L-1-hydroxymethyl alkaneamide derivatives of .alpha.-L-aspartic acid have been prepared and have been discovered to be non-nutritive sweeteners having favorable chemical and physiological properties for use in compositions ingested orally.

TECHNICAL FIELD 
The most widely used natural sweetener for food and similar preparations is 
sucrose. Sucrose is safe, naturally occurring, and has a high sweetness 
quality, i.e., a pure, quick onset with no aftertaste or undertaste. One 
drawback to the use of sucrose as a sweetener is its caloric content. 
Persons who have diabetes must carefully control their intake of sugar to 
avoid problems associated with the disease. Persons who have excess weight 
must use non-nutritive sweeteners since the use of sucrose leads to weight 
gain rather than weight control or reduction. 
A second drawback to sucrose is that it is cariogenic and therefore cannot 
be used in dentifrices and is undesirable in chewing gums. A third 
drawback is that sucrose does not have a sufficiently high sweetness 
intensity for some compositions, e.g. dentifrices. If enough sucrose is 
used to make the composition sweet, the product becomes tacky and 
hygroscopic. Additionally, for the amount of sweetness delivered, sucrose 
is expensive. 
It can be appreciated that the search continues for compounds which have 
high sweetness intensity and quality, are non-nutritive, and are safe for 
oral consumption. 
Numerous compounds have been discovered which are non-nutritive sweeteners. 
However, most have drawbacks of one sort or another. Sodium cyclamate has 
been banned for oral use because it may be carcinogenic or mutagenic. 
Saccharin is also being questioned as a possible carcinogen; additionally, 
saccharin has a bitter aftertaste. Neohesperidine dihydrochalcone has 900 
times the sweetness of sucrose; however, the sweetness is slow to develop 
and there is a licorice-like aftertaste. Aspartame.RTM., a dipeptide, has 
a high quality sweetness of approximately 150 times sucrose, but 
hydrolyzes in aqueous solution to its non-sweet component amino acids. 
Other aspartic acid derivatives are sweet but hydrolyze in the 
gastrointestinal tract to release potent vasopressors. 
Non-nutritive sweeteners have been known for almost one hundred years 
(saccharin, 1879) and theories have been proposed to account for the 
perception of sweetness and the chemical structures that produce that 
perception. Yet, there seems to be no common molecular property which can 
be used to predict either the level or, especially, the quality of 
sweetness. Ingenious models have been proposed to explain the sweetness of 
known compounds, but not all compounds fitting the models are sweet and 
the theories cannot be used to predict or construct new sweeteners. The 
prediction of the quality of sweetness, as well as the intensity of 
sweetness, appears to remain a complete mystery. 
The compounds of the present invention, L-1-hydroxymethyl alkaneamide 
derivatives of .alpha.-L-aspartic acid, have not previously been prepared. 
It has now been discovered that, surprisingly, the compounds are sweet and 
are physiologically safe for oral use in sweetening amounts, even though 
similar alkaneamide derivatives have drug activity. The compounds of the 
present invention do not have a labile ester linkage and so are much more 
stable in aqueous solution than dipeptides such as 
L-aspartyl-L-phenylalanine methyl ester. Additionally, the preferred 
compound disclosed herein also has a sweetness quality equivalent to 
sucrose while having a sweetness intensity some 50 times greater than 
sucrose. 
BACKGROUND ART 
Investigations into derivatives of aspartic acid as non-nutritive 
sweeteners stem from the accidental discovery that 
L-aspartyl-L-phenylalanine methyl ester (Aspartame.RTM.) is sweet, 100-150 
times sucrose, and free of unpleasant aftertaste. R. H. Mazur, J. M. 
Schlatter, and A. H. Goldkamp, JACS, 91, 2684 (1969). The authors 
disclosed that the L-aspartic acid portion of the molecule is critical for 
sweetness, but that considerable modification of the phenylalanine portion 
could be tolerated. 
Subsequent work investigated the structural relationships of aspartic acid 
amides as regards sweetness. R. H. Mazur, A. H. Goldkamp, P. A. James, and 
J. M. Schlatter, J. Med. Chem. 13, 12-17 (1970). The authors' 
investigations revealed that the structural requirements for good 
sweetness in derivatives of L-aspartic acid are quite specific, as is 
revealed by tests of the L-aspartate amides: 
##STR1## 
4-methylpentylamide--tasteless 1-ethylbutylamide--bitter 
hexylamide--sweet, 1-2 X sucrose 
heptylamide--sweet, 1-2 X sucrose 
1-methylbutylamide--tasteless 
1-methylpentylamide--sweet, 30 X sucrose 
1-methylhexylamide--sweet, 20-50 X sucrose 
1-methylheptylamide--sweet, 10 X sucrose 
1,3-dimethylbutylamide--bitter 
1,3-dimethylpentylamide--sweet, 1-2 X sucrose 
1,4-dimethylpentylamide--sweet, 50-100 X sucrose 
All the sweet isomers were found to be L--L. The 1-methylhexylamide was 
about 20-50 times the sweetness of sucrose and the 1,4-dimethylpentylamide 
was about 50-100 times the sweetness of sucrose. 
