Products of ozonolysis of L-1,4-cyclohexadienylalanine. Intramolecular cyclization and cyclization with hydroxylamine. The synthesis of two isomers of L-isoxazolylalanine.

Protected L-phenylalanine was reduced to L-1,4-cyclohexadienylalanine followed by ozonolysis of the unsaturated ring. Intramolecular cyclization of the ozonolysis product occured upon treatment with acid, The cyclization of the product of ozonolysis with hydroxylamine was studied as well. The formation of both 5- and 3-isoxazolylalanine is demonstrated. Mechanism of formation of these products and structure of intermediates are discussed. (C) 1997 Elsevier Science Ltd.