2-guanidino-4-arylthiazoles for treatment of peptic ulcers

2-Guanidino-4-arylthiazole compounds of the formula ##STR1## a pharmaceutically acceptable cationic or acid addition salt thereof wherein PA0 R.sup.1 is hydrogen, (C.sub.1 -C.sub.10)alkyl, optionally substituted phenyl or certain optionally substituted aralkyl groups; PA0 R.sup.2 is hydrogen or (C.sub.1 -C.sub.4)alkyl, and PA0 Ar is certain optionally substituted pyrrolyl or indolyl groups; method for their use in treatment of gastric ulcers, by inhibition of parietal cell H.sup.+ /K.sup.+ ATPase, and antiinflammatory conditions in combination with piroxicam, for use in mammals, and pharmaceutical compositions containing said compounds.

TECHNICAL FIELD 
The present invention relates to novel 2-guanidino-4-arylthiazole compounds 
wherein said 4-aryl group is a pyrrolyl or indolyl, each aryl group being 
optionally substituted, which are cytoprotectants and inhibitors of the 
H.sup.+ /K.sup.+ ATPase enzyme, method for their use in treating peptic 
ulcers in mammals, including humans; compositions containing said 
compounds; and method for treatment of inflammation in said mammals by 
administering said compounds in combination with piroxicam and 
compositions containing said combination with piroxicam. 
BACKGROUND ART 
Chronic gastric and duodenal ulcers, together known as peptic ulcers, are a 
common ailment for which a variety of treatments, including dietary 
measures, drug therapy and surgery, may be employed, depending on the 
severity of the condition. Particularly valuable therapeutic agents useful 
for the treatment of gastric hyperacidity and peptic ulcers are the 
histamine-H.sub.2 receptor antagonists, which act to block the action of 
the physiologically active compound histamine at the H.sub.2 -receptor 
sites in the animal body and to thereby inhibit the secretion of gastric 
acid. 
U.S. Pat. No. 4,374,843 issued Feb. 22, 1983, U.S. Pat. No. 4,435,396 
issued Mar. 6, 1984 and U.S. Pat. No. 4,560,690 issued Dec. 24, 1985 
disclose 2-guanidino-4-imidazolylthiazoles, 
2-guanidino-4-(1,2,4-triazolyl)thiazoles and 
2-guanidino-4-thiazolylthiazoles which are useful for treatment of gastric 
hyperacidity and peptic ulcers, some of which are also cytoprotective 
agents. Piroxicam, 
4-hydroxy-2-methyl-N-2-pyridinyl-2H-1,2-benzothiazine-3-carboxamide 
1,1-dioxide, is a known anti-inflammatory agent, see, e.g., U.S. Pat. No. 
3,591,584; and J. Lombardino et al., J. Med. Chem., 16, 493 (1973). 