British Pat. No. 1,381,826, Neely, January 29, 1975, claims the use of 
L-aspartyl-L-1,4-dimethylpentylamide in oral compositions as a sweetener. 
Y. Ariyoshi, N. Yasuda, K. Yamatani, Bull. Chem. Soc. Japan, 47, 326 (1974) 
describe investigations into the sweetness of hydroxy-substituted 
derivatives of L-aspartyl dipeptides. They report that 
.alpha.-L-aspartyl-L-1-methyl-2-phenethylamine (aspartyl amphetamine) was 
50 times as sweet as sucrose; however, 
L-aspartyl-L-1-hydroxymethyl-2-methyl-2-phenethylamine was only 1 to 2 
times as sweet as sugar. The authors report that with an L,L 
configuration, hydroxyl substitution always decreased potency of 
sweetness, while with L,D configurations, hydroxy substitution sometimes 
increased potency and sometimes decreased it. Methyl substitution at the 2 
or 3 position produced bitter tasting compounds. 
1-(1-hydroxyethyl) derivatives of .alpha.-L-aspartic acid have no 
sweetness. L. B. P. Brusse, H. C. Peer, A. van der Heijden, Z. Lebensm. 
Unters. Forsch., 159, 339 (1975). 
M. Miyoshi, K. Nunami, H. Sugano, T. Fujii, Bull. Chem. Soc. Japan, 51, 
1433 (1978) disclose L-aspartyl dipeptides of the formula: 
##STR2## 
as being sweet. The authors state that none of the 
O-acyl-L-aspartylamino-L-alkanols synthesized were sweet and that the 
C-terminal amino acid must be the D form to exhibit sweetness. 
Belgian Pat. No. 851,368, Ferrer, May 5, 1977 discloses the compound 
.alpha.-L-aspartyl-1,5-dimethyl-5-hydroxyhexylamide (claimed as the 
L-aspartate of 6-amino-2-methyl-2-heptanol) for use in the treatment of 
cardiac and pulmonary insufficiency. 
In the gastrointestinal tract, L-aspartyl alkaneamides and 
L-aspartyl-1-hydroxymethyl alkaneamides are hydrolyzed to aspartic acid 
and the corresponding amine by aminopeptidase enzymes. E. F. Marsh, D. A. 
Herring, J. Pharm. Exp. Therapy, 102-178 (1951) describe a study of the 
comparative pharmacology of hydroxyl and methyl derivatives of 
1,5-dimethylhexylamine (named as 6-methyl-2-heptylamine by the authors). 
These compounds would be produced by the hydrolysis of the L-aspartyl 
dimethylhexylamide. The data show the amine compound to have vasopressor 
and myocardial stimulant activity. This activity is shown to be lessened 
somewhat by 5-hydroxyl or 2- or 3-methyl substitution. 
1,5-dimethylhexylamine has been sold commercially as a vasoconstrictor 
(Octodrine); 1,3-dimethyl pentylamine has been sold as a vasoconstrictor 
(Forthane); 1,5-dimethylaminohexan-5-ol hydrochloride has been sold as a 
cardiac stimulant and coronary vasodilator (Heptanol). 
DISCLOSURE OF THE INVENTION 
The present invention encompasses compounds of the formula: 
##STR3## 
wherein said compound is in the L, L form; and wherein R.sup.1 =H, 
##STR4## 
R.sup.2 =H or CH.sub.3 ; R.sup.3 =H or CH.sub.3 ; and R.sup.4 =CH.sub.3, 
C.sub.2 H.sub.5, i--C.sub.3 H.sub.7, or t--C.sub.4 H.sub.9, except that 
where R.sup.4 is i--C.sub.3 C.sub.7 or t--C.sub.4 H.sub.9, R.sup.2 and 
R.sup.3 are H; and toxicologically acceptable salts thereof. 
The present invention also encompasses compositions of matter comprising an 
ingestible carrier, i.e., food, beverage, drug, mouthwash, dentifrice, or 
other compositions designed for oral use, containing an effective 
sweetening amount of a compound having formula I, above. 
The present invention arises from the discovery that hydroxymethyl 
substitution at the 1-position in the L-alkaneamide moiety of L-aspartyl 
amides of formula I, above, not only reduces the pharmacological activity 
of the amine portion of the amide (and therefore of the amide itself) but 
also produces intensely sweet amides. 
