The Synthesis Of Several8-amino Baicalein Derivatives

The flavonoid compound, Baicalin which is produced in the root of traditional Chinese medicine radix scutellaria, has many pharmacological activities, such as anti-inflammatory antibacterial, antiviral and antioxidant, anti-infection, HIV, and treatment of cardiovascular diseases. It is the main active material of traditional Chinese medicine radix scutellariae. It has found that baicalin can also restrain some cancer cell proliferation in recent years. Structure-activity relationship research shows that, if A ring of flavonoids contains both of hydroxyl and the amino, it may have a stronger bacteriostasis anti-inflammatory activity, and it is expected to become a potential tyrosine kinase inhibitor and antitumor agents.This paper use Yunnan fertility of drug resources baicalin as raw material, which is changed to acetylizad baicalein as potential hydroxyl of A ring. Then A ring is introduced amino into the C-8, so as to achieve the structure characteristics of hydroxyl and amino in A ring, to study the anti-inflammatory, antibacterial activities of structure-activity relationship, especially the existence of the activity of amino to influence, make the preparations for the future research.For the moment, there is some reports of structure modification with baicalin, whether through modified synthetic or total synthesis. An amino introduced into C-8to get8-amino baicalin element and its derivatives are barely reported. This paper use baicalin as raw materials, in Py-Ac2O systerm, realize the step of nucleoside off sugar and implementation of acetylation to get6,7-two acetoxyl baicalein, then through the acylation, nitrification, selective hydrolysis, etherification methods and other steps, bring acetyl, methoxy, nitro into the baicalein, get a series of baicalin midbody as8-nitro-6,7-two acexotyl baicalein;8-nitro-baicalein;8-nitro-6-acexotyl baicalein;8-nitro-6,7-two methoxy baicalein. Then, although exploring a variety of reduction methods, we want to put these intermediates into the corresponding8-amino baicalein, but only obtain8-amino-6-acetxoyl baicalein A;8-amino-6,7-two methoxy baicalein B and8-amino baicalein C; and we use A by various acyl chloride, also only isolate8-phenylac-etamido-6-acexotyl baicalein D and through acetylation reaction in baicalin element C-7, C-8introduced into an oxazole ring, received a particular flavonoids E and the hydrolyzation of the new flavonoids F. The synthesis methods of A-F is not found in the reports.The structure of all key intermediate and target compounds have been confirmed by1H-NMR,13C-NMR, compound E by X-ray.