2-amino-1,3-propanediol compounds for the treatment of acute pain

1. A method for the treatment of acute pain, said method comprising administering to a patient in need thereof an effective amount of a 2-amino-1,3-propanediol compound of formula I-4

wherein:

Ra is a straight- or branched chain alkyl having 12 to 22 carbon atoms, said alkyl chain being unsubstituted or substituted in the chain by a substituent selected from the group consisting of double bonds, triple bonds and hetero atom-containing substituents selected from oxygen, sulfinyl, sulfonyl, sulfur, —N(R6)- where R6 is selected from hydrogen, acyl, alkoxycarbonyl, alkyl and aralkyl: said alkyl chain being optionally further substituted by one or more of acyl, acylamino, alkenyloxy, alkoxy, alkoxycarbonyl, alkoxycarbonylamino, alkylamino, alkylcarbamoyl, alkylthio, alkynyloxy, amino, aralkyloxy, aralkyloxyacyloxy, carboxyl, halogen, hydroxyl, hydroxyimino and nitro; and

R2b, R3b, R4b and R5b are the same or different and each is selected from hydrogen, acyl and alkyl;

or a pharmaceutically acceptable salt thereof.

2. A method for the treatment of acute pain, said method comprising administering to a patient in need thereof an effective amount of a 2-amino-1,3-propanediol compound of formula I-8,

wherein

Re is selected from the group consisting of phenylalkyl, wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms; phenylalkyl, wherein the alkyl moiety is a straight- or branched chain alkyl having 1 to 30 carbon atoms, said phenylalkyl being substituted by a straight- or branched chain C6-C20 alkyl optionally substituted by halogen, a straight- or branched chain C6-C20 alkoxy optionally substituted by halogen, a straight- or branched chain C6-C20 alkenyloxy, phenylalkoxy, halophenyl alkoxy, phenylalkoxyalkyl, phenoxyalkoxy or phenoxyalkyl; a cycloalkylalkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms; a cycloalkylalkyl substituted by a straight- or branched chain alkyl having 6 to 20 carbon atoms; a heteroarylalkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms; a heteroarylalkyl substituted by a straight- or branched chain alkyl having 6 to 20 carbon atoms; a heterocyclic alkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms; or a heterocyclic alkyl substituted by a straight- or branched chain alkyl having 6 to 20 carbon atoms; wherein the alkyl moiety may have, in the carbon chain, a bond or a hetero atom selected from a double bond, a triple bond, oxygen, sulfur, sulfonyl, —N(R6)-(where R6 is hydrogen, alkyl, aralkyl, acyl or alkoxycarbonyl), and carbonyl, and may have as a substituent, alkoxy, alkenyloxy, alkynyloxy, aralkyloxy, acyl, alkylamino, alkylthio, acylamino, alkoxycarbonyl, alkoxycarbonylamino, acyloxy, alkylcarbamoyl, nitro, halogen, amino, hydroxyl or carboxyl; or a pharmaceutically acceptable salt thereof.

3. A method for the treatment of acute pain, said method comprising administering to a patient in need thereof an effective amount of a 2-amino-1,3-propanediol compound of formula I-9,

wherein Rf is a phenylalkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms which may have, in the carbon chain, one or two oxygen atoms; a phenylalkyl, wherein the alkyl moiety is a straight- or branched chain alkyl having 1 to 30 carbon atoms, said phenylalkyl being substituted by a straight- or branched chain C6-C20 alkyl optionally substituted by halogen, a straight- or branched chain C6-C20 alkoxy optionally substituted by halogen, a straight- or branched chain C6-C20 alkenyloxy, phenylalkoxy, halophenyl alkoxy, phenylalkoxyalkyl, phenoxy alkoxy or phenoxyalkyl; a cycloalkylalkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms which may have, in the carbon chain, one or two oxygen atoms; a cycloalkylalkyl substituted by a straight- or branched chain alkyl having 6 to 20 carbon atoms; a heteroarylalkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms which may have, in the carbon chain, one or two oxygen atoms; a heteroarylalkyl substituted by a straight- or branched chain alkyl having 6 to 20 carbon atoms; a heterocyclic alkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms which may have, in the carbon chain, one or two oxygen atoms; or a heterocyclic alkyl substituted by a straight- or branched chain alkyl having 6 to 20 carbon atoms;

wherein the alkyl moiety has in the carbon chain a substituent selected from alkoxy, alkenyloxy, alkynyloxy, aralkyloxy, acyl, alkylamino, alkylthio, alkoxycarbonyl, alkoxycarbonylamino, acyloxy, alkylcarbamoyl, nitro, halogen, amino, hydroxyl and carboxyl; or a pharmaceutically acceptable salt thereof.

