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312213 Mar26-09 02:39 PM

Organic Naming
 
1. The problem statement, all variables and given/known data
Name each of the following cyclic alkanes, and indicate the formula of the compound.
http://img230.imageshack.us/img230/1...anicnaming.jpg


2. Relevant equations



3. The attempt at a solution
a. The rectangle has four corners so four carbon for butane. The branch off has two carbons so eth-. Numbering the branch C as 1, the naming is 1-ethylcyclobutane with C6H12 because each corner is 1 C plus the C written and the H comes from subtracting 4 with the number of bonds connected to each of the C. Is this correct?

b. The pentagon has five corners so five corner for pentane. The branch off is prop- and meth-. Naming starts with alphabetical order so meth- first so the prop- is three. 1-methyl-3-propylcyclopentane. Logic from a., C9H18. Is this correct?

c. Hexane from six corners. Dimethyl and ethyl here. Is this named 1-ethyl-2,6-dimethylcyclohexane or 2-ethyl-1,3-dimethylcyclohexane? C10H20.

If there is a mistake, which part?

Mtnbiker Mar27-09 06:44 PM

Re: Organic Naming
 
Quote:

Quote by 312213 (Post 2134282)
1. The problem statement, all variables and given/known data
Name each of the following cyclic alkanes, and indicate the formula of the compound.
http://img230.imageshack.us/img230/1...anicnaming.jpg


2. Relevant equations



3. The attempt at a solution
a. The rectangle has four corners so four carbon for butane. The branch off has two carbons so eth-. Numbering the branch C as 1, the naming is 1-ethylcyclobutane with C6H12 because each corner is 1 C plus the C written and the H comes from subtracting 4 with the number of bonds connected to each of the C. Is this correct?

b. The pentagon has five corners so five corner for pentane. The branch off is prop- and meth-. Naming starts with alphabetical order so meth- first so the prop- is three. 1-methyl-3-propylcyclopentane. Logic from a., C9H18. Is this correct?

c. Hexane from six corners. Dimethyl and ethyl here. Is this named 1-ethyl-2,6-dimethylcyclohexane or 2-ethyl-1,3-dimethylcyclohexane? C10H20.

If there is a mistake, which part?

A is just ethylcyclobutane. There is no need to number the substituent, since a cycloalkane with 1 substituent will always have it at the #1 carbon. You had the formula right.

B is correct.

C is 2-ethyl-1,3-dimethylcyclohexane (you number so as to give your substituents the lowest number possible, in the absence of priority substituents such as OH). Formula is correct.


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