FIELD OF THE INVENTION:
The present invention relates to robust, safe and industrially applicable process for preparing Aminoacetaldehyde dimethyl acetal.
BACKGROUND OF THE INVENTION:
Aminoacetadehyde dialkyl acetals are used as intermediates, agricultural chemicals, modifiers for high molecular weight compounds.
Aminoacetaldehyde dialkyl acetals are represented as below.
Ri & R2 are each hydrogen or alkyl. R3 is alkyl.
Some examples of such "aminoacetal' product compounds are aminoacetaldehyde dimethyl acetal, aminoacetaldehyde diethyl acetal, aminoacetaldehyde dipropyl acetal, methylaminoacetaldehyde dimethyl acetal, methylaminoacetaldehyde diethyl acetal, methylaminoacetaldehyde dipropryl acetal, ethylaminoacetaldehyde dimethyl acetal, ethylaminoacetaldehyde diethyl acetal, ethylaminoacetaldehyde dipropryl acetal, N,N-dime thylaminoacetaldehyde dimethyl acetal, N,N-dimethylaminoacetaldehyde diethyl acetal, N,N-diethylaminoacetaldehyde dimethyl acetal, N,N-diethylacetaldehyde diethyl acetal, etc.
In present invention, process for preparing aminoacetaldehyde dimethyl acetal of formula-! is disclosed. Aminoacetaldehyde dimethyl acetal is also known as 2,2-dimethoxyethanamine.
Prior art Org. Synth. 111,50 (1955), J.Amer.Chem.Soc. 71,4002 (1949), discloses the process for preparing aminoacetaldehyde dialkyl acetals by reacting a halogenoacetaldehyde dialkyl acetal with an amine in a non-aqueous system.

However, the said prior art process requires expensive hazardous alkali substance for neutralizing excess amine present in the reaction mixture during work up. Hence the said process is expensive and non-applicable to large scale.
RU 2654853 describes the method of producing aminoacetaldehyde dialkylacetals by reduction of the corresponding dimethyl-,diethyl-,dipropyl-, dibutyl- acetals of azidoacetaldehyde with triphenylphosphene in presence of methanol.
US 4137268 discloses the process for preparing amino acetaldehyde dialkylacetals by reduction of dialkoxyacetonitrile with hydrogen in presence of Nickle catalyst and liq. Ammonia.
US 4792630 discloses the process for preparing aminoacetaldehyde dialkyl acetals by reacting a halogenoacetaldehyde dialkyl acetal with ammonia or an alkylamine in an aqueous medium in presence of an alkali metal hydroxide or of an alkaline earth metal hydroxide.
The disadvantages of prior art methods are unfeasible due to use of explosive hydrogen, toxic ammonia. Moreover the said processes are uneconomical due to using special expensive apparatus, tedious workup methods.
Thus it is necessity to develop easy, economical process for preparing aminoacetaldehyde dimethyl acetal. The present invention process for producing aminoacetaldehyde dimethyl acetal is one pot process having excellent workability, energy saving without using highly toxic reagents, expensive apparatus.
SUMMARY OF THE INVENTION:
The present invention relates to advantagous, simple and economical process for the preparation of Aminoacetaldehyde dimethyl acetal of formula-1
One aspect of the present invention provides preparing Aminoacetaldehyde dimethyl acetal of formula-1 comprises;

(a) Reacting phthalimide with base in presence of solvent to get potassium salt of phthalimide
(b) Reacting potassium phthalimide with catalyst and haloacetaldehyde dialkyl acetal in presence of solvent
(c) Treating with base to get Aminoacetaldehyde dimethyl acetal
DETAIL DESCRIPTION OF THE INVENTION:
The present invention relates to improved, safe, economical and industrially applicable process for the preparation of Aminoacetaldehyde dimethyl acetal of formula-1
One aspect of the present invention provides preparing Aminoacetaldehyde dimethyl acetal of formula-1 comprises;
(a) Reacting phthalimide with base in presence of solvent to get potassium salt of phthalimide
(b) Reacting potassium phthalimide with catalyst-and haloacetaldehyde dialkyl acetal in presence of solvent
(c) Treating with base to get Aminoacetaldehyde dimethyl acetal
The process for preparation of Aminoacetaldehyde dimethyl acetal of Formula-1 given in the below reaction scheme-1

The base used in step (a) and step (c) is inorganic base. The inorganic base is selected from hydroxides like sodium hydroxide, potassium hydroxide, lithium hydroxide, carbonate salts of alkali and alkaline earth metals like potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, cesium carbonate and mixture thereof.
The solvent used for step (a) and (b) is Polar protic solvents and selected from the group
consisting of methanol, ethanol, isopropanol, acetamide and mixture thereof.
The catalyst used for step(b) is potassium iodide.
The haloacetaldehyde dialkyl acetal for step (b) is selected from the group consisting of
chloroacetaldehyde dimethyl acetal, chloroacetaldehyde diethyl acetal, chloroacetaldehyde
dipropryl acetal, bromoacetaldehyde dimethyl acetal, bromoacetaldehyde diethyl acetal, or
the like.
The main advantage of the present invention is recovery of phthalic acid as a byproduct which is further used. Moreover solvents are recovered from the reaction and reused in the reaction which makes the process cost-effective and plant feasible. The present invention process gives 67-78% yield.
The following examples explain various other embodiments without limiting the scope of the present invention.
Example-1: Preparation of Aminoacetaldehyde dimethyl acetal
Phthalimide was charged followed by potassium hydroxide and methanol. The reaction mass was maintained for 8h at 60°C. After completion of reaction, filtered to get potassium phthalamide. Charged acetamide and reaction mass was heated to 80-90°C. Potassium iodide and Chloroacetaldehydedimethylacetal was charged and refluxed for 24h at 130-170°C. After completion of reaction, reaction mass was cooled and DM Water was added. Reaction mass was maintained for next 2h and filtered to furnish intermediate-]. Intermediate-1 was further treated with aq. Sodium hydroxide base. Reaction mass was further refluxed for 8h at 95-100°C. Reaction mass was cooled and extracted with dichloromethane. After complete extraction, dichloromethane was evaporated and distilled to furnish aminoacetaldehydedimethylacetal.
GC Purity: 99.8%