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Preparation of N-(2-alkoxyvinyl)sulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines
Published on: January 3, 2018
Rapid Access to 1,2,3,4-Tetrasubstituted Benzenes and 3‑Alkenyl-1,2-dihydropyridines
Buse Aysen Dundar Ozdogan1, Metin Zora1
1Department of Chemistry, Faculty of Arts and Science, Middle East Technical University, 06800 Ankara, Turkey.
Abstract:
Herein, we report unprecedented protocols for the synthesis of 1,2,3,4-tetrasubstituted benzenes and 3-alkenyl-1,2-dihydropyridines from readily available N-methyl-N-propargyl β-enaminones. When subjected to the reaction with dialkyl acetylenedicarboxylates in refluxing toluene under gold catalysis, N-methyl-N-propargyl β-enaminones afforded 1,2,3,4-tetrasubstituted benzenes. On the other hand, the reaction of N-methyl-N-propargyl β-enaminones with dialkyl acetylenedicarboxylates in refluxing acetonitrile under copper catalysis formed 3-alkenyl-1,2-dihydropyridines as the major product, accompanied by 1,2,3,4-tetrasubstituted benzenes as the minor product. An internal alkyne-tethered N-methyl-N-propargyl β-enaminone yielded a pentasubstituted benzene derivative under both gold and copper catalysis. The skeletal diversity of the synthesized 1,2,3,4-tetrasubstituted benzenes and 3-alkenyl-1,2-dihydropyridines may be of use in medicinal and pharmaceutical chemistry as new and novel molecular entities and structural leads.
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