Sulfur-containing heterocyclic compounds

A sulfur-containing heterocyclic compound of the formula (I):

• ##STR73## wherein ring A is a benzene ring which may be substituted by 1 to 4 substituents, which are the same or different, selected from the group consisting of:
• (1) halogen;
• (2) nitro,
• (3) C.sub.1-10 straight-chain or branched alkyl or C.sub.3-7 cycloalkyl group which may be substituted by 1 to 3 substituents, which are the same or different, selected from the group consisting of a halogen, hydroxyl, C.sub.1-6 alkoxy, mono- or di(C.sub.1-6 alkoxy)phosphoryl and phosphono group,
• (4) (i) hydroxyl, or
• (ii) C.sub.1-10 straight-chain or branched alkoxy, C.sub.4-6 cycloalkoxy, C.sub.2-10 alkenyloxy, C.sub.6-19 aralkyloxy, C.sub.2-10 alkanoxyloxy or C.sub.6-14 aryloxy group which may be substituted by 1 to 3 substituents, which are the same or different, selected from the group consisting of a halogen, hydroxyl, C.sub.1-6 alkoxy and mono- or di(C.sub.1-6 alkoxy)phosphoryl group,
• (5) (i) mercapto, or
• (ii) C.sub.1-10 straight-chain or branched alkylthio, C.sub.4-6 cycloalkylthio, C.sub.7-19 aralkylthio or C.sub.2-10 alkanoylthio group which may be substituted by 1 to 3 substituents, which are the same or different, selected from the group consisting of a halogen, hydroxyl, C.sub.1-6 alkoxy and mono- or di(C.sub.1-6 alkoxy)phosphoryl group,
• (6) amino group which may be substituted by 1 or 2 substituents, which are the same or different, selected from a group consisting of a C.sub.1-10 alkyl, C.sub.2-10 alkenyl, C.sub.6-14 aryl and C.sub.7-19 aralkyl group wherein the substituent may be further substituted by a halogen, C.sub.1-3 alkoxy, mono- or di(C.sub.1-6 alkoxy)phosphoryl or phosphono group,
• (7) C.sub.1-19 acyl group,
• (8) mono- or dialkoxyphosphoryl,
• (9) phosphono,
• (10) aryl group which may be substituted by 1 to 3 substituents, which are the same or different, selected from the group consisting of a C.sub.1-6 alkyl, halogen, hydroxyl and C.sub.1-6 alkoxy group,
• (11) C.sub.7-19 aralkyl group which may be substituted by 1 to 3 substituents, which are the same or different, selected from the group consisting of a C.sub.1-6 alkyl, halogen, hydroxyl and C.sub.1-6 alkoxy group and
• (12) 5- or 6-membered aromatic heterocyclic group having 1 to 4 nitrogen, oxygen and/or sulfur atoms, which may be substituted by 1 to 3 substituents, which are the same or different, selected from the group consisting of a C.sub.1-6 alkyl, halogen, hydroxyl and C.sub.1-6 alkoxy group;
• R is (i) a hydrogen atom or (ii) a C.sub.1-10 alkyl, C.sub.2-10 alkenyl, C.sub.6-14 aryl or C.sub.7-19 aralkyl group which may be substituted by a 5- or 6-membered aromatic heterocyclic group having 1 to 4 nitrogen, oxygen and/or sulfur atoms, halogen, dialkoxyphosphoryl or phosphono group;
• B is a carboxyl group which may be esterified or amidated, X is --CH(OH)-- or --CO--, and n is an integer of 0, 1 or 2, or its salt.