A-Cyclohexyl-

High Peroxide Process. An alternative to maximizing selectivity to KA in the cyclohexane oxidation step is a process which seeks to maximize cyclohexyUiydroperoxide, also called P or CHHP. This peroxide is one of the first intermediates produced in the oxidation of cyclohexane. It is produced when a cyclohexyl radical reacts with an oxygen molecule (78) to form the cyclohexyUiydroperoxy radical. This radical can extract a hydrogen atom from a cyclohexane molecule, to produce CHHP and another cyclohexyl radical, which extends the free-radical reaction chain. 

Plus sulfui, 1.2 paits A/-cyclohexyl-2-ben2othia2olesulfenamide, 0.8 pait tetiamethylthiuiamdisulfide, 0.4 pait Santoflex 13, 2 paits. 

The ring contraction of a cyclohexyl cation to a methylcyclopentyl cation is thermodynamically favorable but would require a substantial energy of activation if the rearrangement proceeded through a primary cyclopentylmethyl catiotL... 

The hydrolysis of l-alkyl-2-acyldiaziridines to A -alkyl-A -acyl-hydrazines possesses preparative interest. For example, A -cyclohexyl-A" -toluenesulfonylhydrazine [Eq. (51), yield 67% ] and 1-cyclohexyl-4-phenylsemicarbazide [Eq, (52) yield 73%] can be prepared by hydrolysis of the substituted diaziridines 46 and 62. ... 

Chemical Name a -Cyclohexyl-3-thiopheneacetic acid 2-(hexahydro-1 H-azepin-1 -yDethyl ester... 

Chemical Name a-cyclohexyl-a-hydroxybenzeneacetic acid 4-(diet)iylamino)-2-butynyl ester hydrochloride... 

Chemical Name a-cyclohexyl-a-phenyl-1-piperidinepropanol hydrochloride Common Name Benzhexol chloride Structural Formula ... 

Cyclohexyl-2,5-diphenyl-3,4,7-triazanorcara-2,4-dienc gives 4-cyclohexyl-3,7-diphenyl-4//-1,2.4-triazepine (59%) together with A-cyclohexyl-3,6-diphenylpyridazin-4-amine and 1-cyc-lohexyl-2.3-diphenylpyrrole. No further details were reported. 

In the case of an aromatic 7t-nucleophile, a dramatic reversal of diastercoscleetivity is found on going from a phenyl to a cyclohexyl or fert-butyl substituent, which is attributed to a balanee of. syn-axial and A(1,3) interactions, while a boat-like transition state may also play a role149. 

Addition of organolithiutn reagents in toluene to A-cyclohexyl enimines in the presence of chiral nonracemic diethers or diamines (1.2-2,4 equiv) gives, after hydrolysis, //-substituted aldehydes2. It is important to note that these reactions do not occur in the absence of the chiral additive which can be recovered quantitatively for reuse without loss of enantiomeric purity6. 

Benzenediamine (218) and the hydrochloride of ethyl 2-[A-cyclohexyl-(ethoxyformimidoyl)]glyoxalate [Et02CCOC(OEt)=N(CeHn)] (prepared in situ) gave A-cyclohexyl-3-oxo-3,4-dihydro-2-quinoxalinecarboxamide (222) (PhH-EtOH-CH2Cl, 40°C, 2 h 81% clearly needing an hydrolytic step). o-Anilinoaniline gave ethyl 3-oxo-4-phenyl-3,4-dihydro-2-quinoxalinecarboxy-... 

Poly(ether ether ketone), known as PEEK, is a crystalline high-temperature thermoplastic. It is produced by a step (condensation) process (see Chapter 2) in which 4,4-difluorobenzophenone is reacted with the anion of hydro-quinone. This reaction is carried out in a high boiling point polar solvent, such as A -cyclohexyl-2-pyrrolidone (1.13). 

CN a-cyclohexyl-3-thiopheneacetic acid 2-(hexahydro-l//-azepin-l-yl)ethyl ester citrate (1 1)... 

CN ( )-A/-cyclohexyl-/V -[4-[3-[(l,l-dimethylethyl)amino]-2-hydroxypropoxy]phenyl]urea... 

Hydrogenation of ( )-l,2-diphenylpropene was chosen as a model reaction to test the potential of these catalysts [Scheme 46]. The best results (99% yield and 98% ee) were obtained with the complex 72a in which R = 1-Ad and R = 2,6-(i-Pr)2C6H3. The corresponding t-butyl-, diphenyhnethyl- and phenyl-substituted oxazohne complexes (72b, 72c and 72d) were foimd to be less effective. The complex 72f obtained with R = 1-Ad and by changing the R group into a cyclohexyl group was inactive. In the case of R = 1-Ad and just... 

Inspired by Gif or GoAgg type chemistry [77], iron carboxylates were investigated for the oxidation of cyclohexane, recently. For example, Schmid and coworkers showed that a hexanuclear iron /t-nitrobenzoate [Fe603(0H) (p-N02C6H4C00)n(dmf)4] with an unprecedented [Fe6 03(p3-0)(p2-0H)] " core is the most active catalyst [86]. In the oxidation of cyclohexane with only 0.3 mol% of the hexanuclear iron complex, total yields up to 30% of the corresponding alcohol and ketone were achieved with 50% H2O2 (5.5-8 equiv.) as terminal oxidant. The ratio of the obtained products was between 1 1 and 1 1.5 and suggests a Haber-Weiss radical chain mechanism [87, 88] or a cyclohexyl hydroperoxide as primary oxidation product. 

From these data, some key information can be drawn in both cases, the couple methane/pentane as well as the couple ethane/butane have similar selectivities. This implies that each couple of products (ethane/butane and methane/pentane) is probably formed via a common intermediate, which is probably related to the hexyl surface intermediate D, which is formed as follows cyclohexane reacts first with the surface via C - H activation to produce a cyclohexyl intermediate A, which then undergoes a second C - H bond activation at the /-position to give the key 1,3-dimetallacyclopentane intermediate B. Concerted electron transfer (a 2+2 retrocychzation) leads to a non-cychc -alkenylidene metal surface complex, C, which under H2 can evolve towards a surface hexyl intermediate D. Then, the surface hexyl species D can lead to all the observed products via the following elementary steps (1) hydrogenolysis into hexane (2) /1-hydride elimination to form 1-hexene, followed by re-insertion to form various hexyl complexes (E and F) or (3) a second carbon-carbon bond cleavage, through a y-C - H bond activation to the metallacyclic intermediate G or H (Scheme 40). Under H2, intermediate G can lead either to pentane/methane or ethane/butane mixtures, while intermediate H would form ethane/butane or propane. 

Treatment of 2 -anilinofluorans with ketones such as acetone or 2-butanone in hydrochloric acid in the presence of iron(III) chloride gives 4,4 -alkylidenebis(A-fluoran-2-ylaniline)s. Thus, 2 -anilino-6 -(A-cyclohexyl-/V-methylainino)-3 -methylfluoran, (86) is treated with acetone in hydrochloric acid in the presence of iron(III) chloride to give 2,2-bis(4-[6 -(N-cy c 1 o hexyl-Ar-methy 1 amino)-3 -methylfluoran-2 -ylamino]phenyl (propane (87)60 (Eq. 9). 

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