The preferred sweetener compound herein is 
N-(.alpha.-L-aspartyl)-L-1-hydroxymethyl-4-methylpentylamide, of the 
formula: 
##STR5## 
The preferred sweetener compound II is approximately 50 times as sweet as 
sucrose and has a sweetness quality approximately equal to sucrose. 
Additionally, compound II is sweet in both aqueous solution and granular 
form. Compound II is particularly useful as a sugar substitute for 
diabetics or weight conscious persons. 
Non-nutritive sweeteners which are amide derivatives of L-aspartic acid are 
most commonly used in the form of salts. Salts are preferred as the salts 
dissolve rapidly and also provide a more rapid onset of sweetness than the 
amide compound per se. "Toxicologically acceptable salts" as used herein 
refers to salts of the instant compounds which are physiologically 
acceptable for ingestion. Typical toxicologically acceptable salts of the 
present sweeteners are sodium, potassium, calcium, and ammonium salts as 
well as hydrohalide, and especially hydrochloride, addition salts. 
The 1-hydroxymethyl substituent group present in compounds of formula I can 
be in the unsubstituted alcohol form or can be esterified with lower alkyl 
carboxylic acids, especially formic or acetic acid. Although the ester 
itself may not be sufficiently sweet for all purposes, once the 
esterified-1-hydroxymethyl amide is placed in an aqueous environment, 
ester hydrolysis will begin to occur to produce the preferred, sweet 
aspartyl-1-hydroxymethyl substituted amide. 
The L-aspartyl-L-1-hydroxymethyl alkaneamides of the invention are useful 
for sweetening a variety of food products such as fruits, vegetables, 
juices, meat products such as ham or bacon, sweetened milk products, egg 
products, salad dressings, ice creams and sherbets, gelatins, icings, 
syrups, cake mixes and frostings, as well as for sweetening beverages such 
as carbonated soft drinks and wines. The compounds of the invention can 
also be used to sweeten dentifrices, mouthwashes, and chewing gums, as 
well as drugs such as liquid cough remedies. 
The instant sweetening agents are stable substances and can be used in a 
variety of physical forms, e.g., as powders, tablets, syrups, pastes, 
solutions, etc. Liquid or solid carriers such as water, glycerol, starch, 
sorbitol, salt, citric acid and other suitable nontoxic substances can 
also be used as carriers. The sweetening agents can readily be used in 
pharmaceutical compositions to impart a sweet taste. 
The sweetening agents are used in effective sweetening amounts. By 
"effective sweetening amounts" as used herein is meant sufficient 
sweetening agent to provide a sweet taste of the desired intensity for the 
orally ingested composition. The amount added will generally depend upon 
commercial needs as well as individual sweetness sensitivity. 
Representative sweetener compounds of formula I include 
N-.alpha.-L-aspartyl L-amide derivatives wherein the L-amide moiety is: 
1-hydroxymethyl-4,4-dimethylpentylamide 
1-hydroxymethyl-5-methylhexylamide 
1-hydroxymethylhexylamide 
1-hydroxymethyl-4-methylhexylamide 
1-hydroxymethyl-4,4-dimethylhexylamide 
1-hydroxymethylpentylamide 
1-hydroxymethyl-5,5-dimethylhexylamide 
Some of the above compounds, although sweet, are not as preferred as the 
L-1-hydroxymethyl-4-methylpentylamide by reason of solubility or sweetness 
quality. For example, the aspartyl L-1-hydroxymethyl-5-methylhexylamide is 
somewhat slow to dissolve. The aspartyl 
L-1-hydroxymethyl-4,4-dimethylpentylamide, is sweet in both granular form 
and in aqueous solution, but has somewhat of a melon-like undertaste. 
The synthesis of the compounds of formula I is a multi-step process. In 
general, the compounds can be made through either of two generalized 
synthetic procedures, (A and B, below) both involving an enzymatic optical 
isomer resolution step and both of which, although time consuming, involve 
only standard organic synthesis techniques. 
Procedure A 
Step 1--Using standard techniques, the appropriate D,L-2 aminoalkanoic acid 
is prepared by the reaction of diethylacetamidomalonate with sodium 
ethoxide in anhydrous ethanol followed by the addition of the appropriate 
alkylhalide. The compound thus formed is deacetylated, and the sodium salt 
form, by refluxing with an alkali metal hydroxide, and decarboxylated by 
acidification. Purification yields the D,L-2-amino-alkanoic acid racemic 
mixture. 
Step 2--The D,L amino alkanoic acid racemate from Step 1 is enzymatically 
resolved. After N-acetylation of the D,L- amino alkanoic acid in glacial 
acetic acid with acetic anhydride, the N-acetyl-D,L-acid is contacted with 
Acylase I. Acylase I is a commercially available compound, N-acylamino 
acid aminohydrolase, obtained from hog kidneys. After reaction with the 
aminohydrolase, acidification with acetic acid yields the desired 
L-2-amino alkanoic acid L-2-amino-5-methylhexanoic acid, for example, upon 
evaporation of the filtrate. 
