2-aminobenzoxazole process
View Patent ↗A method for forming an optionally substituted 2-aminobenzoxazole compound includes: contacting an optionally substituted 2-aminophenol compound with (1) an amine of the formula NHR 2 R 3 , wherein R 2 and R 3 are each independently selected from H, an optionally substituted alkyl group or an optionally substituted aryl group, or R 2 and R 3 , taken together with the nitrogen atom to which they are attached, form an optionally substituted heterocyclic ring; and (2) a reactant selected from the group consisting of: (a) C(OR) 4 , wherein R represents an alkyl group; (b) C(OAr) 4 , wherein Ar represents an aryl group; and (c) CCl 2 (OAr) 2 , wherein Ar represents an aryl group, in combination with a base; thereby forming the optionally substituted 2-aminobenzoxazole compound.
1. A method for forming an optionally substituted 2-aminobenzoxazole compound, said method comprising:
contacting an optionally substituted 2-aminophenol compound with
(1) an amine of the formula NHR 2 R 3 , wherein R 2 and R 3 are each independently selected from H, an optionally substituted alkyl group or an optionally substituted aryl group, or R 2 and R 3 , taken together with the nitrogen atom to which they are attached, form an optionally substituted heterocyclic ring; and
(2) a reactant selected from the group consisting of:
(a) C(OR) 4 , wherein R represents an alkyl group;
(b) C(OAr) 4 , wherein Ar represents an aryl group; and
(c) CCl 2 (OAr) 2 , wherein Ar represents an aryl group, in combination with a base;
thereby forming said optionally substituted 2-aminobenzoxazole compound.
2. The method of claim 1 wherein said contacting is carried out in the presence of a solvent.
3. The method of claim 2 wherein said solvent is selected from the group consisting of methanol, ethanol, isopropyl alcohol, acetonitrile, tetrahydrofuran, ethyl acetate, toluene, chloroform, and combinations thereof.
4. The method of claim 3 wherein said solvent further includes an acid.
5. The method of claim 1 wherein R represents a methyl group or an ethyl group.
6. The method of claim 1 wherein Ar represents a phenyl group.
7. The method of claim 1 wherein said contacting is carried out at a temperature of about normal room temperature to about 80° C.
8. The method of claim 1 wherein said base comprises a tertiary amine or an aromatic nitrogen heterocycle.
9. The method of claim 8 wherein said base comprises triethylamine.
10. The method of claim 1 wherein at least one of R 2 and R 3 comprises an alkyl group.
11. The method of claim 1 wherein R 2 and R 3 together comprise an alkylene group.
12. The method of claim 1 wherein said amine comprises a primary amine.
13. The method of claim 1 wherein said amine comprises a cycloalkyl secondary amine.
14. The method of claim 1 wherein said amine comprises a heterocyclic secondary amine.
15. The method of claim 14 wherein said heterocyclic secondary amine is N-Boc-piperazine.
16. The method of claim 1 wherein said optionally substituted aryl group in said amine comprises substituents selected from alkyl, aryl, heteroaryl, halo, alkoxy, hydroxyl, acyl, carboalkoxy, carboxy, nitro, and combinations thereof.
17. The method of claim 1 wherein said amine of the formula NHR 2 R 3 is selected from the group consisting of:
18. The method of claim 1 wherein said optionally substituted 2-aminophenol compound is selected from the group consisting of:
19. The method of claim 1 wherein said optionally substituted 2-aminobenzoxazole compound is selected from the group consisting of: