Substituted 2-Pyridinyl Benzimidazoles, and Their Use for Inhibiting Gastric Acid Secretion

The present invention is related to new benzimidazole derivatives having valuable therapeutic properties especially in affecting gastric acid secretion and providing gastrointestinal cytoprotective effect in mammals, including man, as well as processes for the preparation of the new compounds, pharmaceutical compositions comprising them and a method of affecting gastric acid secretion and providing gastrointestinal cytoprotective effect when using them.

In several documents e.g. No. EP-A1-005 129, No. GB-A-20 38 825, U.S. Pat. No. 4,327,102, U.S. Pat. No. 4,182,766 and No. EP-A-80 602 heterocyclic compounds active as inhibitors of gastric acid secretion have been described. Two of these documents namely No. EP-A1-1 0 005 129 and No. EP-A-80 602 describe substituted [[(2-pyridinyl)-methyl]-sulfinyl]-1H-benzimidazoles and also in U.S. Pat. No. 4,097,603 such compounds and their thioanalogoues have been described. According to the last mentioned document the compounds are known as cytoprotective agents. Because of their antisecretory effect the known compounds may be used in the treatment of gastrointestinal diseases, e.g. peptic ulcer.

According to the present invention it has now surprisingly been found that a new type of substituted benzimidazoles, namely compounds of the general formula ##STR2## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are the same or different and are hydrogen, an alkyl, cycloalkyl, alkoxy, alkoxyalkyl, alkoxyalkoxy, halogen, --CN, --CF.sub.3, --NO.sub.2, --COR.sup.12, alkylthio, alkylsulfinyl, aryl, arylalkyl, aryloxy or arylalkoxy group, or wherein R.sup.1 and R.sup.2, R.sup.2 and R.sup.3 or R.sup.3 and R.sup.4 together with the adjacent carbon atoms in the benzimidazole ring form one or more 5-, 6- or 7-membered rings, which each may be saturated or unsaturated and may contain 0-3 hetero atoms selected from N, S and O, and whereby each ring may be optionally substituted with 1-4 substituents selected from alkyl groups with 1-3 carbon atoms, or two or four of the mentioned substituents together form one or two oxo groups ##STR3## whereby if R.sup.1 and R.sup.2, R.sup.2 and R.sup.3 or R.sup.3 and R.sup.4 together with the adjacent carbon atoms in the benzimidazole ring form two rings these rings may be condensed with each other; R.sup.5, R.sup.6 and R.sup.8 are the same or different and are selected from hydrogen and alkyl; R.sup.7 is hydrogen, an alkyl, alkoxy, aryl, arylalkyl, aryloxy, arylalkoxy, alkenyloxy or alkynyloxy group; or R.sup.6 and R.sup.7, or R.sup.7 and R.sup.8 together with the adjacent carbon atoms in the pyridine ring form a 5- or 6-membered, saturated or unsaturated ring, which may optionally contain an oxygen or an optionally alkylated nitrogen atom; R.sup.9 is --CN, --SO.sub.2 H, --SO.sub.2.sup..crclbar., --S--A--R.sup.10, --S--R.sup.11, ##STR4## or a group --BI (which is the part of the structure within broken lines as defined in formula I); A is an alkylene or cycloalkylene group; R.sup.10 is a hydrogen, a --CN, --CF.sub.3, --NO.sub.2, --COR.sup.13, --NR.sub.2.sup.4, --OR.sup.14, --SR.sup.14, ##STR5## --NHCOR.sup.15, --OCOR.sup.15, --SCOR.sup.15, aryl, arylalkyl, aryloxy or arylalkoxy group; R.sup.11 is an aryl group which may be optionally substituted by one or more substituents selected from alkyl, alkoxy, halogen, --CN, --CF.sub.3, --NO.sub.2 and --COR.sup.13 ; R.sup.12 and R.sup.15 are the same or different and selected from alkyl, aryl, aryloxy and alkoxy; R.sup.13 is selected from alkyl, aryl, aryloxy, alkoxy and hydroxy; and R.sup.14 is hydrogen or an alkyl group, as well as pharmaceutically acceptable acid addition salts (IA) thereof and in applicable cases pharmaceutically acceptable alkaline salts thereof (e.g. when R.sup.9 is S--CH.sub.2 CH.sub.2 COOH) are effective as gastrointestinal cytoprotectives and as inhibitors of gastric acid secretion in mammals and man.

