Cyclohexanol, 4- , tran

Two stereoisomers of 1 bromo 4 methylcyclohexane are formed when trans 4 methyl cyclohexanol reacts with hydrogen bromide Write structural formulas or make molecular mod els of... 

The mechanisms of these acid-catalyzed epoxide openings are more complex than they at first appear. They seem to be neither purely SN1 nor SN2 but instead to be midway between the two extremes and to have characteristics of both. Take the reaction of 1,2-epoxy-l-methylcyclohexane with HBr shown in Figure 18.2, for instance. The reaction yields only a single stereoisomer of 2-bromo-2-methyl-cyclohexanol in which the —Br and —OH groups are trans, an S 2-li.ke result caused by backside displacement of the epoxide oxygen. But the fact that Br attacks the more hindered tertiary side of the epoxide rather than the less hindered secondary side is an SN1 -like result in which the more stable, tertiary carbocation is involved. 

Cyclohexanedione, 46, 25 Cyclohexanimine, N-chloro-, 46,16 Cyclohexanol acetate, 46, 61 Cycloiiexanol, 4-1-butyl, trans-, 47,... 

A-tert-hutyl-t-(2-propenyl)cyclohexanol yield 87% d.r. (cts/trans) 88 12... 

In a 250-ml., three-necked, round-bottomed flask equipped with a mechanical stirrer, a gas inlet, and a stopper are placed 540 mg. (0.00346 mole) of a mixture of cis- and dimethyl sulfoxide (Note 3). While a slight positive pressure of argon is maintained... 

Mit substituierten Boranen werden Oxirane zu substituierten Alkoholen reduziert. 7-Oxa-bicyclo[4.1.0]heptan liefert z.B. mit Phenylmercapto-boran 69% d.Th. trans-2-Phenylmercapto-cyclohexanol neben 8% d.Th. Cyclohexanol2 ... 

Irans-2-Iodocyclohexyl acetate Cyclohexanol, 2-iodo-, acetate, trans- (9) (43084-75-9)... 

An interesting example of etherification of close boiling cis and trans 2-tert-butyl-cyclohexanol with .v amylene may be cited. At 353 K, and Indian 130 as cataly.st at 10 % loading, about 94% selectivity for the cis isomer was realized with a feed consisting of about 68.5 % cis and 31.5% trcms isomer (Matkar and Sharma, 1995). 

Baba, A., Yamamoto, T., Yamamoto, H., Suzuki, T., and Moroji, T., Effects of the major metabolite of phencyclidine, the trans isomer of 4-phenyl-4-(l-piperidinyl) cyclohexanol, on [3H]N-(l-[2-thie-nyl]cyclohexyl)-3,4-piperidine([3H TPC) binding and [3H] dopamine uptake in the rat brain, Neurosci. Lett., 182, 119, 1994. 

The oxidation of cyclic 2-amino alcohols has been studied.88 In the 2-amino-cyclopentanol series, the ds form was oxidized four times as fast as the trans but, in the 2-amino-cyclohexanol series, the ds form reacted slightly more slowly than did the tram. 

An interesting stereochemical profile of this cyclization is that in the five-membered product structures, substituents PhS and OH groups are placed cis to each other, whereas in six-membered products the placement is trans (Table 6, entry 7). The cis selectivity in the five-membered ring systems is not affected by a and fi-substituents of the alkoxides (entries 2, 3 and 4), indicating that the steric effect is not the dominant factor. Instead, interaction between the oxido and carbene center composes a five- (or seven-) membered transition state 28, which allows the carbene to abstract the nearest quasi axial hydrogen as a hydride to produce a carbonyl intermediate 29, leading to the cyclization products 27 and 30 (Scheme 13, Eq. 1). Similarly, the stereoselective stepwise cyclization of cis- and rra s-2-(3,3-dithiopropyl)cyclohexanol to 2-phenylthio-... 

HETHYL-1-PENTENE 4-METHYL-cis-2-PENTENE 4-METHYL-trans-2-PENTENE TRIETHYLENEDIAMINE BUTYL VINYL ETHER CYCLOHEXANOL... 