Step 3--L-2-aminoalkanol is prepared by lithium aluminum hydride reduction 
of the methyl ester hydrochloride of the L-aminoalkanoic acid from Step 3. 
Step 4--The sweetening agent of formula I is produced from the reaction in 
an anhydrous aprotic solvent of commercially available 
N-trifluoroacetyl-L-aspartic acid with the L-1-hydroxymethyl alkaneamine. 
An alternate procedure is as follows: 
Procedure B 
Step 1--The appropriate .alpha.-bromoalkanoic acid, prepared by reaction 
with bromine and PCl.sub.3, is added to a solution of ammonium carbonate 
and ammonium hydroxide. After precipitation, filtration, and 
recrystallization, the D,L-2-amino alkanoic acid is obtained. 
Step 2--The racemic alkanoic acid mixture is resolved, as in Step 2 of 
Procedure A. 
Step 3--The L-1-hydroxymethyl alkaneamine is produced by reaction of the 
L-aminoalkanoic acid with a diborane/tetrahydrofuran solvent system, 
followed by acid hydrolysis. 
Step 4--The sweetening agent of formula I is recovered after reaction of 
N-carbobenzoxy-L-aspartic acid .beta.-benzyl ester with the 
L-1-hydroxyalkaneamine in methylene chloride in the presence of 
dicyclohexylcarbodiimide, followed by dissolution of the 
N-carbobenzoxy-.alpha.-L-aspartyl L-1-hydroxy methyl alkaneamide so 
produced in acetic acid to which Pd on charcoal is added. After 
hydrogenation, the sweetener of formula I is recovered after purification 
by high pressure liquid chromatagraphy (HPLC) and recrystallization. 
The various solvents, derivatives of aspartic acid ane techniques used in 
Procedures A and B are well known and are in the synthetic chemist's 
repertoire. 
BEST MODE 
The following illustrates the complete synthesis of the preferred sweetener 
compound of this invention (formula II). The procedure is readily modified 
to provide the various salts, esters, and the like, disclosed hereinabove. 
Synthesis of N-(.alpha.-L-Aspartyl)-L-1-hydroxymethyl-4-methylpentylamide 
according to General Procedure A. 
Step 1: Synthesis of D,L-2-amino-5-methyl hexanoic acid. 
3.80 g of sodium was added to 300 ml anhydrous ethanol and allowed to react 
completely. To this was added 39.6 g diethylacetamidomalonate (under an 
N.sub.2 stream); the resulting solution was stirred for 45 minutes. 
3-methyl-1-bromobutane was then added dropwise, with heating, over the 
next 20 minutes. The mixture was refluxed for 20 hours. The solution was 
then filtered to remove salts; the resulting filtrates were evaporated to 
yield 48.97 g yellow solid. This material was taken up in 100 ml ether and 
applied to a 450 g silica gel column. Elution with 2700 ml ether afforded 
28.0 g of solid after evaporation. This material was refluxed for 20 hours 
with 150 ml of 20% NaOH (to remove the N-acetyl group). The resulting 
solution was chilled in an ice-water bath and acidified through slow 
addition of 150 ml conc. HCl. This solution was then refluxed for 2 hours, 
cooled to room temperature, and adjusted to pH 6 with 25% NaOH. After 
standing at room temperature for 2 hours, the solids which precipitated 
were filtered, and dried in vacuo to yield 10.4 g product (80% yield), 
D,L-2-amino-5-methylhexanoic acid. 
Step 2: Synthesis of L-2-amino-5-methylhexanoic acid (resolution of racemic 
amino acid). 
20.0 g of DL-2-amino-5-methylhexanoic acid and 150 ml glacial acetic acid 
were combined in a 250 ml flask and the suspension stirred at 57.degree. 
C. To this mixture was added dropwise 30.9 g acetic anhydride over a 
period of 20 minutes at 47.degree. C. The resulting solution was then 
stirred at room temperature for 2 hours, after which solvents were removed 
in vacuo to yield a white semi-solid. This material was suspended in 20 ml 
H.sub.2 O and re-dried three times to yield a white solid, which was 
recrystallized from ether/acetone to yield 20.7 g of the product, 
N-acetyl-DL-2-amino-5-methylhexanoic acid. 
18 g of N-acetyl-D,L-2-amino-5-methylhexanoic acid material was taken up in 
700 ml H.sub.2 O, and concentrated. NH.sub.4 OH was added to reach pH 7.2. 
The solution was heated to 36.degree. C. and 11.0 mg Acylase I was added. 