The group alkyl in the definitions of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.11, R.sup.12, R.sup.13, R.sup.14 and R.sup.15 is preferably a lower alkyl group having 1-7 carbon atoms, especially preferred 1-4 carbon atoms, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl or isobutyl.

The group alkoxy in the definitions of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.7, R.sup.11, R.sup.12, R.sup.13 and R.sup.15 is preferably a lower alkoxy group having 1-7 carbon atoms, especially preferred 1-3 carbon atoms, e.g. methoxy, ethoxy, n-propoxy or isopropoxy.

Halogen in the definitions of R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.11 is preferably chloro, bromo, fluoro or iodo.

In R.sup.1, R.sup.2, R.sup.3 and R.sup.4 representing alkylthio or alkylsulfinyl is the alkyl preferably a lower alkyl having 1-7 carbon atoms, especially preferred 1-4 carbon atoms, e.g. methylthio, methylsulfinyl, ethylthio, ethylsulfinyl, isopropylthio, n-butylsulfinyl or isobutylthio.

R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.7, R.sup.10, R.sup.11, R.sup.12, R.sup.13 and R.sup.15 representing an aryl group have preferably up to 10 carbon atoms, especially preferred up to 6 carbon atoms, e.g. a phenyl group.

R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.7, R.sup.10, R.sup.12, R.sup.13 and R.sup.14 representing an aryloxy group have preferably up to 10 carbon atoms, especially preferred up to 6 carbon atoms, e.g. a phenoxy group.

R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.7 and R.sup.10 representing an arylalkyl or arylalkoxy group have preferably up to 10 carbon atoms in the aryl group and 1-7 carbon atoms in the alkyl group or alkoxy group, respectively, especially preferred are 6 carbon atoms in the aryl group and 1-3 carbon atoms in the alkyl group or alkoxy group, respectively, e.g. phenylmethyl, phenylethyl, phenylmethoxy, phenylethoxy, phenylpropyl and phenylisopropoxy.

R.sup.1, R.sup.2, R.sup.3 and R.sup.4 representing an cycloalkyl group have preferably 3-7 carbon atoms, especially preferred 5-6 carbon atoms, e.g. cyclopentyl, cyclohexyl and methylcyclopentyl.

R.sup.1, R.sup.2, R.sup.3 and R.sup.4 representing an alkoxyalkyl or alkoxyalkoxy group have preferably 1-7 carbon atoms in the alkoxy group or groups and alkyl group, respectively, especially preferred 1-3 carbon atoms in the alkoxy group or groups and the alkyl group, respectively, e.g. methoxyethyl, methoxypropyl, ethoxyethyl, propoxyethyl, methoxyethoxy, methoxypropoxy, ethoxyethoxy and propoxyethoxy.

R.sup.7 representing an alkenyloxy or alkynyloxy group has preferably 2-7 carbon atoms, especially preferred 3-4 carbon atoms, e.g. allyloxy, propargyloxy, 2-butenyloxy and 2-butynyloxy.

Illustrative examples of ring structures formed by R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, R.sup.3 and R.sup.4 are --CH.sub.2 CH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 --, --CH.sub.2 C(CH.sub.3).sub.2 CH.sub.2 --, --(CH.sub.2).sub.5 --, --CH.dbd.CH--CH.dbd.CH--, --CH.sub.2 COCH.sub.2 --, --OCH.sub.2 O--, --OCH.sub.2 CH.sub.2 O--, --OCH.sub.2 CH.sub.2 CH.sub.2 O--, --OCH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 NH--, --CH.dbd.CH--CH.dbd.N--, --COCH.sub.2 CO--, --SCH.sub.2 CH.sub.2 --, --SCH.sub.2 S-- and --SCH.sub.2 CH.sub.2 S--.

