Initially, I performed the reaction with L-trytophan and SOCl2, in MeOH, and checked by using TLC. The product will be hydrochloride salt of L-trytophan in theory. After 10 hours, the TLC (MeOH:H2O = 2:1) only showed a single spot at Rf = 0, and it did not give a ninhydrin response (I assume this was the salt form of L-tryptophan methyl ester).

However, after rotary evaporation to remove the solvent, all the HCl in the flask evaporated, and I checked again using TLC afterwards. The spot (Rf = 0) was pushed upwards (This is the L-trytophan methyl ester, I've compared it with the control).

Can someone tell me how to solve this problem?