After stirring for 18 hours, an additional 5 mg Acylase I was added and 
the solution stirred an additional 24 hours. The solution was then 
acidified with 18.0 ml acetic acid and filtered. Evaporation of the 
filtrate yielded the product, a white solid, L-2-amino-5-methylhexanoic 
acid, (5.8 g, 83% yield). 
Step 3: Synthesis of L-2-amino-5-methylhexanol 
L-2-amino-5-methylheptanoic acid (5.8 g) was suspended in 250 ml anhydrous 
methanol and anhydrous HCl gas bubbled into the stirred mixture in an 
ice-water bath to achieve saturation. The reaction was stirred at 
10.degree. C. for 1 hour and at room temperature for 18 hours further. 
Evaporation of the solvent yielded 8.02 g of L-2-amino-5-methylhexanoic 
acid methyl ester.HCl (white solid). 
Under N.sub.2 atmosphere, 2.3 g lithium aluminum hydride and 300 ml 
anhydrous tetrahydrofuran were placed in a 500 ml flask and the amino 
methylhexanoic acid methyl ester.HCl salt (8.0 g) was added in small 
portions over 1/2 hour. The mixture was stirred at room temperature for 1 
hour. 25 ml ethyl acetate was added and the mixture stirred an additional 
1/2 hour. 160 ml H.sub.2 O was added dropwise, and the solution extracted 
with 1 liter ether and 500 ml ether. The combined ether fractions were 
washed with 3.times.100 ml portions of saturated NaCl, and dried over 
MgSO.sub.4. After evaporation of the solvent, 4.9 g yellow oil, 
L-2-amino-5-methylhexanol, was obtained (91% yield). 
Step 4: Synthesis of 
N-(.alpha.-L-Aspartyl-L-1-hydroxymethyl-4-methylpentylamide 
Trifluoracetic anhydride (149 g) was placed in a 500 ml flask and chilled 
to -78.degree. C. L-aspartic acid (37.8 g) was then added in small 
portions over 5 minutes and the resulting slurry stirred for 10 minutes 
while chilled to -78.degree. C. After removal of the cooling bath, the 
mixture was stirred for an additional 2 hours. After the vigorous reaction 
subsided, the solution was refluxed for one hour, allowed to cool, and 
poured into 300 ml hexane, yielding a white solid. After washing 
successively with 200 ml hexane and 400 ml ether, the material was dried 
in vacuo, yielding 57.2 g N-trifluoroacetyl-L-aspartic acid anhydride (96% 
yield). 
1.0 g of this material was added to 20 ml anhydrous tetrahydrofuran in a 
sealed flask and 0.62 g of L-2-amino-5-methylhexan-1-ol added in small 
portions under N.sub.2 atmosphere. After 3 days, the solvent was removed, 
yielding N-(trifluoroacetyl)-L-aspartyl-DL-2-amino-5-methylhexanol (2.0 g 
including some solvent). This material was combined in a flask with 15 ml 
of 7.4 N NH.sub.4 OH and heated to 80.degree.-85.degree. C. for 7 minutes. 
The mixture was cooled, and the solvents removed in vacuo yielding the 
crude product. After recrystallization of this material from 
butanol/water, the yield was 254 mg of 
N-(.alpha.-L-aspartyl)-L-1-hydroxymethyl-4-methylpentylamide (Mp. 
216.degree.-218.degree. C.). 
The following is an alternative method for synthesizing 
N-(.alpha.-L-aspartyl)-L-1-hydroxymethyl-4-methylpentylamide according to 
general Procedure B. 
Step 1: Synthesis of DL-2-amino-5-methyl hexanoic acid 
To a 250 ml flask was added, successively, 76 g 5-methylhexanoic acid, 30 
ml Br.sub.2 and 2.0 ml PCl.sub.3. The solution was warmed to 
65.degree.-75.degree. C. for 4 hours, after which 2 ml additional Br.sub.2 
was added. The reaction was then warmed to 100.degree.-105.degree. C. for 
an additional 2 hours. The solution was then cooled to room temperature 
and stirred for 18 hours. Excess Br.sub.2 and HBr were removed by heating 
to 80.degree. C. under light vacuum (20 minutes). Distillation of the 
resulting solution yielded 93.2 g product (115.degree. C., 0.4 mm). (76% 
yield). 
The .alpha.-bromo acid (93 g) was then added dropwise to a warmed 
(45.degree. C.) solution containing 196 g ammonium carbonate, 70 ml 
H.sub.2 O and 200 ml concentrated ammonium hydroxide. This solution was 
stirred for 22 hours at 45.degree. C. and the material that precipitated 
was filtered and recrystallized from 1700 ml MeOH/H.sub.2 O (75/25) to 
yield 21.6 g D,L-2-amino-5-methyl hexanoic acid (34% yield from 
.alpha.-bromo acid). 