R.sup.6 and R.sup.7, or R.sup.7 and R.sup.8 representing a 5- or 6- membered saturated or unsaturated ring is preferably a saturated carbocyclic ring or a saturated ring containing an oxygen atom in the 4-position in the pyridine ring, e.g. --CH.sub.2 CH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 --, --O--CH.sub.2 CH.sub.2 --, or --O--CH.sub.2 CH.sub.2 CH.sub.2 --. --A-- representing an alkylene group is preferably a lower alkylene group containing 1-7 carbon atoms, especially preferred 1-4 carbon atoms, e.g. methylene, ethylene, propylene or butylene. --A-- representing a cycloalkylene group is preferably a lower cycloalkylene containing 3-7 carbon atoms, especially preferred 5 or 6 carbon atoms, e.g. cyclopentylene or cyclohexylene.

Acids suitable for giving acid addition salts of compounds of the formula I are relatively strong acids such as HCl, HBr, HI, HBF.sub.4, HPF.sub.6, HAuCl.sub.4 and HClO.sub.4.

Bases suitable for giving alkaline salts of compounds of the formula I are LiOH, NaOH, KOH, Mg(OH).sub.2 and Ca(OH).sub.2.

Preferred groups of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are hydrogen, alkyl, alkoxy, --CF.sub.3, --COOCH.sub.3, phenyl, phenoxy, --OCH.sub.2 O-- and --CH.sub.2 CH.sub.2 CH.sub.2 --.

Further preferred groups of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are hydrogen, methyl, ethyl, isopropyl, CF.sub.3.

Preferred groups of the radical R.sup.5 is hydrogen and methyl. An especially preferred group of the radical R.sup.5 is hydrogen.

Preferred groups of the radicals R.sup.6 and R.sup.8 are hydrogen, methyl and ethyl.

Preferred groups of the radical R.sup.7 are hydrogen, alkyl, alkoxy, aryl, aryloxy, alkenyloxy and cyclic structures with --OCH.sub.2 CH.sub.2 -- and --OCH.sub.2 CH.sub.2 CH.sub.2 --. Further preferred groups of the radical R.sup.7 are hydrogen, methyl, methoxy, phenyl, phenoxy and allyloxy. Particularly preferred are hydrogen, methoxy, phenyl and phenoxy.

Preferred groups of the radical R.sup.9 are --CN, --SO.sub.2.sup..crclbar., alkylthio, hydroxyalkylthio, carboxyalkylthio, phenylthio. Further preferred groups of the radical R.sup.9 are --CN, --SO.sub.2.sup..crclbar., ethylthio, t-butylthio, hydroxyethylthio, carboxymethylthio and phenylthio. Still further preferred groups of the radical R.sup.9 are ethylthio, hydroxyethylthio and phenylthio.

Preferred of the pyridine fragments are ##STR6## For the compounds with the general formula I containing an unsymmetric centre, e.g. compounds wherein R.sup.5 is other than hydrogen, both the pure enantiomers and the racemic mixtures are within the scope of the present invention.

It should be noted that for all the compounds of the invention R.sup.1 and R.sup.4 as well as R.sup.2 and R.sup.3 are considered to be equivalent. This is due to the tautomerism in the imidazole part of the benzimidazole nucleus causing an equilibrium between the two possible >NH-- forms.

