosylacylamides and eight esters thereof, are presented and discussed. For comparison, the spectra of thirteen 1,1-bis(acylamido)-1-deoxyalditols and eight esters thereof are also given and discussed. The useful correlations between structure and infrared absorption made by Barker and co-workers for certain carbohydrates, and by Nanasi and co-workers for some N-arylglycosylamines, cannot be extended to the 1-acylamido compounds we have studied. Certain of Verstraeten's correlations may have some diagnostic value.