Cyclohexane carboxylic acids

The active variety of the terpene d-sylvestrene has been prepared synthetically by preparing the methyl-cyclohexane-carboxylic acid described above, and recrystallising its brucine salt. The acid contains a small quantity of the A acid, although the A variety predominates. The A acid was resolved by the brucine crystallisations, and an acid of rotation -t- 90° obtained. The synthetic process was then proceeded with, and the resulting terpene was found to be d-sylvestrene, having a rotation of -1- 66°. 

After one day standing in a refrigerator, the product was filtered and washed with water, thus yielding 5 g of 2-phenyl-2-hydroxy-cyclohexane-carboxylic acid, melting point (Kofler) 143°C to 145°C. 

In the petrochemical field, hydrogen is used to hydrogenate benzene to cyclohexane and benzoic acid to cyclohexane carboxylic acid. These compounds are precursors for nylon production (Chapter 10). It is also used to selectively hydrogenate acetylene from C4 olefin mixture. 

KA oil is used to produce caprolactam, the monomer for nylon 6. Caprolactam is also produced from toluene through the intermediate formation of cyclohexane carboxylic acid. 

The first step in producing caprolactam from benzoic acid is its hydrogenation to cyclohexane carboxylic acid at approximately 170°C and 16 atmospheres over a palladium catalyst ... 

As further examples, compounds 10 and 11 are both keto acids and mus be named as acids, but the parent name in 10 is that of a ring system (cyclo hexanecarboxylic acid) and the parent name in 11 is that of an open chair (propanoic acid). The full names are frrt/ s-2-(3-oxopropyl)cyclohexane carboxylic acid (10) and 3-(2-oxocyclohexyl)propanoic acid (11). 

Taylor DG, PW Trudgill (1978) Metabolism of cyclohexane carboxylic acid by Alcaligenes strain Wl. / Bacteriol 134 401-411. 

In a subsequent reaction, n-BuSnClg was reacted with the silver salt of cyclohexane carboxylic acid in the presence of wet solvent. This reaction gave the ladder formulation, 3, identified above, Equation 2. 

An example of a compound having a preferred boat conformation is that of [2.2.2] bicyclooctane. This compound must necessarily exist as a boat because its cis-4 hydroxy cyclohexane-carboxylic acid easily forms lactose and the water elimination must proceed through the boat conformation. The trans isomer will not lactonize. 

Nitrosylsulfuric acid reacts with cyclohexane carboxylic acid to form caprolactam. The starting material in such large-scale production of caprolactam is benzoic acid. The reactions are ... 

Supported catalysts were used for the hydrogenation of the aromatic ring of 4-amino-benzoicacid and its ethyl ester, whereas Raney nickel was applied to catalyze the cis trans isomerization of 4-amino-cyclohexane carboxylic acid. 

Aromatization of alicyclic compounds. Cyclohexane carboxylic acids maybe metabolized by a mitochondrial enzyme system to an aromatic acid such as benzoic acid. This enzyme system requires CoA, ATP, and oxygen and is thought to involve three sequential dehydrogenation steps after the initial formation of the cyclohexanoyl CoA (Fig. 4.36). The aromatase enzyme also requires the cofactor FAD. 

O 25.17% oil evolving CO at RT large quants can expl without apparent reason was obtd when the anhydride of cyclohexane carboxylic acid in abs eth was shaken with 93% of the ealed quant of finely powd Ba02.8H20. Rapid concn of the eth soln in vacuo yielded the desired product... 

Rate of reaction of trans-4-substituted cyclohexane carboxylic acids with diazodiphenylmethane EtOH 30 C02Me 0.320... 

Fig. 33 Examples of supramolecular rod4ike mesogens formed by self assembly of fluorinated benzoic acid and a /ra s-4-RF-cyclohexane carboxylic acid ( / / C) [120, 122]...

Hydrogen bonded dimers of 4-RF-substituted benzoic acids [119, 120, 122, 126], /rhydrogen bonded complexes of benzoic acids with 4,4 -bipyridine and stilbazole [166, 243-246] can be regarded as supramolecular rod-like mesogens with two fluorinated chains. Figures 33 and 34 show comparisons of selected benzoic acid dimers and their bipyridine and stilbazole complexes. Comparison of the benzoic acid dimers 122 and 123 with -alkyl chains and F-terminated -alkyl chains, respectively, indicates that a single F-atom at the end of the alkyl chain reduces the mesophase stability... 

Furthermore unsaturated aldehydes can be obtained by the reaction of 12 with e. g. cyclohexane carboxylic acid chloride, subsequent alkaline cleavage of the remaining silyl grouping and reduction with sodium borohydride give 3-hydroxy-3-cyclohexyl-1,1-dimethoxypropane (54) which yields 3-cyclohexyl-acrolein (JJ)51 via acid treatment under dehydratation. 

Aromatization and ring enlargement of propylcyclobutane were observed over Pt/Si02, whereas only aromatization took place on Pd/Si02 and Rh/ Si02.514 Aromatization was also found during the hydrogenolysis of bicy-clo[3.1.0]hex-2-ene-endo-6-carboxylic acid (40), where cyclohexane carboxylic acid and benzoic acid were the products (Scheme 4.135).515... 

ER Blakley The microbial degradation of cyclohexane carboxylic acid a pathway involving aromatization to form / -hydro ybcnzoic acid. Can J Microbiol 20 1297-1306, 1974. 

EM Rho, WC Evans. The aerobic metabolism of cyclohexane carboxylic acid by Acinetobacter antitratum. Biochem J 148 11-15, 1975. 

---