Process for preparing quinazolines

Details Process for preparing quinazolines Process for preparing quinazolines

1977-06-20

1978-07-04

Coughlan, Jr., Paul M.

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

Organic compounds

Nitrogen attached directly or indirectly to the purine ring...

260553A, C07D23994

Patent

active

040987884

ABSTRACT:
2-Halo-4-aminoquinazolines are produced by a two-step process involving cyclization of 1-phenyl-3-cyanoureas or 1-phenyl-3-cyanothioureas in the presence of phosphorus halides and phosphorus oxyhalides to provide a phosphoquinazoline intermediate which is hydrolyzed to the quinazoline. Exemplary of the process is the intramolecular cyclization of 1-(3,4-dimethoxyphenyl)-3-cyanourea in the presence of phosphorus pentachloride and phosphorus oxychloride to a phosphoquinazoline intermediate which is subsequently hydrolyzed with formic acid to 2-chloro-4-amino-6,7-dimethoxy-quinazoline. The 2-halo-4-aminoquinazolines of the instant process are particularly valuable as intermediates in the preparation of 4-amino-2-(4-substituted-piperazin-l-yl)quinazolines useful in the treatment of cardiovascular disease, e.g. hypertension.

REFERENCES:
patent: 2517824 (1950-08-01), Appelquest
patent: 3511836 (1970-05-01), Hess
patent: 3669968 (1972-06-01), Hess
patent: 3920636 (1975-11-01), Takahashi et al.
patent: 4001237 (1977-01-01), Partyka et al.
patent: 4001238 (1977-01-01), Partyka et al.
Elderfield, Heterocyclic Compounds, vol. 6, pp. 328-358, pub. by Wiley & Sons, (1957).

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