DISCLOSURE OF THE INVENTION 
The present invention relates to a novel class of compounds which are 
useful in treating gastric ulcers in mammals by virtue of their activity 
as inhibitors of the gastric parietal cell, H.sup.+ /K.sup.+ ATPase, the 
enzyme ultimately responsible for hydrogen ion secretion. Said compounds 
are of the formula 
##STR2## 
a pharmaceutically acceptable cationic or acid addition salt thereof, 
wherein 
R.sup.1 is H, a straight chain or branched chain (C.sub.1 -C.sub.10)alkyl, 
(R.sup.4).sub.p C.sub.6 H.sub.3 or (R.sup.4).sub.p Ar.sup.1 
(CH.sub.2).sub.n where p is zero, 1 or 2; n is an integer from 1 to 4, the 
R.sup.4 groups are the same or different and are H, F, Cl, Br, I, 
CH.sub.3, CH.sub.3 O, NO.sub.2, OH, CN, COOR.sup.5 or OCOR.sup.5 and 
R.sup.5 is (C.sub.1 -C.sub.3)alkyl; 
Ar.sup.1 is the residue of a phenyl, naphthyl, furyl, thienyl, pyridyl, 
pyrimidinyl, thiazolyl or imidazolyl group, R.sup.2 is H or (C.sub.1 
-C.sub.4)alkyl; and 
Ar is 
##STR3## 
where 
m is 1, 2 or 3; 
R.sup.6 is H, (C.sub.1 -C.sub.4)alkyl or R.sup.10 SO.sub.2 and R.sup.10 is 
(C.sub.1 -C.sub.4)alkyl, phenyl, tolyl, benzyl or phenylethyl; and 
R.sup.3 is a substituent attached to any carbon atom in the Ar group other 
than one at a ring junction, at least one R.sup.3 is H or (C.sub.1 
-C.sub.4)alkyl and each of the remaining R.sup.3 is H, (C.sub.1 
-C.sub.4)alkyl, (C.sub.1 -C.sub.4)alkoxy, (R.sup.4).sub.2 C.sub.6 H.sub.3, 
(R.sup.4).sub.2 C.sub.6 H.sub.3 (CH.sub.2).sub.n, (R.sup.4).sub.2 C.sub.6 
H.sub.3 (CH.sub.2).sub.n O, COOR.sup.7, COR.sup.8, NHCOR.sup.8, NHCH.sub.2 
R.sup.8, NR.sup.8 R.sup.9, (CH.sub.2).sub.n NR.sup.8 R.sup.9, 
(CH.sub.2).sub.n-1 CONR.sup.8 R.sup.9, OH, CN, CF.sub.3, F, Cl or Br, 
wherein n and R.sup.4 are as previously defined; 
R.sup.7 is H, (C.sub.1 -C.sub.4)alkyl or benzyl; 
R.sup.8 and R.sup.9 taken separately are each H, (C.sub.1 -C.sub.10)alkyl, 
phenyl or benzyl, or when taken together with the nitrogen atom to which 
they are attached, form a 5-membered or 6-membered ring, optionally 
containing an atom of O or S or the group NR.sup.11 as a ring member and 
R.sup.11 is H, methyl or ethyl; 
with the proviso that when Ar is 
##STR4## 
and each R.sup.3 is H, at least one of R.sup.1, R.sup.2 or R.sup.6 is 
other than H; 
In each case, above, the bracketed range of carbon atoms refers to the 
total number of carbon atoms in the group. The carbon chain can be 
straight or branched. 
Pharmaceutically acceptable acid addition salts are those with from one to 
three equivalents of the acid, and especially with one or two equivalents. 
Suitable acids include, but are not limited to, HCl, HBr, H.sub.2 
SO.sub.4, H.sub.3 PO.sub.4, CH.sub.3 SO.sub.3 H, p-toluenesulfonic acid, 
maleic acid, fumaric acid, succinic acid and citric acid. For a current 
list of such salts see, e.g., Berge et al., J. Pharm. Sci., 66, 1-19 
(1977). 
Because of their facile preparation and high level of antisecretory 
activity, H.sup.+ /K.sup.+ ATPase inhibitory activity and/or 
cytoprotective activity as evidenced in tests for inhibition of 
ethanol-induced ulcers, preferred compounds of formula (I) are: 
(1) of the formula 
##STR5## 
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.6 are as defined above; 
particularly preferred such compounds are those wherein R.sup.1 is H, 
(R.sup.4).sub.2 C.sub.6 H.sub.3 CH.sub.2, (C.sub.4 -C.sub.8)alkyl, 
furylmethyl or thienylmethyl; R.sup.2 is H or methyl, one R.sup.3 is a 
substituent bonded to the 2-position of the pyrrole group and another 
R.sup.3 is H, (C.sub.1 -C.sub.4)alkyl, COOR.sup.7, CHO, (CH.sub.2).sub.n 
NR.sup.8 R.sup.9 or CONR.sup.8 R.sup.9 ; 
(2) of the formula 
##STR6## 
and particularly such compounds wherein R.sup.1 is H, (R.sup.4).sub.2 
C.sub.6 H.sub.3 CH.sub.2, (C.sub.4 -C.sub.8)alkyl, furylmethyl or 
thienylmethyl; R.sup.2 is H or CH.sub.3, R.sup.3 is H, F, Cl, Br, OH, 
(C.sub.1 -C.sub.4)alkoxy, (C.sub.1 -C.sub.4)alkyl, R.sup.4 C.sub.6 
H.sub.4, NHCOR.sup.8, (CH.sub.2).sub.n NR.sup.8 R.sup.9, R.sup.4 C.sub.6 
H.sub.4 CH.sub.2 O, CN or COOR.sup.7 ; and the thiazole group is bonded to 
the 2, 3 or 5-position of the indole; 
Especially preferred pyrrolyl thiazoles (II) of the invention are of the 
formula 
##STR7## 
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.6 are as previously defined. 
