Re: purifying phosphates on sugars

cds_catch22@xxxxxxxxx wrote:
> By thin layer chromatography, I can observe a spot with low rf that
> should correspond to acetate-protected mannose with a
> diphenylphosphate at the anomeric position; however, when I attempt
> to purify the product via column chromatography I never observe the
> desired material. I suspect it is the result of the phosphate being
> hydrolyzed. My current column conditions are as follows:
>
> gradient elution: 10% EtOAc, Hexane to 100% EtOAc using silica gel
>
> I have tried pretreating the silica gel with TEA, and I run the column
> as quickly as possible.
>
> any other suggestions, concerns, comments would be more than welcome.
> Thanks.

Why do people insist on using ethyl acetate??? I hate it. Always falls
apart when you least expect it. I seen so many papers with "extract with
ethyl acetate", as sure as eggs is eggs, you *know* it will never scale
up... there'll be ethanol and acetic acid all over the place... sigh... rant
over...

--
--
Ron Jones

Don't repeat history, see unreported near misses in chemical lab/plant
at http://www.crhf.org.uk
Only two things are certain: The universe and human stupidity; and I'm
not certain about the universe. ~ Albert Einstein


.