Note: Descriptions are shown in the official language in which they were submitted.
Backgrouncl of the Invention
____ _
The present invention relates to a method for the
treatment of glaucoma. More particularly, the invention
relates to a novel method of treatment of glaucoma or
lowering of intraocular pressure by topically
administering beta-adrenergic blocking agents to the
eye.
Glaucoma is a condition of the eye characterized by
increased intraocular pressure~ Untreated, the
condition can eventually lead to irreversible retinal
damage and blindness. Conventional therapy for glaucoma
has involved topical administration of pilocarpine
and/or epinephrine, administered to the eye several
times daily.
Various beta-blocking agents may also be used to
lower intraocular pressure. Such use is described, for
example, in reviews by W. P. Boger in Dru~s, 18, 25-32
(1979) and by T. J. Zimmerman and W. P. Boger in Survey
Ophthalmol. 23(b), 347 (1979). The use of beta-blockers
-
for the treatment of glaucoma is also described in the
patent literature. For example, U S. Patent No.
4,195,085 to Stone discloses a method for treatment of
glaucoma by the ocular administration of a beta-blocking
compound, timolol maleate. U.S~ Patent No. 4,127,674
discloses treating glaucoma with labetalol, a known
antagonist of both alpha and beta adrenergic receptors.
Howeverl these methods also possess significant
drawbacks, in that the absorption of the beta-blocking
compound into the systemic circulation can cause
undesirable side effects. Such side effects result from
prolonged beta-blocking action on the heartl bronchioles
and blood vessels. For example, according to
Physicians' Desk Reference, Charles E. Baker, Jr., 35th
Edition, 1981, p. 1233, adverse reactions to the
topical use of timolol maleate can include bronchospasm,
33
--2~
heart failure, as well as cardiac conduction deEects.
Accordingly, there is a need for a method of treatment
of glaucoma or for lowering intraocular pressure which
is relatively free of unwanted systemic side-effects.
Certain bet_-blocking agents which contain
enzyrnatically labile ester groups are known to exhibit
short-acting beta-blocking effects in the systemic
circulation. Such short-acting beta-blocking compounds
(SAABs) have been suggested for treatment or prophylaxis
of cardiac disorders as a means for reducing heart work
or improving rhythmicity for a short duration. Such
short-acting beta-blocking compounds avoid the sometimes
counterproductive effects of conventional beta-blocking
agents, whose effects are long-lived and therefore
difficult to precisely control.
Summary of the Invention
In accordance with the present invention, disclosed
herein is a method for the treatment of glaucoma or for
lowering intraocular pressure in a mammal, comprising
topically administering to the eye of such mammal a
beta-blocking compound of the formula:
O 0~
Il I
;9r~C-C)-CH2-CH-CH2-NHR
wherein R represents lower alkyl of straight or branched
carbon chains from 1 to about 10 carbon atoms;
cycloalkyl of from 3 to about 7 carbon atoms; alkenyl of
from about 2 to about 10 carbon atoms; alkynyl of from 3
to about 10 carbon atoms; hydroxyalkyl of from 2 to
about 7 carbon atoms; aralkyl, wherein the alkyl portion
contains from 1 to about 5 carbon atoms, and the aryl
portion represents substituted or unsubstituted
monocyclic or polycyclic aromatic or heterocyclic ring
-3- ~
systems of from about 6 to about 10 carbon atoms; a
group of the formula
o
Il
_z--C-O-Rl
wherein Z represents lower alkylene of straight or
branched carbon chains of from 1 to about 10 carbon
atoms, and Rl is lower alkyl of from 1 to about 5 carbon
atoms; and Ar represents substituted or unsubstituted
aromatic; or a pharmaceutically-acceptable salt thereof.
