Chair conformations drawing alternative

We saw early in Section 3.3.2 that, if we draw cyclohexane in typical two-dimensional form, the bonds to the ring could be described as up or down , according to whether they are wedged or dotted. This is how we would see the molecule if we viewed it from the top. When we look at the molecule from the side, we now see the chair conformation the ring is not planar as the two-dimensional form suggests. Bonds still maintain their up and down relationship, but this means bonds shown as up alternate axial-equatorial around the ring they are... 

The alternative chair conformation, should we draw it instead, would be less favoured than that shown because of the increased number of axial substituents. The conformation of o-glucose is the easily remembered one, in that all the substituents are equatorial. 

Glucose has its substituents on alternating sides of the ring. In drawing the chair conformation, just put all the ring substituents in equatorial positions. 

Ihe easiest way of drawing an alternative perspective a half-chair. Carbons 1-4 of a haif-chair conformation are all in the same plane... 

Draw the structure of ambroxol in the alternative chair conformation. Which of the two conformations is more stable ... 

Glucose has its substituents on alternating sides of the ring. In drawing the chair conformation, just put all the ring substituents in equatorial positions. (In the Haworth projection, the —OH on C4 is opposite the —CH2OH on C5, and the — OH on C3 is opposite that on C4.)... 

We can also draw the cis and trans isomers of 1,4-dimethylcyclohexane as nonplanar chair conformations. In working with alternative chair conformations, it is helpful to remember that all groups axial on one chair are equatorial in the alternative chair, and vice versa. In one chair conformation of tran l, 4-dimethylcyclohexane, the two methyl groups are axial in the alternative chair conformation, they are equatorial. Of these chair conformations, the one with both methyls equatorial is considerably more stable. 

Following is a planar hexagon representation of one isomer of 1,2,4-trimethylcyclohexane. Draw the alternative chair conformations of this compound, and state which is the more stable. 

Draw the alternative chair conformations for the cis and trans isomers of 1,2-dimethylcyclohexane, 1,3-dimethylcyclohexane, and 1,4-dimethylcyclohex-ane. (See Examples 3.10, 3.11)... 

Draw alternative chair conformations for each substi- 3.48 How many six-membered rings exist in adamantane ... 

Conformations of Alkanes and Cycloalkanes HOW TO Draw Alternative Chair Conformations of Cyclohexane 2- Cis,Trans Isomerism in Cycloalkanes and Bicycloalkanes HOW TO Convert Planar Cyclohexanes to Chair Cyclohexanes 2-7 Physical Properties of Alkanes and Cycloalkanes 2-8 Reactions of Alkanes... 

Draw the alternative chair conformation for the trisubstituted cyclohexane given in Example 2.10. Label all CHj/H 1,3-diaxial interactions in this chair conformation. 

Draw a chair conformation of 1,4-dimethylcyclohexane in which one methyl group is equatorial and the other is axial. Draw the alternative chair conformation and calculate the ratio of the two conformations at 25°C. 

Draw the alternative chair conformations for the product formed by the addition of bromine to 4-tert-butylcyclohexene.The Gibbs free energy differences between equatorial and axial substituents on a cyclohexane ring are 21 kj (4.9 kcal)/mol for ferf-butyl and 2.0-2.6 kJ (0.48-0.62 kcal)/mol for bromine. Estimate the relative percentages of the alternative chair conformations you drew in the first part of this problem. 

Draw the alternative chair conformations for fludeoxyglucose F-18 and select the more stable of the two. 

On a cyclohexane ring, an axial carboxyl group has a conformational energy of 5.9 kj (1.4 kcal)/mol relative to an equatorial carboxyl group. Consider the equilibrium for the alternative chair conformations of trans-l,4-cyclohexanedicarboxylic acid. Draw the less stable chair conformation on the left of the equilibrium arrows and the more stable chair on the right. Calculate AG for the equilibrium as written and calculate the ratio of the more stable chair to the less stable chair at 25"C. 

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