Like the ester question, your question is too vague and bad formulated.

At first you need a pure sample of indigo as standard with very good elemental analysis values + or- 0,1 % from calculated value.

The sample must be dried and water free!

What is the NMR solvent used for C13 NMR? What a kind of NMR spectrometer?

You write compounds in plural. Do you mean the derivatives with halogen or another substituent or different samples of indigo or another structure?

Thank you.

JRG

I send you the calculated C13 NMR of indigo via ACD Labs software. Can you send me your NMR spectrum as pdf e.g. the values given by your C13 NMR spectrometer

if you cannot send the spectrum as pdf file.

JRG

Don´t be afraid . CH4 CH4 is my trade mark for send spectra.

Here the attachment without trade mark. The values are the same

Thank you so much sir. I wrote in hurry m sorry for that .I am working on natural products I meant other isomers also. But for indigo I had bought analytical standard from sigma that also not showing peaks. Sir i will collect my spectra ,the plight is we dont have NMR intstrument here but I took it at different places .I will collect deatails and send it to you. Thank you so much.

Please contact or read the papers of Warjeet S Laitonjam (member of res.gate

Comparative study of the major components of the indigo dye obtained from Strobilanthes flaccidifolius Nees. and Indigofera tinctoria Linn

Warjeet S Laitonjam, Sujata D Wangkheirakpam

08/2013;

ABSTRACT Investigation on the chemical constituents including the chemical structure of major components in the water extracts from Strobilanthes flaccidifolius Nees. and Indigofera tinctoria Linn. was done. It was found that the indigo from fresh leaves of S.

on Research gate

Good luck

JRG

Thank you so much sir but you are telling me to read my paper Warjeet S Laitonjam is my guide i did the work in this guidance .But thank you very much. I wuold like to you to see that spectra i am searching . But i dint get aromatic protons .Thank you again.

Well, I know that you are co-author of this paper but a guide or supervisor MUST HELP YOU in his function.

Indigo Standard:

Prior to NMR investigation your sample must pure (acting later as standard) and dry and have a good elemental analysis and MS.

Sample of your natural indigo:

Have you received good MS spectra of your samples?

Can you tell me how you prepare your sample for C13 NMR (Solvent, MW , how mg a.s.o.) and the name of the NMR spectrometer e.g. Bruker, Varian..)

JRG

We dont have in institute inspite of my guides' good handling experiance so we cant say how they must be handling the sample.Its bruker and i send it to three places and suprisingly they gave the same pattern of wrong peaks without the carbons with aromatic protons FOR BOTH PLANT SAMPLE AND STANDARD FROM SIGMA. I FELT SOMETHING LIKE DECOMPOSING MUST HAVE HAPPEN SO I WAS CURIOUS.

hey, did you solve your issue? I am not seeing the 1H spectrum of indigo I prepared in DMSO-d6 so I am wondering if it might be related?

Thank you