Browsing by Author "Ho, Pei-Heng"

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Copper catalyzed aerobic oxidative cyclization and ketonization: one pot synthesis of benzoimidazo[1,2-a]imidazolones
(2016)
Selvaraju, Manikandan
;
Ye, Tzuen-Yang
;
Li, Chia-Hsin
;
Ho, Pei-Heng
;
Sun, Chung-Ming
A highly efficient synthesis of benzoimidazo[1,2-a]imidazolone through a novel oxidative 5-exo-dig cyclization-ketonization cascade of 2-aminobenzimidazole, aldehyde and terminal alkyne has been explored under aerobic conditions. The reaction proceeds through copper-catalyzed addition of terminal alkynes to imines derived from 2-aminobenzimidazole with aldehyde followed by intramolecular cyclization. The atmospheric molecular oxygen acts as an oxygen source for the newly formed carbonyl group in the final product.
Enantiospecific Synthesis of Imidazoquinazolin-2-ones via Base-Catalyzed Tandem Cyclization
(2017-09-29)
Kumar, Sunil
;
Ho, Pei-Heng
;
Barve, Indrajeet J.
;
Sun, Chung-Ming
;
應用化學系
A facile protocol for the enantiospecific synthesis of novel (S)-3-substituted imidazo[2,l-b]quinazoline-2-ones via tandem reaction of substituted (S)-3-amino-4-aminomethylbenzoates and cyanogen bromide under basic conditions is explored. This tandem process involves addition reaction of substituted (S)-3-amino-4-aminomethylbenzoates to CNBr to yield 2-imino tetrahydroquinazoline carboxylate intermediates followed by insitu intramolecular aminolysis to afford the triheterocyclic imidazo[2,l-b]quinazoline-2-ones in good yields and high enantiomeric purity.