Note: Descriptions are shown in the official language in which they were submitted.
10~296g
This invention relates to preparing a novel sub-
stituted p-aminobenzoic acid that is useful for treatment
of hypolipidemia.
It is recognized that cholesterol and trigly-
cerides play a major role in the formation of arthero-
sclerotic plaques by accelerating the deposition of blood
lipids in the arterial wall.
The present invention concerns the novel compound
4-(1,3-benzodioxol-5-ylmethylamino)benzoic acid, which is
useful for reducing plasma lipid level in animals.
More particularly, this invention provides a
process for producing 4-(1,3-benzodioxol-5-ylmethylamino)-
benzoic acid which comprises selecting a process from the
group consisting of (A) reacting piperonal with p-amino-
benzoic acid followed by reduction of the Schiff base thus
formed and (B) saponification of an ester of said acid
followed by acidification. A convenient method of carrying
out the Schiff base procedure involves mixing the Schiff
base with an excess of ethanol and water. Dilute aqueous
sodium hydroxide, for example about l molar equivalent of
the Schiff base, optionally can be added to the mixture.
Sodium borohydride, NaBH4, (1 molar equivalent) is added
at room temperature and stirred until it dissolves. The
mixture is then heated to reflux for l to 2 hours. The
mixture is poured onto ice and acidified~ The product
may be filtered off as a precipitate and further purified
by known procedures.
The compound of the invention also can be pre-
pared by saponification of an ester, preferably a lower
alkyl ester, of 4-(1,3-benzodioxol-5-ylmethylamino)benzoic
acid followed by acidification according to known procedures.
17,869-F -l-
The compound of the present invention is a crystal-
line solid w~ich is soluble in many common organic solvents
such as, for example, acetone, benzene, alcohols, or liquid
alkanes.
The compound has shown hypolipidemic activity in
animals and in particular in mammals. Hypolipidemic activity
as used herein refers to the effect of lowering the blood
lipid content and in particular the cholesterol and tri-
glyceride content of the serum. The compound of the present
invention is therefore suitable for use in treating serum
hyperlipidemia in mammals and in particular is useful for
the treatment of hypercholesterolemia and hypertriglyceridemia,
that is, abnormally high levels of lipids, cholesterol, or
triglycerides, respectively, in the serum. The compound
can be administered orally or parenterally by subcutaneous,
intravenous, or intraperitoneal injection or by implantation,
oral administration being preferred.
~he hypolipidemic amount of the p-aminobenzoic acid
compound to be administered to an animal, that is, the
amount which is effective to significantly lower the serum
lipid level, can vary depending upon such factors as the
animal treated, the desired lipid level to be obtained,
whether or not the animal is hyperlipidemic, the period of
administration and the method of administration. In general,
an effective daily dosage range is from 1 to 400 mg/kg of
body weight, with a daily dosage range of from about 5 to
30 mg/kg of body weight being preferred.
For oral administration, pharmaceutical prepara-
tions of the compound can be made by conventional techniques.
These techniques involve granulating and compressing when
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96g
necessary or variously mixing and dissolving or suspending
the ingredients as appropriate to the desired end product.
Numerous pharmaceutical forms to carry the compound can be
used. For example, the pure compound can be used or it can
be mixed with a solid carrier. Generally, inorganic pharma-
ceutical carriers are preferable and particularly solid
inorganic carriers. One reason for this is the large number
of inorganic materials which are known to be pharmaceuti-
cally safe and acceptable, as well as very convenient in
preparing formulations. The compositions may ta~e the form
of tablets, linguets, powders, capsules, slurries, troches,
or lozenges, and such compositions can be prepared by
stan~ard techniques. Tablet compositions may be coated or
uncoated and they may be effervescent or non-effervescent.
Conventional excipients for tablet formations may be used.
For example, inert diluents, such as magnesium carbonate or
lactose, disintegrating agents such as maize starch or
alginic acid, and lubricating agents such as magnesium
stearate may be used.
If a liquid carrier is used, the preparation may
be in the form of a soft gelatin capsule, a syrup, a liquid
solution or suspension.
The hydrocarbon solubility of the compound of this
invention is high enough to allow the use of pharmaceutically-
-acceptable oils as carriers. For example, vegetable or
animal oils such as sunflower oil, safflower oil, maize oil
or cod liver oil can be used. Glycerine can also be used.
With this latter solvent, from 2 to 30 percent water may be
added. When water alone is the carrier, or when the solu-
bility of the compound in the oil is low, the preparations
can be administèred in the form of a slurry.
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Emulsion compositions may be formulated using
emulsifying agents such as sorbitan trioleate, polyoxyethylene
sorbitan monooleate, lecithin, gum acacia or gum tragacanth.
Aqueous based suspensions may be prepared with the aid of
wetting agents such as polyethylene oxide condensation
products of alkylphenols, fatty alcohols or fatty acids
with the suspending agents, for example, a hydrophilic
colloid such as polyvinylpyrrolidone. The emulsions and
suspensions may contain conventional excipients such as
sweeting agents, flowing agents, coloring materials, or
preservatives.
The compound of the invention can also be incorpor-
ated in a nutritive foodstuff such as, for example, butter,
margarine, edible oils, casein, or carbohydrates. Such
nutritive compositions are adapted to be administered as a
partial or total diet or as a supplement to the diet. Such
compositions preferably contain from 0.02 to 2.0 percent by
weight of the active ingredient when administered as the
total diet. The compositions can contain higher concen-
trations of the active ingredient when administered as a
supplement.