Detailed DescrLption of the Invention
The above-mentioned short-acting beta-blocking
compounds effectively reduce intraocular pressure in the
eyes of mammals when topically administered. Because of
1~ their short-lived duration of action in the systemic
circulation, toxic side-effects produced by their
migration out of the eye are consequently reduced. It
has further been discovered that certain of these
compounds show an increased longevity of effect when
present in the ocular fluid compared to the duration of
their systemic effects. Consequently, the present
invention resides in the treatment of glaucoma or
lo~ering intraocular pressure with a beta-blocking
compound which exhibits relatively long duration of
action while in the ocular fluid, but which is subject
to relatively rapid breakdown into inactive metabolites
upon passage to the systemic circulation~
Compounds administered by the method of the present
inventlon are represented by the formula:
O OH
Il I
Ar-C-O-CH2-CH-CH2-NHR
wherein R represents lower alkyl of straight or branched
carbon chains from 1 to about 10 carbon atoms;
cycloalkyl of from 3 to about 7 carbon atoms; alkenyl of
from 2 to about 10 carbon atoms; alkynyl of from 2 to
about 10 carbon atoms; hydroxyalkyl of from 2 to about 7
carbon atoms; aralkyl, wherein the alkyl portion
contains from about 1 to about 5 carbon atoms and the
aryl portion represents substituted or unsubstituted
monocyclic or polycyclic aromatic or heterocyclic ring
systems of from 6 to about 10 carbon atoms, such as
benzyl, phenethyl, 3,4-dimethoxyphenethyl, 1,1-dimethyl-
2-(3-indolyl) ethyl, and the like; and Ar represents
substituted or unsubstituted aromatic, including
monocyclic, polycyclic and heterocyclic ring systems.
Aromatic (Ar) substituents may include lower alkyl,
lower alkenyl r lower alkynyl, lower alkoxy, halogen r
acetamido, amino, nitro, lower alkylamino, hydroxy,
hydroxyalkyl, cyano, methylenedioxy, acyloxy, wherein
the acyl portion is a straight or branched chain
alkanoyl o from 1 to about 7 carbon atoms or aroyl of
from 6 to about 10 carbon atoms, optionally substituted
by halogen, lower alkoxy, lower alkyl, acetamido, cyano
or hydroxy/ and groups of the formula
o
ll
Rl-O-c-(cH2)n
wherein R1 is lower alkyl, aryl or aralkyl and n is an
integer from 0 to about 10. The compounds described
herein are not limited to any particular stereoisomeric
configuration. Such compounds may be administered as
their pharmaceutically acceptable acid addition salts,
e.g., as the hydrochloride, sulfater phosphate, oxalater
gluconate, tartrate, et cetera.
733
-s-
In preferred compounds R is lower alkyl o from 1
to about 5 carbon atomst such as isopropyl, n-butyl, t-
butyl~ n-pentyl, and the like; alkynyl of from 3 to
about 5 carbon atoms~ such as propargyl,
dimethylpropargyl and the like; hydroxyalkyl of from 2
to about 5 carbon atoms r such as hydroxy-t-butyl and the
like; or aralkyl wherein the alkyl portion contains from
1 to about 3 carbon atoms and the aryl portion contains
from 6 to about 10 carbon atoms, such as benzyl,
phenethyl, 3,4-dimethoxyphenethyl and the like; and Ar
is unsubstituted phenyl, or phenyl substituted with
lower alkyl of from 1 to about 5 carbon atoms, fluoro,
chloro, nitro, hydroxy, amino, acyloxy, wherein the acyl
portion is alkanoyl of from 2 to about 5 carbon atoms,
or benzoyl optionally substituted by halogen, alkoxy,
alkyl vr hydroxy, or a group of the formula
Rl~O~C~(cH2)n
wherein R1 is lower alkyl of from 1 to about 5 carbon
atomsr and n is an integer from 0 to about 5. In
particularly preferred embodiments of the present
: invention, R is selected from the group consisting of
isopropyl, t-butyl, hydroxy-t-butyl, dimethylpropargyl,
~5 and 3,4-dimethoxyphenethyl, and Ar is unsubstituted
phenyl or phenyl substituted with methyl, fluoro,
chlorog nitro, hydroxy, amino, acyloxy such as acetoxy,
isobutyryloxy, pivaloyloxy, benzoyloxy or 4-
methoxybenzoyloxy.
