Substituted Quercitols

The 6-substituted quercitols include those having a univalent substituent (Y) of the type OR, NH2, NHR, NRa, NO2, SH, SR, Cl, Br, or I. The substituted inositols (Y = OR), and the inosamines and their congeners (Y = NH2, NHR, NRo, NO2) have been extensively reviewed, and will not be considered here. Previous reviews - have also discussed the numerous ketoquercitols (inososes) and related compounds. 

So far as is known, mercapto- or haloquercitols do not occur in Nature. It seems probable that some of these cyclitols will show inositol activity or anti-inositol activity in biological systems. However, tests of four haloquercitols with human, cancer-cell cultures gave negative results.  

The di-O-isopropylidene acetal (46), of 1,2-anhydro-cfs-inositol on reaction with a-toluenethiol gave the 8-benzyl derivative (47) which, on 

Configuration Formula Br at C-6) Related querdtol Related inositol [a]D, degrees, and m.p.  

A better method is to treat an anhydroinositol (or its diacetal) with concentrated, aqueous hydrochloric acid at room temperature. By this method, chloroquercitols having the configurations n(123/456), dl(124/356), d(125/346), dl(12346/5), and meso(12345/6) were synthesized (formulas 40, 19, 39, 12, and 9, respectively). The dl(124/356) product (pentaacetate, m.p. 108 ) possibly corresponds to the Muller or Nelson pentaacetate of m.p. 110° or 118° (see Table II). 

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In this Section, synthetic methods and configurational evidence for the ten quercitols (listed alphabetically) are briefly described. Simple derivatives (other than acetates, see Table I) are mentioned. The 6-substituted quercitols, and the nuclear magnetic resonance or optical rotatory configurational proofs, are described in later Sections. 

Tables II to X give the melting points and, where applicable, the optical rotations of the inositols, inososes, inosamines, and quercitols, and of all of their known O-substituted derivatives. Anhydroinositols, although not substitution products in the strict sense, are included, as are the carbonyl-functional derivatives of the inososes. Halogen- and nitro-substituted cyclitols, and the C-methyl-inositols and their derivatives, are not included most of these compounds are referred to in the text. The derivatives are arranged in the following order salts (inosamines) or functional derivatives (inososes), carboxylic esters, borates, nitrates, sulfonic esters, phosphates, glycosides, acetals (and Schiff bases), ethers (and IV-alkyl derivatives), and anhydrides.

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