[paradiesisch]

Hello! Sorry if this is a pretty easy question to you all (To me, it's not so. I've been trying to answer but I can't get the right one. The website does not give the correct answers, only tells me that I have a mistake in which item.)

If you would so kindly help me know the name of the first hydrocarbon.. Thank you so so much! It's been bugging me for some time now since I can't get it right.

[discodermolide]

As you have to so how your efforts to answer this question.
I'll ask what are the functional groups present in this molecule and which do you think is the most important one?

[paradiesisch]

As you have to so how your efforts to answer this question.
I'll ask what are the functional groups present in this molecule and which do you think is the most important one?

I think it's the cyclopentene. I've answered "3-ethenyl-2-methylcyclopentene " but the website says it's wrong. I changed it to "5-ethenyl-1-methylcyclopentene" but it's still wrong.

[discodermolide]

You also have to define where the C=C is in the cyclopentene.

[paradiesisch]

You also have to define where the C=C is in the cyclopentene.

Sorry, is it still necessary? Since the location of the double bond is in point 1, I didn't add the part where the double bond is located anymore. Or maybe I really have gotten everything wrong...

[discodermolide]

1-methyl-5-vinylcyclopent-1-ene is the name.
You still need to include it because that's the starting point for the numbering of the substituents.
e.g.


4-methyl-3-vinylcyclopent-1-ene

[paradiesisch]

Thank you! However, I have input-ed that answer in the website where I got the questions, and the website says it's incorrect. Here it is, in case you're interested http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/Questions/Nomencl/nomencl.htm#begin

I answered "1-methyl-5-vinylcyclopentene" and it is  the correct one. Thank you so so much for helping me! I still have lots to go in this topic. 

[insertwittyname]

can the first compound be named as:
1-methyl-2-(ethene)-cyclopent-1-ene ?

[discodermolide]

Nope, see above. Vinyl is perfectly acceptable, ethene does not mean anything. If anything ethylene but the ring has precedence.

[orgopete]

can the first compound be named as:
1-methyl-2-(ethene)-cyclopent-1-ene ?

Two points here. Yes, the name could have been ethenyl not (ethene).

The second point is, "what is the deal with IUPAC nomenclature?" This is in part a throwback to searching by name. If you are to try to find a compound, it is better if it only had a single name. IUPAC is one system of nomenclature, but in my opinion, it is just one system of systematic names. When I was teaching, I placed greater emphasis upon understanding systematic nomenclature than matching every character of a name. The reality is a compound may have more than one IUPAC name, for example, they may include some accepted abbreviations or they differ in the U.S. from other countries. IUPAC names work well for simple compounds, but become unwieldy for complex structures (try the IUPAC for cholesterol). Here, it may be more efficient to use a variant or combination of a common name and substituent, for example 1-methyl-2-ethylchickenwire. The chemical literature does not become updated with naming conventions. If a compound had been given a common name like acetone, that name will remain. If you encounter a CAS, German, French, trade, or other name, you should be prepared to convert it into a structure.

The other side of this is that compounds now have connection tables to convert a drawn structure into a searchable form. We can find a compound with SciFinder without having to give it a proper Chemical Abstracts name. Yes, they may differ from IUPAC names. (When I went to academics, I came thinking CAS nomenclature was the more important, or the one I encountered most frequently.) Obviously, none of this helps if your professor is a stickler for IUPAC names, but I would hope you could draw the structure of 1-methyl-5-vinylcyclopentene (or 5-ethenyl-1-methylcyclopentene).

[insertwittyname]

discodermolide and orgopete, thanks for the help and clarification.

[cbn]

may be....

1.)  5-Ethene 1- methyl cyclopentene 

[orgopete]

may be....

1.)  5-Ethene 1- methyl cyclopentene

A point I was trying to make is that while this suggested name is somewhat understandable, if this was compared to THE iupac name, character for character (as must be done on the MSU website), it will be wrong. Ethene is a parent name and not a substituent. In addition, an extra space or leaving out a hyphen will also make it wrong. That is different than substituting an approved IUPAC variant such as vinyl for ethenyl. In the case of this substitution, I believe this is what motivated the original poster to comment as he or she was using ethenyl and the form was expecting vinyl.

Whereas the number of flagged posts increased by two upon my stating my opinion about the importance of IUPAC names, here is a little fun. Give the common name for this IUPAC name, (8R,9S,10R,13S,14S,17S)-17-hydroxy-10,13-dimethyl-6,7,8,9,10,11,12,13,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3(2H)-one (I'm presuming ChemDraw is giving a correct IUPAC name). If you resort to Google, you are virtually conceding that you could not draw this very recognizable compound from its IUPAC name.

Here is another, give the IUPAC name for ameisensäureethylester (Wikipedia title). I'm not advocating nor deriding IUPAC names, I'm just saying you could come across ameisensäureethylester in Wikipedia. I just think if you read enough chemical literature, you would know this. For myself, CAS nomenclature searches were my primary searching tool at one point in my career. Because Chemical Abstracts translated given names into CAS names, you also had to recognize the original name in the reference. This is still true, though you can now search directly with a structure.

[discodermolide]

I asked this very question in the ChemDraw support fora and here's what I got back.
1 Question:
Which naming convention (IUPAC, etc.) is used to generate names using the Structure to Name tool?
Answer:
The names generated by ChemBioDraw are the ones that we feel are the most appropriate for chemists to use. In most cases, those names are consistent with at least one set of IUPAC recommendations. However, the IUPAC recommendations have changed over time, resulting in conflicts between different sets of recommendations and even within the same set of recommendation. Some IUPAC recommendations have never been accepted by the chemistry community, and are in fact rarely or never seen in real-life usage. Accordingly, there is no simple answer to this question.

2 Question:
I drew a structure, used the Structure to Name command to generate a name, then I used the Name to Structure command to generate the structure, but did not get the starting structure. Why?
Answer:
There is no particular reason to expect this process to work both ways. The name generated by ChemDraw is probably an accurate name for the structure you originally drew. The structure generated from the name is probably an accurate interpretation of the name. The name itself is probably slightly ambiguous, but not incorrect. There are probably other names that would regenerate the original structure. There are also other names that would generate even more dissimilar structures. Currently the IUPAC recommendations offer considerable flexibility when generating chemical names, and that flexibility inevitably leads to ambiguities.
3. Question:
I entered the name [name1], but the structure it gave me was really [name2].
I entered a name that violated IUPAC rules, and it gave a structure anyway!
The structure it gave isn't the one I meant.
Answer:
Name/Structure is designed to give a correct structure based on the name entered.  If you enter a name that is ambiguous, you're rolling the dice with regard to the structure you get back.  For example, the explosive TNT is really 2,4,6-trinitrotoluene. If you enter "trinitrotoluene", however, you should not expect to get this structure.  You might, but you might also receive the 2,3,4-, 2,3,5-, alpha,alpha,alpha-, or any of several other isomers.  None of these would be incorrect for the ambiguous name "trinitrotoluene". If you want a specific isomer, you must enter a specific name.
In a similar vein, Name/Structure supports many types of nomenclature that are not condoned by any naming body, including IUPAC, IUBMB, and CAS. There is absolutely nothing ambiguous about a name like 5-chloropentane. The correct name for that compound would be 1-chloropentane, but that does not prevent Name/Structure from interpreting the name it was given and producing a reasonable structure based on that name.

So it would seem that even the mighty ChemDraw makes guesses when it names structures or produces structures from names! These answers come from the ChemDraw FAQ database.
So good luck!