Online article for Non-subscribers

Pay per view

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact:

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

Paper | Regular issue | Vol 29, No. 10, 1989, pp.1929-1941
Published online, 1st January, 1970
DOI: 10.3987/COM-89-5063
New 4-Ring Fused Heterocyclic Systems Derived from Pyrimido[6,1-a]isoquinolin-4-ones. Potent c-AMP Phosphodiesterase Inhibitors

Graham A. Howarth*

*Central Research Laboratories, Ciba-Geigy PLC, Tenax Road, Trafford Park, Manchester M17 1WT, U.K.


The pyrimido[6,1-a]isoquinolin-4-one ring system has been annelated to form new 4-ring fused heterocyclic systems of interest as c-AMP phosphodiesterase inhibitors. The new ring systems prepared represent derivatives of triazolo[4,5-d]pyrimido[6,1-a]isoquinolin-5-one, imidazo[4,5-d]pyrimido[6,1-a]isoquinolin-5-one and thiazolo-[5,4-d]pyrimido[6,1-a]isoquinolin-5-one.