X-S(3
We claim:
1. A process for the preparation of Isoproterenol hydrochloride (I), comprises:
a) acylating pyrocatechol (V) with 2-chloroacetyl chloride (IV) in the presence of a Lewis acid catalyst to form 2-chloro-l-(3,4-dihydroxyphenyl) ethanone (III);
b) reacting 2-chloro-1 -(3,4-dihydroxyphenyl) ethanone (III) with propane-2-amine to form l-(3,4-dihydroxyphenyl)-2-(isopropyl amino) ethanone hydrochloride (II); and
c) hydrogenating l-(3,4-dihydroxyphenyl)-2-(isopropyl amino) ethanone hydrochloride (II) in the presence of a metal catalyst to form 4-(l-hydroxy-2-(isopropyl amino) ethyl) benzene-1,2-diol hydrochloride (Isoproterenol hydrochloride) (I).

2. The process according to claim 1, wherein step a) the Lewis acid catalyst is selected from aluminum chloride and ferric chloride
3. The process according to claim 1, wherein aprotic solvent is selected from acetone, acetonitrile, 1,4-dioxane, diethyl ether, dichloromethane, ethyl acetate, N, N-dimethylformamide, methyl tertiary butyl ether, hexane, cyclohexane, toluene and tetrahydrofuran
4. The process according to claim 1, wherein protic solvent is selected from water, methanol, ethanol, isopropyl alcohol, n-propanol, n-butanol or mixture thereof

5. The process according to claim 1, wherein step c) the metal catalyst is selected from nickel applied on to kieselguhr, palladium on carbon (NMC103N), platinum as platinum black or as platinum oxide,
6. The process according to claim 1, wherein step c) the protic solvents selected from water, methanol, ethanol, isopropyl alcohol, n-propanol, n-butanol, preferably methanol, water.
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7. The process for the purification of Isoproterenol hydrochloride (I) comprising:
a) dissolving Isoproterenol hydrochloride (I) in a suitable protic solvent
b) cooling the reaction mass to 5-10 °C.
c) isolating pure Isoproterenol hydrochloride (I).

8. The process according to claim 7, wherein the protic solvent is selected from a group comprising of water, methanol, ethanol, isopropyl alcohol, n-propanol, n-butanol or mixture thereof.
9. The Isoproterenol hydrochloride (I) according to claim 7 having purity greater than 99.0%.
10. The Isoproterenol hydrochloride (I) according to claim 7 having X-ray powder diffraction pattern as shown in figure 1 and differential scanning calorimetry as shown in figure 2.
Dated this on 10 June 2019 Manik Reddy Pullagurla
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