Take a look at this for vernolide http://cpb.pharm.or.jp/cpb/200304/c04_0425.pdf

Vernodalin NMR data could be find here: http://dx.doi.org/10.1016/j.sajb.2008.10.001

the carbon resonances for the 11,13-dihydroderivative may be very similar to those of vernodalin here reported.

The main difference is the absence of the exocyclic-terminal double bond at the 11,(13) positions which give two signals around 125 and 135 ppm, the latter of low intensity since is due to a quaternary carbon. These two signals will be replaced by those relative to a CH-CH3 moiety around 38 and 17 ppm, respectively. The methyl in 13 position should be also clearly visible in the proton spectrum as a doublet integrating for three protons (J value 6-7 Hz) in the aliphatic region of the spectrum, around 1.2 ppm.

@Wintner, Thank you for the link, it was very useful for the vernolide,.

@Venditti, Thank you so much, I sincerely appreciate. Pls could you kindly assist me with the 13C NMR of 11,13-dihydrovernolidalin. your explanation looks interesting unfortunately am a biochemist and not a chemist. So I would be much more grateful for your kind assistance.

Thank you.

Dear Dr Okoduwa thank you for your reply. If you have nmr spectra to be resolved I may assist you since one of my expertise is the structure elucidation by means of NMR spectroscopy.

@Prof. Venditti, Thanks so much for your kind consideration to be of help to me. I sincerely appreciate. Kindly see to the attached for the NMR spectroscopy for 1H and 13C. You may send me the structural elucidation result via [email protected]

Thank you.

NMR spectroscopy

@Prof. Venditti, Thanks so much for your kind consideration to be of help to me. I sincerely appreciate. Kindly see to the attached for the NMR spectroscopy for 1H and 13C. You may send me the structural elucidation result via [email protected]

Thank you.

I will check these spectra as soon as possible. 

Please may you provide me also the mass spectrum, maybe in ESI inonization mode?

Its alright sir. I will be waiting to receiving from you soonest. Thank you

Dear Stanley,

on the basis of the provided spectra I think that the hypothesis of the presence of 11,13-dihydrovernodalin is improbable. Theoretically you should have 6 quaternary carbons, 6 methilenes, 6 methines and one only methyl, but from the DEPT experiments are visible 6 quaternary carbons, 9 methilenes, 6 methins and 3 (at least 2) methyls.

There should be present 3 methilenes on sp2 carbons between 120 and 130 ppm but from DEPT experiments only one is visible.

I cannot exclude that you have a mixture of (at least) two compounds (the decoupled 13C spectrum presents all the signals splitted, may be also due to some setting problems), and none of them is 11,13-dihydrovernodalin, maybe more than one unsaturation of vernodalin is in saturated form. In any case, more experimental details are necessary to make a solid based hypotesis, i.e. a 13C-NMR without splitting of resonances, an HSQC experiment, two HMBC (one with JnC-H = 8 Hz one with 4 Hz), a TOCSY and an ESI-MS in both negative and positive ionization modes.

Anyway, time is required for the interpretation of the data.

@Prof. Venditti sir,

Thanks for your kind attention. I sincerely appreciate, I have other results like the gcosy, dept and gcms, ftir available. Hope these will help in the structural elucidation?

Dear Stanley. These data may give additional information on the structure. It should be of help to have also the ESI-MS spectrum or a mass spectrum conducted with a ionization mode which led to little fragmentation so the pseudomolecular ion may be observed. 

At this point we may continue the conversation in private message. 

@Prof. Venditti, thank you so much I really do appreciate. So let's continue in private message.