Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
2001-03-30
2002-05-21
Higel, Floyd D. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
Reexamination Certificate
active
06392095
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention concerns intermediate compounds useful in the preparation of N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (CMHEIDA), also referred to as carboxymethoxyhydroxyethylimino diacetic acid.
Chelants or chelating agents are compounds which form coordinate-covalent bonds with a metal ion to form chelates. Chelates are coordination compounds in which a central metal atom is bonded to two or more other atoms in at least one other molecule or ion, called a ligand, such that at least one heterocyclic ring is formed with the metal atom as part of each ring.
Chelating agents for metal ions, such as calcium, magnesium, iron, and magnesium, are required for a wide range of technical fields. Examples of fields of application and end-uses of chelants are detergents, in electroplating, in water treatment, photography, textile industry, paper industry and also various uses in pharmaceuticals, cosmetics, foodstuffs and plant nutrition. Some of these activities may result in the chelating agents entering the environment. For example, agricultural uses or use in detergents may result in measurable quantities of the chelants in water.
As chelants many enter the environment from various uses, it is desirable to have chelants that would readily degrade after use. It would be particularly advantageous to have a chelant which is biodegradable, that is, susceptible to degradation by microbes which are generally naturally present in environments into which the chelants may be introduced.
Iminodiacetic acid derivatives are known to possess metal sequestering properties. U.S. Pat. No. 5,051,212 discloses that iminodiacetic acid derivatives, when combined with organic solvents, provide very good results in terms of soil removal from hard surfaces. The use of iminodiacetic acid derivatives in aqueous compositions for cleaning hard surfaces is reported in PCT Application No. WO 94/12606. The iminodiacetic acid derivatives in WO 94/12606 are also reported to have good biodegradable characteristics.
SUMMARY OF THE INVENTION
The present invention concerns compounds represented by the formula
wherein R and R
1
independently represent H, —CH
2
CN or —CH
2
CO
2
X, with the proviso that R and R
1
can not be both H or —CH
2
CO
2
X; and X represents hydrogen, an alkali metal or alkaline earth metal.
In another aspect, the present invention concerns a process for the preparation of N-[2-(carboxymethoxy)ethyl]aminoacetonitrile (III) which process comprises alkylating 3-morpholinone with formaldehyde and hydrogen cyanide or glycolonitrile under alkaline conditions.
Still in another aspect, the present invention concerns a process for the preparation of N-[2-(carboxymethoxy)ethyl]glycine (V) which process comprises hydrolyzing an aqueous solution of a compound of the formula:
wherein X is hydrogen or an alkali or alkaline-earth metal with an acid or base.
Still in another aspect, the present invention concerns a process for the preparation of N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (Formula IX) which process comprises hydrolyzing an aqueous solution of a compound of the formula:
wherein X is hydrogen or an alkali or alkaline-earth metal with an acid or base.
In another aspect, the present invention concerns a process for the preparation of N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX) which process comprises reacting (2-aminoethoxy)acetic acid with glycolonitrile or hydrogen cyanide and formaldehyde under alkaline conditions.
Still in another aspect, the present invention concerns a process for the preparation of N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX) which process comprises reacting (2-aminoethoxy)acetic acid with hydrogen cyanide and formaldehyde under acidic conditions followed by hydrolysis.
Yet in another aspect, the invention concerns a multi step process for the preparation of N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX) which process comprises the steps of
(1) reacting 3-morpholinone with a base to form (2-aminoethoxy)acetic acid (Ib);
(2) alkylating (2-aminoethoxy)acetic acid salt formed in step (1) with formaldehyde to form [2-(hydroxymethylamino)ethoxy]acetic acid (II);
(3) reacting [2-(hydroxymethylamino)ethoxy]acetic acid salt formed in step (2) with hydrogen cyanide to form [2-(cyanomethylamino)ethoxy]acetic acid (III);
(4) hydrolysing [2-(cyanomethylamino)ethoxy]acetic acid formed in step (3) with a base to form N-[2-(carboxymethoxy)ethyl]glycine salt (V);
(5) reacting N-[2-(carboxymethoxy)ethyl]glycine formed in step (4) with formaldehyde and hydrogen cyanide to form N-[2-(carboxymethoxy)ethyl]-N-(cyanomethyl)glycine (VII); and
(6) hydrolysing N-[2-(carboxymethoxy)ethyl]-N-(cyanomethyl)glycine formed in step (5) with a base to form N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX).
This process is illustrated in Scheme I below.
Yet in another aspect, the present invention relates to aqueous hard surface cleaning compositions comprising N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX).
Still in another aspect, the present invention concerns a method of cleaning a hard surface by contacting said hard surface with an aqueous hard surface cleaning composition comprising N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX).
DETAILED DESCRIPTION OF THE INVENTION
The compounds of the present invention represented by the formula
wherein R and R
1
independently represent H, —CH
2
CN or —CH
2
CO
2
X, with the proviso that R and R
1
can not be both H or —CH
2
CO
2
X; and X represents hydrogen, an alkali metal or alkaline earth metal are useful as intermediates in the synthesis of N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX).
One preferred embodiment of the compounds of the present invention is represented by the formula
wherein X represents hydrogen, an alkali metal or alkaline earth metal.
Still another preferred embodiment of the compounds of the present invention is represented by the formula
wherein X represents hydrogen, an alkali metal or alkaline earth metal.
Yet another preferred embodiment of the compounds of the present invention is represented by the formula
wherein X represents hydrogen, an alkali metal or alkaline earth metal.
Starting materials for making the intermediate compounds of the present invention of formula IX include 3-morpholinone and hydrogen cyanide and formaldehyde, or glycolonitrile. A suitable reaction scheme for the synthesis of the intermediate compounds of the present invention is shown in Scheme I below.
M in Scheme I independently in each occurrence represents an alkali or alkaline-earth metal.
In the multi step process of the present invention 3-morpholinone (Ia) is first contacted with a suitable base such as sodium hydroxide, followed by alkylation with formaldehyde and hydrogen cyanide to form [2-(cyanomethylamino)ethoxy]acetic acid (III). The molar ratio of 3-morpholinone (Ia) to formaldehyde and hydrogen cyanide is generally about 1:1.
The hydrolysis of [2-(cyanomethylamino)ethoxy]acetic acid (III) with a base gives N-[2-(carboxymethoxy)ethyl]glycine (V).
N-[2-(carboxymethoxy)ethyl]glycine (V) is then reacted with additional formaldehyde and hydrogen cyanide to form N-[2-(carboxymethoxy)ethyl]-N-(cyanomethyl)glycine (VII). The molar ratio of N-[2-(carboxymethoxy)ethyl]glycine (V) to formaldehyde and hydrogen cyanide is generally about 1:1.
In the above reactions, glycolonitrile can be substituted for formaldehyde and hydrogen cyanide.
N-[2-(carboxymethoxy)ethyl]-N-(cyanomethyl)glycine (VII) is then hydrolyzed using a base such as sodium hydroxide to give the alkali metal salt of N-[2-(carboxymethoxy)ethyl]-N-(carboxymethyl)glycine (IX). Hydrolysis of the cyanomethyl group proceeds through the amide intermediate as depicted by structure (VIII) in Scheme
Athey Phillip S.
Wilson David A.
Higel Floyd D.
Sackey Ebenezer
The Dow Chemical Company
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