Process for the preparation of substituted 2-chloropyridines

Details Process for the preparation of substituted 2-chloropyridines Process for the preparation of substituted 2-chloropyridines

1989-11-01

1991-04-23

Lee, Mary C.

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

546318, 546321, 546323, 546345, 546286, C07D21361

Patent

active

050102010

ABSTRACT:
A new process has been found for the preparation of substituted 2-chloropyridine derivatives of the formula (I) ##STR1## wherein R.sup.1 to R.sup.4 have the meanings as defined in the description.
The new process is characterized in that pyridine 1-oxides of the formula II ##STR2## are reacted with a chlorine-containing phosphoric acid derivative from the series of the chlorophosphoric esters and chlorophosphoramides in the presence of an inert organic solvent and in the presence of an acid acceptor at temperatures between -20.degree. C. and 200.degree. C., and the resulting product is separated further, if appropriate.
Compound (I) is known as an intermediate product for medicaments (cf.DE-A 2,812,585) or for insecticidel nitromethylene derivatives (cf. EP-A 163,855).

REFERENCES:
patent: 4211873 (1980-07-01), Pews et al.
patent: 4897488 (1990-01-01), Gallenkamp et al.
Ichiro Kawase et al., Cancer Research, vol. 48, pp. 1173-1179 (1988).
Preparation of 2-Chloro--3--Cyanopyridine and 2--Chloronicotinic Acid, Apr. 14, 1982, vol. 6, No. 57, p. 935, Patent Abstracts of Japan.
Chemical and Pharmaceutical Bulletin Band 36, No. 6, 1988, pp. 2244-2247; H. Yamanaka et al: Site-Selectivity in the Reaction of 3--Substituted Pyridine 1--Oxides with Phosphoryl Chloride.
Chemistry of the Heterocyclic N-Oxides 1971 Academic Press, London, pp. 260-265; Katritzky et al.
The Synthesis of 2--Chloromethylpyridine from 2--Picoline--N--Oxide, Journal of Heterocyclic Chemistry Band 18, No. 5, Aug. 1981, pp. 939-940.

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