Patent ID: 7202368

Claim:
A process for preparing an optionally substituted 4-benzimidazol-2-ylmethylamino)benzamidine of formula (I) wherein: R 1 is a C 1-6 -alkyl or C 3-7 -cycloalkyl group; R 2 is (i) a C 1-6 -alkyl group or a C 3-7 -cycloalkyl group optionally substituted by a C 1-3 -alkyl group, wherein the C 1-3 -alkyl group is optionally additionally substituted by a carboxyl group or by a group which can converted in vivo into a carboxy group, or (ii) an R 21 NR 22 group, wherein: R 21 is a C 1-6 alkyl group optionally substituted by a carboxy, C 1-6 alkoxycarbonyl, benzyloxycarbonyl, C 1-3 -alkylsulfonylaminocarbonyl, phenylsulfonylaminocarbonyl, trifluorosulfonylamino, trifluorosulfonylaminocarbonyl, or 1H-tetrazolyl group, a C 2-4 -alkyl group substituted by a hydroxy, phenyl-C 1-3 -alkoxy, carboxy-C 1-3 -alkylamino, C 1-3 -alkoxycarbonyl-C 1-3 -alkylamino, N-(C 1-3 -alkyl)-carboxy-C 1-3 -alkylamino, or N-(C 1-3 -alkyl)-C 1-3 -alkoxycarbonyl-C 1-3 -alkylamino group, wherein the α-carbon atom to the adjacent nitrogen atom thereof is not substituted, or a piperidinyl group optionally substituted by a C 1-3 -alkyl group, and R 22 is a hydrogen atom, a C 1-6 -alkyl group, or a C 3-7 -cycloalkyl group optionally substituted by a C 1-3 -alkyl group, a C 3-6 -alkenyl, or C 3-6 -alkynyl group, wherein the unsaturated moiety is not linked directly to the nitrogen atom of the R 21 NR 22 group, a phenyl group optionally substituted by a fluorine, chlorine, or bromine atom or by a C 1-3 -alkyl or C 1-3 -alkoxy group, a benzyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, pyrrolyl, thienyl, or imidazolyl group optionally substituted by a C 1-3 -alkyl group, or R 21 and R 22 together with the nitrogen atom between them are a 5- to 7-membered cycloalkyleneimino group optionally substituted by a carboxy or C 1-4 -alkoxycarbonyl group, to which a phenyl ring is optionally additionally fused; and R 3 is a hydrogen atom, a C 1-9 -alkoxycarbonyl, cyclohexyloxycarbonyl, phenyl-C 1-3 -alkoxycarbonyl, benzoyl, p-C 1-3 alkylbenzoyl, or pyridinoyl group, wherein the ethoxy moiety in the 2-position of the abovementioned C 1-9 -alkoxycarbonyl group is optionally additionally substituted by a C 1-3 -alkylsulfonyl or 2-(C 1-3 -alkoxy)ethyl group, the process comprising: (a) reacting a phenyldiamine of formula (II) wherein R 1 and R 2 have the meanings given for formula (I), with 2-[4-(1,2,4-oxadiazol-5-on-3-yl)phenylamino]acetic acid to obtain the product of formula (III) wherein R 1 and R 2 have the meanings given for formula (I); (b) hydrogenating the product obtained from step (a) to obtain a compound of formula (I) where R 3 is hydrogen; and (c) optionally reacting the product obtained from step (b) with a compound of formula (IV) R 3 —X (IV) wherein R 3 has the meaning given for formula (I) and X is a suitable leaving group.