Most especially preferred invention compounds are the indolylthiazoles of 
the formulae 
##STR8## 
where R.sub.a.sup.3 and R.sub.b.sup.3 are as defined above for R.sup.3 and 
R.sub.c.sup.3 is H or (C.sub.1 -C.sub.4)alkyl; and 
##STR9## 
wherein R.sup.1, R.sup.2 and R.sup.3 are as previously defined. 
The most particularly preferred specific compounds of the invention are 
2-guanidino-4-[(2-piperidinocarbonyl)pyrrol-4-yl]thiazole, 
2-guanidino-4-(2-methylpyrrol-4-yl)thiazole, 
2-guanidino-4-(5-methylpyrrol-2-yl)thiazole, 
2-guanidino-4-[(2-methyl-1-phenylsulfonyl)pyrrol-4-yl]thiazole, 
2-guanidino-4-[(5-methyl-1-phenylsulfonyl)pyrrol-2-yl]thiazole, 
2-(N-benzylguanidino)-4-(2-methylpyrrol-4-yl)thiazole, 
2-(N-benzylguanidino)-4-(pyrrol-2-yl)thiazole, 
2-(N-benzylguanidino)-4-(2-methylpyrrol-3-yl)thiazole, 
2-(N-benzylguanidino)-4-(1-phenylsulfonyl-2-methyl)pyrrol-3-yl]-5-methylthi 
azole, 
4-(1H-indol-3-yl)-2-(N-benzylguanidino)thiazole, 
4-(5-methoxy-1H-indol-3-yl)-2-(N-benzylguanidino)thiazole, 
4-(5-chloro-1H-indol-3-yl)-2-(N-benzylguanidino)thiazole, 
4-(1H-indol-3-yl)-2-guanidinothiazole, 
4-(5-methoxy-1H-indol-3-yl)-2-guanidinothiazole, 
4-(5-chloro-1H-indol-3-yl)-2-guanidinothiazole, 
4-(2-methyl-1H-indol-3-yl)-5-methyl-2-guanidinothiazole, 
4-(2-methyl-1H-indol-3-yl)-5-methyl-2-(N-benzylguanidino)thiazole, 
4-(1H-indol-2-yl)-2-guanidinothiazole, and 
4-(1H-indol-2-yl)-2-(N-benzylguanidino)thiazole. 
The present invention further relates to a pharmaceutical composition 
useful for treating gastric ulcers in a mammal, including a human, by 
inhibiting gastric parietal cell H.sup.+ /K.sup.+ ATPase which comprises a 
pharmaceutically acceptable diluent or carrier and a gastric parietal cell 
H.sup.+ /K.sup.+ ATPase inhibiting amount of a compound of formula (I). 
Additionally, the invention relates to a method of treating gastric ulcers 
in a mammalian subject in need of such treatment by inhibiting parietal 
cell H.sup.+ /K.sup.+ ATPase which comprises administering to the subject 
a parietal cell H.sup.+ /K.sup.+ ATPase inhibiting amount of a compound of 
formula (I). 
