Methods for ultrasonication-assisted chlorination of aromatic compounds
View Patent ↗Chlorinated aromatic compounds are prepared by ultrasonicating a mixture of ICl and an aromatic compound.
1. A method of preparing a chlorinated aromatic compound comprising:
ultrasonicating a mixture comprising ICl, ICl 2 − , or a mixture thereof; and an aromatic compound;
wherein:
the chlorinated aromatic compound is prepared without preparing an iodinated aromatic compound in an amount that is greater than about 10% on a molar basis; and
the chlorinated aromatic compound is prepared at a higher yield than without ultrasonicating.
2. The method of claim 1 , wherein the amount of an iodinated aromatic compound is less than about 5% on a molar basis.
3. The method of claim 1 , wherein the amount of an iodinated aromatic compound is less than about 0.01% on a molar basis.
4. The method of claim 1 , wherein no iodinated aromatic compounds are prepared.
5. The method of claim 1 , wherein the mixture comprises iodine monochloride and the aromatic compound in a molar ratio from about 1:1 to about 5:1.
6. The method of claim 1 , wherein the ultrasonicating is performed at a frequency of about 20 kHz to about 80 kHz.
7. The method of claim 1 , wherein the ultrasonicating is performed at a temperature of about 25° C. to about 100° C.
8. The method of claim 1 , wherein the ultrasonicating is performed for a period of about 15 minutes to about 4 hours.
9. The method of claim 1 , wherein the mixture further comprises a solvent.
10. The method of claim 9 , wherein the solvent comprises methylene chloride, methanol, or ethanol.
11. The method of claim 1 , wherein the aromatic compound comprises an electron donating group, wherein the aromatic compound is chlorinated at a position that is para to the electron donating group.
12. The method of claim 11 , wherein the electron donating group is an alkoxy, hydroxy, amino, monoalkylamino, or dialkylamino group.
13. The method of claim 11 , wherein the electron donating group is an alkoxy group.
14. The method of claim 1 , wherein the aromatic compound is a phenylalkyl ether, an allocryptopine, or a salt thereof.
15. The method of claim 14 , wherein the aromatic compound comprises a phenylalkyl ether that is phenylmethyl ether, 2,4-dimethylphenylmethyl ether, or 3,5-dimethylphenylmethyl ether, or the aromatic compound is α-allocryptopine or a salt thereof.
16. The method of claim 14 , wherein:
the aromatic compound comprises a phenylalkyl ether and the chlorinated aromatic compound is 4-chloro-phenylmethyl ether, or
the aromatic compound is α-allocryptopine and the chlorinated aromatic compound is 12-chloro-α-allocryptopine, or a salt thereof.
17. The method of claim 15 , wherein:
when the aromatic compound comprises a phenylmethyl ether, the chlorinated aromatic compound is 4-chlorophenylmethyl ether, 6-chloro-2,4-dimethylphenylmethyl ether, 5-chloro-2,4-dimethylphenylmethyl ether, 3-chloro-2,4-dimethylphenylmethyl ether, or 4-chloro-3,5-dimethylphenylmethyl ether, or
when the aromatic compound is α-allocryptopine, the chlorinated aromatic compound is 12-chloro-α-allocryptopine or a salt thereof.
18. The method of claim 1 , wherein the aromatic compound is a polycyclic aromatic compound.
19. The method of claim 18 , wherein the polycyclic aromatic compound is naphthalene, anthracene, phenanthrene, or a salt thereof.
20. The method of claim 1 , wherein the aromatic compound is berberine, chelerythrine, chelidonine, protopine, sanguinarine, or a salt thereof.