Cyclitols, fractionation

According to the modified Maquenne system (18,19,31) used in this chapter, the diastereomeric configuration of any cyclitol is expressed by a fraction, and position-numbering, if otherwise equivocal, is so assigned that the numerator will have the lowest possible numbers. For example, proto-quercitol (12 or 13) is designated (134/25,), not (14/ 235) or (25/134). 

The very widespread occurrence of meso-inositol (m. p. 225°) in both plant and animal sources makes this substance by far the most extensively investigated of the cylitols in fact, the comparative rarity of the other inositols has justified the general retention of the name inositol to denote meso-inositol although, as pointed out above, the term has been extended to its isomers, meso-inositol and the equally common name, inactive inositol, are obviously poor names for this compound since six of the other inositols are also optically inactive. The sole attempt at a rigorous systematic nomenclature for the cyclitols is that of Maquenne who suggested the use of a fraction to denote the positions of the hydroxyl... 

The fractional notation for cyclic stereoisomers proposed long ago by Lespieau and Maquenne, being nearly self-explanatory to any organic chemist, is strongly recommended for cyclitols. The larger set of ds groups is placed in the numerator. For example, the tetrol diastereoisomer... 

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