ISSN:
0009-2940
Keywords:
Pyrimido[6,1-a]isoquinolines / Pseudobases, heterocyclic / Ring-chain tautomerism
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In basis media, 4-substituted pyrimido[6,1-a]isoquinolin-2-imine hydrochlorides (4) constitute an equilibrium system involving the tautomeric forms characteristic of pseudobases 5, 6, 7 and the anhydro base 9. In aqueous solution in the pH range 7-13 the ammonium hydroxide form 5 is present. Between pH 13 and 14 the pseudobase 6 probably arises from this by covalent binding of the hydroxy group. 6 is then converted to the more stable imino type anhydrobase 9. Ring cleavage of 4 by excess alkali or of 9 by a small amount of water gives 1-(acylamidinomethylen)isoquinolines 7. Compounds 7 and 9 are stable in the solid state or in aprotic solutions but revert to cation 5 in dilute protic solutions.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230315
