Статья

Nitrogen bridgehead compounds. Part 35. Structures of α‐formyl‐2,3‐polymethylene‐3,4‐dihydroquinazolin‐4‐ones

Ágnes HorváthCHINOIN Pharmaceutical and Chemical Works Ltd., Research Centre, H-1325 Budapest, P. O. Box 110, Budapest, HungaryIstván HermeczCHINOIN Pharmaceutical and Chemical Works Ltd., Research Centre, H-1325 Budapest, P. O. Box 110, Budapest, HungaryM. PONGOR‐CSAKVARICHINOIN Pharmaceutical and Chemical Works Ltd., Research Centre, H-1325 Budapest, P. O. Box 110, Budapest, HungaryZ. MESZAROSCHINOIN Pharmaceutical and Chemical Works Ltd., Research Centre, H-1325 Budapest, P. O. Box 110, Budapest, HungaryJózsef KökösiPharmaceutical Chemical Institute of the Semmelweis Medical University, H-1088 Budapest, Puskin u. 7, HungaryGábor TóthNMR Laboratory of the Institute for General and Analytical Chemistry, Technical University, H-1521 Budapest, P. O. Box 91, HungaryÁron SzöllősyNMR Laboratory of the Institute for General and Analytical Chemistry, Technical University, H-1521 Budapest, P. O. Box 91, Hungary

1984en

ABI

Аннотация

Abstract The structures of the title compounds bearing a five‐, six‐ or seven‐membered A ring have been investigated by uv and 1 H and 13 C nmr spectroscopy. The imine‐enol‐enamine (I‐II‐III) tautomerism of these compounds depends greatly on the ring size. A significant solvent‐dependence is observed only for the five‐membered‐ring compounds 1 and 2 , which in ethanolic solution exist predominantly in the imine form I, and in chloroform solution in the enol form II. The compounds with a six‐membered A ring, 3 and 4 , are mainly in the enamine form III. On protonation, 3 and 4 change into the E and Z isomeric mixture of the enol tautomer II. The seven‐membered‐ring compound 5 is a mixture of the imine I and the enamine III tautomers.

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Идентификаторы

DOI: 10.1002/jhet.5570210144

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