BACKGROUND OF THE INVENTION

The synthesis of α-aminonitriles by the reaction of a carbonyl compound, such as an aldehyde, an amine, and a source of cyanide is a well known reaction (the so-called

Strecker synthesis) . One early example relating to this type of reaction is U.S. Patent No. 2,164,781 to C. Platz et al. in which an aldehyde- or ketone-like "body" such as "glucose" was mentioned as one representative aldehyde which could be used.

More recently, H. Kunz and co-workers have proposed the reaction of an O-pivaloyl-galactosylamine with aldehydes and a cyanide source to form the N-galactosyl α-amino nitriles (see Liebigs Ann. Chem. 1991, 649-654 and International Patent Application No. WO88/00592) . The galactosylamine reagent by Kunz can be envisioned as a derivative of an "amino sugar" (which for purposes of this invention is defined as an amine-functionalized sugar molecule) where the anomeric oxygen has been replaced with a nitrogen atom and the hydroxyl groups have been protected.

SUMMARY OF THE INVENTION

This invention relates to the formation of an α-amino- nitrile compound by reaction of an amino sugar, a carbonyl compound, and a cyanide source.

DESCRIPTION OF PREFERRED EMBODIMENTS

As indicated before, the desired α-amino compounds are formed by the reaction of an amino sugar, a carbonyl compound, and a cyanide source.

The term "amino sugar" as used herein is intended to relate to sugar, or carbohydrate, molecules which contain one or more amino groups in place of the hydroxy moiety or moieties ordinarily contained as substituents thereon. It is within the contemplation of the present invention to cover both acyclic as well as cyclic sugar species. Monosaccharides, disaccharide, and polysaccharide-derived amino sugars can be utilized. Acyclic monosaccharides such as glucamine and fructamine are representative of amino sugars which can be used herein. An example of a cyclic amino sugar which can be employed herein is glucosamine. The amino sugar reagent used in the present process does not require protection of the hydroxyl groups contained therein, for example. The carbonyl compound which is used herein as a second reagent is preferably a bisulfite addition product of an aldehyde having the structure RC(0)H, where R can be alkyl, aryl, alkylaryl, or arylalkyl. Preferably R is either straight chain or branched chain alkyl of from one to fourteen carbon atoms. Some representative aldehydes which can be used include isobutyraldehyde, 2-ethylhexanal, and decanal. Ketones of the formula R-C(0)-R, with R being the same or different and defined as above can also be used. The cyanide source is preferably an alkali metal cyanide, such as sodium cyanide.

The reaction of amino sugar, carbonyl compound, and cyanide source can be carried out in organic solvent, a mixed organic/aqueous solvent, or an all aqueous solvent medium. The organic solvent, if used, can be a water-miscible polar protic solvent (e.g., an alcohol), or a water-miscible polar aprotic solvent (e.g., tetrahydrofuran or dimethyl sulfoxide) . Polar and non-polar solvents that are water immiscible (e.g. , methylene chloride or toluene) can also be used. The reaction temperature can vary widely (e.g., from

about 0°C to the reflux temperature of the reaction medium, preferably 20°C to 60°C) . Stoichiometric amounts of amino sugar, carbonyl compound, and cyanide source are preferred.

The α-aminonitrile products derived from the process are intended as surfactants, chelants, or dispersants with the moiety derived from the amino sugar improving such properties as water solubility, biodegradability and chelation.

The Examples which follow further illustrate the invention.

EXAMPLES 1-4

The aldehydes listed in Table 1, below, and sodium bisulfite were reacted in an aqueous media to form the bisulfite adduct. After bisulfite adduct formation, glucamine, the amino sugar, was added followed by sodium cyanide. The reaction mixture was stirred at room temperature until aminonitrile formation was completed:

TABLE 1

Aldehvde Yield Product Distribution* isobutyraldehyde 89% >99% isomeric amino- nitriles

2-ethylhexanal 91% 94% isomeric amino- nitriles, 5% acid* 1% acetal structures decanal ⁰ 75% imine,

25% acid* and ester ^b decanal ^d >80% 88% isomeric amino- nitriles, 7% acid, 5% acetal structures

* Determined by quantitative ¹³ C NMR. a Acid from oxidation of aldehyde. b Ester from oxidation of aldehyde followed by reaction with isopropanol. c Used isopropanol (IPA) as cosolvent for aldehyde, no heating. (Presented for comparative purposes) . d Used IPA as cosolvent and heated aldehyde and bisulfite at 60°C for one hour and then cooled to room temperature prior to the addition of the amino sugar and cyanide.

EXAMPLES 5-6

The following results were obtained using the procedure of Examples 1-4 with glucosamine and N-methyl glucamine as indicated:

TABLE 2

Amino Product Sugar Aldehyde Yield (%) Distribution*

Glucosamine Isobutyraldehyde 80 >95% isomeric aminonitriles

N-methyl glucamine Decanal 88 90.4% isomeric aminonitriles

5.8% cyano- hydrin

2.9% acid

0.9% aldehyde

by ¹³ C and *H NMR.

The foregoing Examples are presented to illustrate certain embodiments of the claimed invention and should not be construed in a limiting sense for that reason. The scope of protection sought is set forth in the claims which follow.