Halo every one
I have isolated a compound from the methanolic plant extract. The compound is UV positive at both 254 and 365 nm. It seems to be insoluble in most solvents like CDCl3, CD2Cl2, acetone and acetonitrile. Warming the sample in methanol at 40- 50 degrees the compound dissolves very well.
I am worried how I can do its NMR analysis since it starts precipitating after some time
You can get NMR analysis by dissolving your compound in polar solvents such as pyridine (pyridine-D5), water (D2O) and DMSO (DMSO-D6). There is a water peak in these solvents and the solvent peak(s) like that of pyridine in the aromatic region is a disadvantage as compared with CDCl3. Removing the solvent after the analysis is a challenge especially for the DMSO but if you have enough material for the analysis you can get decent NMR data using polar solvents. So, consider buying a range of NMR solvents for polar compounds.
I would go with the DMSO option. I have also used trifluoroacetic acid with some D2O added. It will solubilise most things - so long as you do not want your sample back afterwards.
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