hmtlion - 28-9-2009 at 01:34
Dear all,
I made 2-phenylpyridine via Organic synthesis procedure (Organic Syntheses, Coll. Vol. 2, p.517 (1943); Vol. 18, p.70 (1938).) and then did amination
with sodamide (NaNH2) and purified by CC. but now I am facing a problem to get its hydrochloride salt in pure form. I took the RM in acetone and
passed Dry HCl gas (3 M Eq.) and evaportaed the acetone I got the brown ppts insted of off white ppts. Please help me to purify it.
Thanks
Hardik
grind - 28-9-2009 at 01:51
Acetone + HCl ---> condensation products.
Acetone + Amine ---> condensation products.
I believe your product is (at least partially) destroyed.
Never use acetone or other ketones to prepare hydrochlorides!
Your desired hydrochloride:
Take the neat base, add 1,2 equiv. (or more) of conc. HCl and sufficient alcohol to make a homogeneous solution. Stir a few minutes, evaporate the
alcohol, dry the salt at the pump on the waterbath. Crystallize from a suitable solvent.
EDIT:
try the following to "rescue" your remaining substance:
Evaporate solvent and condensation product residues in (high) vacuum. Add enough dil. HCl to form salt + 300% more and boil for 1h. If the HC salt is
in solution, add ether and extract 3 times. Discard the ether extracts. Basify to get the amine base. Extract it with ether and purify in a suitable
way.
Now you can synthesize the hydrochloride again, without acetone of course 
.
[Edited on 28-9-2009 by grind]