Illustrative examples of compounds included in the scope of the invention are given in the following Table 1. Illustrative examples of compounds included in the scope of the invention ##STR7## R.sup.1 R.sup.2 R.sup.3 R.sup.4 R.sup.5 R.sup.6 R.sup.7 R.sup.8 R.sup.9 I/X.sup..crclbar. H H H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I CH.sub.3 HH H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I H CH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I CH.sub.3 CH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I H CH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I CH.sub.3 H CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I CH.sub.3 H H CH.sub.3 H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I CH.sub.3 CH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I CH.sub.3 H CH.sub.3 CH.sub.3 H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I CH.sub.3 CH.sub.3 CH.sub.3 CH.sub.3 H CH.sub.3 OCH.sub. 3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I H C.sub.2 H.sub.5 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH Cl.sup.- H CH(CH.sub.3).sub.2 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH Br.sup.- H ##STR8## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH BF.sub.4.sup.- CH.sub.3 C.sub.2 H.sub.5 CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH PF.sub.6.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OC.sub.2 H.sub.5 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I H Cl H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH Cl.sup.- H CN H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH Br.sup.- H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H NO.sub.2 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I H SCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH BF.sub.4.sup.- H ##STR9## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H COOCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H COOCH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H ##STR10## CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H ##STR11## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H ##STR12## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H ##STR13## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H ##STR14## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H ##STR15## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H COCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H COCH.sub.2 CH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H CH.sub.3 CH.sub.3 H CH.sub.3 CH.sub.3 H CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H CH.sub.3 CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- CHCHCHN H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H CHCHCHCH H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H CH.sub.2 CH.sub.2 CH.sub.2 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.2 O H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- ##STR16## H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 H CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 CH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 CH.sub.3 H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H CH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H OCH.sub.3 H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H OCH.sub.3 C.sub.2 H.sub.5 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H ##STR17## H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H ##STR18## H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H ##STR19## C.sub.2 H.sub.5 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H ##STR20## C.sub.2 H.sub.5 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 ##STR21## CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.2 CHCH.sub.2 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.2 CCH CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CHCHCHCH H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H CHCHCHCH SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H OCH.sub.2 CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.2 CH.sub.2 CH.sub.2 O H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.2 CH.sub.2 O H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H OCH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.2 CH.sub.2 CH.sub.2 H SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H H CH.sub.2 CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.3 ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR22## ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SC(CH.sub.3).sub.3 ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR23## ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 COOH ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SO.sub.2.sup.- I H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 CN I H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR24## ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR25## ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR26## 2 .times. ClO.sub.4.sup.- H CH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 H ##STR27## 2 .times. Cl.sup.- H COOCH.sub.3 CH.sub.3 H H CH.sub.3 H H SCH.sub.2 CH.sub.2 OH I H COOCH.sub.3 CH.sub.3 H H CH.sub.3 H H SCH.sub.2 CH.sub.3 I H COOCH.sub.3 CH.sub.3 H H CH.sub.3 H H ##STR28## Cl.sup.- H CH.sub.3 H H H CH.sub.3 H CH.sub.3 ##STR29## Br.sup.- H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR30## I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 NH.sub.2 I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR31## I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR32## Cl.sup.- H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 ##STR33## Br.sup.- H CF.sub.3 H H H H OCH.sub. 3 CH.sub.3 ##STR34## ClO.sub.4.sup.- H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 N(CH.sub.3).sub.2 I H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 ##STR35## I H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 ##STR36## Cl.sup.- H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 ##STR37## Cl.sup.- H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OCH.sub.3 Cl.sup.- H CF.sub.3 H H H H OCH.sub.3 H SCH.sub.2 CH.sub.2 CH.sub.2 SC.sub.2 H.sub.5 I H CF.sub.3 H H H H OCH.sub.3 H SCH.sub.2 CH.sub.2 CN I H CF.sub.3 H H H H OCH.sub.3 H SCH.sub.2 CH.sub.2 COOCH.sub.3 I H CF.sub.3 H H H H OCH.sub.3 H SCH.sub.2 CH.sub.2 OH Br.sup.- H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR38## .times. 2Br.sup.- H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 ##STR39## 2BF.sub.4.sup.- H CF.sub.3 H H H H OCH.sub.3 H ##STR40## 2Cl.sup.- CH.sub.3 OCH.sub.2 CH.sub.2 OCH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H CH.sub.2 CH.sub.2 OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H ##STR41## H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- C H.sub.3 Br CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- ##STR42## H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H CHCHNCH H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH ClO.sub.4.sup.- H CH.sub.2 CH.sub.2 S H H CH.sub.3 H CH.sub.3 SCH.sub.2 CH.sub.3 I H OCH.sub.2 CH.sub.2 H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH I H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 NH.sub.2 Br.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OCH.sub.3 Cl.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 COOCH.sub.3 I H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 OH Br H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR43## I H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR44## Cl H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 SCH.sub.2 CH.sub.2 CN ClO.sub.4.sup.- H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR45## I H CH.sub.3 H H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR46## I H CH.sub.3 H H H CH.sub.3 H CH.sub.3 ##STR47## 2 .times. Cl.sup.- H CH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR48## 2 .times. Br.sup.- H CH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 H ##STR49## 2 .times. ClO.sub.4.sup.- H CH.sub.3 H H H H OCH.sub.3 C.sub.2 H.sub.5 ##STR50## I H CH.sub.3 CH.sub.3 H H H OCH.sub.3 C.sub.2 H.sub.5 ##STR51## I H CH.sub.3 H H H CH.sub.3 CH.sub.3 H ##STR52## I H CH.sub.3 H H H H CH.sub.3 CH.sub.3 ##STR53## I H CH.sub.3 CH.sub.3 H H CH.sub.3 CH.sub.3 H ##STR54## I H CH.sub.3 CH.sub.3 H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR55## I CF.sub.3 H H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR56## I CF.sub.3 H H H H CH.sub.3 OCH.sub.3 H ##STR57## I CF.sub.3 H H H H H OCH.sub.3 H ##STR58## I CF.sub.3 H H H H H OCH.sub.3 CH.sub.3 ##STR59## I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR60## I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 H ##STR61## I H CF.sub.3 H H H H OCH.sub.3 H ##STR62## I H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 ##STR63## I H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR64## I H CH.sub.3 H H H CH.sub.3 OCH.sub.3 H ##STR65## 2 .times. Cl.sup.- CF.sub.3 H H H H CH.sub.3 OCH.sub.3 H ##STR66## I H CF.sub.3 H H H CH.sub. 3 OCH.sub.3 H ##STR67## I H OCH.sub.3 H H H CH.sub.3 OCH.sub.3 H ##STR68## I H CH.sub.3 H H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR69## 2 .times. Cl.sup.- H CH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR70## 2 .times. Br.sup.- H CH.sub.3 CH.sub.3 H H CH.sub.3 OCH.sub.3 H ##STR71## I H CH.sub.3 H H H H OCH.sub.3 C.sub.2 H.sub.5 ##STR72## I H CH.sub.3 CH.sub.3 H H H OCH.sub.3 C.sub.2 H.sub.5 ##STR73## I H OCH.sub.3 H H H H OCH.sub.3 C.sub.2 H.sub.5 ##STR74## I H OCH.sub.3 H H H H CH.sub.3 CH.sub.3 ##STR75## I H OCH.sub.3 H H H CH.sub.3 CH.sub.3 H ##STR76## I H CH.sub.3 CH.sub.3 H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR77## I H CH.sub.3 H H H CH.sub.3 H CH.sub.3 ##STR78## I CF.sub.3 H H H H CH.sub.3 OCH.sub.3 H ##STR79## I CF.sub.3 H H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR80## I CF.sub.3 H H H H H OCH.sub.3 CH.sub.3 ##STR81## I CF.sub.3 H H H H H OCH.sub.3 H ##STR82## I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 CH.sub.3 ##STR83## I H CF.sub.3 H H H CH.sub.3 OCH.sub.3 H ##STR84## I H CF.sub.3 H H H H OCH.sub.3 CH.sub.3 ##STR85## I H CF.sub.3 H H H H OCH.sub.3 H ##STR86## I

