1,2,3,4-Cyclohexanetetrol


1,2,3,4-Cyclohexanetetrol is an organic compound whose molecule can be described as a cyclohexane with four hydroxyl groups substituted for hydrogen atoms on four consecutive carbon atoms. Its formula can be written,, or 42.
There are 10 isomers with this same structural formula, which are among the 43 isomers of cyclohexanetetrol. They are all polyols, more specifically tetrols and cyclitols. Some of them have biologically important roles in some organisms.

Isomers and nomenclature

There are 10 different isomers of this compound, that differ in the orientation of the four hydroxyls relative to the mean plane of the ring. They can be denoted by the letter "α" or "β" after each carbon index, to indicate the corresponding side of the plane relative to the 1-hydroxyl; or by listing all the "α" indices, then a slash "/", then the "β" indices.
The possible isomers are:
Synthesis of 1,2,3,4-cyclohexanetretrols was first reported in 1933 by Pierre Bedos and Adrien Ruyer, by hydrolysis of 1,2;3,4-diepoxy-cyclohexane. They separated the reaction products into two isomers, with melting points 210C and 187C, respectively, in 1:2 ratio.
In 1953, Théodore Posternak and H. Friedli obtained the achiral 1,4/2,3 isomer and racemic mixtures of the 1,2/3,4, 1,3/2,4, and 1,2,4/3 isomers. By biochemical oxydation, they removed the D- enentiomers of the last three, leaving the L- enantiomers.
Posternak and Reymond observed in 1953 that the 1,3/2,4 isomer is not attacked by a certain strain of A. suboxydans, whereas all the others were metabolized with consumption of 1 atom of oxygen, except the 1,2/3,4 isomer that consumed 2 atoms.
In 1955, Posternak and Reymond studied the oxydation of the 1,4/2,3 isomer by Acetobacter suboxydans, producing a trihydroxyketone. They also characterized the chiral isomers 1,3/2,4, 1,2,3/4,and 1,2,4/3.

Synthesis

Methods which have been employed for the preparation of 1,2,3,4-cyclohexanetetrols include: reduction or hydrogenation of cyclohexenetetrols, tri-hydroxycyclohexanones, pentahydroxycyclohexanones, hydroxylated aromatics, or hydroxylated quinones; the hydrogenolysis of dibromocyclohexanetetrols; the hydration of diepoxycyclohexanes; and the hydroxylation of cyclohexadienes or cyclohexenediols.
In 2007, Peter Valente and others described the preparation of achiral 1,4/2,3-cyclohexanetetrol from 2,3-dioxabicyclooct-5-ene, a cyclohexene with a peroxide bridge replacing hydrogens in carbons 3 and 6. The previous route was reduction of the peroxide brige to yield 3α,6α-dihydroxy cyclohexene, followed by di-hydoxylation of the double bond; which yielded a mixture of the 1,4/2,3 and 1,2,3,4/0 isomers. The authors found that, by reversing the order of the two steps, they could obtain 1,4/2,3 in 80% yield.