Further, the invention provides an antiinflammatory composition comprising 
an antiinflammatory effective amount of piroxicam or a pharmaceutically 
acceptable salt thereof and a gastric parietal cell H.sup.+ /K.sup.+ 
inhibiting amount of a compound of the formula (I); and a method of 
treating inflammation in a mammal comprising administration to said mammal 
of an antiinflammatory effective amount of piroxicam or a pharmaceutically 
acceptable salt thereof and a gastric parietal cell H.sup.+ /K.sup.+ 
ATPase effective amount of a compound of the formula (I). 
DETAILED DESCRIPTION OF THE INVENTION 
The 4-aryl-2-guanidinothiazoles of formula (I) are prepared, for example, 
by the following reaction scheme: 
##STR10## 
Approximately equimolar amounts of the guanylthiourea of formula (X) and 
aryl-R.sup.2 -substituted-alpha-haloketone of formula (IX), wherein 
R.sup.1, R.sup.2 and Ar are as previously defined and X is chloro or 
bromo, are reacted in the presence of a reaction-inert solvent such as 
tetrahydrofuran, a lower alkanol such as methanol, ethanol or isopropanol; 
a lower alkyl ketone such as acetone or methylethylketone; 
dimethylsulfoxide or N,N-dimethylformamide. Preferred solvents are acetone 
and N,N-dimethylformamide. A preferred temperature for the above reaction 
to provide compounds of formula (I) is from about 20.degree. to 
120.degree. C. and especially from about 25.degree. to 60.degree. C. Under 
these conditions the formation of the desired product of formula (I) is 
substantially complete in from about 30 minutes to 24 hours, after which 
the product (I) is isolated by standard methods, well known in the art. 
For example, by cooling the reaction mixture to form a precipitate, 
evaporation of solvent or by addition of a nonsolvent, such as ethyl 
ether, to obtain the product in the form of its hydrochloride or 
hydrobromide salt. The salt is readily converted to the free base of 
formula (I) by standard neutralization/extraction methods. To obtain other 
pharmaceutically acceptable acid addition salts, the free base is taken up 
in an organic solvent and either one, two or three equivalents of acid 
corresponding to the desired salt is added. The salt is then recovered by 
filtration, concentration or addition of a nonsolvent, or by a combination 
of these methods. 
Preferred values of Ar for the invention compounds of formula (I) give rise 
to compounds of formula (II) and (III) as defined above. 
Compounds of formulae (II) or (III) where R.sup.3 is CH.sub.2 NH.sub.2, 
(CH.sub.2).sub.n NR.sup.8 R.sup.9 or NHCH.sub.2 R.sup.8 are prepared, for 
example, by reduction of the corresponding compounds wherein R.sup.3 is CN 
or an amide of formula (CH.sub.2).sub.n-1 CONR.sup.8 R.sup.9 or 
NHCOR.sup.8, respectively. Preferred reducing agents for the above 
reactions are the commercially available metal hydrides known in the art 
to be useful for such reductions. Examples of such metal hydrides are 
lithium aluminum hydride, lithium triethylborane, borane or diborane. 
Preferred reducing agents are borane/tetrahydrofuran, 
diborane/tetrahydrofuran and lithium aluminum hydride. Typically, the 
reduction is carried out under substantially anhydrous conditions and in 
the presence of a suitable reaction inert solvent, e.g., ethyl ether, 
tetrahydrofuran, 1,2-dimethoxyethane or diethyleneglycol dimethylether. A 
preferred range of temperature for these reduction reactions is from 
-70.degree. to 80.degree. C. and especially from room temperature to 
60.degree. C. Under these conditions the reduction is completed in from 
about 2 to 24 hours, after which the excess reducing agent is quenched, 
e.g., by cautious addition of wet solvent or ethyl acetate and the product 
isolated by standard extraction/evaporation methods and purified, if 
desired, by recrystallization or by column chromatography. 
In like manner aldehydes of formula (II) or (III) where R.sup.3 is CHO are 
reduced, preferably with sodium borohydride, to obtain the corresponding 
compounds wherein R.sup.3 is methyl. Typically such a reduction is carried 
out in a lower alkanol solvent such as methanol, ethanol or isopropanol at 
a temperature of from room temperature up to the reflux temperature of the 
solvent. 
