FORM 2
The Patents Act, 1970 [39 of 1970]
Complete Specification [See section 10; Rule 13]
1. "A NOVEL PROCESS FOR THE PREPARATION OF 2-AMINO-4,5-DMETHOXY BENZONITRILE [ABN]"
(A) STRIDES ARCOLAB LTD.
(B) 201, Devavrata, Sector 17, Vashi, Navi Mumbai - 400 703, India
(C) Nationality - Indian

The following specification particularly describes the nature of this invention and the manner in which it is to be performed:-

3. Field of the Invention
This invention relates to a novel process for the preparation of 2-amino-4,5-dimethoxy benzonitrile [ABN]. The process herein described is particularly suitable for large-scale manufacture, it being cost and time efficient with the use of a suitable solvent and specific compound as catalyst.
Background of the Invention
The title compound is commercially used for the preparation of the antimalarial quinozoline derivatives. Previously few reports concerning the possible antimalarial activity of quinozoline derivatives have been disappointing. First of all in the chemical laboratory of University of North Carolina, a report indicated in the Journal of American Chemical Socity, 1946, Vol 68,pp 1902-1903 by R.L. McKee, M.K.Mckee and R.L. Bost discloses the use of title compound for preparing of quinozoline derivatives are warranted for antimalarial activity.
Known Art
There are reports available describing the uses of the title compound, certain relevant reports having prior art significance is cited below: -
The title compound used for preparation of antiarrythmatic agents by Cussans, Nigel, Jhon, Euro. Pat.308, 059 (CLCO7D401) 22 Mar 1989, G.B. April 87/19, 378 Aug, 1987.14pp.
Byk-Gulden Lomberg Chemische Fabrik G. M. B. N. .Brit. 1,166,596(CL.C0.7D) 08 Oct, 1969. Ger. Appl. 22 March 1967. The title compound used for the preparation of Piperazinyl propanoic acid anilides, useful for sedative, neuroleptic and analgesic medicines.
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Hess, Hans, J.F. (Pfizer Inc.) Ger. Offer, 2,457,911(CL.C0. 7D), 12 Jun 1975, Vs. Appl. 421,992 05 Dec, 1973; 18pp. Antihypertensive quinozolines were prepared by treating Anilines.
Belg. 861,822(CL.C0.7D) 31 Mar, 1978, Finn. Appl. 76/3614,15th Dec. 1976; 11pp. The title compound used as an intermediate for the synthesis of piperazinylquinozolines dervatives.
N.V. Konin Klijke pharmaceutische Fabrieken Voorheen Brocades-stheeman en Pharmacia Neth. Appl. 7,206,067 (CL.A61K, A23K, C07D), 09th Nov., 1972, Brit. Appl. 13,802/71, 07th May 1971; 19pp. The title compound used for the preparation of amino quinozolines which are pyrimidine derivatives.
J. Hetrocycle.Chem. 1980, 17(4), 797-8(Eng.), The title compound used for the new practical synthesis of parazosin.
There are reports of various processes available for the preparation of title compound 2- amino-4,5-dimethoxy benzonitrile [ABN], but they are neither synthetically simple or commercially viable as suffer from various disadvantages like, formation of huge amount of inorganic which makes isolation of compound a laborious one. Some processes takes more time as 15 to 20 hrs. due to use of unsuitable catalyst.
Description of the Invention
The present invention aims to providing distinctive process for producing 2-amino-4,5-dimethoxy benzonitrile [ABN], from 2-Nitro-4,5-dimethoxy benzonitrile by use of catalyst acting more reactively and more selectively, the obtainment of high yield at lower temperature and with shortened time, specially with the use of 5% Pd/c through which aromatic nitro compound are hydrogenated very easily to amino compound. With the process according to the present invention better results are obtained surprisingly under mild condition, relatively short reaction time and with high degree of purity and an excellent yield.


The preferred catalyst used herein the present invention is palladium catalyst system. Palladium is very effectively used for hydrogenation process. According to the present invention there is provided an improved process to producing 2-amino-4,5-dimethoxy benzonitrile [ABN] by hydrogenating 2-Nitro-4,5-dimethoxy benzonitrile employing the said catalyst palladium over carbon in presence of methanol to get pure and excellent yield of 2-amino-4,5-dimethoxy benzonitrile.
Example
Charge 2-nitro 4,5-dimethoxy benzonitrile [NBN](1), (100 g) in to the pressure reactor, Charge 5 g of 5% Pd/c after wetting with DM water, Charge calcium carbonate (2.5 g) and remaining 300 ml methanol, Close the reaction vessel and purge nitrogen to keep the pressure 5 Kg., Check the leakage and release nitrogen, Repeat the same for once more, then purge Hydrogen and maintain pressure to 10 Kg/cm2 and temp, se to 50° C, keep the pressure at 10 Kg/cm2 and temp, at 50°C for 4 hrs., then cool the reaction mixture, discharge the reaction mass and filter to recover the catalyst, Distill out the clear methanol layer to 150 ml, cool the methanol layer and precipitate the product in 2L DM water kept at 10°C, stir for one hour and filter, suck dry, dry the product at 40 to 50°C under vacuum for 12 hrs. Yield-71.4 gm, Efficiency-84%, MP-92°C.
Reaction Scheme:





(I)

(II)

4. We Claim:
1. A process for preparation of 2-amino-4,5-dimethoxy
benzordtrile[ABN] comprising:
hydrogenating 2-nitro-4, 5-dimethoxy benzonitrile [NBN] by charging 100 g 2-nitro-4,5-dimethoxy benzonitrile, 5 g of 5% Pd/c catalyst, 300 ml methanol and 2.5 g of calcium carbonate in a reaction vessel and maintaining the pressure at 5 Kg/cm2;
purging hydrogen and maintaining pressure to 10 Kg/cm2 and temperature to about 50°C till 4 hrs;
cooling the reaction mixture;
discharging the reaction mass and filtering the same to recover the catalyst;
distilling out the methanol layer;
cooling the methanol layer;
precipitating the product in 2L DM water at 10°C with stirring for 1 hr; and
filtering the resultant and drying the same at 40°C to 50°C under vacuum for 12 hrs to obtain 2-amino-4,5-dimethoxy benzonitrile [ABN].
2. A process for preparing 2-amino-4, 5-dimethoxy benzonitrile [ABN]
as claimed in claim 1 and as herein described with reference to the description and the


Agent for the Applicant Lex Orbis
Intellectual Property Practice 709/710, Tolstoy House, 15-17, Tolstoy Marg, New Delht-110 001
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example.

ABSTRACT
A novel process for the preparation of 2-amino-4,5-dimethoxy benzonitrile [ABN] by hydrogenation of 2-nitro-4,5-dimethoxy benzonitrile [NBN] using 5% Pd/c catalyst in methanol media in presence of calcium carbonate at a varying pressure level between 5 and 10 Kg/cm2