A new method for synthesizing proton transfer compound [pyda•H][pydc] from 2,6-pyri- dinedicarboxylic acid (pydc•H) and 2,6-pyridinediamine (pyda) was explored under ultrasonic. Some factors on the yields of proton transfer compound [pyda•H][pydc] were investigated including different solvents, reaction time and reactant concentration. The results indicated that the proton transfer compound [pyda•H][pydc] could be synthesized in different types of solvents within a relatively short time under ultrasonic. The synthetic method was very convenient without catalyst and heating but short reaction time and high yield.

Key words: 2,6-pyridinedicarboxylic acid, 2,6-pyridinediamine, proton transfer compound, ultrasonic synthesis