The compounds described herein may be prepared by a
number of synthetic methods, depending upon the
particular structure desired.
Compounds of the invention may be advantageously
prepared by either of the following two methods:
--6--
Method I:
O O
Il /~
Ar-C-Cl + HO-CH~-C~I-CH2 ~ ~
O O H2N--R
Ar-C-O-ClH 2-CH -C~ 2
O OH
11 1
Ar-C-O-CH~-CH-CH2~NHR; or
Method II
O OH
/~ I
,~ Ho_cH2-cH-C~2 ~ B2N-R ~ HO-CH2-CH-CM2-NHR
O O OH
11 11
Ar-C-Cl Ar-C-O-CH2CH-CH2-NHR
The latter method is particularly preferred for
compounds in which R is an ester-containing group.
The compounds of this invention are advantageously
administered topically to the eye in the form of a
solution, ointment, or solid insert such as is described
in U.S. Patent No. 4,195,085. Formulations may contain
2S the active compound~ preferably, in the form of a
soluble acid addition salt, in amounts ranging from
about 0.01% to about 10% by wto, preferably, from about
0.5~ to about 5% by wt. Unit dosages of the active
compound can range from about 0.001 to about 5.0 mg.,
preferably from about 0.05 to about 2.0 mg. The dosage
administered to a patient will depend upon the patient's
needs and the particular compounds employed.
Carriers used in the preparations of the present
invention are preferably non-toxic pharmaceutical
organic or inorganic compositions such as water;
~a
--7--
mixtures of water and water-miscible solvents, such as
lower alcohols; mineral oils; petroleum jellies; ethyl
cellulose; polyvinylpyrrolidone and other conventional
carriers. In addition, the pharmaceutical preparations
may also contain additional components such as
emulsifying, preserving, wetting and sterilizing agents.
These include polyethylene glycols 200, 300, 400 and
600, Carbowaxes 1,000, 1,500, 4,000, 6,000 and 10,000,
bacteriocidal components such as quaternary ammonium
compounds, phenylmercuric salts known to have cold
sterilizing properties and which are non-injurious in
user thimerosal, methyl and propyl paraben, benzyl
alcohol, phenyl ethanol, buffering inyredients such as
sodium chloride, sodium borate, sodium acetates,
gluconate buffers, and other conventional ingredients
such as sorbitan monolaurate, triethanolamine, oleate~
polyoxyethylene sorbitan monopalmitylate, dioctyl sodium
sulfosuceinate, monothioglycerol~ thiosorbitol,
ethylenediamine tetracetic acid, and the like.
~0 Additionally, suitable ophthalmie vehicles can be used
as carrier media for the present purpose ineluding
conventional phosphate buffer vehicle systemsr isotonic
borie acid vehicles, isotonic sodium chloride vehieles,
isotonic sodium borate vehicles and the like.
2~ The method of treatment of this invention
advantageously involves the topical administration of
eye drops containing the active compound. Formulations
for eye drops preferably include the active compound as
a soluble aeid addition salt in a properly buffered,
sterile, aqueous isotonie solution.
The compounds of the present invention are ester
group-containing beta-blockers that have a selective,
localized, beta-blocking ef~ect in the eye after topical
administration. Such compounds are thought to be
rapidly metabolized by plasma and/or liver esterases
into inactive by-products, upon entering the systemic
* Trade Mark
J
~L-a-
circulation. It has been discovered that these same
compounds are relatively stable in ocular fluids, i.e.,
lacrimal fluids and aqueous humor. Consequently, such
compounds are useful for the treatment of glaucoma or
for lowering intraocular pressure since they remain
stable when topically applied to the eye but rapidly
metabolize when subsequently absorbed into the systemic
circulat ion .
Some of the compounds break down in the aqueous
humor more rapidly than others. Such compounds may
advantageously be employed when only a temporary
reduction in intraocular pressure is desired, say for
diagnostic procedures. Longer-acting compounds are
generally used for effecting longer-term reductions in
intraocular pressure, such as is desired when treating
chronic glaucoma. Thus, the method of the present
invention provides a very useful therapeutic alternative
for the treatment of glaucoma or for lowering
intraocular pressure.
