1. A process for the preparation of Salcaprozate sodium (1) having purity greater than
99.5% by High performance liquid chromatography (HPLC),
5 which comprises:
a) reacting salicylamide of formula (6)
with diethyl carbonate in the presence of a base and solvent to provide 2Hbenzo[e][1,3]oxazine-2,4(3H)-dione of formula (5);
10
b) reacting the compound of formula (5) with ethyl 8-bromo octanoate of
formula (4)
in the presence of a base to provide compound of formula (3);
15
c) hydrolyzing the compound of formula (3) with a base in the presence of a
catalyst to provide Salcoprazate of formula (1a);
12
and
d) reacting Salcoprazate of formula (1a) with sodium hydroxide and solvent
to provide Salcoprazate sodium (1).
5 2. The process as claimed in claim 1, wherein in step a) the base is selected from
sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium
methoxide, potassium ethoxide, potassium tert-butoxide and/or mixtures
thereof; and the solvent is selected from methanol, ethanol, isopropyl alcohol,
n-propanol, butanol and/or mixtures thereof.
10 3. The process as claimed in claim 1, wherein in step b) the base is selected from
lithium carbonate, sodium carbonate, potassium carbonate and/or mixtures
thereof; and the solvent is selected from dimethylformamide,
dimethylacetamide, dimethyl sulfoxide and/or mixtures thereof.
4. The process as claimed in claim 1, wherein in step c) the catalyst is tri n-butyl
15 phosphine.
5. The process as claimed in claim 1, wherein in step c) the base is selected from
lithium hydroxide, sodium hydroxide, potassium hydroxide and/or mixtures
thereof; and the solvent is water.
6. The process as claimed in claim 1, wherein in step d) the solvent is selected
20 from methanol, ethanol, isopropyl alcohol, n-propanol, butanol, water and/or
mixtures thereof