STEREOSPECIFIC PREPARATION OF 5-(1-HYDROXY-2-URETHANETHYLIDENE)-2,2-DIMETHYL-1,3-DIOXANE-4,6-DIONE DERIVATIVE, WHICH IS PRECURSOR OF CHIRAL TETRAMIC ACID DERIVATIVE

摘要

PURPOSE: To obtain the subject derivative, to be used for the synthesis of amino acids, which are important for chemotherapy, stereospecifically by reacting an N-protected amino acid carboxy anhydride with Meldrum's acid in the presence of a specific tertiary amine. ;CONSTITUTION: This derivative is obtained by reacting (A) an N-urethane- protected α-amino acid N-carboxy-anhydride represented by formula I (wherein R is an α-amino acid residue; and X is a protecting group for forming an urethane functional group) in the presence of (B) at least one tertiary amine selected from the group consisting of tertiary amines each having at least one aliphatic or alicyclic group, (preferably diisopropylethyl amine, triethylamine or N-methylmorpholine) of 2 or more equivalent with respect to the component A in (C) an inert organic solvent (such as dichloromethane, toluene, or the like) with (D) Meldrum's acid represented by formula II of a theoretical amount.;COPYRIGHT: (C)1995,JPO