Step 2: Synthesis of L-2-amino-5-methylhexanoic acid (resolution of racemic 
amino acid) 
20.0 g of D,L-2-amino-5-methylhexanoic acid and 150 ml glacial acetic acid 
were combined in a 250 ml flask and the suspension stirred at 57.degree. 
C. To this mixture was added dropwise 30.9 g acetic anhydride over a 
period of 20 minutes at 47.degree. C. The resulting solution was then 
stirred at room temperature for two hours, after which solvents were 
removed in vacuo to yield a white semi-solid. This material was suspended 
in 20 ml H.sub.2 O and re-dried three times to yield a white solid, which 
was recrystallized from ether/acetone to yield 20.7 g of the product, 
N-acetyl-D,L-2-amino-5-methylhexanoic acid. 
18 g of this material was taken up in 700 ml H.sub.2 O, and conc. NH.sub.4 
OH added to reach pH 7.2. The solution was heated to 36.degree. C. and 
11.0 mg Acylase I was added. After stirring for 18 hours, an additional 5 
mg Acylase I was added and the solution stirred an additional 24 hours. 
The solution was then acidified with 18.0 ml acetic acid and filtered. 
Evaporation of the filtrate yielded the product, a white solid, 
L-2-amino-5-methyl hexanoic acid, (5.8 g, 83% yield). 
Step 3: Synthesis of L-2-amino-5-methylhexanol 
To 220 ml of 1.0 M BH.sub.3 in tetrahydrofuran, chilled to 15.degree. C. 
and under N.sub.2 atmosphere, was added 8.0 g of 
L-2-amino-5-methylhexanoic acid in small portions over 30 minutes. The 
resulting solution was stirred at room temperature for 20 hours. The 
mixture was then chilled to -15.degree. C. and 3 N NaOH was added dropwise 
over 2 hours until the vigorous evolution of gas subsided, after which 150 
ml additional 3 N NaOH was added and the mixture stirred at room 
temperature for 20 hours. The resulting solution was then extracted with 
3.times.450 ml portions of ether, and the combined ether fractions 
evaporated to dryness yielding 7.1 g of a pale yellow oil. This material 
was added to 50 ml 3 N NaOH and refluxed for two hours. Extraction of this 
mixture with 3.times.100 ml portions of ether and evaporation of solvents 
yielded 1.53 g of pure product, L- 2-amino-5-methylhexanol (B.P. 
96.degree.-103.degree. C./5 mm). 
Step 4: Synthesis of 
N-(.alpha.-L-aspartyl)-L-1-hydroxymethyl-4-methylpentylamide 
14.6 g N-carbobenzoxy-L-aspartic acid .beta.-benzyl ester was suspended in 
300 ml methylene dichloride and chilled in an ice-water bath. To the 
stirred suspension was added dropwise a slurry of 8.44 g 
dicyclohexylcarbodiimide in 25 ml methylene dichloride. The mixture was 
stirred for one hour at 5.degree.-10.degree. C. To this was added 4.13 g 
of L-2-amino-5-methylhexanol over 15 minutes while stirring at 5.degree. 
C. The mixture was stirred for 60 hours, after which the mixture was 
filtered and the solvent was evaporated. The resulting residue from the 
evaporated filtrate were taken up in ether and filtered. The filtrate was 
evaporated to a solid which was taken up in 700 ml ether and washed 
successively with 2.times.150 ml portions each of 10% HCl, H.sub.2 O, 10% 
NaOH and saturated NaCl. The washed ether layer was dried over MgSO.sub.4 
and evaporated to yield 13.7 g 
N-carbobenzoxy-.alpha.-L-aspartyl-L-2-amino-5-methylhexanol, .beta.-benzyl 
ester (71% yield). 
This material was taken up in 150 ml acetic acid, to which 100 mg Pd on 
charcoal was added. The mixture was hydrogenated in a Parr apparatus at 50 
psi H.sub.2 to yield the crude product. The solvent was evaporated, 
affording a sticky yellow solid. This material was taken up in 18 ml 
acetic acid and further purified by HPLC on a preparative silica gel 
column using as solvent CHCl.sub.3 :methanol:water:acetic acid 
(64:30:4:2). Recrystallization from n-butanol/H.sub.2 O (6:1) yielded 0.39 
g of product, 
N-(.alpha.-L-aspartyl)-L-1-hydroxymethyl-4-methylpentylamide.

INDUSTRIAL APPLICABILITY 
The sweetener agents of the present application can be used in many, varied 
preparations. 