Hydrolysis of a compound (II) or (III) wherein R.sup.6 is R.sup.10 SO.sub.2 
as defined above affords the corresponding compound where R.sup.6 is H. 
Typically the reaction is carried out in the presence of a strong base 
such as sodium hydroxide, sodium carbonate or potassium hydroxide, in 
aqueous solvent, preferably aqueous methanol or ethanol. While the 
hydrolysis can be carried out over a broad range of temperatures, a 
preferred temperature is from about room temperature up to 85.degree. C., 
and the reflux temperature of the solvent is especially preferred for 
reasons of efficiency and convenience. 
The starting alpha-halomethylaryl ketones (IX) are prepared, for example, 
by acylation of the appropriate ArH compound with an alpha-haloacid halide 
by the well-known Friedel-Crafts reaction. 
##STR11## 
where Ar, R and X are as previously defined. For a review of the 
Friedel-Crafts reaction see e.g., Groves, Chem. Soc. Rev. 1, 73 (1972). 
Alternatively, the starting ketones (IX) are obtained by Friedel-Crafts 
acylation with an acid anhydride followed by halogenation as shown below. 
##STR12## 
For starting compounds (IX) where Ar is one of the above pyrrole 
derivatives, the reaction is typically carried out with anhydrous aluminum 
chloride or boron trifluoride etherate as catalyst in a halogenated 
hydrocarbon solvent, preferably 1,2-dichloroethane or chloroform, at or 
about room temperature. For preparation of the indole derivatives of 
formula (XI), however, the acylation is typically carried out in the 
presence of pyridine and toluene at somewhat elevated temperature, 
preferably 40.degree.-80.degree. C. The halogenation of intermediate 
ketones (XI) is ordinarily carried out by controlled addition of an 
equimolar amount of elemental bromine or chlorine to a solution of the 
intermediate (XI) in a halogenated hydrocarbon solvent such as chloroform 
or methylene dichloride at a temperature of from about -20.degree. to 
+25.degree. C. The resulting mixture is then stirred at the temperature of 
the addition and/or at room temperature for several hours to complete the 
reaction. 
A useful method for preparation of compounds (IX) where Ar is indolyl is by 
acylation of the appropriate indolyl Grignard reagent. For example, 
reaction of a 5-substituted, or 2,5-disubstituted indole with 
methylmagnesium chloride in ethyl ether under anhydrous conditions in the 
cold affords a 1,3-bis-methylmagnesium indole intermediate in situ. This 
is immediately acylated with an acid halide of the formula R.sup.2 
CH(X.sup.1)COX.sup.2 where X.sup.1 is H, Cl or Br and X.sup.2 is Cl or Br, 
to provide the corresponding 1,3-diacylated indole. The latter is then 
selectively hydrolyzed to remove the 1-acyl group, e.g., with methanolic 
potassium carbonate at ambient temperature, to provide the desired 
3-alkanoyl- or 3-(.alpha.-haloalkanoyl)indole of formula (IX). 
Other methods for obtaining the starting alphahaloketones of formula (IX) 
are outlined below. 
##STR13## 
In the first reaction sequence the aryl carbonyl chloride, obtained by 
reaction of the corresponding carboxylic acid with thionyl chloride, 
phosgene or acetyl chloride/phosphorus pentachloride by well-known 
methods, is reacted with diazomethane in reaction inert solvent, such as 
ethyl ether, to form the diazo ketone. The diazo ketone is then reacted 
with gaseous hydrogen halide to form the desired starting compound (IX) 
where R.sup.2 is H. In the second such method the corresponding 
arylnitrile (ArCN) is reacted with an equimolar amount of Grignard 
reagent, R.sup.2 CH.sub.2 MgX, where X is Cl or Br, followed by contacting 
the resulting iminomagnesium halide complex with water to generate the 
ketone, ArCOCH.sub.2 R.sup.2, which is then halogenated as described above 
to form the starting compound (IX). 