The compounds of formula IA as defined above are prepared by reacting a compound of the formula II ##STR87## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are as defined above under formula I with a compound of the formula III

wherein R.sup.9 is as defined above under formula I, to give a compound of the formula IA. The reaction of a compound of formula II above with a compound of formula III is carried out in the presence of an acid in a suitable solvent. Suitable acids include for example HCl, HClO.sub.4, CF.sub.3 COOH, HPF.sub.6, HBF.sub.4, HBr. Suitable solvents for the above described reaction include, for example, water, alcohols, preferably lower alkanols such as methanol and ethanol, and halogenated hydrocarbons, such as methylene chloride. If desired a compound of formula IA may be converted to the corresponding compound of formula I by treatment with a base, such as hydroxides, carbonates or hydrocarbonates of alkali metals.

The invention also relates to pharmaceutical compositions containing the new benzimidazole derivatives as active ingredient; to the use of the novel benzimidazole derivatives in therapy, especially for providing gastrointestinal cytoprotective effects in mammals and man; to the use of the novel benzimidazole derivatives in the prevention and treatment of gastrointestinal inflammatory diseases in mammals and man; to a method for inhibiting gastric acid secretion in mammals and man by administering a compound of the formula I; to a method for the treatment of gastrointestinal inflammatory diseases in mammals and man by administering a compound of the formula I; and to a method for providing gastrointestinal cytoprotective effects in mammals and man by administering a compound of the formula I.

