Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
1998-02-06
2001-06-12
Killos, Paul J. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C510S522000
Reexamination Certificate
active
06245941
ABSTRACT:
The present invention relates to an alkylation process. In particular, the present invention relates to a process for alkylating amino acids.
More in particular, the present invention relates to a process for the N-alkylation of amino acids, and especially a process for preparing (S,S)-ethylenediaminedisuccinic acid or a salt thereof.
Certain compounds having amino acid moieties linked by a group joining their nitrogen atoms have a variety of uses mainly based on their metal chelating properties. Typical examples include their use as corrosion inhibitors, and in detergents, photographic developing solutions, rubber and resin formulations and metal treatments. One particular example is ethylenediaminedisuccinic acid (“EDDS”) which has two chiral centres. The S,S-enantiomer of EDDS is preferred because of its biodegradability and its better chelating properties. EDDS is shown in FIG.
1
.
Racemic EDDS is usually prepared by the reaction of maleic anhydride with ethylenediamine in NaOH solution, according to the procedure by W. M. Ramsey and C. Kerzerian of the Stauffer Chemical Company, U.S. Pat. No. 3,158,635. (S,S)-EDDS can be manufactured by a variety of different routes. A typical route is the reaction of NaOH with L-aspartic acid and dibromoethane following the protocol of Neal, J. A. and Rose, N. J. (Inorganic Chemistry, Vol. 7, No. 11, November 1968, pages 2405-2412, particularly page 2406). However, even though this synthetic route is the one that is typically used it is usually difficult to obtain economic yields of (S,S)-EDDS. Furthermore it is difficult to obtain highly pure (S,S)-EDDS.
The present invention seeks to overcome the problems associated with the known processes. In particular, the present invention seeks to provide a process that enables compounds like EDDS, more especially (S,S)-EDDS, to be prepared in high yields, economic yields and/or high purity.
According to the present invention there is provided an alkylation process comprising reacting at least a first nitrogen compound and a second nitrogen compound with a carbonyl compound in the presence of a reducing agent to form a product comprising at least two nitrogen groups; wherein the carbonyl compound comprises at least two carbonyl groups, the first nitrogen compound comprises a first nitrogen group reactive with one carbonyl group of the carbonyl compound and the second nitrogen compound comprises a second nitrogen group reactive with the other (or another) carbonyl group of the carbonyl compound, and wherein at least the first nitrogen compound or at least the second nitrogen compound comprises at least one other functional group.
There are a number of advantages associated with the present invention. For example, it enables compounds like EDDS, more especially (S,S)-EDDS, to be prepared in high yields. It also enables compounds like EDDS, more especially (S,S)-EDDS, to be prepared in economic yields. It also enables compounds like EDDS, more especially (S,S)-EDDS, to be prepared at a high purity. The present invention also provides a reliable process for preparing optically active compounds, such as (S,S)-EDDS, by use of a substantially aqueous reaction medium/media. Furthermore, the present invention provides a process that allows reduction in situ without requiring the need to isolate any intermediates in the reaction process. In some cases the intermediate or intermediates could be isolated, but preferably the intermediate or intermediates is/are not isolated.
In the process of the present invention the first nitrogen compound and/or the second nitrogen compound can comprise more than one additional nitrogen group, which need not be reactive with the carbonyl groups of the carbonyl compound. Also, in the process of the present invention an additional nitrogen compound or additional nitrogen compounds may be reacted. Also, an additional carbonyl compound or additional carbonyl compounds may be reacted, which carbonyl compound or carbonyl compounds can independently comprise one or more carbonyl groups. Also, a mixture of reducing agents may be used in the process of the present invention. In addition, at least the first nitrogen compound and/or at least the second nitrogen compound can comprise an additional functional group or additional functional groups. Other reactive compounds may be present in the reaction medium.
Preferably the first nitrogen group and the second nitrogen group are independently selected from a primary amine group or a secondary amine group.
Preferably each of the first nitrogen group and the second nitrogen group is a primary amine group, which may be the same or different.
Preferably the functional group is an acid group.
Preferably the acid group is a carboxylic acid group.
Preferably at least the first nitrogen compound or at least the second nitrogen compound comprises at least one chiral centre. More preferably at least the first nitrogen compound and at least the second nitrogen compound comprises at least one chiral centre.
Preferably the first nitrogen compound or the second nitrogen compound comprises 1-20 carbon atoms, more preferably 1-12 carbon atoms.
Preferably the first nitrogen compound or the second nitrogen compound is an amino acid.
Typical amino acids for use in the process of the present invention include any one or more of the 26 or so naturally occurring amino acids listed in standard textbooks, including the derivatives thereof. The amino acid may be any one or more of a “neutral” amino acid, a “basic” amino acid or an “acidic” amino acid. However, preferably the amino acid for use in the process of the present invention is not cysteine. This is because this amino acid has an -SH group which could undergo unwanted side reactions.
In the process of the present invention an amino acid having an &agr;-amino group (e.g. aspartic acid) can be reacted. Alternatively, or in addition, in the process of the present invention an amino acid having a &bgr;-amino group (e.g. &bgr;-alanine) can be reacted.
Examples of neutral amino acids that may be used in the present invention include glycine, alanine, valine, leucine, norleucine, phenylalanine, tyrosine, serine, cystine, threonine, methionine, di-iodotyrosine, thyroxine, dibromotyrosine, tryptophan, proline and hydroxyproline.
Examples of basic amino acids that may be used in the present invention include ornithine, arginine, lysine and histidine.
Examples of acidic amino acids that may be used in the process of the present invention include aspartic acid, glutamic acid and &bgr;-hydroxyglutainic acid.
The preferred amino acids for the process of the present invention are those with two carboxyl groups and one amino group—i.e. the acidic amino acids listed above. Aspartic acid and glutamic acid are the most preferred of the three.
Specific optical isomers, particularly the L-form, are desirable because they increase biodegradability and in some cases, may also improve the chelating effect.
Preferably, therefore, the first nitrogen compound or the second nitrogen compound is an acidic amino acid.
Preferably the first nitrogen compound or the second nitrogen compound is aspartic acid.
Preferably the first nitrogen compound or the second nitrogen compound is an L-amino acid.
Preferably the first nitrogen compound or the second nitrogen compound is L-aspartic acid.
Alternatively, other amino acids may be reacted in the process of the present invention, such as D- or DL- amino acids, for example D-aspartic acid or DL-aspartic acid, to generate corresponding R,R- or racemic products having at least two nitrogen groups, such as R,R- or racemic EDDS.
Preferably the first nitrogen compound is the same as the second nitrogen compound.
Preferably at least one of the carbonyl groups of the carbonyl compound is an aldehyde group or a ketone group.
Preferably at least one of the carbonyl groups of the carbonyl compound is an aldehyde group or a ketone group, and wherein at least one other of the carbonyl groups of the carbonyl compound is an aldehyde group or a ketone group.
Preferably at least one carbonyl group is an a
Bassett Derek A.
Cowton Elizabeth L. M.
Killos Paul J.
Oh Taylor V.
Sheridan & Ross P.C.
The Associated Octel Company Limited
LandOfFree
Reductive alkylation process for the preparation of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reductive alkylation process for the preparation of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reductive alkylation process for the preparation of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2485531