Leukotriene biosynthesis inhibitors

A compound having the following formula:

• ##STR22## wherein X is O or S
• R.sub.1 and R.sub.2 are each, independent of one another, hydrogen;
• C.sub.1 -C.sub.6 alkyl;
• halo ;
• CF.sub.3 ;
• nitrile;
• C.sub.1 -C.sub.6 alkoxy;
• --CO.sub.2 R.sub.7 wherein R.sub.7 is hydrogen or C.sub.1 -C.sub.6 alkyl;
• NO.sub.2 ;
• --C(O)NR.sub.8 R.sub.9 wherein R.sub.8 and R.sub.9 are hydrogen, C.sub.1 -C.sub.3 allyl or methoxy;
• --NR.sub.10 R.sub.11 wherein R.sub.10 and R.sub.11 are hydrogen or C.sub.1 -C.sub.6 alkyl;
• --C(O)R.sub.12 wherein R.sub.12 is C.sub.1 -C.sub.6 alkyl;
• 'SO.sub.2 R.sub.12, --NHC(O)R.sub.12 ;
• --NHSO.sub.2 R.sub.12 ;
• or --SO.sub.2 NR.sub.13 R.sub.14 wherein R.sub.13 and R.sub.14 are hydrogen or C.sub.1 -C.sub.6 alkyl;
• R.sub.3 is cyclohexyl or an optionally substituted phenyl ring wherein the substituents are selected from halo, CF.sub.3, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy;
• --SO.sub.2 R.sub.12 ;
• --NHC(O)R.sub.12 ;
• --NHSO.sub.2 R.sub.12 ;
• SO.sub.2 NR.sub.13 R.sub.14 ;
• or NO.sub.2 ;
• or R.sub.3 may be a 2-, 3- or 4-pyridine ring;
• or R.sub.3 may be a dialkylamine (C.sub.1 -C.sub.4);
• or may be an alkyl ether, (C.sub.1 -C.sub.4)
• R.sub.4 is 2-, 3-, or 4-pyridyl.
• R.sub.5 and R.sub.6 are each, independent of one another, hydrogen or methyl and
• n is an integer of b 0, 1 or 2, in racemic form, or the pure or substantially pure enantiomers thereof.