Configuration carbohydrate

The task of relating carbohydrate configurations to names requires either a world class memory or an easily recalled mnemonic A mnemonic that serves us well here was pop ularized by the husband-wife team of Lours F Fieser and Mary Fieser of Harvard Uni versity m their 1956 textbook Organic Chemistry As with many mnemonics it s not clear who actually invented it and references to this particular one appeared m the chem ical education literature before publication of the Fiesers text The mnemonic has two features (1) a system for setting down all the stereoisomeric d aldohexoses m a logical order and (2) a way to assign the correct name to each one... 

Figure 6. Effect of carbohydrate configuration on inversion reaction. ...

The reactions of boric acid solutions with diols have been used for almost a century to examine structural differences among carbohydrates. The complexity of these reactions seems to arise not only from simple structural differences but also from differences in carbohydrate configuration and conformation. The precise nature of these reactions is not clear. Recent studies of the chemistry of polyol-boric acid solutions have clarified some aspects of these reactions that have important bearing on the structure of carbohydrates in solution. Nevertheless, some of the most fundamental questions about the nature of the reaction are still unanswered. 

An understanding of stereochemistry is particularly important to understanding the properties of carbohydrates. Configurational and conformational isomerism play an important role. For this reason, you may wish to review Chapter 5 and Sections 12-3 and 19-5. 

The spectrum of sucrose in aqueous solution has been studied to examine further the potential of F.t.i.r. spectroscopy for determining carbohydrate configurations. While bands characteristic of an a- rather than 6-linked D-glucopyranosyl unit were present, no criteria for discerning the stereochemistry of the fructose unit were found. Some bands in the hydroxyl stretching region of crystalline carbohydrates have been identified through a... 

The copper(II) complexes of 1-thio-a- and -i8-D-glucopyranose and 2-amino-2-deoxy-l-thio- -D-glucopyranose and their peracetates have been synthesised by action of copper(II) acetate on the respective sodium thiolates, followed by acid catalysed acetylation, for an investigation of their anti-inflammatory activity The mesogenic properties of the C4 - dialkyl dithioacetals of ten standard pentoses and hexoses have been examined. Most of them form thermotropic liquid crystals with the notable exception of all L-rhamnose derivatives. A model has been proposed to correlate carbohydrate configuration and melting behaviour. Despite the intrinsic chirality of all carbohydrate mesogens no evidence for chiral mesophases was detected. 

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