Originator
Primperan,Delagrange,France,1964
Definition
ChEBI: A member of the class of benzamides resulting from the formal condensation of 4-amino-5-chloro-2-methoxybenzoic acid with the primary amino group of N,N-diethylethane-1,2-diamine.
Manufacturing Process
The N-(diethylaminoethyl)-2-methoxy-4-aminobenzamide used as the starting
material may be prepared from o-toluidine. The o-toluidine is initially nitrated
with nitric acid to produce 4-nitro-o-toluidine. The 4-nitro-o-toluidine is then
converted to 2-hydroxy-4-nitrotoluene by heating with nitrous acid. By
reacting the resulting 2-hydroxy-4-nitrotoluene with dimethyl sulfate, 2-
methoxy-4-nitrotoluene is formed. The 2-methoxy-4-nitrotoluene is oxidized
with potassium permanganate to produce 2-methoxy-4-nitrobenzoic acid. The
latter substituted benzoic acid is treated with thionyl chloride to form 2-
methoxy-4-nitrobenzoyl chloride. A methyl ethyl ketone solution of the 2-
methoxy-4-nitrobenzoyl chloride is added over a period of about 1? hours to
a methyl ethyl ketone solution containing an equal molecular quantity of N,Ndiethylethylene diamine while stirring and maintaining the temperature
between 0°C and 5°C. The N-(diethylaminoethyl)-2-methoxy-4-
nitrobenzamide hydrochloride formed precipitates. It is filtered, washed twice
with methyl ethyl ketone, dissolved in alcohol, and reduced catalytically in an
absolute isopropyl alcohol solution to form N-(diethylaminoethyl)-2-methoxy-
4-aminobenzamide. The base is obtained by precipitating with sodium
hydroxide.
80 g (0.3mol) of N-(2-diethylaminoethyl)-2-methoxy-4-aminobenzamide are
dissolved in small portions in 150 cc of acetic acid. The mixture is cooled and
45 g (0.45 mol) of acetic anhydride are added, and the solution obtained is
heated for two hours on a water bath. After cooling, the solution is decanted
into a round-bottomed flask with a stirrer, a thermometer and a tube for
introducing the chlorine. It is stirred and the current of chlorine is passed
through, the temperature being maintained between 20°C and 25°C. The
stirring is continued for one hour after the completion of the absorption of the
chlorine.
The mixture obtained is poured into 2 liters of water and the base is
precipitated with 30% soda. The precipitated base is extracted with 400 cc of
methylene chloride. After evaporation of the solvent, the N-(2-
diethylaminoethyl)-2-methoxy-4-acetamino-5-chlorobenzamide formed
crystallizes. The melting point is 86°C to 87°C and the yield is 95%.
To obtain the corresponding amino derivative, 109 g of base are heated under
agitation in a round-bottomed flask with 300 cc of 35-36% concentrated
hydrochloric acid and 600 cc of water. It is heated on a water bath until
dissolution is complete, then maintained at boiling point for 90 minutes,
cooled, diluted with 1 liter of water, and neutralized with about 350 cc of 30%
soda. The N-(2-diethylaminoethyl)-2-methoxy-4-amino-5-chlorobenzamide
formed crystallizes, is centrifuged and washed in water. Its melting point is
122°C and the yield is 74%.
To obtain the corresponding dihydrochloride, the base is dissolved in absolute
alcohol (3 volumes) and to that solution is added 5 N alcoholic hydrochloric
acid. The dihydrochloride precipitates, is centrifuged and washed with alcohol.
It is a solid white material, having a melting point of 134°C to 135°C.
