You can try methanolic HCl with one or two drops water refluxed.After completion of reaction concentrate reaction mass under high vacuum.

Thank you (Bilash Kuila) for your response,

previously I tried with 10% aq. KOH method and another with Barium hydroxide octa hydrate reagents. Shure I'll try with methanolic HCl (shall go for 10%?) and wish to reply positive result.

You can try LiOH /Methanol

Thank you,

I have a small query, does this can hydrolyse N-alkyl esters also?

because out of five four are N-alkyl esters and one is simple methyl ester.

I had positive results with methyl, ethyl and benzyl esters but never had the opportunity to hydrolyze longer akyl chains. Normally it shoud work.