Claims
- 1. A process for preparing a 2-halopyridine compound, comprising reacting a 1,3-dihalopropene compound of the formula: ##STR17## wherein X is halo, R.sub.4 is H or a straight chain lower alkyl or benzyl group, and R.sub.2 and R.sub.3 are each H or a lower alkyl or benzyl group, with:
- (1) acrylonitrile so as to form a cyclizable intermediate, and then cyclizing said intermediate so as to form a 2-halo-5-substituted-pyridine of the formula: ##STR18## with the proviso that R.sub.4 is H, and wherein X, R.sub.2 and R.sub.3 are as defined above, W is H when said cyclizing is conducted in the absence of a halogenating agent, and W is halo when said cyclizing is conducted in the presence of a halogenating agent; or
- (2) a compound of the formula CN--CH.sub.2 --R.sub.5 wherein R.sub.5 is COOR.sub.6, CN, CON(R.sub.6).sub.2, or COR.sub.6, wherein R.sub.6 is H or an alkyl, aryl or aralkyl group having 1 to about 10 carbon atoms, so as to form a cyclizable intermediate, and then cyclizing said intermediate to form a corresponding 2-halo-3-substituted-pyridine compound of the formula: ##STR19## wherein X, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as defined above; or (3) a compound of the formula CN--XC.sup.- --R.sub.5 where X is halo, R.sub.5 is COOR.sub.6, CN, CON(R.sub.6).sub.2, or COR.sub.6, wherein R.sub.6 is H or an alkyl, aryl or aralkyl group having 1 to about 10 carbon atoms, so as to form a cyclizable intermediate, and then cyclizing said intermediate to form a corresponding 2-halo-3-substituted-pyridine compound of the formula: ##STR20## wherein X, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as defined above.
- 2. A process according to claim 1, for forming a 2-halo-5-methylpyridine compound, which comprises:
- reacting a 1,3-dihalopropene of the formula ##STR21## wherein X is halo and R.sub.2 and R.sub.3 are each H or a lower alkyl or benzyl group, with acrylonitrile so as to form a cyclizable intermediate; and
- cyclizing said intermediate so as to form a 2-halo-5-substituted-pyridine of the formula: ##STR22## wherein X, R.sub.2 and R.sub.3 are as defined above, and W is H or halo.
- 3. The process of claim 2 wherein said cyclizing is in the presence of a halogenating agent, and wherein W is halo.
- 4. The process of claim 2 wherein said cyclizing is in the absence of a halogenating agent, and wherein W is H.
- 5. A process according to claim 1, for preparing a 2-halo-3-substituted-pyridine, comprising:
- reacting a 1,3-dihalopropene of the formula ##STR23## wherein X is halo and R.sub.2, R.sub.3 and R.sub.4 are each H or a lower alkyl or benzyl group, with a compound of the formula CN--CH.sub.2 --R.sub.5 wherein R.sub.5 is COOR.sub.6, CN, CON(R.sub.6).sub.2, or COR.sub.6, wherein R.sub.6 is H or an alkyl, aryl or aralkyl group having 1 to about 10 carbon atoms, so as to form a cyclizable intermediate; and
- cyclizing said intermediate to form a 2-halo-3-substituted-pyridine compound of the formula: ##STR24## wherein X, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as defined above.
- 6. The process of claim 5 wherein the 1,3-dihalopropene is 1,3-dichloropropene, X is Cl, and R.sub.2, R.sub.3, and R.sub.4 are each H.
- 7. The process of claim 6 wherein R.sub.5 is COOR.
- 8. The process of claim 7 wherein R.sub.5 is COOH.
- 9. A process according to claim 1, for preparing a 2-halo-3-substituted-pyridine, comprising:
- reacting a 1,3-dihalopropene of the formula ##STR25## wherein X is halo and R.sub.2, R.sub.3 and R.sub.4 are each H or a lower alkyl or benzyl group, with a compound of the formula CN--XC.sup.- --R.sub.5 wherein X is halo, R.sub.5 is COOR.sub.6, CN, CON(R.sub.6).sub.2, or COR.sub.6, wherein R.sub.6 is H or an alkyl, aryl or aralkyl group having 1 to about 10 carbon atoms, so as to form a cyclizable intermediate; and
- cyclizing said intermediate to form a 2-halo-3-substituted-pyridine compound of the formula: ##STR26## wherein X, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as defined above.
- 10. The process of claim 1, wherein said cyclizing is conducted under heat, or in the presence of acid, or both.
- 11. The process of claim 2, wherein R.sub.2 and R.sub.3 are each H or a lower alkyl group.
- 12. The process of claim 11, wherein R.sub.2 and R.sub.3 are each H.
- 13. The process of claim 2, which comprises reacting 1,3-dichloropropane with acrylonitrile in the presence of hydrogen halide to form a cyclizable intermediate, and cyclizing said intermediate in the presence of a halogenating agent to form a 2-halo-5-halomethylpyridine, or in the absence of a halogenating agent to form a 2-halo-5-methylpyridine.
- 14. The process of claim 13, wherein said cyclizing is conducted in the presence of halogenating agent to form a 2-halo-5-halomethylpyridine.
- 15. The process of claim 14, wherein said halogenating agent is or provides molecular chlorine, molecular bromine, or molecular iodine.
- 16. The process of claim 15, wherein said halogenating agent is or provides molecular chlorine.
- 17. The process of claim 5, wherein R.sub.2, R.sub.3 and R.sub.4 are each H or a lower alkyl group.
- 18. The process of claim 17, wherein R.sub.5 is COOR.sub.6 wherein R.sub.6 is H or and alkyl group.
- 19. The process of claim 17, wherein R.sub.5 is CN.
- 20. The process of claim 17, wherein R.sub.5 is CON(R.sub.6).sub.2 wherein R.sub.6 is H or an alkyl group.
- 21. The process of claim 17, wherein R.sub.5 is COR.sub.6 wherein R.sub.6 is H or an alkyl group.
- 22. The process of claim 5, wherein X is chloro, bromo, or iodo.
- 23. The process of claim 22, wherein X is chloro.
- 24. The process of claim 9, wherein R.sub.2, R.sub.3 and R.sub.4 are each H or a lower alkyl group.
- 25. The process of claim 24, wherein R.sub.5 is COOR.sub.6, wherein R.sub.6 is H or an alkyl group.
- 26. The process of claim 24, wherein R.sub.5 is CN.
- 27. The process of claim 24, wherein R.sub.5 is CON(R.sub.6).sub.2, wherein R.sub.6 is H or an alkyl group.
- 28. The process of claim 9, wherein X is chloro.
- 29. The process of claim 9, wherein the 1,3-dihalopropene is 1,3-dichloropropene.
REFERENCE TO RELATED APPLICATION
This application claims priority upon U.S. patent application Ser. No. 60/042,738, filed Apr. 7, 1997, which is hereby incorporated herein by reference in its entirety.
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