The ln vitro studies hereinafter described indicate
that the compounds used in the method of the present
invention will undergo different rates of enzymatic
hydrolysis depending on their location withi~ the body
(See Table I). For example, compound of Example III is
completely hydrolyzed within 60 minutes in both dog
blood and liver homogenate while only 19% hydrolyzed
after one hour in aqueous humor, and only 51.9%
hydrolyzed after two hours. Compound of Example IV is
less stable in aqueous humor, hydrolyzing 61.4% after
one hour, 10Q% after two hours.
The present invention is further illustrated by the
following examples which are not intended to be
limiting.
Example I
This example describes the synthesis of a compound
of the formula:
d~9~
_9_
O OH CH3
~ -C-O-CH2-CH-CH2-N-CH HCl
H CH3
C1
2,3 Epoxypropyl-2-chlorobenzoate
A mixture containing 14.8g (0.2 mole) of glycidol,
150 ml of anhydrous ether, 169 (0.4 mole) of pyridine
and 35.2g (0.2 mole) of 2-chlorobenzoyl chloride was
stirred at room temperature for two hours. The mixture
was filtered and the ether was evaporated to leave an
oil. This oil was distilled to give a colorless oilD
The NMR and IR spectra were consistent with the assigned
; 15 structure.
[3-(Isopropylamino)-2-hydroxy]propyl 2-chlorobenzoate
hydrochloride
To 19 of the epoxide from the previous experiment
were added 10g of isopropylamine. The resultant
solution was refluxed for 16 hours and evaporated to
dryness. The oily residue was chromatographed on a
column (silica yel/EtOH:CH2Cl2 = 1.5:3.5) to yield
the free amine product. The amine was converted to its
HCl salt by addition o~ ethereal HCl. The amine salt
2~ was collected by filtration and recrystallized in
2-propanol to give white crystals: m.p. 129C. The NMR
and IR spectra were consistent with the assigned
structure and the elemental analysis was consistent with
the empirical formula C13H263NCl2-
Example Ia
This example describes an alternate synthesis of
the compound of Example I.
A mixture of 37g (0~5 mole) of glycidol and 35.49
(0.6 mole) of isopropylamine was stirred at 25C.overnight. Excess isopropylamine was evaporated in
vacuo and the mixture was distilled to give 53g of
___
product~ b.p~ 80C/0.1mm Hg. The NMR and IR spectra
were consistent with the assigned structure and the
elemental analysis was consistent with the empirical
formula C6H152~1~
[3-(Isopropylamino) 2-hydroxy]propyl 2-chlorobenzoate
hydrochlorid_
A sol~tion of 109 (75 mmole) of the diol from the
previous experiment and 5.9g (75 mmole) of pyridine
hydrochloride in 20 ml of pyridine was treated with
13.1g t75 mmole) of 2-chlorobenzoyl chloride. The
mixture was stirred at room temperature for two hours
and 100 ml of water was added. The pyridine was
evaporated in vacuo at 55-60~C. and the aqueous solution
was washed with 100 ml of ether. The aqueous layer was
then basified with K2CO3 and extracted with methylene
chloride. The methylene chloride layer was acidified
with ether-HCl and evaporated to dryness. The residue
was crystallized in 2-propanol to give 12.59 (54%) of
product: m.p. 129C.
Example II
-
This example describes the synthesis of a compound
of the formula:
O OH CH3
25F- ~ -C-O-CH2-CH-CH~-N-CH HCl
H CH3
The experiment of Example la was repeated in all
essential details to produce the above compound, except
the reactant 4-fluorobenzoyl chloride was substituted
for 2-chlorobenzoyl chloride. The compound was prepared
as the acid addition salt. The compound was identified
by NMR and IR spectroscopy, elemental analysis, and had
a melting point of 139-140C.
