Production of bepromoline

1. A process for the preparation of a compound of formula (Ib):

comprising contacting a compound of formula (Ia):

with toluene and HCl gas to provide said compound of formula (Ib), wherein the process further comprises one or more of the following steps:

(a) purifying the compound of formula (Ia);

(b) adding fresh toluene and HCl gas;

(c) adjusting the pH to 3 to 4;

(d) cooling to 0° C. to 5° C.;

(e) stirring for at least 1 hour; and

(f) isolating the end product of formula (Ib), wherein the compound of formula 1(b) has a degree of purity of at least 99.5%.

2. The process as defined by claim 1 , wherein said toluene and HCl gas are added to the medium of reaction at a temperature of up to 50° C.

3. The compound of formula (Ia):

having a degree of purity of at least 99.5%.

4. The compound of formula (Ib):

having a degree of purity of at least 99.5%.