4. The method of claim 2 wherein said 2-amino-1,3-propanediol compound is a compound of formula I-10,

wherein

Rg is a phenylalkyl wherein the alkyl moiety is a straight- or branched chain having 6 to 20 carbon atoms which may have, in the carbon chain, one or two oxygen atoms; a phenylalkyl, wherein the alkyl moiety is a straight- or branched chain alkyl having 1 to 30 carbon atoms, said phenylalkyl being substituted by a straight- or branched chain C6-C14 alkyl optionally substituted by halogen, a straight- or branched chain C6-C14 alkoxy optionally substituted by halogen, a straight- or branched chain C6-C14 alkenyloxy, phenylalkoxy, halo-phenylalkoxy, phenyl-alkoxyalkyl, phenoxy-alkoxy or phenoxy-alkyl; a cycloalkylalkyl wherein the alkyl moiety has 6 to 20 carbon atoms; a cycloalkylalkyl substituted by a straight- or branched chain alkyl having 6 to 14 carbon atoms; a heteroarylalkyl wherein the alkyl moiety has 6 to 20 carbon atoms; a heteroarylalkyl substituted by a straight- or branched chain alkyl having 6 to 14 carbon atoms; a heterocyclic alkyl wherein the alkyl moiety has 6 to 20 carbon atoms; or a heterocyclic alkyl substituted by a straight- or branched chain alkyl having 6 to 14 carbon atoms; or

a pharmaceutically acceptable salt thereof.

5. A method for the treatment of acute pain, said method comprising administering to a patient in need thereof an effective amount of a 2-amino-1,3-propanediol compound is a compound of formula I-12,

wherein

Ri is a phenylalkyl, wherein the alkyl moiety is a straight- or branched chain alkyl having 1 to 30 carbon atoms, said phenylalkyl being substituted by a straight- or branched chain C6-C14 alkyl optionally substituted by halogen, a straight- or branched chain C6-C14 alkoxy optionally substituted by halogen or a straight- or branched chain C6-C14 alkenyloxy,

wherein the alkyl moiety of phenylalkyl may be substituted by hydroxyl; or a pharmaceutically acceptable salt thereof.

6. The method of claim 5 wherein said 2-amino-1,3-propanediol compound is a compound of formula I-13,

wherein

Rj is a phenylalkyl, wherein the alkyl moiety is a C2-C6 alkyl optionally substituted by hydroxyl, said phenylalkyl being substituted by a straight- or branched chain C6-C14 alkyl optionally substituted by halogen, a straight- or branched chain C6-C14 alkoxy optionally substituted by halogen, or a straight- or branched chain C6-C14 alkenyloxy, or a pharmaceutically acceptable salt thereof.

7. A method for the treatment of acute pain, said method comprising administering to a patient in need thereof an effective amount of a 2-amino-1,3-propanediol compound selected from the group consisting of:

2-amino-2-[2-(4-heptylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol hydrochloride,

2-amino-2-[2-(4-nonylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-decylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-undecylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-dodecylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-tridecylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-tetradecylphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-hexyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-heptyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-octyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-nonyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-decyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-undecyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-dodexyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-tridecyloxyphenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-(8-fluorooctyl)phenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-(12-fluorododecyl)phenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-(7-fluoroheptyloxy)phenyl)ethyl]-1,3-propanediol,

2-amino-2-[2-(4-(11-fluoroundecyloxy)phenyl)ethyl]-1,3-propanediol and

2-amino-2-[2-(4-(7-octenyloxy)phenyl)ethyl]-1,3-propanediol, and the pharmaceutically acceptable salts thereof.

8. The method of claim 1 for the treatment of acute pain, wherein said acute pain is selected from pain occurring after injuries, postoperative pain, pain occurring during acute gout, and pain occurring during operations.

9. The method of claim 2 for the treatment of acute pain, wherein said acute pain is selected from pain occurring after injuries, postoperative pain, pain occurring during acute gout, and pain occurring during operations.

10. The method of claim 3 for the treatment of acute pain, wherein said acute pain is selected from pain occurring after injuries, postoperative pain, pain occurring during acute gout, and pain occurring during operations.

11. The method of claim 5 for the treatment of acute pain, wherein said acute pain is selected from pain occurring after injuries, postoperative pain, pain occurring during acute gout, and pain occurring during operations.

12. The method of claim 7 for the treatment of acute pain, wherein said acute pain is selected from pain occurring after injuries, postoperative pain, pain occurring during acute gout, and pain occurring during operations.