Chlorocyclohexane

The flask was charged with 48 g of magnesium and 200 ml of dry diethyl ether. 1,2-Dibromoethane (4 ml) was added. After a few minutes a vigorous reaction started and the diethyl ether began to reflux. When this reaction had subsided, 500 ml of dry diethyl ether were added. Stirring was started and 1.0 mol of chlorocyclohexane (note 1) was added from the dropping funnel at a rate such that the diethyl ether gently refluxed (note 2). After this addition, which was carried out in 1 h, the flask was heated under reflux for a further 1 h. 

Note 1. The chlorocyclohexane should be free from cyclohexanol, which may lead to inactivation of the magnesium. 

Note 2. It is advisable to add first about 15 g of the chlorocyclohexane in one portion. After 5-15 min the diethyl ether should again begin to reflux. If this does not occur, one should not add more, since the magnesium apparently has not been sufficiently activated. 

Compare the elec tronic charges at chlorine in chlorocy clohexane and chloroben zene on Learning By Modeling to verify that the C—Cl bond IS more polar in chlorocyclohexane... 

Because carbon is sp hybridized m chlorobenzene it is more electronegative than the sp hybridized carbon of chlorocyclohexane Consequently the withdrawal of electron density away from carbon by chlorine is less pronounced m aryl halides than m alkyl halides and the molecular dipole moment is smaller... 

Chlorocyclohexane [542-18-7] M 118.6, b 142.5 , d 1.00, n 1.46265. Washed several times with dilute NaHC03, then repeatedly with distilled water. Dried with CaCl2 and fractionally distd. 

Draw the most stable conformation of ds-l-te/t-butyM-chlorocyclohexane. By how much is it favored ... 

Anti periplanar geometry for E2 reactions is particularly important in cyclohexane rings, where chair geometry forces a rigid relationship between the substituents on neighboring carbon atoms (Section 4.8). As pointed out by Derek Barton in a landmark 1950 paper, much of the chemical reactivity of substituted cyclohexanes is controlled by their conformation. Let s look at the E2 dehydro-halogenation of chlorocyclohexanes to see an example. 

On using Barton-oxidation procedures cyclohexane is oxidized by 1949, in the presence of FeCb and the Fe "-picolinate complex, to give cyclohexanone and cyclohexanol [166] whereas with FeCl2 1-chlorocyclohexane is the mayor product, with cyclohexanone and a small amount of cyclohexanol [167] (Scheme 12.47). 

Triphenylmethane leuco dyes are used for photographic materials. The photographic system requires a polymer binder such as acrylic acid-methyl methacrylate copolymer115 or a copolymer of isophthalic and terephthalic acids116 a sensitizer such as 4-(4-n-amyloxyphenyl)-2,6-bis(3-ethylphenyl)-thiapyrilium perchlorate,117 a photo initiator such as hexaarylbisimi-dazole,118 and phenyl tribromomethyl sulfone, cycloalkane such as 1,2,3, 4,5-pentabromo-6-chlorocyclohexane,119 or 3-benzylidene-9-methyl-2,3-dihydro- 1 TZ-cyclopenta [b] quinoline.120... 

To date, within the scope of the writers information, there has been no residual deposit or poison residue recovered from treated fruits or vegetables, where proper formulations and amounts of the pure gamma isomer have been used not later than 2 weeks prior to crop harvest. Likewise, there is no known record of poisoning to man or animals from applying the insecticide or eating food treated with the insecticide. Freedom from poisonous residue and undesirable taste in the use of the pure gamma isomer of hexa-chlorocyclohexane is achieved therfeore by proper formulation, timing, and application of insecticide treatments. 

Treatment of the olefin 49 with Zeise s dimer leads to the chloroplatination complex 50 [26], The addition adduct 50 is hydrogenated stereospecifically to the trans-disubstituted chlorocyclohexane 51. The insertion of carbon monoxide into 50, in the presence of methanol, yields the ester 52 stereoselectively. 

Chlorocyclohexane is converted into cyclohexane in dichloromethane using ethyldichlorosilane as reducing agent.192 The product yield is 40% with 25 mol% aluminum chloride and 45% with aluminum bromide. 1-Chloro-l-methylcyclohex-ane gives a 94% yield of methylcyclohexane using aluminum chloride and a 92% yield with aluminum bromide. Ethyldichlorosilane is superior as a hydride donor to either cumene or dicumylmethane.192... 

Even though we define the atropisomerism as above for present purposes, there remain some ambiguities. sym-Tetrabromoethane was obtained in different modifications according to the method of crystallization at low temperature (13). These were found by spectroscopy to correspond to retainers. Similar situations occur in other alkyl halides and acetates (14,15). Such cases will not be included in the discussion, mainly because crystalline atropisomers are isolated at far lower temperatures than die ambient, and their barriers to rotation have not been determined by equilibration. Also excluded is the isolation of chlorocyclohexane (16). The isolation of the equatorial and axial conformational isomers was possible only by crystallization of the former at - 150°C, although it was possible to observe equilibration between the equatorial and the axial forms at higher temperatures. 

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