--1 1--
E mple III_
This example describes the synthesis of a compound
of the formula:
o OH CH3
-C-O-CH2-CH-CH2-N-C CH3 .HC1
H CH3
The experiment of Example Ia was repeated in all
essential details to produce the above compound, except
the reactants t-butylamine and benzoyl chloride were
substituted for isopropylamine and 2-chlorobenzoyl
chloride, respectively. The compound was prepared as
the acid addition salt. The compound was identified by
NMR and IR spectroscopy, elemental analysis, and had a
melting point of 105-106C.
Example IV
This example describes the synthesis of a compound
of the formula:
O OH CH3
-C-O-CH2-CH-CH2-N-C _ CH3
H CH3
F
The experiment of Example Ia was repeated in all
essential details to produce the above compound, except
the reactants t-butylamine and 2-fluorobenzoyl chloride
were substituted for isopropylamine and 2-chlorobenzoyl
chloride, respectively. The compound was prepared as
the free base. The compound was identified by NMR and
IR spect:roscopy, elemental analysis, and had a melting
point o 97.5-98C.
Examples V~-VIII
The en~ymatic hydrolysis rates of the compounds of
Examples I-IV were examined in dog blood, liver
homogenate, and aqueous humor. All of the compounds
tested were synthesized in accordance with the previous
examples. Acetonitrile was "HPLCI' grade. Distilled
water was used to dissolve the compounds and 0.01 N HCl
was used to dissolve compounds requiring an acidic pH
for dissolutioll.
Fresh aqueous humor was collected from eyes of dogs
using a 23 gauge needle while fresh dog blood was
collected into heparinized Vacutainer~ tubes. Fresh
liver was homogenized in 0.9~ NaCl using a Potter-
Elvehjem Teflon pestle and glass homogenizer making a
1~ 25% (W/V) homogenate.
A 0~5 ml aliquot of dog aqueous humor, blood, or
liver homogenate was incubated with 12.5 u9 (0.5 ml) of
beta-blocker in a Dubnoff shaking metabolic incubator
at37C. for 60 and 120 minutes. Denatured tissue
~0 controls were prepared by adding 2.0 ml of acetonitrile
into 005 ml of aqueous humor, blood, or liver homogenate
to destroy esterase activities prior to addition of the
beta-blockers. These controls were then incubated at
37C. for 120 minutes. After 60 and 120 minutes, ~he
2~ incubations were terminated by addition of 2 ml of
acetonitrile and immediately mixed using a Vortex~ mixer
to stop esterase activitiesO
All samples were centrifuged at 4000 RPM for 10
minutes to sediment denatured proteins. The resultant
supernatants were transferred to WISP~ vials and
analyzed by high pressure liquid chromatography. The
hydrolysis of beta-blockers in aqueous humor, blood, and
liver homogenate was determined by disappearance of the
compounds. The extent of enzymatic hydrolysis in each
tissue was determined by comparing the amount of each
compound (absolute peak area~ recovered at each time
* Trade l~ark
~3
-13-
point to the amount of each compound (absolute peak
area) in denatured tissue control and a~ueous control
samples.
All of the compounds examined were initially tested
for chemical hydrolysis in 0.1 N potassium phosphate
buffer, pH 7.40, and all were found to be stable for at
least three hours (data not shown3.
Table 1 summarizes the results of these
experiments. The extent of hydrolysis is expressed in
terms of the amount of each compound recovered after the
incubation period relative to the amount of each
compound recovered in the denatured tissue control.
Most of the b _ blockers were hydrolyzed very rapidly
(> 90~ in 120 minutes) when incubated with dog blood and
liver homosenate. In contrast, all of the compounds
tested were resistant to enzymatic hydrolysis by
esterases in dog aqueous humor having hydrolysis rates
of 19-61% in 60 minutes and 52-100% in 120 minutes.
Example IX
This example describes the synthesis of a compound
of the formula:
O O CH3
2S CH3-O-c-cH2- ~ -C-O-CH2-CH-CH2-N-C~ ~Cl
OH ~ CH3
2,3 Epoxypropyl 4-[Metho~ycarbonyl)methyl] benzoate
A mixture containing 14.8g (0.2 mole) of glycidol,
150 ml o~ anhydrous ether, 169 (0.4 mole of pyridine and
30 43g l0.2 mole) of 4-[methoxycarbonyl)methyl]benzoyl
chloride is stirred at room temperature for two hours.
