What do you mean by crude? The underivatized compound?
No, I mean the unpurified reaction mixture.
I see a few possibilities here:
1. The ester is not forming
2. The ester is not surviving the purification procedure
3. The ester product doesn't fly by the MS method you are using
So I would try alternative detection methods with the crude material. "TLC equipment" is minimal - a pack of TLC plates and a jam jar is all you need to run a TLC. If you partition your reaction mixture between aqueous bicarbonate and ethyl acetate, you should be able to see if anything's happened by TLC.
Also, I would try the exact conditions as have been used before in the literature to prepare this compound (ie dry HCl), then see if you can detect it before and after LC.