Browsing by Author "Haung, Jia-Yun"

Now showing 1 - 2 of 2

Enantioselective Synthesis of Hydantoin and Diketopiperazine-Fused Tetrahydroisoquinolines via Pictet-Spengler Reaction
(2019-04-01)
Liu, Shih-I
;
Haung, Jia-Yun
;
Barve, Indrajeet J.
;
Huang, Sheng-Cih
;
Sun, Chung-Ming
An enantioselective synthesis of iso-, isothio-, and isoselenohydantoin and diketopiperazine-fused tetrahydroisoquinolines from L-Dopa was reported. The route consists of an Pictet-Spengler reaction of (S)-2-amino-3-(3,4-dimethoxyphenyl)propanoates with various aldehydes to afford diastereomeric tetrahydroisoquinolines. Next step, the tetrahydroisoquinolines were further reacted with iso-, isothio-, or isoselenocyanates to construct hydantoin. Similarly, the diketopiperazine moiety was constructed by subjecting tetrahydroisoquinolines to a condensation reaction with chloroacetyl chloride followed by nucleophilic addition with various primary amines.
One-pot synthesis of 4-arylidene imidazolin-5-ones by reaction of amino acid esters with isocyanates and alpha-bromoketones
(2019-03-21)
Haung, Jia-Yun
;
Barve, Indrajeet J.
;
Sun, Chung-Ming
;
應用化學系
;
Department of Applied Chemistry
A simple and new multicomponent reaction for the one-pot synthesis of substituted 4-arylidene imidazolin- 5-ones from L-amino acid methyl esters, iso-, isothio-or isoselenocyanates, and alpha-bromoketones is demonstrated. Isolation of thiohydantoin and 5-benzylidene 2-thioxoimidazolidin-4-one intermediates revealed a possible reaction mechanism. The strategy was further extended to the synthesis of 2-iminothiazolines and 2-thioxoimidazolin-4-ones.