EXAMPLE I 
The preparation of a typical sweetened orange soda is as follows: 
A stock supply of bottler's syrup is prepared by mixing 5.5 ml. of a 50% 
aqueous citric acid solution with 150 ml. of water, dissolving 2 g. of 
N-(.alpha.-L-aspartyl)-L-1-hydroxymethyl-4-methylpentylamide in that 
solution, adding successively 7.02 ml. of the orange flavor base 
manufactured by A. E. Illes, Dallas, Texas, labeled FO-78, and 2.7 g. of 
sodium benzoate and diluting that mixture to 200 ml. with water. One oz. 
samples of the syrup so prepared are transferred to 6 oz. bottles and 110 
ml. of cold tap water is added to each bottle. To each bottle, 42 ml. of 
cold charged bottling water (5 volumes carbon dioxide) is then added to 
achieve carbonation. Each bottle is capped and the contents mixed. 
The bottled orange soda preparations possess a sweetness comparable to 
those containing a quantity of sucrose approximately 50 times that of the 
named aspartate amide. 
Orange soda of similar sweetness intensity can be prepared using 
N-.alpha.-L-aspartyl derivatives wherein the L-amide moiety is: 
1-hydroxymethyl-4,4-dimethylpentylamide, 
1-hydroxymethyl-5-methylhexylamide, 
1-hydroxymethylhexylamide, 
1-hydroxymethyl-4-methylhexylamide, 
1-hydroxymethyl-4,4-dimethylhexylamide, 
1-hydroxymethylpentylamide, or 
1-hydroxymethyl-5,5-dimethylhexylamide. 
The sweetener compounds can also be used in various formulations for use in 
oral hygiene. 
EXAMPLE II 
A toothpaste composition is prepared by blending the following ingredients: 
______________________________________ 
Ingredient Percent by weight 
______________________________________ 
Calcium pyrophosphate* 
40.00 
Sorbitol (70% aqueous solution) 
20.40 
Glycerine 10.20 
Sodium coconut monoglyceride 
sulphonate 0.80 
Sodium carboxymethyl cellulose 
1.20 
Sodium coconut alkyl sulphate 
(20% active) 2.30 
Sodium fluoride 0.22 
Sweetener (N-.alpha.-L-aspartyl-L-1- 
hydroxymethyl-4,4-dimethyl- 
hexylamide) 0.40 
Flavor 0.90 
Green urea formaldehyde 
agglomerates 0.65 
Water and minor ingredients 
Balance 
______________________________________ 
*Standard dentifrice abrasive 
The toothpaste of this Example is prepared in standard fashion by blending 
the ingredients until a smooth paste is secured and deaerating and tubing 
the product. The product possesses highly desirable sweetness, flavor and 
stability characteristics. 
Toothpaste of similar sweetness intensity can be prepared using 
N-.alpha.-L-aspartyl derivatives wherein the L-amide moiety is: 
1-hydroxymethyl-4,4-dimethylpentylamide, 
1-hydroxymethyl-5-methylhexylamide, 
1-hydroxymethylhexylamide, 
1-hydroxymethyl-4-methylhexylamide, 
1-hydroxymethyl-4,4-dimethylhexylamide, 
1-hydroxymethylpentylamide, or 
1-hydroxymethyl-5,5-dimethylhexylamide. 
EXAMPLE III 
A mouthwash is prepared by co-dissolving the following ingredients: 
______________________________________ 
Ingredient Percent by Weight 
______________________________________ 
Glycerine 10.00 
Ethyl alcohol 17.00 
Cetyl pyridinium chloride 
0.05 
Sorbitan monooleate poly- 
oxyethylene 0.13 
Flavor (Oil of Wintergreen) 
0.09 
Sweetening agent (L-aspartyl-L- 
1-hydroxymethyl-4-methyl- 
pentylamide) 0.5 
Water and minor ingredients 
Balance 
______________________________________ 
The above composition possesses highly desirable mouth-freshening 
characteristics and is desirably stable and sweet, with no noticeable 
bitter after-taste. 
Mouthwash of similar sweetness intensity can be prepared using 
N-.alpha.-L-aspartyl derivatives wherein the L-amide moiety is: 
1-hydroxymethyl-4,4-dimethylpentylamide, 
1-hydroxymethyl-5-methylhexylamide, 
1-hydroxymethylhexylamide, 
1-hydroxymethyl-4-methylhexylamide, 
1-hydroxymethyl-4,4-dimethylhexylamide, 
1-hydroxymethylpentylamide, or 
1-hydroxymethyl-5,5-dimethylhexylamide. 