The mixture is filt`ered and the ether evaporated to
leave an oil. This oil is distilled to give a colorless
oil.
.,, , , ~
,
--lq--
_-(Is~ ylamino)-2-hydroxy]propyl 4-[Me hoxycarbonyl)
methyl~ benzoate
To 1.6g of the epoxide from the previous experiment
is added 10g of isopropylamine. The resultant solution
is refluxed for 16 hours and evaporated to dryness. The
oily residue is chromatographed on a column (silica
gel/EtOH:CH2Cl2=1.5:3.5) to the freene product. The
ami amine was converted to its HCl salt ddition of
by a ethereal HCl. The amine salt was ted by
1Q collec filtration and recrystallized in nol to give
2-propa white crystals.
Example X
This example describes the synthesis of a compound
of the formula:
O OH OCH3
HOCH2 ~ -C-O-CH2-lH-CH2-l-CH2 CH2 ~ -OCH3-(COo~)2
3-[N-[(4-methoxvbenzvl)oxycarbonyl]-N-(3,4-
dimethoxyphenethyl)] amino-1,2-pro~ diol
A mixture of 26g (0.102 mole) of 3-(3,4-
dimethoxyphenethyl)amino 1,2-propanediol, 29g (0.345
mole) of sodium bicarbonate and 249 ~0.116 mole) of p-
methoxybenzyloxycarbonyl azide in 200 ml of dioxane and
10 ml of water was stirred at room temperature for 24
hours. After evaporation of the dioxane in vacuo, the
residue was partitioned between water and CHCl3.
Evaporation of CHCl3 gave an oil which was purified by
chromatography (silica gel/10% ethanol in methylene
chloride) to give 13g (30.5%) of product.
[2-Hydroxy-3-[[N-~(4-Methoxybenzyl)oxycarbonyl]-N-(3,4-
dimethoxyphenethyl)]amino]propyl 4-formylbenzoate
The diol from the previous experiment was allowed
to react with 4-formylbenzoyl chloride in a similar
manner as described in the preparation of [2-Hydroxy-3-
-15
(isopropylamino)]propyl 2-chlorobenzoate hyclrochloride
in Example II. The product was purified by
chromatography (silica gel/2% ethanol in ether). The
yield was 27%.
[2-Hydroxy-3-[(3,4-dimethoxyphenethyl)amino]propyl 4-
(hydroxymethyl) benzoate oxalate
The aldehyde obtained from the previous experiment
was dissolved in ethanol. The resulting solution was
cooled to 0C. and sodium borohydride in a molar amount
equal to the molar amount of the aldehyde was added.
The reaction mixture was stirred at 0C. for ten minu~es
and excess hydride was destroyed by addition of wat~r.
The crude product was dissolved in ether-HCi and stirred
at room temperature for two hours. The ether was
evaporated to dryness and the product was partitioned
between 5% K2CO3 and methylene chloride. A solution
; of oxalic acid in 2-propanol was added to the methylene
chloride layer and the precipitate was recrystallized in
ethanol to give the desired product in 19% yield; m.p.
20 164-164.5~C. The NMR and IR spectra were consistent
with the assigned structure and the elemental analysis
was consistent with the empirical formula
C23H29N01 O-
Exam~le XI
This example describes the synthesis of a compound
of the following formula via Method I~
F
r-~ COOH
-COOCH2CHCH2NC(CH3)2C_CH COOH
OH H
ate
A r;~ixture containiny 379 (0.5 mole) of glycidol,
500 ml of anhydrous ether, 500 ml of pyridine and 80g
(0.5 mole) of o-fluoro-benzoyl chloride was stirred at
0C. for 1 hour and 25~C. for 2 hours. The mixture was
-16-
filtered and the ethanol filtrate was washed with 100 ml
of 5% HCl. Evaporation of the ether gave an oil which
was distilled to give 69.5g (71%) of product/ b.p.