For parenteral use, the compound can be formulated
with sterile ingredients, compounded and packaged ascepti-
cally and may be administered intravenously or intramuscu-
larly. Useful solvents for formulation in such use are the
polyhydric aliphatic alcohols and mixtures thereof. Es-
pecially satisfactory are the pharmaceutically acceptable
glycols, such as propylene glycol, and mixtures thereof.
Glycerine is particularly useful. Up to 25-30 percent by
volume of water may be incorporated in the vehicle if
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desired. An 80 percent aqueous propylene glycol solution
is a particularly convenient solvent system. A pH, about
7.4, and isotonicity compatible with body isotonicity, is
desirable. Basicity may be controlled by addition of a
base as required, and a particularly convenient base is
monoethanolamine. It may often be desirable to incorporate
a local anesthetic such as known to those skilled in the
art.
The percentage of the compound to be used in the
pharmaceutical carrier may be varied. It is necessary that
the compound constitute a proportion such that a suitable
dosage will be obtained, and it is preferred to use pharma-
ceutical compositions containing at least 10 weight percent
of the compound. Activity increases with concentration of
the agent in the carrier, but those compositions containing
a significant amount of carrier, e.g. at least 1 percent
and preferably at least 5 percent, are preferred as they
allow for the easier administration of the compound.
The invention is illustrated by the following
examples.
EXAMPLE 1
A mixture of 2 moles piperonal, 2 moles p-amino-
benzoic acid, and 2 liters toluene was heated at reflux for
2 hours. The reaction mixture was cooled and filtered,
giving 520 g. t96.6% yield) of Schiff base having a melting
point of 235-238C.
Analysis:
C _H N
Calculated 66.91 4.12 5.20
Found 66.7 4.26 5.51
: ! .
;
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l~Z969
The above Schiff base (1.89 moles) was reduced
with sodium borohydride in 1 1. ethanol and 2 1. IN NaOH.
Recrystallization of the crude product (322.8 g.) from iso-
propyl alcohol and then from ethanol gave 221.2 g. 4-(1,3-
benzodioxol-5-ylmethvlamino)benzoic acid, m.p. 196-198C.
Analysis: -
C H N
Calculated 66.42 4.83 5.16
Found 66.5 4.83 5.23
EXAMPLE 2
A mixture of 22.5 grams (0.15 mol) piperonal and
24.8 grams (0.15 mol) ethyl p-aminobenzoate in 500 ml of
benzene was refluxed until 0.15 mol. of water had been
collected in a trap. The reaction was cooled and yellow
crystals formed. The mixture was filtered and the crystal-
line product was washed with benzene and vacuum dried. This
Schiff base weighed 31.97 grams (0.107 mol.).
The Schiff base was dissolved in 500 ml of anhy-
drous ethanol and warmed to 40C. Sodium borohydride (4.5
grams) was added, and the resulting slurry was refluxed for
45 minutes. The reaction mass was cooled, poured over 800
ml. of ice water, and the crude 4-(1,3-benzodioxol-5-ylmethyl-
amino)benzoic acid ethyl ester precipitated out. The pre-
cipitate was collected and washed with water. After vacuum
dxying, 30.4 grams of the white crystalline ester was ob-
tained.
The ester had a melting point of 120-122C. Ele-
mental analysis:
- C H N
Calculated 68.21 5.72 4.68
Found 68.1 5.82 4.74
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4-(1,3-Benzodioxol-5-ylmethylamino)benzoic acid
was prepared from the above ester as follows. 15 Grams of
the ester was mixed with 150 ml. of 20~ sodium hydroxide and
150 ml of ethyl alcohol. The resulting slurry was refluxed
for 4 hours and then cooled. The clear solution that result-
ed was poured onto 800 grams of ice. The reaction mass
was acidified with concentrated HCl. Crystalline 4-(1,3-
benzodioxol-5-ylmethylamino)benzoic acid formed and was
filtered off, washed with water, and dried. The product was
recrystallized from acetonitrile. The compound had a melting
point of 193-196C. Elemental analysis:
C H N
Calculated 66.42 4.83 5.16
Found 66.7 4.90 5.50
The hypolipidemic effect of the active compound
of the invention is illustratively demonstrated in rats. In
this procedure, the compound is dissolved in acetone, taken
up on a silica gel, and mixed with ground feed to yield
concentrations of 0.125 weight percent of the compound in
the animal feed. The treated feed was administered to male
rats weighing 150-160 grams over a 14 day period. Following
the feeding period, the rats were sacrificed, and blood
samples were collected. The liver was removed, weighed, and
frozen for future analysis. The relative levels of serum
cholesterol in the blood samples was determined by the Henly
method; A. A. Henly, Analyst, 82, 286 (1957). Liver choles-
terol was measured by the Sperry-Webb method; Journal of
Biological Chemistry 187, 97 (1950). The relative levels of
i
triglycerides in the blood and liver samples were determined
~`1, ' ~.
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by the Van Handel and Zilversmit method; J. Lab. Clin. Med.
50, 152 (1957j and Clin. Chem. 7, 249 (1961). Taking the
average levels of the control rats as standard, the mean
results obtained in the treated groups is thereby ascertained.
The data below represent relative change in values for the
treated animals compared to the control group.
Serum cholesterol -32
Serum triglycerides -77
Liver cholesterol +15
Liver triglycerides -21
Liver weight + 5
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