The requisite starting guanylthioureas of formula (X) wherein R.sup.1 is as 
previously defined, are prepared, for example, by reaction sequence 
outlined below. 
##STR14## 
In the first step above the N-cyanoguanidine compounds (XII) are prepared 
by reaction of the appropriate amine (R.sup.1 NH.sub.2) and dicyanimide in 
approximately equimolar amounts by methods previously described by Curd et 
al., J. Chem. Soc., 1630 (1948) and by Redmon and Nagy in U.S. Pat. No. 
2,455,807. Typically, the reactants are heated in the presence of a polar 
organic solvent, e.g., a (C.sub.1 -C.sub.4)alkanol, water or mixtures 
thereof, preferably n-butanol, at a temperature of from 40.degree. to 
120.degree. C., preferably at the reflux temperature of the solvent. The 
N-cyanoguanidine product is then isolated, e.g., by cooling, filtering to 
remove precipitated salts and evaporation of the filtrate. 
The guanylthiourea intermediates (X) are obtained by reaction of the 
appropriate N-cyanoguanidine (XII) with hydrogen sulfide. This reaction is 
ordinarily carried out in the presence of a polar organic solvent such as 
a (C.sub.1 -C.sub.4)alkanol, acetone, ethyl acetate or dimethylsulfoxide; 
a preferred solvent is methanol. Typically, the reaction is carried out in 
the presence of a catalytic amount of a secondary amine, preferably 
diethylamine. The reaction can be carried out at atmospheric pressure or a 
higher pressure, e.g., at 3 to 10 atmospheres, and at a temperature of 
from about 10.degree. to 100.degree. C., preferably from 25.degree. to 
80.degree. C. Of course, when the reaction is run at a higher temperature 
within the preferred range, the reaction time will be shorter. Conversely, 
at a lower temperature the reaction time required will be longer. The 
product is ordinarily isolated simply by evaporation of solvent. In many 
cases the crude product, thusly obtained, is of sufficient purity for use 
in the next reaction step. Alternatively, the crude product can be 
purified, e.g., by column chromatography. 
The details of the methods for providing the starting guanylthioureas (X) 
and the amines, R.sup.1 NH.sub.2, used in their preparation are set forth 
in the embodiment below, and in U.S. Pat. No. 4,560,690. 
The pharmaceutically acceptable acid addition salts of the novel compounds 
of formula (I) are also embraced by the present invention. The salts are 
readily prepared by contacting the free base with an appropriate mineral 
or organic acid in either aqueous solution or in a suitable organic 
solvent. The solid salt may then be obtained by precipitation or by 
evaporation of the solvent. Especially preferred salts are the 
hydrochloride and dihydrochloride. 
The utility of the present compounds as antiulcer agents is reflected in 
vitro by their inhibition of H.sup.+ / K.sup.+ ATPase isolated from 
canine gastric mucosa. The enzyme activity was assayed according to Beil 
et al., Brit. J. Pharmacol. 82, 651-657 (1984) with slight modifications. 
The enzyme (1-2 micrograms) was preincubated at 37.degree. C. for 45 
minutes with a medium containing 2.times.10.sup.-3 M MgCl.sub.2, 0.05M 
Tris-Cl buffer (pH 7.5) with or without 0.01M KCl, and the acid activated 
test drug in a final volume of 0.590 ml. The reaction was started by the 
addition of 0.010 mmol of ATP (final concentration 3.times.10.sup.-3 M). 
