Re: are the Polarity of these two compounds similar: Cholesteryl acetate vs cholest-methyl ester?

Sureming wrote:
> 
> Dear all:
> 
>      I have question on the polarity of esters: Cholesteryl acetate vs
> cholest-methyl ester (at Carbon 3). Are the polarity of these two
> compounds equivalent to each other or pretty similar?
>      If yes, how do I synthesize cholesteryl acetate from cholesterol,
> which we have plenty?
> 
>         Thanks in advance for any hints!

Clean cholesterol dissolved in anhydrous ether.  Add somewhat more
than an equivalent of anhydrous pyridine.  Cool; slowly add smehat
more than an equivalent of acetyl chloride with stirring.  After the
reaction is complete, filter off the Py.HCl (Buchner) and immediately
wash with more ether.  Clean up the filtrate and isolate your neutral
ester product.  TLC to monitor.

I suppose you could add clean cholestrol to ethyl acetate plus a drop
or two of sulfuric acid and reflux it for a day or two, slowly drawing
off the EtOH as it formed.  Then clean up the product after killing
the acid with excess solid Na bicarbonate or ground Na2SO4, then
filtration, etc.  

Chlesterol is a monoalcohol with no other functionality.  What is
"cholest-methyl ester (at Carbon 3)"?


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