[dmtr19]

Hello,

could you please help me
which name of chemical compound is correct:
4'-(Dimethylamino)-3-hydroxyflavone     or    4′-N,N-dimethylamino-3-hydroxyflavone  ?

And which chemical structure (in attached) is correct for it?
Because I have found two different structures: difference in double bonds in phenyl group

[Arkcon]

Hi there, define "phenyl group" for us.  That is, what is the textbook definition.  Can you discover a reason for the differences in images?

Sorry to answer a question, with another question, but that's what we do here.  Its all defined in our our Forum Rules{click}.  We want to help you, learn to help yourself.

[dmtr19]

Thanks for the reply!

Im not chemist, im physicist. so I can make mistakes in this question.
But the order of double bonds in the right phenyl group in both structures are different.
Is it matter or not? And which name of this structure is correct?

I have fund these both names and structures in various articles

[Elric82]

It doesn’t matter that the  order of the double bonds in a phenyl group are different. They “ alternate” per se. look up “pi symmetry” and aromaticity.

[Babcock_Hall]

Chemists sometimes use multiple structures to portray the electron density in a way that a single structure could not convey.

[Elric82]

Chemists sometimes use multiple structures to portray the electron density in a way that a single structure could not convey.

I was going to explain how the electrons work in a phenyl group, but I was afraid I might break a rule about spoon feeding.

[dmtr19]

Thanks for the replies!

But why if its not matter here,
in following case its matter
https://www.sigmaaldrich.com/catalog/product/aldrich/419753
https://www.sigmaaldrich.com/catalog/product/aldrich/h4530

[Arkcon]

Those pages use two different images, for the same name.  Sigma-Aldrich is a fine company, but mistakes are not impossible.  A useful way, for a student trying to learn organic chemistry, is to draw each one out.  Its understood, from undergraduate chemistry, that carbon forms 4 bonds, and a double bond counts as two, benzene being a special case that is noted in textbooks.  The missing bonds are hydrogen, and can be drawn out.  Do it and see if one of those molecules doesn't add up.

[sjb]

Minor, but one is flavanone (the ketone), the other flavone (the enone)

[Arkcon]

Aha.  Like the O.P., I didn't read the name carefully.

[pgk]

4′-N,N-Dimethylamino-3-hydroxyflavone is more correct but 4’-Dimethylamino-3-hydroxyflavone can also be used because there is only one amine group and thus, nomenclature cannot give rise to confusions, e.g. N,N-Dimethylaminoputrescine or N,N'-Dimethylaminoputrescine.
The parenthesis is not necessary because there is no individual numbering of the substituent, e.g. 4’-(4-Methoxyphenyl)-3-hydroxyflavone.
Sigma-Aldrich’s nomenclature is also correct because for natural products, it is accepted to follow the Beilstein priority numbering system, which is different than IUPAC and CAS numbering systems (Note that IUPAC and CAS numbering systems may slightly differ sometimes). 

[dmtr19]

4′-N,N-Dimethylamino-3-hydroxyflavone is more correct but 4’-Dimethylamino-3-hydroxyflavone can also be used because there is only one amine group and thus, nomenclature cannot give rise to confusions, e.g. N,N-Dimethylaminoputrescine or N,N'-Dimethylaminoputrescine.
The parenthesis is not necessary because there is no individual numbering of the substituent, e.g. 4’-(4-Methoxyphenyl)-3-hydroxyflavone.
Sigma-Aldrich’s nomenclature is also correct because for natural products, it is accepted to follow the Beilstein priority numbering system, which is different than IUPAC and CAS numbering systems (Note that IUPAC and CAS numbering systems may slightly differ sometimes).

thank you a lot!!