Process for preparing 4-pentafluorosulfanylbenzoylguanidines

A process for preparing compounds of the formula I

• wherein:
• R1 is hydrogen, alkyl having 1, 2, 3 or 4 carbon atoms, alkoxy having 1, 2, 3 or 4 carbon atoms, NR10R11, —Op—(CH2)n—(CF2)o—CF3 or —(SOm)q—(CH2)r—(CF2)s—CF3;
• R10 and R11 are, independently of one another, hydrogen, alkyl having 1, 2, 3 or 4 carbon atoms or —CH2—CF3;
• m is zero, 1 or 2
• n, o, p, q, r and s are, independently of one another, zero or 1;
• R2 is —(SOh)z—(CH2)k—(CF2)l—CF3, alkyl having 1, 2, 3, 4, 5 or 6 carbon atoms, cycloalkyl having 3, 4, 5, 6, 7 or 8 carbon atoms, in which 1, 2, 3 or 4 hydrogen atoms may be replaced by fluorine atoms;
• h is zero, 1 or 2;
• z is zero or 1;
• k is zero, 1, 2, 3 or 4;
• l is zero or 1;
• or R2 is —(CH2)t-phenyl or —O-phenyl, which are unsubstituted or substituted by 1, 2 or 3 radicals selected from the group consisting of −Ou—(CH2)v—CF3, alkoxy having 1, 2, 3 or 4 carbon atoms, alkyl having 1, 2, 3 or 4 carbon atoms and —SO2CH3;
• t is zero, 1, 2, 3 or 4;
• u is zero or 1;
• v is zero, 1, 2 or 3;
• or R2 is —(CH2)w-heteroaryl which is unsubstituted or substituted by 1, 2 or 3 radicals selected from the group consisting of —Ox—(CH2)y—CF3, alkoxy having 1, 2, 3 or 4 carbon atoms and alkyl having 1, 2, 3 or 4 carbon atoms, —SO2CH3;
• w is zero, 1, 2, 3 or 4;
• x is zero or 1;
• y is zero, 1, 2 or 3;
• and
• R3 and R4, independently of one another, are hydrogen or F;
• and the salts thereof, said process comprising the steps of:
• a) reducing a 4-nitrophenylsulfur pentafluoride compound to a 4-aminophenylsulfur pentafluoride compound;
• b) halogenating the 4-aminophenylsulfur pentafluoride compound in the ortho position to the amino group with a halogenating agent;
• c) replacing the halogen substituent added in step b) with an R2 radical by reacting the 4-aminophenylsulfur pentafluoride compound with a nucleophile or an organometalic compound;
• d) replacing the amino group added in step a) with a halogen by reacting the 4-aminophenylsulfur pentafluoride compound with a halogenating agent;
• e) replacing the halogen substituent added in step d) with a nitrile functional group;
• f) hydrolyzing the nitrile function to a carboxylic acid group;
• and
• g) converting the carboxylic acid group to an acylguanidine compound of formula I, wherein R2 is as previously defined.