For clinical use the compounds of the invention are formulated into pharmaceutical formulations for oral, rectal, parenteral or other mode of administration. The pharmaceutical formulation contains a compound of the invention suitably in combination with a pharmaceutically acceptable carrier. The carrier may be in the form of a solid, semisolid or liquid diluent, or a capsule. These pharmaceutical preparations are a further object of the invention. Usually the amount of active compound is between 0.1-95% by weight of the preparation.

In the preparation of pharmaceutical formulations containing a compound of the present invention in the form of dosage units for oral administration the compound selected may be mixed with a solid, powdered carrier, e.g. calcium phosphate, lactose, saccharose, sorbitol, mannitol, starch, amylopectin, cellulose derivatives or gelatin, as well as with lubricating agents e.g. magnesium stearate, sodium steryl fumarate and polyethylene glycol waxes. The mixture is then processed into granules or pressed into tablets. The tablets may be film coated by a suitable film-forming material.

Soft gelatine capsules may be prepared with capsules containing a mixture of the active compound or compounds of the invention and a suitable vehicle for soft gelatine capsules. Hard gelatine capsules may also contain the active compound in combination with a solid powdered carrier e.g. lactose, saccharose, sorbitol, mannitol, potato starch, corn starch, amylopectin, cellulose derivatives or gelatine.

The oral dosage forms may be enteric coated. The enteric coating is chosen among pharmaceutically acceptable enteric-coating materials e.g. beeswax, shellac or anionic film-forming polymers such as cellulose acetate phthalate, hydroxypropyl methylcellulose phthalate, partly methyl esterified methacrylic acid polymers and the like, if preferred in combination with a suitable plasticizer. To this coating various dyes may be added in order to distinguish among tablets or granules with different active compounds or with different amounts of the active compound present.

The typical daily dose of the active substrate varies within a wide range and will depend on various factors such as for example the individual requirement of each patient, the manner of administration and the disease. In general, oral and parenteral dosages will be in the range of 1 to 400 mg per day of active substance.

The invention is illustrated by the following examples.

5-Methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzi midazole (3.45 g, 0.01 mol) was added under stirring to a solution of mercapto ethanol (0.8 g, 0.011 mol) and HClO.sub.4 (1.9 g, 0.013 mol) in 100 ml of CH.sub.2 Cl.sub.2. A few minutes later 50 ml of H.sub.2 O was added. Extraction with CH.sub.2 Cl.sub.2, separation of the phases, drying of the organic phase and evaporation of the solvent gave the desired product as the ClO.sub.4.sup.- acid salt (4.0 g, 79%), NMR

2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole (0.53 g, 0.0017 mol) was added to 17 ml of 0.1M HCl in methanol and stirred for 7 min. at 37.degree. C. Mercaptoethanol (0.14 g, 0.0018 mol) was added dropwise to the stirred solution. After stirring for 10 min. HPF.sub.6 (0.35 ml) in 5 ml of methanol was added. After evaporation of some of the solvent the solution was cooled. The crystallized product was filtered off and suspended in water. After filtration the desired product was obtained as the PF.sub.6.sup.- salt (0.62 g, 70%), NMR

5-Methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzi midazole (1 g, 0.0029 mol) was added to a solution of KCN (0.57 g, 0.0088 mol) and CF.sub.3 COOH (1 g, 0.0088 mol) in 100 ml of H.sub.2 O. To get a clear solution another amount of CF.sub.3 COOH was added and the mixture was stirred for 30 min. at room-temperature. The solution was made alkaline with NaHCO.sub.3. The precipitate was filtered off and suspended in water. Filtration and drying gave the desired product (0.7 g, 68%), NMR

5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulphinyl]-1H-benz imidazole (1.73 g, 0.005 mol) was added to 50 ml of 0.1 mol HCl in methanol and stirred for 7 minutes at 37.degree. C. Cysteine (0.7 g, 0.0058 mol) was added to the stirred solution. After stirring for 10 minutes HBF.sub.4 (35%) (1.5 ml) was added dropwise to the solution. Some of the solvent was evaporated and 50 ml of water was added. The water solution was washed twice with CH.sub.2 Cl.sub.2. The water was evaporated and the desired compound was isolated as a crude material.

