Cis-Cyclohexane-l,4-dicarboxylic acid

C12H20O4 cis-cyclohexane-l,2-dicarboxylic acid diethyl ester 17351-07-4... 

Draw the three-dimensional structures of the following, indicating the interactions that may exist (a) -butane in its staggered form (b) -butane in its eclipsed form about the 2,3-bond (c) 1,2-dibromoethane in its most stable form (d) cyclopropane (e) 1,2-epoxyethane (ethylene oxide) showing the lone pairs of electrons on the oxygen (f) cis- and rart.v-1,4-dimethylcyclohexane in the chair form (g) /ran.v-cyclohexane-l,2-dicarboxylic acid (h) cyclohexene. 

Octahydro- (we have used this nomenclature throughout) or perhydrobenzo[c]thiophene (35) exists as the cis and trans isomers and is more commonly named 2-thiahydrindane or 8-thiabicyclo-[4.3.0]nonane. Each stereoisomer may be prepared by treating the corresponding isomer of l,2-di(bromomethyl)cyclohexane with sodium sulfide (details of the products are given in Table IV).45 Cyclization of the cis isomer may be effected partially with thiourea via the formation of cis-hexahydro-o-xylylenebis(isothiouronium bromide) with sodium disulfide it gives a mixture of cis-octahydro-benzo[c]thiophene and cis-2,3-dithiadecalin.46 Optically pure ( —)-(8 R,9I )-lran -octahydrobenzo[c]thiophene has been prepared from (+ )-dicarboxylic acid via reduction of the diacid to the diol, tosylation, and ring closure of the bistosylate with sodium sulfide.47... 

Particularly high yields of cyclic tetrafluoro ethers are obtained from acids in which the carboxylic groups are fixed in cis positions relative to one another. Thus, reaction of d.v-cyclo-hexanc-l,2-dicarboxylic acid gives the cyclic ether 12 in 70% yield with very limited formation of 1,2-bis(trifluoromethyl)cyclohexane.118... 

The experiment that follows involves the conversion of 4-cyclohexene-cis-1,2-dicarboxylic acid (3) to cyclohexane-cis-l,2-dicarboxylic acid (4), as shown in Equation 17.8. The catalytic hydrogenation of 3 is considered to be selective because the carboxylic acid groups, -CO2H, are not reduced under the reaction conditions. The starting material for this reduction may be readily prepared by the hydrolysis of 4-cyclohexene-czs-l,2-dicarboxylic acid anhydride, which is the product of the Diels-Alder reaction between butadiene and maleic anhydride, according to the procedure outlined in Section 12.3, Part Cl. 

Consider the spectral data for cyclohexane-cis-l,2-dicarboxylic acid (Figs. 17.1 and 17.2). 

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