I. NOMENCLATURE AND FORMULA 323 



A. DISCUSSION OF TERMINOLOGY^ 

 HENRY A. LARDY 



There are nine possible stereoisomeric forms of hexahydroxycyclohexane, 

 commonly called inositols or cyclohexitols.^^ Several of these isomers occur 

 naturally, and a few others have been synthesized. Of the nine isomers, 

 seven are optically inactive or meso forms, and two are asymmetric enantio- 

 morphs which have been designated d and I. The isomer which is most 

 widely distributed in nature, and which is of importance for the nutrition 

 of animals and certain microorganisms, has been called meso-inositol or i- 

 inositol (referring to the fact that it is optically inactive). It has been re- 

 named m?/o-inositol.^ The prefixes i or meso are not at all suitable for dis- 

 tinguishing this isomer from the other six optically inactive isomers, since 

 they too are meso forms. Furthermore, derivatives of ?n?/o-inositol. may 

 become optically active by asymmetric substitution, and to use i or meso in 

 the name of such derivatives is chemically incorrect and confusing. For 

 these reasons it seemed desirable, when proposing a systematic nomencla- 

 ture for the inositols and their derivatives,^ to rename this isomer. Since 

 Scherer* had originally isolated this compound from muscle and had in 

 fact called it "muscle sugar," the name w^o-inositol^ (Greek, iMva, fivos, 

 muscle) was proposed^ and soon adopted in the chemical literature.^ 



In Table I the structures of the nine stereoisomeric inositols are shown, 

 together with their trivial names and a designated^ sequence for numbering 

 the carbon atoms. In the formulas the hydroxyl groups are indicated by 

 vertical lines. Four of the isomers — myo-, D-, and L-inositols, and scyllitol — 

 occur naturally, either in the free form or as a wide variety of derivatives.^- ^ 

 Three of the remaining isomers — epi, alio, and muco — have been synthe- 

 sized, the first by Posternak^ and the latter two by Dangschat.^-^'' 



1 {Editors' note.) At the present time the nomenclature of the inositols is confusing. 

 This section was written by Dr. Lardy in an attempt to eliminate this confusion. The 

 systemic nomenclature suggested by Dr. Lardy has not yet been approved and 

 adopted by the American Association of Biological Chemists, or some similar sci- 

 entific body. For this reason the Editors have not insisted that all contributors to 

 this chapter use the proposed nomenclature. Instead, each author has been permitted 

 to use the nomenclature he prefers. 

 1" L. Maquenne, Les Sucres et leurs Principau.x D^riv^s, p. 190, Carre et Naud, 

 Paris, 1900. 



2 H. G. Fletcher, Jr., L. Anderson, and H. A. Lardy, J. Org. Chem. 16, 1238 (1951). 



3 J. Scherer, Ann. Chem. Justus Liebigs 73, 322 (1850). 



* Compare the analogous myoglobin, myoblast, myocyst, myosin. 



6B. Magasanik, J. Am. Chem. Sac. 73, 5919 (1951). 



8 H. G. Fletcher, Jr., Advances in Carbohydrate Chem. 3, 45 (1948). 



^ W. W. Pigman and R. M. Goepp, Jr., Carbohydrate Chemistry. Academic Press, 



New York, 1948. 

 8T. Posternak, Helv. Chim. Acta 19, 1333 (1936). 

 ' G. Dangschat, Naturwissenschaften 31, 146 (1942). 