METHYL-trans-2-PENTENE TRIETHYLENEDIAMINE BUTYL VINYL ETHER CYCLOHEXANOL... 

From the similarity of the activation energy of dehydration of the aliphatic alcohols and of some of the cyclohexanols it can be assumed that the mechanism of the dehydration of the two groups of alcohols is identical. The presence of a neopentyl-type carbon atom as in 2,2-dimethylcyclohexanol diminishes the reactivity only slightly, but among stereoisomeric alkylcyclohexanols the cis isomer reacts much faster than the trans. The distinct dissimilarity in activation energies of the two... 

Kochloefl et al. 62) did not report the structure of the olefins from cis- and lmws-2-methylcyclohexanol however the unpublished data by Pines and Blanc 64) showed that the cis-l-methyl-2-cyclohexanol forms 1- and 3-methylcyclohexene, while the trans isomer produces mainly 3-methylcyclohexene. 

Catalytic hydrogenation transforms keto esters to hydroxy esters under very gentle conditions. In cyclic ketones products of different configuration may result. Ethyl 3,3-dimethylcyclohexanone-2-carboxylatC on hydrogenation over platinum oxide in acetic acid gave 96.3% yield of cis, and over Raney nickel in methanol gave 97% yield of trans ethyl 3,3-dimethyl-cyclohexanol-2-carboxylate, both at room temperature and atmospheric pressure [847]. 

In the reactions of cis- and rrans-2-aminomethyl-l-cyclohexanol or -1-cycloheptanol or cis- and trans-2-hydroxymethyl-l-cyclohexylamine or -1-cycloheptylamine with ethyl 4-chlorobenzimidate, the stereo- and regio-isomeric derivatives and homologs 164 and 165 were prepared (79T799). The amidine intermediate 166 of the benzimidate ring closure was also... 

The ring-chain tautomerism of tetrahydro-l,3-oxazines is very sensitive to the stability differences, the substituents and the ring-fusion effect (Section IV,A). It also reveals a considerable stability difference in favor of the cis isomers. In the reactions of the cis- and trans-2-amino-l-cyclohexanols, as compared with the hydrindane analog systems, where the heteroatoms form an oxazolidine ring cis- or tra 5-fused with cyclohexane, the corresponding stability differences were again found to be in favor of the cis isomer (93JOC1967). 

Lipase Catalyzed Kinetic Resolution of Alcohols via Chloroacetate Esters (-)-(lR,2S)-trans-2-Phenylcyclohexano1 and (+)-(lS,2R)-trans-2-Phenyl cyclohexanol... 

In chromic acid oxidation of isomeric cyclohexanols, it is usually found that axial hydroxyl groups react more rapidly than equatorial groups. For example, trans-4-t-butylcyclohexanol is less reactive (by a factor of 3.2) than the cis isomer. An even larger difference is noted with cis- and trans-3,3,5- trimethylcyclohexanol. The trans alcohol is more than 35 times more reactive than the cis. Are these data compatible with the mechanism given on p. 748 What additional detail do these data provide about the reaction mechanism Explain. 

A second batch of product was obtained by concentration ctnd recrystallization of the mother liquor to provide another 1.89 g (4.4%) of (-)-(1R,2S)-trans-2-phenyl-1-cyclohexanol of a slightly lower enantiomeric purity (98.6% ee). 

Cyclohexanol, 2-phenyl-, (1S-trans)- and Cyclohexanol, 2-phenyl-, (1R-lrans)- ... 

As stoich. [Ru(0)((N 0)p7CH3CN it oxidised primary alcohols to aldehydes, secondary alcohols to ketones, alkenes to aldehydes, tetrahydrofuran to y-butyrolactone. Styrene, cis- and tran -stilbenes gave benzaldehyde and adamantane gave 1-adamantol exclusively, while cyclohexanol gave cyclohexanone, suggesting that the complex is an effective oxidant for unactivated C-H bonds [636]. Immobilisation of the catalyst within Nation films on a basal plane pyrohtic graphite electrode was achieved, but the... 

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