115C./0.5 mmHg. The NMR and IR spectra were consistent
with the assigned structure.
3-(1,1-Dimethylpropargylamino ? -2-hydroxypropyl 2-
Fluorobenzoate Oxalat_
To 9g (0.046 mole) of the epoxide from the previous
experiment in 50 ml of THF was added 8.59 (0.092 mole)
of 1,1-dimethylpropargylamine. The reaction mixture was
refluxed for 16 hours and evaporated to dryness. The
residue was dissolved in 100 ml of iPrOH and 6.5g (0.07
mole) of oxalic acid was added. Addition of 50 ml of
ether into the iPrOH solution induced crystallization of
the desired product, 3.84g (23%); m.p. 124-5~. The NMR
and IR spectra were consistent with the assigned
structure and elemental analysis was consistent with the
empirical formula C17H20NO7F.
Example XII
The example describes the synthesis of a compound
of the following formula via Method II~
HO OH
2 5 H O~)--COOC H 2CH CH 2--21C ( CH 3 ~ 3 ~ HC l
Ethyl 3,4-Dihydroxybenzoate
A mixture which contained 43g ~0.28 mole) of 3,4-
dihydroxybenzoic acid, 300 ml of ethanol and 0.5 ml of
concentrated H2SO4 was refluxed for 48 hours. Water
was trapped with 3A molecular sieves. The reaction
mixture was evaporated to dryness in vacuor and
partitioned between ether and 5% NaHCO3 solution. The
ether layer was evaporated to give 399 ~69~) of solid;
m.p. 128-130C. The NMR and IR spectra were
consistent with the assigned structure.
' - ~
~7X~33
-17-
3,4-Dibenæylox~enzoic Acid
llo 60 g (0.33 mole) of ethyl 3,4-dihydroxybenzoate
in 50 ml of methyl ethyl ketone was added 105.5g (0.76
mole) of K2CO3 and 168.8g (0.76 mole) of benzyl
bromide. The mixture was refluxed for 16 hours and
filtered. Evaporation of the filtration gave an oil.
This oil was mixed with 40g of KOH, 350 ml of water and
350 ml of methanol and refluxed for 2.5 hours. The
methanol was evaporated and the reaction mixture was
acidified with concentrated HCl. The precipitate was
filtered to give 101g (92~) of the desired product; m.p.
184-5C. The NMR and IR spectra were consistent with
the assigned structure.
3-t-Butylamino-2-hydroxypropyl 3,4-dibenzyloxybenzoate
To 20g (0.06 mole~ of the 3,4-dibenzyloxybenzoic
acid in 200 ml of toluene was added 60g (0.33 mole) of
thionyl chloride. The reaction mixture was evaporated
to dryness in vacuo to give a solid; m.p. 85-86. The
solid was dissolved in 100 ml of dry THF and added
dropwise into a solution of 17.7g (0.06 mole) 3-~t-
butylamino)-1,2-propanediol in 50 ml of pyridine and 50
ml of toluene. The reaction mixture was stirred for 1
hour at 25VC. and partitioned between ether and 5%
K2CO3 solution. The ether layer was evaporated to
dryness to give 309 of solid.
3=tert-Butylamino-2-~ roxypropyl 3,4-Dihydroxybenzoate
H drochloride
Y
To 25g of the dibenzyloxybenzoate obtained from the
previous experiment was added 50 ml of ether and acidi-
fied with hydrogen chloride. The ether layer wasdecanted and the oily residue was dissolved in 200 ml of
methanol with 2g of 10% Pd/catalyst~ The mixture was
agitated for 16 hours under 50 psi of hydrogen. The
catalyst was filtered and the filtrate was evaporated to
dryness. The product was crystallized in iPrOH to give
- 1 8
14g (73~) of the product; m.p. 201-202. The NMR and IR
spectra were consistent with the assigned structure and
elemental analysis was consistent with the empirical
formula C14H22N5Cl-
Examples XIII-XV
The experiment of Example XII was repeated in all
essential detail to produce Examples XIII-XV described
in Table 2 except that different benzyloxybenzoic acids
were used to react with the 3-(t-butyl-amino)-1,2-
propanediolsO Each of the compounds was identified by
NMR, I~ and elemental analysis.
