Methyl cyclo alkanes

Fig. 3.5. Relationship between log (retention time) and boiling point for a range of hydrocarbons on squalane at 43°C. A, aliphatics (and benzene) B, alicyclics, 1-4 = C5-Cg n-alkanes 5 = 2-methyl-butane 6 = 2-methylpentane 7 = 2,3-dimethylbutane 8-12 = C4-C8 1-olefins 13,15,17 = trans-(but-2-ene, pent-2-ene and hept-2-ene) 14,16,18 = e/s-(but-2-ene, pent-2-ene and hept-2-ene) 19 = 2-methylbut-l-ene 20 = 2-methylpent-l-ene 21 = 4-methylpent-l-ene 22 = 2-methylbut-2-ene 23 = cyclopentane 24 = cyclohexane 25 = methylcyclopentane 26 = methylcyclohexane 27 = cyclo-pentene 28 = cyclohexene 29 = 4-methylcyclohexane 30 = 1,3-butadiene 31, 32 = trans- and cis-1,3-pentadiene 33 = diallyl 34, 35 = trans- and c s-2-methyl-l,3-pentadiene 36 = cyclopentadiene ...

Cyclic alkenes are known compounds. As with cyclic alkanes, the parent name for cyclic alkenes is based on the number of carbon atoms in the ring derived from the analogous linear alkene, but the prefix cyclo is added to the name. The six-carbon cyclic molecule that contains a C=C unit is called cyclohexene (4). Substituents are named in the usual manner, and one carbon of the C=C unit must be Cl. The choice of which C=C carbon becomes Cl is dictated by giving the substituents the lowest number. Compound 5 is a cycloheptene, but the substituents can be numbered 6-ethyl-3,6-dimethyl- or 4-ethyl-4,7-di-methyl. The smaller numbers dictates the priority, which also give the ethyl group the lower number, and 5 is 4-ethyl-4,7-dimethylcycloheptene. Note that the 1-heptene is unnecessary in the name... 

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