Carboxamide compounds, processes for preparing the same and a pharmaceutical composition containing the same

A carboxamide compound represented by the general formula (I), ##STR66## wherein R.sup.1 and R.sup.2 are each:

• a hydrogen atom;
• a lower alkyl group;
• a phenyl group which may have 1 to 3 substituents selected from the group consisting of a halogen atom, a carbamoyl group, an N-(lower alkyl)carbamoyl group, an N-(cycloalkyl)carbamoyl group, an N-(phenyl)carbamoyl group which may have halogen atoms, lower alkoxy groups or lower alkyl groups as substituents on the phenyl ring, an N-(phenyl-lower alkyl)carbamoyl group, a lower akanoyl group, a benzoyl group, an N,N-di(lower alkyl)amino group, a phenylthio group, a lower alkylthio group, a lower alkylsulfinyl group, a phenylsulfinyl group, a 4-phenylpiperazinylcarbonyl group, a 4-(phenyl-lower alkyl)piperazinylcarbonyl group, a piperidinylcarbonyl group and a sulfamoyl group;
• a lower alkoxycarbonyl-lower alkyl group;
• a pyridyl group which may have 1 to 3 substituents selected from the group consisting of a halogen atom, a lower alkoxy group and a lower alkoxycarbonyl group;
• an N-phenylamino group;
• a naphthyl group which may have halogen atoms as substituents;
• a pyrimidinyl group;
• an isoxazolyl group which may have lower alkyl groups as substituents;
• or
• an N-phthalazinylamino group;
• further, R.sup.1 and R.sup.2 together with the adjacent nitrogen atom bonded thereto form a heterocyclic group consisting of an indolin-1-yl group, a 1,2,3,4-tetrahydroquinolin-1-yl group which may have halogen atoms as substituents, 1,2,3,4-tetrahydroisoquinolin-2-yl group, a 2,3-dihydro-4H-1,4-benzoxazin-4-yl group which may have a phenyl group at the 2- or 3-position in the benzoxazine ring, and a phenothiazin-10-yl group which may have halogen atoms as substituents in the benzene ring;
• provided that, R.sup.1 and R.sup.2 are not hydrogen atoms at the same time;
• and when any one of R.sup.1 and R.sup.2 is a lower alkyl group, then the other is a phenyl group having a halogen atom and a benzoyl group as substituents;
• or when any one of R.sup.1 and R.sup.2 is a phenyl group having a halogen atom as a substituent, then the other is a lower alkoxycarbonyl-lower alkyl group;
• further, when any one of R.sup.1 and R.sup.2 is a phenyl group, then the other is an N-phenylamino group;
• R.sup.3 is a lower alkyl group;
• and
• X is an oxygen atom or a sulfur atom.