EXAMPLE IV 
A gel dentifrice is prepared by conventional means having the following 
formulation: 
______________________________________ 
Ingredients Percent by Weight 
______________________________________ 
Silica xerogel 12.00 
Silica aerogel 5.00 
Hydroxyethyl cellulose 
1.50 
Glycerine 34.76 
Stannous fluoride 0.41 
Flavor (Wintergreen) 
0.95 
Color (FD & C Blue #1) 
0.03 
21% sodium lauryl sulphate-79 
glycerine mixture 6.00 
Sweetener (N-.alpha.-L-aspartyl-L- 
1-hydroxymethyl-5-methyl- 
hexylamide 0.30 
Water and minor ingredients 
Balance 
______________________________________ 
The above composition is prepared by blending and deaerating the listed 
ingredients in standard fasion. The product is a stable, effective, 
translucent dentifrice having desirable sweetness characteristics. 
EXAMPLE V 
A cough syrup is prepared by conventional means by using the sweeteners of 
the present invention to mask the bitter taste of the active ingredient, 
e.g., Pholcodine citrate syrup: 
______________________________________ 
Ingredients Percent by Weight 
______________________________________ 
Pholcodine 8 mg 
Citric acid 80 mg 
90% Ethanol 0.6 ml 
Syrup (prepared by adding 
purified water to 13 g 
N-.alpha.-L-aspartyl-L-1-hydroxy- 
methyl-4-methylpentylamide 
to a total of 1000 g) 
to 4 ml 
______________________________________ 
The composition is prepared by mixing the Pholcodine and the citric acid 
separately in 0.3 ml portions of the 90% ethanol, mixing the two portions 
of ethanol together, and combining the Pholcodine/citric acid/ethanol 
mixture with the syrup. 
A dose of 2-4 ml administers an effective, non-bitter tasting, cough 
suppressing dose of Pholcodine without the use of the heavy sucrose syrups 
usually employed to mask the bitter taste of such products. 
EXAMPLE VI 
A chewing gum is prepared by replacing the sucrose normally added to 
chewing gum with the sweeteners of the instant invention. A gum base is 
prepared from: 
______________________________________ 
Ingredients Weight in Grams 
______________________________________ 
60% latex 18 
Hydrogenated rosin esters 
44 
Paracumarine resin 7.5 
Candellila wax 6 
Glyceryl tristearate 
2.5 
Ethyl cellulose 2 
Calcium carbonate 20 
______________________________________ 
The aforesaid gum base is used with the sweeteners of this invention to 
prepare a chewing gum having a greatly reduced sucrose content, hence less 
cariogenic potential, while maintaining a desirable sweetness level: 
______________________________________ 
Ingredients Percent by Weight 
______________________________________ 
Gum base 68 
N-(.alpha.-L-aspartyl)-L-1- 
hydroxymethyl-4-methyl 
pentylamide 15 
Corn syrup 16 
Flavor 1 
______________________________________ 
Chewing gum of similar sweetness intensity can be prepared using 
N-.alpha.-L-aspartyl derivatives wherein the L-amide moiety is: 
1-hydroxymethyl-4,4-dimethylpentylamide, 
1-hydroxymethyl-5-methylhexylamide, 
1-hydroxymethylhexylamide, 
1-hydroxymethyl-4-methylhexylamide, 
1-hydroxymethyl-4,4-dimethylhexylamide, 
1-hydroxymethylpentylamide, or 
1-hydroxymethyl-5,5-dimethylhexylamide. 
EXAMPLE VII 
Sweetening compositions for addition to foods and beverages (e.g., coffee 
and tea) to enable edible materials to be sweetened to suit individual 
tastes can be prepared in liquid or solid form. A liquid sweetener can be 
prepared using from 5-10% sweetener, 0.1% benzoic acid and 0.05% methyl 
paraben in purified water. Sweetening tablets, for addition to coffee, for 
example, can be prepared using 20-80 mg of sweetener per tablet and 
standard excipients such as sodium bicarbonate, sodium benzoate, soda ash, 
sodium citrate, tartaric acid, and sodium gluconate in standard tabletting 
procedures. The following are representative. 
______________________________________ 
Ingredients Amount 
______________________________________ 
Tablet A 
Starch 120 mg 
N-(.alpha.-L-aspartyl)-L-1-hydroxy- 
methyl-4-methylpentylamide 
60 mg 
Magnesium Stearate 5 mg 
Tablet B 
Carboxymethylcellulose 
80 mg 
N-(.alpha.-L-aspartyl)-1-hydroxy- 
methyl-5-methylhexylamide 
80 mg 
Mg Stearate 3 mg 
Tablet C 
Lactose 10 mg 
Starch 100 mg 
N-(.alpha.-L-aspartyl)-1-hydroxy- 
methyl-4,4-dimethylpentylamide 
70 mg 
Magnesium Stearate 3 mg 
______________________________________ 
As can be seen from the foregoing, compositions intended for oral ingestion 
can be sweetened by using at least about 0.01 mg, usually about 20 mg to 
about 1500 mg, of the compounds of their invention, per 100 g of 
composition.