Angular Regioselectivity in the Reactions of 2-Thioxopyrimidin-4-ones and Hydrazonoyl Chlorides: Synthesis of Novel Stereoisomeric Octahydro[1,2,4]triazolo[4,3- a]quinazolin-5-ones

Awad I Said; Márta Palkó; Matti Haukka; Ferenc Fülöp

doi:10.3390/molecules25235673

Angular Regioselectivity in the Reactions of 2-Thioxopyrimidin-4-ones and Hydrazonoyl Chlorides: Synthesis of Novel Stereoisomeric Octahydro[1,2,4]triazolo[4,3- a]quinazolin-5-ones

Molecules. 2020 Dec 1;25(23):5673. doi: 10.3390/molecules25235673.

Authors

Awad I Said^{1

2}, Márta Palkó^{1

3}, Matti Haukka⁴, Ferenc Fülöp^{1

3}

Affiliations

¹ Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
² Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt.
³ Interdisciplinary Excellence Center, Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Hungary.
⁴ Department of Chemistry, University of Jyväskulä, FIN-40014 Jyväskulä, Finland.

Abstract

The regioselective synthesis of cis and trans stereoisomers of variously functionalized octahydro[1,2,4]triazolo[4,3-a]quinazolin-5-ones was performed. The 2-thioxopyrimidin-4-ones used in the synthesis reacted with hydrazonoyl chlorides in a regioselective manner to produce the angular regioisomers [1,2,4]triazolo[4,3-a]quinazolin-5-ones rather than the linear isomers [1,2,4]triazolo[4,3-a]quinazolin-5-ones. The synthesis process took place with electronic control. The angular regiochemistry of the products was confirmed by X-ray experiments and two-dimensional NMR studies.

Keywords: 2-thioxopyrimidin-4-ones; [1,2,4]triazolo[4,3-a]quinazolin-5-ones; hydrazonoyl chlorides; regioselective reactions.

MeSH terms

Chlorides / chemistry*
Pyrimidines / chemistry*
Quinazolines / chemistry*
Stereoisomerism
Structure-Activity Relationship
Triazoles / chemistry*

Substances

Chlorides
Pyrimidines
Quinazolines
Triazoles