Claims
- 1. A process for the preparation of 6,7-dichloro-1,5-dihydroimidazo(2,1-b)quinazolin-2(3H)-one or a pharmaceutically acceptable salt thereof, which comprises subjecting a 2-cyanoiminoquinazoline of the formula ##STR15## wherein R' stands for cyano or a group of the formula COOR.sup.1, in the latter R.sup.1 representing lower alkyl optionally carrying a phenyl substituent, to thermal cyclization in an acidic medium, said process further comprising carrying out the reaction in a solvent selected from the group consisting of ethylene glycol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 2-methoxyethanol, 2-ethoxyethanol, acetonitrile, dioxane, acetic acid, and ethylene glycol dimethyl ether.
- 2. A process as claimed in claim 1, which comprises carrying out the reaction in a mixture of said solvent and a mineral acid.
- 3. A process as claimed in claim 2, which comprises carrying out the reaction at a temperature between 80.degree. C. and 130.degree. C.
- 4. A process as claimed in claim 2, which comprises using hydrogen chloride.
- 5. A process as claimed in claim 4, which comprises carrying out the reaction at a temperature between 80.degree. C. and 130.degree. C.
- 6. A process as claimed in claim 1, which comprises carrying out the reaction at a temperature between 80.degree. C. and 130.degree. C.
- 7. A process as claimed in claim 1, wherein said process is accomplished in 20 to 180 minutes.
- 8. A process as claimed in claim 1, wherein said solvent is ethylene glycol.
- 9. A process as claimed in claim 1, wherein said solvent is diethylene glycol dimethyl ether.
- 10. A process as claimed in claim 1, wherein said solvent is diethylene glycol diethyl ether.
- 11. A process as claimed in claim 1, wherein said solvent is 2-methoxyethanol.
- 12. A process as claimed in claim 1, wherein said solvent is 2-ethoxyethanol.
- 13. A process as claimed in claim 1, wherein said solvent is acetonitrile.
- 14. A process as claimed in claim 1, wherein said solvent is dioxane.
- 15. A process as claimed in claim 1, wherein said solvent is acetic acid.
- 16. A process as claimed in claim 1, wherein said solvent is ethylene glycol dimethyl ether.
Priority Claims (2)
Number |
Date |
Country |
Kind |
1707/91 |
May 1991 |
HUX |
|
1708/91 |
May 1991 |
HUX |
|
Parent Case Info
This application is a continuation-in-part of application Ser. No. 07/886,605, filed May 21, 1992, now abandoned, which application is entirely incorporated herein by reference.
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
3932407 |
Beverung, Jr. et al. |
Jan 1976 |
|
3932467 |
Miyano |
Jan 1976 |
|
4146718 |
Jenks et al. |
Mar 1979 |
|
4208521 |
Crenshaw et al. |
Jun 1980 |
|
5120845 |
Freyne et al. |
Jun 1992 |
|
Non-Patent Literature Citations (1)
Entry |
Chem. Pharm. Bul. (1980), vol. 28, pp. 1307-1310, Ishikawa et al. |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
886605 |
May 1992 |
|