Analgesic compounds, their preparation, and pharmaceutical compositions containing them

A pharmaceutical composition comprising an effective analgesic amount of a compound of formula (I):

• ##STR7## and stereoisomeric forms thereof in which,
• R.sup.1 and R.sup.2 are the same or different and each is selected from the group consisting of a hydrogen atom and C.sub.1 -C.sub.6 alkyl groups, or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached form a heterocyclic ring;
• E is an oxygen atom;
• ring A is selected from the group consisting of unsubstituted aryl rings;
• unsubstituted heteroaryl rings;
• aryl rings substituted with at least one substituent of Group (i);
• and heteroaryl rings substituted with at least one substituent of Group (i);
• said at least one substituent of Group (i) is selected from the group consisting of halogen atoms, C.sub.1 -C.sub.6 alkyl groups, halogenated C.sub.1 -C.sub.6 alkyl groups, C.sub.1 -C.sub.6 alkoxy groups, halogenated C.sub.1 -C.sub.6 alkoxy groups, C.sub.1 -C.sub.6 alkylthio groups, aryl groups, acyl groups, nitro groups, and hydroxy groups;
• R.sup.3 and R.sup.4 together represent a group of formula (IV):
• --(CR.sup.a R.sup.b).sub.m --C(.dbd.Y)-- (IV)
• wherein each R.sup.a and R.sup.b represents hydrogen or a C.sub.1 -C.sub.3 alkyl groups, m represents 1, 2, or 3, and Y represents two hydrogen atoms or an oxygen atom;
• or a pharmaceutically acceptable salt thereof;
• together with a pharmaceutically acceptable carrier.

A method for the relief of pain, which comprises administering to a susceptible animal an effective analgesic amount of an analgesic drug, wherein said analgesic drug comprises at least one compound which is a compound of formula (I):

• ##STR8## and stereoisomeric forms thereof in which,
• R.sup.1 and R.sup.2 are the same or different and each is selected from the group consisting of a hydrogen atom and C.sub.1 -C.sub.6 alkyl groups, R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached form a heterocyclic ring;
• E is an oxygen atom;
• ring A is selected from the group consisting of unsubstituted aryl rings;
• unsubstituted heteroaryl rings;
• aryl rings substituted with at least one substituent of Group (i);
• and heteroaryl rings substituted with at least one substituent of Group (i);
• said at least one substituent of Group (i) is selected from the group consisting of halogen atoms, C.sub.1 -C.sub.6 alkyl groups, halogenated C.sub.1 -C.sub.6 alkyl groups, C.sub.1 -C.sub.6 alkoxy groups, halogenated C.sub.1 -C.sub.6 alkoxy groups, C.sub.1 -C.sub.6 alkylthio groups, aryl groups, acyl groups, nitro groups, and hydroxy groups;
• R.sup.3 and R.sup.4 together represent a group of formula (IV):
• --(CR.sup.a R.sup.b).sub.m --C(.dbd.Y)-- (IV)
• wherein each of R.sup.a and R.sup.b represents hydrogen or a C.sub.1 --C.sub.3 alkyl group, m represents 1, 2, or 3, and Y represents two hydrogen atoms or an oxygen;
• or a pharmaceutically acceptable salt thereof.

A compound of the formula (I):

• ##STR9## and stereoisomeric forms thereof in which,
• R.sup.1 and R.sup.2 are the same or different and each is selected from the group consisting of a hydrogen atom and C.sub.1 -C.sub.6 alkyl groups, or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached form a heterocyclic ring;
• E is selected from the group consisting of an unsubstituted imino group, and an imino group substituted with a substituent selected from the group consisting of C.sub.1 -C.sub.6 alkyl groups and aralkyl groups;
• ring A is selected from the group consisting of unsubstituted aryl rings;
• unsubstituted heteroaryl rings;
• aryl rings substituted with at least one substituent of Group (i);
• and heteroaryl rings substituted with at least one substituent of Group (i);
• said at least one substituent of Group (i) is selected from the group consisting of halogen atoms, C.sub.1 -C.sub.6 alkyl groups, halogenated C.sub.1 -C.sub.6 alkyl groups, C.sub.1 -C.sub.6 alkoxy groups, halogenated C.sub.1 -C.sub.6 alkoxy groups, C.sub.1 -C.sub.6 alkylthio groups, aryl groups, acyl groups, nitro groups, and hydroxy groups;
• R.sup.3 represents a hydrogen atom or a C.sub.1 -C.sub.6 alkyl group,
• R.sup.4 represents a hydrogen atom, or R.sup.3 and R.sup.4 together represent a group of formula (IV):
• --(CR.sup.a R.sup.b).sub.m --C(.dbd.Y)-- (IV)
• wherein each of R.sup.a and R.sup.b represents hydrogen or a C.sub.1 -C.sub.3 alkyl group;
• m represents 1,2, or 3, and Y represents two hydrogen atoms or an oxygen atom;
• and pharmaceutically acceptable salts thereof.