Studien über dieThorpe-Ziegler-Reaktion Eine neue Synthese des Pyrimidinteils von Thiamin
摘要:
AbstractThorpe‐Ziegler cyclization of N′‐cyano‐N‐(2‐cyanoethyl)‐acetamidine (5a) yields 4‐amino‐2‐methyl‐1,6‐dihydro‐5‐pyrimidinecarbonitrile (8a). The acetamidine 5a is accessible either from the N‐cyanoimidate 1 and β‐aminopropionitrile (3a) or the N‐cyanoamidine 2 and acrylonitrile (4). The dihydropyrimidine 8a is easily converted to 4‐amino‐2‐methyl‐5‐pyrimidine‐carbonitrile (13) by dehydrogenation or to 4‐amino‐5‐aminomethyl‐2‐methylpyrimidine (15) by hydrogenation‐dehydrogenation. Both products are important intermediates in the synthesis of thiamine.
Studien über dieThorpe-Ziegler-Reaktion Eine neue Synthese des Pyrimidinteils von Thiamin
摘要:
AbstractThorpe‐Ziegler cyclization of N′‐cyano‐N‐(2‐cyanoethyl)‐acetamidine (5a) yields 4‐amino‐2‐methyl‐1,6‐dihydro‐5‐pyrimidinecarbonitrile (8a). The acetamidine 5a is accessible either from the N‐cyanoimidate 1 and β‐aminopropionitrile (3a) or the N‐cyanoamidine 2 and acrylonitrile (4). The dihydropyrimidine 8a is easily converted to 4‐amino‐2‐methyl‐5‐pyrimidine‐carbonitrile (13) by dehydrogenation or to 4‐amino‐5‐aminomethyl‐2‐methylpyrimidine (15) by hydrogenation‐dehydrogenation. Both products are important intermediates in the synthesis of thiamine.