New Method For Synthesis Of Unnatural α-cyclic Amino Acid

α-cyclic amino acid have the characters of conformation restriction, which facilitate the formation and stability of the conformation of the polypeptide with biological activity. Studies have shown that polypeptide containing α-cyclic amino acids display good anti-inflammatory activity, anti-diuretic activity, antitumor activity, and also can be used to treat cardiovascular disease. Further, the a-cyclic amino acids may also be used as plant growth hormone regulators, fungicides, sweeteners etc.There may be three approaches to the synthesis of α-cyclic amino acids currently: 1. intermolecular cyclization of amino acid derivatives and dihalogenated alkanes.2. functional group transformation of cyclic carboxylic acid compound.3. hydrolysis of hydantoin compound after Bucher-Bergs reaction or aminolysis of mandelic nitrile after Streeker Reaction starting from cyclic ketones.In this thesis, a new efficient method for synthesis of α-cyclic amino acid has been developed. Lactone, commonly used in chemical industry as a starting material, was transformed to α-cyclic amino acid through the ring-opening/bromination, intramolecular cyclization, amination and followed by hydrolysis. The general advantages of this method are: easily available raw materials, short reaction route, mild reaction conditions, simple intermediate purification operations, high yield, efficient for the synthesis of 3 to 6 ring-membered a-amino acids.