The following Table 2 gives data for example 1-21 of compounds of the invention. The compounds according to examples 4-21 were prepared using the same method of preparation as illustrated in examples 1-3.

Identifying data for the compounds according to examples 1-21 are given in the following Table 3.

Pharmaceutical preparations containing a compound of the invention as active ingredient are illustrated in the following example.

250 g of the compound according to example 1 was mixed with

500 g lactose anhydrous

500 g microcrystalline cellulose

100 g crosslinked polyvinylpyrrolidone

in a mixer. 5 g of magnesium stearate was admixed and the mixture was pressed into tablets each weighing 275 mg.

I. In vitro inhibition of gastric H.sup.+,K.sup.+ -ATPase

Hog gastric H.sup.+,K.sup.+ -ATPase was purified according to Saccomani et al., Biochim. Biophys. Acta 465, 311-330, 1977. 10 .mu.g of membrane protein (GI-fraction in the reference listed above) was incubated with 2 mmol/l of piperazine-N,N'bis-(2-ethane sulfonic acid) buffer pH 7.4 and the test compound in concentrations 10.sup.-7 -10.sup.-4 M in a final volume of 1 ml. (The test compound was dissolved in methanol. Aliquots of these stock solutions were diluted to a final methanol concentration below 1%, which on its own had no effect on the enzyme activities.) After 30 minutes of incubation, the remaining H.sup.+,K.sup.+ -ATPase activity was determined, according to Wallmark et al., Biochim. Biophys. Acta, 728, 31-38, 1983. A dose-response curve was constructed and the concentration at half-maximal inhibition (IC.sub.50) could be determined. The test result is given in Table 4 below.

II. Inhibiting effect in vivo on gastric acid secretion in conscious dog

Chronic gastric fistula dogs were used. These dogs have been surgically provided with a gastric cannula in the stomach and a duodenal fistula used for direct intraduodenal administration of test compounds. Following a 4 week's recovery period after surgery, tests were performed once a week on each dog. Food and water were withdrawn 18 hours before each test.

The test compound dissolved in 5% ethanol in 0.5% Methocel.RTM. (90 HG, 15.000, Dow Chem Corp.) was administered orally by using a stomach tube. After 1 hour gastric acid secretion was induced by continuous infusion of histamine at individual doses (400-600 nmol/kg, h), resulting in approx. 90% of maximal secretion of gastric acid. The gastric juice was collected by free flow from the gastric cannula in consecutive 30 minutes samples for 2 hours. The samples were titrated to pH 7.0 with 0.1M NaOH using a Radiometer automatic titrator and the acid output was calculated. The percent inhibition of acid secretion was calculated by comparing in each dog the acid output in the test to the acid output in control tests when only the vehicle was given. The peak inhibitory effect for each compound was determined. The test result is given in Table 4 below.

III. In vivo cytoprotective effect: Effect on ethanol-induced gastric lesions in the rat

Two groups of female Spraque-Dawley rats (190-220 g) were used, one for the test compound and one for the control experiment. Food, but not water, was removed 24 h before the experiments.

The animals in the test group were treated orally with the test compound dissolved in 10% ethanol in 0.5% Methocel.RTM. immediately before use and the animals in the control group were given the vehicle only in a dose of 2.5 ml/kg.

Thirty minutes later the rats were given orally 1 ml of absolute ethanol (a standard agent for inducing gastric mucosal lesions).

Sixty minutes later the rats were killed by carbon dioxide asphyxiation, their stomachs dissected out and the gastric mucosae were examined for the presence of necrotic lesions. The total lengths of the lesions in the stomachs were measured in the test group and in the control group, in both cases treated thirty minutes before with ethanol. The test result is given in Table 4 below.

The biological tests thus show that the compounds with the general formula I both inhibit gastric acid secretion and have a gastrointestinal cytoprotecting effect.

The ED.sub.50 -value represents the dose of the compound giving 50% reduction of the total lengths of lesions compared to the total lengths of lesions of the control experiment (11.0 cm).

pIC.sub.50 is the negative logarithm of the concentration (in M) of the test compound giving 50% inhibition.