The reaction was terminated by adding trichloroacetic acid to a 
concentration of 4.2%. Liberated inorganic phosphate was determined using 
Fiske and Subbarow Reducer available commercially (e.g., from Sigma 
Chemical Co., P.O. Box 14508, St. Louis, Mo. 63178, U.S.A.). In this test 
the drugs are preferably first acid activated by incubating in 1:1 
dimethylsulfoxide:0.02N HCl at 37.degree. C. for 30 minutes. In this test 
the preferred compound 4-(1H-indol-3-yl)-2-(N-benzylguanidino)thiazole 
hydrochloride showed an IC.sub.50 (i.e., the concentration which inhibits 
the enzyme to the extent of 50%) of 2.times.10.sup.-6 M; 
4-(5-chloro-1H-indol-3-yl)-2-(N-benzylguanidino)thiazole had an IC.sub.50 
of 0.6.times.10.sup.-6 M; 2-guanidino-4-(2-methylpyrrol-4-yl)thiazole had 
an IC.sub.50 of 15.times.10.sup.-6 M and 
4-(3-methoxyphenyl)-2-(N-benzylguanidino)thiazole had an IC.sub.50 of 
10.times.10.sup.-6 M. 
The in vivo utility of the present compounds as antiulcer agents is also 
particularly shown by their cytoprotective activity. Such activity is 
demonstrated by the inhibition of ethanol-induced gastric ulceration in 
rats, using the method of Example 18 of U.S. Pat. No. 4,560,690. In this 
test, preferred 2-guanidino-4-(2-methylpyrrol-4-yl)thiazole at a dose of 
30 mg/kg gave 100% inhibition and 
2-(N-benzylguanidino)-4-(pyrrol-2-yl)thiazole gave 99% inhibition. 
The in vivo utility of the present compounds as antiulcer agents is, in 
part, reflected by their gastric antisecretory activity in rats by the 
following method: 
A rat is placed in an ether jar until it has no blink reflex or pinch 
reflex (usually the rat is slightly cyanotic). The rat is then placed on 
its back, an ether cone is placed over its nose. It is important to 
monitor the coloring of the rat, and to remove the cone if the rat becomes 
excessively blue. With rat tooth forceps, the skin is lifted and an 
incision is made with small scissors from 2 cm below the sternum to the 
sternum. The muscle layer is cut in the same manner, exposing a view of 
the liver. The large lobe of the liver is gently lifted with straight 
smooth forceps exposing the pancreatic tissue and the intestine. The 
intestine is gently elevated and the pylorus sphincter is localized 
without touching the stomach. Curved forceps are carefully inserted 
beneath the pylorus. A length of silk thread (approximately 10 cm) is 
pulled through and snugly tied in a square knot. If the blood vessel is 
severed during the process, the rat is not used since the blood supply to 
the stomach will have been severely compromised under such conditions. An 
injection of drug or vehicle is made into the duodenum. The rat is lifted 
up by grasping above and below the incision, and the abdominal contents 
are gently inserted back into the cavity. The incision is closed with 
wound clips. Subsequent to stapling of wounds, rats are housed in show box 
cages with other surgerized rats, 4/cage. Within 15 minutes rats appear to 
be fully recovered from the ether anesthesia. They are carefully monitored 
for bleeding, which can occur if the staples are not properly positioned. 
Two hours after surgery the rat is sacrificed by i.p. injection of sodium 
pentabarbitol (1 ml/kg). Rat tooth forceps are used to lift the abdomen, 
and it is then cut open with dissecting scissors. The large lobe of the 
liver is lifted. The esophagus is located under the smaller lobe of the 
liver. Curved forceps are placed under the esophagus and it is lifted. A 
hemostat is used to clamp off the esophagus from the stomach and to gently 
cut the stomach free. In a funnel over a borosilicate tube, the stomach is 
cut along the greater curvature releasing the contents. The last of the 
contents is squeezed out. The fluid containing tubes are spun in the 
centrifuge at 3000.times. rpm for 15 minutes at room temperature. The 
supernatants are carefully removed with pasteur pipettes, and placed in 
the graduated centrifuge tubes. Volumes are recorded. An automatic 
titrator (endpoint=pH 7.0) is used to determine pH and microequivalents of 
acid output/hr/100 g rat body weight. Results are reported as % inhibition 
of acid secretion in mg/kg. 
The oral protective effect of the present compounds on piroxicam-induced 
gastric lesions is determined in rats according to the method of Example 1 
of U.S. Pat. No. 4,559,326. 
