Process for the preparation of 6-(3,4-dihydro-3-oxo-1,4(2H)-benzoxazin-7-yl)-2,3,4,5-tetrahydropyridazi n-3-ones
US5221742A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1990 |
| Grant date | Jun 22, 1993 |
| Priority date | — |
| Expiry date | Dec 21, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D413/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for the synthesis of compounds of the formula I ##STR1## wherein R.sub.1 -R.sub.5 are as defined herein. The process is a multistep process which comprises acylating a 2-benzoxazolinone with an alkanoic anhydride to form an acylated carbamate, hydrolyzing the carbamate, reacting the resultant aminophenol with haloalkanoyl halide to form a substituted benzoxazine, reacting the benzoxazine with an aldehyde, alkylating the resultant aminomethyl compound with an alkylating agent to form a quaternary ammonium salt, reacting the salt with an alkali metal cyanide to form a nitrile, hydrolyzing the nitrile and reacting the resultant carboxylic acid with hydrazine. The compounds are useful as cardiotonic and vasodilating agents and as inhibitors of phosphodiesterase fraction III and platelet aggregation. In addition, the compounds are active as smooth muscle relaxants and bronchodilators.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.