User 4e4b708dbd
12-07-2010 13:42:02
ChemAxon e7b9408ca1
13-07-2010 11:41:56
Dear Imants,
Thank you for the report and the link. Just to clarify: you are refering to generating this name from the structures using ChemAxon? I checked, our current released version indeed generates this incorrect name (just without the leading 0) for those structures. Our development version already fixes that, it will be released soon in 5.3.6 (planned for the end of this week).
For instance, the first structure is now named as:
N-(2-cyanophenyl){[2-(2H-1,3-benzodioxol-5-yl)ethyl]carbamothioyl}formamide
This next version will also have initial support for isotopes, which I know you requested. I would be very interested to hear your experience with it.
Best regards,
Daniel
User bd69837856
13-07-2010 14:13:09
dbonniot wrote: |
For instance, the first structure is now named as:
N-(2-cyanophenyl){[2-(2H-1,3-benzodioxol-5-yl)ethyl]carbamothioyl}formamide
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This name is also subtyl incorrect I believe. The default point of substitution on formamide is if anything the Nitrogen not the carbon. (P-66.1.1.1.2 part d in the IUPAC 2004 draft recommendations and example at the top of p743).
Hence giving you N#CC1=CC=CC=C1N(C(NCCC2=CC3=C(OCO3)C=C2)=S)C=O as the structure. A 1- locant would make it unambiguous but I do not believe the IUPAC recommendations recommend the use of formamide under these situations.
It would also probably be better if Nitric acid was generated as the name for oxoazinic acid as nitric acid is a retained preferred name.
ChemAxon e7b9408ca1
21-07-2010 12:35:07
Thanks for your comments.
dan2097 wrote:
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This name is also subtyl incorrect I believe. The default point of substitution on formamide is if anything the Nitrogen not the carbon. (P-66.1.1.1.2 part d in the IUPAC 2004 draft recommendations
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I'm not sure. That just says both N and C (in this case) are substituable.
and example at the top of p743).
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This example is wrong, at least regarding what the PIN as. In a revision, IUPAC gives the following name:
N-[3-(carbamoylamino)propyl]formamide
Which is also what we generate, and this is consistent with other places. Therefore, a strict application of the rules might mean the name is correct. However, you are right that there seems to be a tradition to consider the nitrogen to be the default substitution place. Therefore, the name could be misunderstood, and it is safer to add a 1- locant. I changed the implementation to do that.
Do you agree this name "1-{[2-(2H-1,3-benzodioxol-5-yl)ethyl]carbamothioyl}-N-(2-cyanophenyl)formamide" is at least unambiguous now? Do you see in the spec a rule that invalidates it, or prefers a different choice for it?
It would also probably be better if Nitric acid was generated as the name for oxoazinic acid as nitric acid is a retained preferred name.
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That's perfectly right, nitric acid was not recognized by mistake. I also fixed that in our development version.
User bd69837856
21-07-2010 16:09:04
dbonniot wrote: |
I'm not sure. That just says both N and C (in this case) are substituable.
This example is wrong, at least regarding what the PIN as. In a revision, IUPAC gives the following name:
N-[3-(carbamoylamino)propyl]formamide
Which is also what we generate, and this is consistent with other places. Therefore, a strict application of the rules might mean the name is correct. However, you are right that there seems to be a tradition to consider the nitrogen to be the default substitution place. Therefore, the name could be misunderstood, and it is safer to add a 1- locant. I changed the implementation to do that.
Do you agree this name "1-{[2-(2H-1,3-benzodioxol-5-yl)ethyl]carbamothioyl}-N-(2-cyanophenyl)formamide" is at least unambiguous now? Do you see in the spec a rule that invalidates it, or prefers a different choice for it?
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N-[3-(carbamoylamino)propyl]formamide makes far more sense as a
PIN. Is this revision to the 2004 guidelines available online?
From reading the recommendations I couldn't ascertain when exactly you were allowed to substitute the aldehydic H of formamide. ACD/Name side steps the problem by naming the compound as a derivative of 2-thioxoacetamide. Hence: (2-{[2-(1,3-benzodioxol-5-yl)ethyl]amino}-N-(2-cyanophenyl)-2-thioxoacetamide). I'm afraid I am not familiar enough with the rules for preffered naming to say with considence what is the preferred way to name this compound is.
Anyway the name you suggest is definitely unambiguous which is most important.
Treating the nitrogen as the default point of substitution on formamide allows names such as dimethylformamide to naturally give their intended structure.
ChemAxon e7b9408ca1
22-07-2010 07:02:10
As far as I know the IUPAC updates on the recommendations are not available yet.
P-65.1.8.3 Substitution of the hydrogen atom of formic acid is permitted when substituent
groups are different from those cited in P-65.1.8.1.
There is a mix-up in the sections in P-66 refering to the limitations for formamide, but I understand that applies to formamide as well.