For the treatment (prophylactic and therapeutic) of gastric ulcers in a 
mammalian subject by inhibiting gastric parietal cell H.sup.+ /K.sup.+ 
ATPase, the products of the present invention are administered by a 
variety of conventional routes of administration including oral and 
parenteral. Preferably, the compounds are administered orally. In general, 
these compounds will be administered orally at doses between about 0.25 
and 50 mg/kg body weight of the mammalian subject to be treated per day, 
preferably from about 0.5 to 30 mg/kg per day, in single or divided doses. 
If parenteral administration is desired, then these compounds can be given 
at total daily doses between about 0.2 and 20 mg/kg body weight of the 
mammalian subject to be treated. In a 100 Kg man, this translates to a 
daily oral dosage of about 25-5000 mg/day (preferably about 50-3000 
mg/day) and a parenteral dosage of about 20-2000 mg/day. However, at the 
discretion of the attending physician, some variation in dosage will 
necessarily occur, depending upon the condition of the subject being 
treated and the particular compound employed. 
When co-administering piroxicam and a compound of the formula (I) to a 
mammal, particularly man, the oral route is preferred. The piroxicam is 
generally dosed in the range of about 0.1 to 1 mg/kg/day (or about 10-100 
mg/day in a 100 Kg man), in single or multiple doses. The compound of the 
formula (I) is dosed according to the dosage regimen noted above. If 
desired, the compounds are dosed separately, but they are preferably 
co-administered in a single, combined formulation suitable for single or 
multiple daily dosage, as desired. Again, at the discretion of the 
attending physician, there can be some variation in this dosage regimen. 
The compounds of the formula (I) are administered alone or in combination 
with piroxicam. In either case, the active ingredients will generally be 
further combined with pharmaceutically acceptable carriers or diluents. 
Suitable pharmaceutical carriers include inert diluents or fillers, 
sterile aqueous solutions and various organic solvents. The pharmaceutical 
compositions formed by combining the novel compounds of formula (I) or 
salts thereof and pharmaceutically acceptable carriers are readily 
administered in a variety of dosage forms such as tablets, powders, 
capsules, lozenges, syrups and the like. These pharmaceutical compositions 
can, if desired, contain additional ingredients such as flavorings, 
binders, excipients and the like. Thus, for oral administration, tablets 
containing various excipients, such as sodium citrate, are employed 
together with various disintegrants such as starch, alginic acid and 
certain complex silicates, together with binding agents such as 
polyvinylpyrrolidone, sucrose, gelatin and acacia. Additionally, 
lubricating agents such as magnesium stearate, sodium lauryl sulfate and 
talc are often useful for tableting purposes. Solid compositions of a 
similar type may also be employed as fillers in soft and hard filled 
gelatin capsules. Preferred materials therefor include lactose or milk 
sugar and high molecular weight polyethylene glycols. When aqueous 
suspensions or elixirs are desired for oral administration, the essential 
active ingredient therein may be combined with various sweetening or 
flavoring agents, coloring matters or dyes and, if desired, emulsifying 
agents or suspending agents, together with diluents such as water, 
ethanol, propylene glycol, glycerin, or combinations thereof. 
Preferably, the products of this invention are administered orally in unit 
dosage form, i.e., as a single physically discrete dosage unit containing 
an appropriate amount of the active compound in combination with a 
pharmaceutically acceptable carrier or diluent. Examples of such unit 
dosage forms are tablets or capsules containing from about 5 to 1,000 mg 
of the active ingredient, the compound of formula (I) comprising from 
about 10% to 90% of the total weight of the dosage unit. 
For parenteral administration, solutions or suspensions of the compounds of 
formula (I) in sterile aqueous solutions, for example aqueous propylene 
glycol, sodium chloride, dextrose or sodium bicarbonate solutions are 
employed. Such dosage forms are suitably buffered if desired. The 
preparation of suitable sterile liquid media for parenteral administration 
will be well known to those skilled in the art.