First aspect of the present Invention is to provide an improved process for
preparation of Pralidoxime chloride of formula (1) thereof comprising steps of:
I) treating 2- -pyridine carboxaldehyde with Hydroxyl amine or its salt' In the presence
of solvent followed by base to obtain oxime of formula (III).
ii) adding ethylating agent to step I)
in solvent to obtain salt of formula (IV),
iii) treating the salt of compound (IV) with solvent HCI and isolating the compound
of formula (I).
iv) optionally purification of compound (I)
The suitable solvent in step (I) is selected from, but not limited to, alcohols such
as methanol, ethanol, propanol, isopropanol. butanol, and the like; esters such as ethyl
acetate and the like; ketone such as, acetone and the like; ethers such as,
tetrahydrofuran. diethyl ether, methyl tertiary butyl ether; nitriles such as acetonitrile
and the like; water or mixtures thereof.
The base used in step (I) is selected from organic and inorganic base but not
limited to, triethylamine, pyridine. piperidine, diethylisopropylamine and the like; alkali
metal hydroxides, such as, for example, lithium hydroxide, sodium hydroxide,
potassium hydroxide, and caesium hydroxide or the like; alkaline earth metal
hydroxides. such as, for example, barium hydroxide, strontium hydroxide, magnesium
hydroxide. calcium hydroxide. or the like; alkali metal carbonates, such as, for
example. sodium carbonate, potassium carbonate. lithium carbonate. celom
carbonate, or the like; alkaline earth metal carbonates. such as, for example.
magnesium carbonate, calcium carbonate, or the like; alkali metal bicarbonates, such
as. for example. sodium bicarbonate. potassium bicarbonate, or the like; alkali
acetates like sodium acetate, or the like and the mixtures thereof.
The suitable solvent In step (ill) is selected from. but not Limited to. alcohols such
as methanol, ethanol, propanol, Isopropanol, butanol, and the like; esters such as ethyl
acetate and the like; ketone such as, acetone and the like; ethers such as,
tetrahydrofuran, diethyl ether. methyl tertiary butyl ether; nitriles such as acetonitrile
and the like; water or mixtures thereof.
The ethylating agent in step (Ii) ls selected from methyl-p-toluene sulfonate,
methyl iodide, Trimethyl sulfoxonlum Iodide, Trimethyl sulfoxonlum chloride and the
like.
The suitable solvent In step (ill) is selected from. but not limited to alcohols such
as methanol. ethanol. propanol, isopropanol, butanol and the like; esters such as ethyl
acetate and the like; ketone such as, acetone and the like; others such as.
tetrahydrofuran, diethyl ether, methyl tertiary butyl ether or mixtures thereof.
Second aspect of the present Invention Is to provide an Improved process for
preparation of Pralidoxime chloride of formula (I) thereof, comprising steps of:
I) treating 2-pyridine carboxaldehyde with Hydroxyl amine or its salt in the
presence of water followed by base to obtain oxime of formula (III).
ii) adding ethylating agent to step I) in solvent to obtain salt of formula (IV),
iii) treating the salt of compound (IV) with solvent HCI and isolating the compound of
formula (I),
iv) optionally purification of compound (I).
The base used in step (i) is selected from organic and inorganic base but not
limited to, triethylamine, pyridine, piperidine. diethylisopropylamine and the like; alkali
metal hydroxides, such as, for example, lithium hydroxide, sodium hydroxide.
potassium hydroxide, and caesium hydroxide or the like; alkaline earth metal
hydroxides. such as. for example, barium hydroxide, strontium hydroxide, magnesium
hydroxide, calcium hydroxide. or the like; alkali metal carbonates, such as, for
example, sodium carbonate, potassium carbonate, lithium carbonate, caesium
carbonate, or the like; alkaline earth metal carbonates, such as, for example,
magnesium carbonate, calcium carbonate. or the like; alkali metal bicarbonates, such
as, for example. sodium bicarbonate, potassium bicarbonate, or the like; alkali
acetates like sodium acetate, or the like and the mixtures thereof.
The suitable solvent In step ,(ii) is selected from, but not limited to, alcohols such
as methanol. ethanol, propanol, isopropanol. butanol, and the like; esters such as ethyl
acetate and the like; ketone such as, acetone and the like; ethers such as.
tetrahydrofuran, diethyl ether, methyl tertiary butyl ether; nitriles such as acetonitrile
and the like; water or mixtures thereof.
