Hi Seva,

Try to use DMF as a solvent, TEA or DIPEA as a base, eventually DRIED NaI as a catalyst and the mentioned 4-methoxybenzyl chloride (slight excess, 15-20%).

Alternatively, you may try PTC, like Na2CO3/TBAHSO4 and 4-methoxybenzyl chloride (in excess).

Good luck,

Lasdzlo

Thank you so much Laszlo :)

try with halides in basic medium with one of mentioned bases in Laszlo comment

good luck

To protect thiol group in 4-mercaptobenzoic acid molecule convert it into thioether by reacting it with CH3I in acetone in presence of anhydrous K2CO3 i.e.S-alkylation reaction.

Thank you Faiq and Madhukar for your answers.