Processes to produce certain 2-(pyridine-3-yl)thiazoles
View Patent ↗The invention disclosed in this document is related to the field of processes to produce certain 2-(pyridine-3-yl)thiazoles as intermediates for the synthesis of pesticidal thiazole amides.
1. A process comprising
(i) reacting compound (I) with compound (IIa) to produce compound (IIb) wherein said reacting is conducted at ambient temperature and pressure and in a polar protic solvent; followed by
(ii) reacting compound (IIb) with compound (IIc) to product compound (III) wherein said reacting is conducted at ambient temperature and pressure and in a polar solvent; followed by
(iii) cyclizing compound (III) using a dehydrating agent to produce compound (IV) wherein said reacting is conducted at ambient temperature and pressure and in a polar aprotic solvent;
wherein
(A) each R 1 is H;
(B) R 2 is a (C 1 -C 6 )alkyl;
(C) R 3 is H; and
(D) R 4 is a (C 1 -C 6 )alkyl.
2. A process according to claim 1 , wherein step a1 said polar protic solvent is formic acid, n-butanol, isopropanol, n-propanol, ethanol, methanol, acetic acid, water, or a mixture thereof.
3. A process according to claim 1 , wherein step a1 said polar protic solvent is methanol.
4. A process according to claim 1 wherein step b compound (III) is cyclized using a dehydrating agent selected from POCl 3 , H 2 SO 4 , SOCl 2 , P 2 O 5 , polyphosphoric acid, p-toluene sulfonic acid, trifluoroacetic anhydride, or a mixture thereof.
5. A process according to claim 1 , wherein step b is conducted at a temperature from about 60° C. to about 120° C.
6. A process according to claim 1 , wherein step b said polar aprotic solvent is acetonitrile.
7. A process according to claim 1 , said process further comprising halogenating said R 3 to F, Cl, Br, or I.
8. A process according to claim 7 , wherein said halogenating is conducted in a solvent selected from dichloromethane, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, and dimethyl sulfoxide.
9. A process according to claim 8 , wherein said solvent is dichloromethane.
10. A process according to any one of claims 7 , 8 , and 9 , wherein said halogenating is conducted at a temperature from 0° C. to ambient.
11. A process according to any one of claims 7 , 8 , and 9 , wherein R 3 is Cl.