1.4- Dimethyl-3-cyclohexen

Construct a molecular model of the product formed by anti addition of Br2 to 1 2 dimethyl cyclohexene... 

Problem 7.3 What product would you expect to obtain from addition of Cl2 to 1,2-dimethyl-cyclohexene Show the stereochemistry of the product. 

So erhalt man z. B. aus 6-Oxo-3,3-dimethyl-cyclohexen/Athylendiamin zu 47% d.Th. 4-Oxo-l,1 -dimethyl-cyclohexan [23 Stdn./25° mit Chrom(II)-acetat, Essigsaure, Metha-... 

Wahrend l-ChIor-6-oxo-3,3-dimethyI-cyclohexen bei -2,05 Vin wasserfreiem Aceto-nitril zum 6-Oxo-3,3-dimethyl-cyclohexen (66% d.Th.) reduziert wird, erhalt man in was-serhaltigem Acetonitril, ebenfalls bei -2,05 V, 2,12-Dichlor-l-hydroxy-3-oxo-6,6,9,9-tetramethyl-tricyclo[6.3.1.02 7]dodecan (18% d. Th.)2 ... 

Ahnliche heterocyclische Dimere werden aus Tetramethyl-l,4-benzochinon (s. S. 644) bzw. l-Chlor-6-oxo-3,3-dimethyl-cyclohexen (s.S. 643) erhalten. 

Figure 12.13 Pyrogram of a natural rubber latex paint. Peak assignments 1, isoprene 2, toluene 3, xylene 4, 4 ethenyl 1,4 dimethyl cyclohexene 5, limonene 6, dehydro p cymene...

More recently Hartog and Zwietering (103) used a bromometric technique to measure the small concentrations of olefins formed in the hydrogenation of aromatic hydrocarbons on several catalysts in the liquid phase. The maximum concentration of olefin is a function of both the catalyst and the substrate for example, at 25° o-xylene yields 0.04, 1.4, and 3.4 mole % of 1,2-dimethylcyclohexene on Raney nickel, 5% rhodium on carbon, and 5% ruthenium on carbon, respectively, and benzene yields 0.2 mole % of cyclohexene on ruthenium black. Although the cyclohexene derivatives could not be detected by this method in reactions catalyzed by platinum or palladium, a sensitive gas chromatographic technique permitted Siegel et al. (104) to observe 1,4-dimethyl-cyclohexene (0.002 mole %) from p-xylene and the same concentrations of 1,3- and 2,4-dimethylcyclohexene from wi-xylene in reductions catalyzed by reduced platinum oxide. 

Skeletal ring contraction steps of primary C7 and Cg rings are more probable than bicyclic intermediates (132b). Aromatization of methylcyclo-pentane indicated no carbonium mechanism with a nonacidic catalyst. Instead, Pines and Chen (132b) proposed a mechanism similar to that defined later as bond shift. This is a methyl shift. Two additional isomerization pathways characteristic of chromia have also been demonstrated vinyl shift (94) and isomerization via C3 and C4 cyclic intermediates (90a). These were discussed in Section III. 1,1-Dimethylcyclohexane and 4,4-dimethyl-cyclohexene gave mainly toluene over various chromia catalysts. Thus, both skeletal isomerization and demethylation activities of chromia have been verified. The presence of an acidic almnina support enhances isomerization dual function effects are thus also possible. 

Dimethyl-cyclohexen-4- -dialkylester XII/1,504 (1,4-Dimethyl-l,3-cyclopentadien-5-yl)-methan- ... 

Diels-Adler 2,3-Dimethyl- butadiene Methyl vinyl ketone ((C4F4S03)2N)3La 4-Acetyl-1,2-dimethyl-cyclohexene 86... 

A selection of A//p gp values has already been given in Table 2-4 in Section 2.2.6. This new Lewis basicity scale is more comprehensive and seems to be more reliable than the donor number scale. Analogously, a Lewis basicity scale for 88 carbonyl compounds (esters, carbonates, aldehydes, ketones, amides, ureas, carbamates) has been derived from their standard molar enthalpies of complexation with gaseous boron trifluoride in dichloromethane solution [143]. The corresponding Aff Q gp values range from 33 kJ mol for di-t-butyl ketone to 135 kJ mol for 3-diethylamino-5,5-dimethyl-cyclohexen-2-one. 

Cyclohexyl-cyclohexen 1,2-Dimethyl-cyclohexen 1 -Methyl-4-isopropyl-cyolohexen 1 -Athyl-4-isopropyl-cyclohexen 3,7,7-Trimethyl-bicyclo[4.1.0]hepten-(3)... 

Benzylidenammo-benzylmercapto-phenyl- 1119 Bis-[2-amino-phenyl]- 1136 Bis-[6-hydroxy-2-oxo-4,4-dimethyl-cyclohexen-(l)-yl]- 1192... 

Eine Mischung aus 6-Oxo-3,3-dimethyl-cyclohexen und 3-Oxo-buten wird mit Magnesium/Essigsaure zu... 

Thermal reaction of 1-butene, cis- and trans-2-butene or isobutylene with butadiene yielded 4-ethylcyclohexene, cis- and transA,5-dimethyl-cyclohexene, or 4,4-dimethylcyclohexene, respectively, accompanied by a larger amount of 4-vinylcyclohexene. Rate constants of these respective reactions were calculated by the method above. 

The relative rates of formation of 4-vinylcyclohexene, cyclohexene, and 4-methylcyclohexene are about 10 4 1 at temperatures from 510° to 600°C, whereas those of 4-ethylcyclohexene, cis- and trans A, 5-dimethyl-cyclohexene, and 4,4-dimethylcyclohexene are less than 0.1 to that of 4-methylcyclohexene. 

The ratio of isomers obtained from the hydrogenation of 2,4-dimethyl-cyclohexene catalyzed by PtOj in methanol is essentially the same at —52 as at 26°. 

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