Use 5 or 6 equivalent of hydrazine w.r.t. ester and reflux in methanol or ethanol for 6 hrs and then concentrate the solution and keep inside the refrigerator.

Your idea is good, but You do not need  absolute alkohol, usual 96% is normal solvent for this reaction. The reaction in reflux aloholic solution us quite fast, and usually after 30-40 min finished. Have a TLC controll for monitoring the reaction

Neat hydrazine hydrate can be used at Reflux to prepare a hydrazide see ARKIVOC 2002, 227.

from an ester see compound 3 in the attached doc (a benzoate is hydrolysed as well, so you can only do it with an ester that does not have sensitive functional groups)    

Kirill I. Petko

Matthew Mcgrath

thank you ..but i didnt get the hydrazide ...it stil get looks llike solution or i get Precipitate but its have the same ester melting point ..

i hop i get more Details of  the reaction

my ester with 214 Molecular weight

 and the hydrazein haydrat have 50 molcular wait

so do i have use 1: 1 ?

The amount of the solvent  affect on the raction ?

You can take some excess (40-60% or up to 2 mol) of hydrazine (calcuate it from hydrate).  And a solvent.... may be minimum volume  to diisolve the ester. Hydrazone may be dropped as a solid but may be not, so TLC control is good

Hi Abdo Kareem

If you tried using abs. ethanol and you did not obtained the hydrazide, try to use neat condition (without solvent) with excess hydrazine under reflux for 5-6 h.

Good luck

I faced this problem, but I obtained hydrazide after increasing the time of reflux to 12 hrs.

i Just prefer the hydrazide .. the problem was with hydra zen the reaction need new and fresh hydra zen ... its need = 1 hour reflux   and put the round in the freezer

thx # Rokaia Abdullah

# Talaat I. El-Emary

Kirill I. Petko

Use 5 or 6 equivalent of hydrazine w.r.t. ester and reflux in methanol or ethanol for 6 hrs and then concentrate the solution and keep inside the refrigerator.

use 5 or more equivalent of hydrazine hydrate (90%) with ethanol solvent at room temp. 24 hrs you get ppt.

Hi,

I am also trying to synthesize Hydrazides from aminoacid methyl esters, but although I followed all the above suggestions, I was not able to get it properly. The problem is that I have the same starting mass and the product mass LC-MS say nothing and since I use Lysine methyl ester.2HCL, I am not able to see anything on TLC. There is this washing process with (3:1) DCM / isopropanol solution which is supposed to get my product but I only obtain a really little amount ( from 50 mg material only 4 mg )

Can anybody suggest me any solutions?

Thanks!

Try Using excess hydrazine ( 20 folds) without solvent (neat) and reflux for about 10h.

Synthesis, characterization and preliminary pharmacological evaluation of new non‐steroidal anti‐inflammatory pyrazoline derivatives.European Journal of Chemistry 6 (4) (2015) 461‐467

Monther Faisal Mahd, Ayad Mohammed Rasheed Raauf and Noor Muneer Mohammed

European Journal of Chemistry 6 (4) (2015) 461‐467

I would recommend to reflux your ester plus 10Eq of hydrazine in dried ethanol or methanol. Sometimes dried THF as cosolvent is needed

Usually I let it stir overnight, you will get a precipitate that you filter it off

Recrystallization from ethanol might be necessary.

Good luck!

www2.hhu.de/Janiak/Pdf/248.pdf

please find attached.