The ethylating agent in step (ii) is selected from methyl-p-toluene sulfonate,
methyl iodide, Trimethyl sulfoxonlum iodide. Trimethyl sulfoxonlum chloride and the
like.
The suitable solvent in step (iii) is selected from, but not limited to alcohols such
as methanol, ethanol, propanol, isopropanol. butanol and the like; esters such as ethyl
acetate and the like; ketone such as, acetone and the like: ethers such as,
tetrahydrofuran, diethyl ether. methyl tertiary butyl ether or mixtures thereof.
Third aspect of the present Invention is to provide an improved process for
preparation of Pralidoxime chloride of formula (I) thereof, comprising steps of:
I) treating 2-pyridine carboxaldehyde with Hydroxyl amine or its salt in the presence
of water followed by sodium acetate to obtain oxime of formula (III),
ii) adding ethylating agent to step I) in solvent to obtain salt of formula (IV).
ill) treating the salt of compound (IV) with solvent HCI and Isolating the compound of
iv) optionally purification of compound (I)
. A process for preparation of Pralidoxime chloride comprising the steps of:
I) treating Z-pyridine carboxaldehyde with Hydroxyl amine or its salt in the presence
of solvent followed by base to obtain oxime of formula (III),
ii) adding ethylating agent to step I) in solvent to obtain salt of formula (IV).
iii) treating the salt of compound (IV) with solvent HCI and isolating the compound of
formula (I).
iv) optionally purification of compound (I).
2. A process for preparation of Pralidoxime chloride comprising the steps of:
I) treating 2-pyridine carboxaldehyde with Hydroxyl amine or its salt in the presence
of water followed by base to obtain oxime of formula (III).
ii) adding ethylating agent to step I) in solvent to obtain salt of formula (IV).
iii) treating the salt of compound (IV) with solvent HCI and isolating the compound of
formula (I).
iv) optionally purification of compound (I).
3. A process for preparation of Pralidoxime chloride comprising the steps of:
i) treating 2-pyrldine carboxaldehyde with Hydroxyl amine or its salt In the presence
of water followed by sodium acetate to obtain oxime of formula (III).
ii) adding ethylating agent to step I) in solvent to obtain salt of formula (IV).
iii) treating the salt of compound (IV) with solvent HCI and isolating the compound of
formula (I).
iv) optionally purification of compound (I).
4. The suitable solvent according to step I) of claim 1 is selected from ,such as. but
not limited to alcohols such as methanol. ethanol, propanol, isopropanol, butanol. and
the like; esters such as ethyl acetate and the like; ketone such as, acetone and the
like; ethers such as. tetrahydrofuran. diethyl ether, methyl tertiary‘ butyl ether; nitriles
such as acetonitrile and the like; water or mixtures thereof.
5. The base used in step (ill) of claims 1' and-2*isrselectedfrom, organic and inorganic _7
base but not limited to, triethylamine, pyridine, piperidine, diethylisopropylamine and
the like; alkali metal hydroxides, such as, lithium hydroxide. sodium hydroxide, and the
like; alkaline earth metal hydroxides, such as. barium hydroxide and the like; alkali
. metal carbonates, such as sodium carbonate, potassium carbonate and the like;
alkaline earth metal carbonates, such as, magnesium carbonate and the like; alkali
metal bicarbonates, such as, sodium bicarbonate, and the like; alkali acetates like
sodium acetate. and the like and the mixtures thereof.
6. The methylation agent used in step (ii) of claims 1-3 is selected from, but not limited
to methyl-p-toluene sulfonate. methyl iodide, Trimethyl sulfoxonlum iodide, Trimethyl
sulfoxohium chloride and the like.
7. The suitable solvent according to step ii) of claims 1-3 is selected from , but not
limited to alcohols such as methanol. ethanol, propanol, isopropanol, butanol. and the
like; esters such as ethyl acetate and the like; ketone such as. acetone and the like:
ethers such as, tetrahydrofuran. diethyl ether. methyl tertiary butyl ether; nitriles such
as acetonitrile and the like; water or mixtures thereof.
8. The suitable solvent according to step iii) of claims 1-3 is selected from, but not
limited to, alcohols such as methanol, ethanol. propanol ,.isopropanol, butanol. and the
like; esters such as ethyl acetate and the like; ketone such as. acetone and the like;
ethers such as, tetrahydrofuran, diethyl ether, methyl tertiary butyl ether; nitriles such
as acetonitrile and the like; water or mixtures thereof.