Examples XVI and XVII
The procedure ~or the preparation of 3-t-
bu~ylamino-2-hydroxypropyl 3,4-dibenzyloxyben20ate in
Example _II was repeated in all essential detail to
produce Example XVII described in Table 2 except that
3,4-dipivaloyloxy benzoic acid was used to react with
the 3-~tert-butylamino)-1,2 propanediol. The crude
product of Example XVII was chromatographed on silica
gel with 10~ EtOH in EtoAc to give Example XVII.
The NMR and IR spectra were consistent with the
assigned structures. Comparative data relating to
Examples XI to XVII are given in Table 2.
Example XVIII
The intraocular pressure lowering effect of the
compounds described in Examples I-IV and IX~XVII are
demonstrated in rabbits with normotensive eyes.
Sterile, isotonic saline solutions of each of the
compounds prepared in procedures of Examples I-IV, IX-
XVII are prepared by dissolving 10, 30 and 100 mg
samples of each of the active compounds in 1 ml of
saline to give 1%, 3% and 10% solutions with pH about
6.0-7Ø Free amines require one equivalent of HCl to
effect dissolution.
~3~
The intraocular pressure lowering effect of each
COll)pOUnd i5 determined by treatinc3 the eyes of healthy
rabbits with the above solutions. Three rabbits are
used to evaluate the effect of each drug concentration.
A standard dose of 50~1 of each drug solution is
applied to one eye of each of the three rabbits.
Intraocular presure of both eyes is measured with a
pressure tonograph or a Mackay-Marg Tonometer before
drug administration and at 15, 30, 45, 60, 120, 180,
240, 300, 360, 420 and 480 minutes after dosing.
Control rabbits are treated similarly with sterile
isotonic saline solution. Intraocular pressure lowering
in the treated eyes is compared with the untreated eyes,
with saline treated eyes and with predrug pressures.
All of the test compounds show intraocular pressure-
lowering activity~
Example XIX
The experiment of Example XVIII is repeated in all
essential details, except that rabbits which have
corticosteroid induced ocular hypertension, as described
by Bonomi, L., et al~, Glaucoma, Eds. R. Pittscrick,
A~D.S~ Caldwell, Academic Press, New York, pp. 98-107
~1980), are substituted or the normotensive rabbits.
Each of the test compounds exhibits intraocular
pressure- lowering activity in this model.
733
--2()--
TAB LE
ENZYMATIC HYDROLYSIS OF BETA BLOCKERS BY DOG BLOOD
L:[VER HOMOGENATE, AND AQUEOUS HUMOR
_ _ _ _ _
% HYDF~)LYZED
BLOOD LIVER AQUEOtlS HUMOR
CO~OUND
E~XAMPLE EX~MPLE 60 min 120 min 60 min 120 min
V III 100 100 100 100 18.9 51.9
Vq II 100 100 100 100 21.9 61.8
10 VIII, Ia 77.4 90.8 90.1 96.1 39.2 71.6
VIIIrv 100 100 100 100 61.4 100
_
:~ lData at each time point are expressed relative to
denatured tissue control.
-21-
TABLE 2
OH
I
ArCOOCH2CHCH2-N-X
H
Add. Crystn.
Example Pr R Method Yield% Salt Solvent
XI ~ -C(c~l3)2c-cH I 22.7(COOH)2 iPrOHo
HO~ C(CH3)3 II73HCl iPrOH
XIII~ CH(CH3)2 II45(CCOH)2 Acetone
HO ~ EtOAC
O
xrv ~ C(CH3)3 II58 ~ICl Acetone
HO,~J EtOAC
HO
XVHO ~ C~CH3)3 II86 HCl Acetone
. ~ HO
HO
XVI ~ C(CH3)3 II3 -
(C~3)3C-CO
o
XVII O C(CH3)3 II 21 - Oil
(CH3)3C-C-O
(CH3)3C-C-O
