PRIORITY

This application claims priority under 35 U.S.C. § 371 to International Application No. PCT/M2019/056791, filed Aug. 9, 2019, which claims the benefit of Indian Provisional Application No. 201821030526, filed Aug. 14, 2018, entitled “PROCESS FOR THE PREPARATION OF SOLRIAMFETAL AND SALT THEREOF”, the contents of each of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to solriamfetol or salt thereof and its process for preparation.

BACKGROUND OF THE INVENTION

Solriamfetol hydrochloride, chemically known as (R)-2-amino-3-phenylpropylcarbamate hydrochloride, is represented by compound of formula Ia.



Solriamfetol, a dopamine and norepinephrine reuptake inhibitor (DNRI), is marketed in the United States under the trade name SUNOSI® as tablets in the dosage strength of 75 mg and 150 mg.

Solriamfetol hydrochloride can be used to improve wakefulness in adult patients with excessive daytime sleepiness associated with narcolepsy or obstructive sleep apnea (OSA).

U.S. Pat. No. 5,955,499 discloses a process for the preparation of solriamfetol hydrochloride

There is a need for an improved process for the preparation of solriamfetol, which avoids the formation of isomeric and other process-related impurities, while affording the desired solriamfetol hydrochloride product with good yield and high purity.

The present invention provides a process for solriamfetol HCl in a high chemical and chiral purity by using novel acid addition salts of solriamfetol without using chromatographic techniques.

SUMMARY OF THE INVENTION

The present invention provides, a process for the preparation of R-solriamfetol HCl of formula Ia,



the process comprising:

(a) reacting solriamfetol of formula I,



with an acid to form solriamfetol acid addition salt of formula II;



(b) optionally purifying the solriamfetol acid addition salt of formula II;

(c) converting the solriamfetol acid addition salt of formula II to solriamfetol HCl of formula Ia; and

(d) optionally purifying the solriamfetol hydrochloride of formula Ia.

The present invention provides solriamfetol dibenzoyl-D-tartaric acid salt of formula IIa characterized by1H NMR having peaks at 2.65-2.71, 2.88, 3.39, 3.72-3.86, 5.69, 6.61, 7.16-7.25, 7.44-7.48, 7.60-8.00 (400 MHz, DMSO d6).

The present invention provides, a process for solriamfetol dibenzoyl-D-tartaric acid salt of formula IIa, comprising reacting solriamfetol of formula I with dibenzoyl-D-tartaric acid.

