What are the other solvents suitable for Wohl-Ziegler Reaction (or other free radical reactions) beside toxic CCl4?

The product I'm trying to isolate is moderately acid sensitive and the only work ups I have seen have used ion exchange resins that are not compatible.

I can probably add silica then subject it directly to flash chromatography but I would rather avoid this.

I have two samples of the same compound and I suspect they are contaminated with acidic impurities. I record 1H NMR spectra in CD2Cl2 and in pure NMR solvent I observe a nice narrow singlet for H2O at 1.53 ppm. When I record the spectrum of one of the samples of my compound (which I assume has less acidic impurities), the water peak disappears and a broad singlet at 1.9 ppm appears. When I record the other sample (presumably more acidic), the broad singlet appears at 4.0 ppm. Then I spike one of the samples with AcOH and along with the CH3- singlet, I now see the broad singlet at 7.3 ppm.

My hypothesis is the following: When acids are present in the sample the H2O signal in the NMR spectrum shifts downfield (gets deshielded). Can anyone confirm/reject this?

Thanks in advance!

Hello community,

I would like to have an efficient drying protocol of deuterated NMR solvents. Which drying agent to use ? How much do I have to use ? Do I have to wait for a certain time (24h or less) ?

Thank you in advance.

I want to do bromination of benzimidazole by NBS kindly suggest me workup process to remove succinimide after complition of reaction?

I was wondering if adding DMSO to activated molecular sieves would be enough to remove humidity. Or, should I distill it over CaH₂? 

Hi,

I have Fmoc protected oligopeptide. This oligopeptide is not linked to any solid support or polymer bead.  My aim is to remove Fmoc protecting group from peptide. I will use polymer supported piperidine (4-Piperidylformylaminomethyl resin) as dibenzofulvene scavenger resin. Unfortunately, I did not find any publication in the literature on this subject.

Is there anyone use the polymer supported scavenger before?

Could you give me an advice on effective protocol, please? (%? in DMF, how much molar excess, deprotection time etc. )

Hi all,

Now a days boronate chemistry is done routinely by most of the chemists. I am synthesizing  boronates in my lab. We generally do not purify the boronates (only filter the reaction mixture and use it as such for next step).

My questions are:

1. How chemists purify the boronates (boronic acids or boronic esters)?

2. What type of columns are proffered for purification (silica ot alumina)?

3. Is there any chemical modification techniques available for purification of boronates?

Please explain as this will help others also.

Best regards

Hello

Anyone have idea that how to make an acetonitrile solution of Iodine?

Thank you

I am working up a reaction which calls for the use of excess 3-chloroperoxybenzoic acid in methylene chloride. Any suggestions on how to quench the excess peroxy acid?