Organic chem, conventions and priorities.

[physics]

Okay, so I just want to be clear about naming amines. 

WARNING!  Heinemann book teaches it wrong.  You can not name something aminoethane.  It has to have amine in the suffix in it, so it is actually ethylamine/ethanamine.

What I would like to like confirmed is the following:

For propane with an amine group attached to carbon 1, the name is propylamine/propanamine
For propane with an amine group attached to carbon 2, the name is 2-propylamine/propyl-2-amine/2-propanamine/propan-2-amine

Is this correct?

Also trimethylamine is just a nitrogen with three methyl groups stuck onto each bond in place of a hydrogen yeah?

r u sure D: about the amino thingo T^T

[happyhappyland]

Okay, so I just want to be clear about naming amines. 

WARNING!  Heinemann book teaches it wrong.  You can not name something aminoethane.  It has to have amine in the suffix in it, so it is actually ethylamine/ethanamine.

What I would like to like confirmed is the following:

For propane with an amine group attached to carbon 1, the name is propylamine/propanamine
For propane with an amine group attached to carbon 2, the name is 2-propylamine/propyl-2-amine/2-propanamine/propan-2-amine

Is this correct?

Also trimethylamine is just a nitrogen with three methyl groups stuck onto each bond in place of a hydrogen yeah?

r u sure D: about the amino thingo T^T

you cant name it amino unless theres a carboxy or alcohol thingy

[stonecold]

Yeah, certain Anna.

Take a look at 8bi.
http://www.vcaa.vic.edu.au/vcaa/vce/studies/chemistry/assessreports/2009/chemistry_assessrep_june09.pdf

[kenhung123]

Yea the textbooks are pretty bad in that it does not clarify the priorities and that the highest priority is assigned the suffix. They seem allow prefixes and suffixes to be used interchangeably.

[Mao]

The difference here is between 'naming' and 'systematic naming'. 2-Aminopropane or even hydroxyethane are perfectly valid names, but are not systematic names (2-propanamine and ethanol).

[stonecold]

Thanks for clearing that up Mao.

What is the systematic name for the following molecule?

[kenhung123]

3-Chloro-6-methylheptane?

[stonecold]

Nah, that was the mistake I first made, but then I picked up on it. 

I said it was 3-chloro-6-methylheptane.  Which VCAA says is wrong.

[cameron_15]

Thats what i thought it would be to. What do VCAA say?

[stonecold]

well this is from Checkpoints, so unless they stuffed it up, VCAA says:

5-chloro-2-methylheptane

I was under the impression that halogens were of a higher priority than alkyl groups...

Can anyone clarify.  What if the chloro was attached to the second carbon from the left, and the methyl group attached to second carbon from the right. Then which end are you supposed to number from...

[kenhung123]

Nah, that was the mistake I first made, but then I picked up on it. 

I said it was 3-chloro-6-methylheptane.  Which VCAA says is wrong.

Lol beaten. Anyway, I think halides>alkyl as it was confirmed by Mao.

[Stroodle]

The exam report says the answer is:

Either of:
•   5–chloro–2–methylheptane
•   3–chloro–6–methylheptane.

[stonecold]

http://www.vcaa.vic.edu.au/vce/studies/chemistry/assessreports/2008/chemistry_assessrep_june08.pdf

We are all good people.  Look at Question 6aii.

Both answers were accepted.  Stupid Checkpoints only put one!
I was devastated when I thought I got that question wrong haha.

Also they didn't say one was right or wrong.  It was a 50-50 split between students haha.  So hopefully they wont give us something so ambiguous in this years paper, or at least they will accept all the reasonable answers.

[kenhung123]

Well thats strange so treating halide=alkyl precedence is accepted..

[kyzoo]

well this is from Checkpoints, so unless they stuffed it up, VCAA says:

5-chloro-2-methylheptane

I was under the impression that halogens were of a higher priority than alkyl groups...

Can anyone clarify.  What if the chloro was attached to the second carbon from the left, and the methyl group attached to second carbon from the right. Then which end are you supposed to number from...

You number the positions of the functional groups and alkyl groups such that the total of the numbers in the systematic name is minimum.