DIKETONEIMINE DERIVATIVE AS AN INTERMEDIATE PRODUCT FOR SYNTHESIS OF RANITIDINE AND METHOD OF ITS SYNTHESIS Russian patent published in 1995 - IPC

FIELD: organic chemistry. SUBSTANCE: product: derivative of diketoneimine of the formula 1-{2-[(5-N,N- dimethylaminomethy l-2-furyl) -methylthio] -ethyl} -2-{ 2- [(5-N,N- dimethylaminomethyl -2-furyl)-methylthio] -1-ethyl- amino} -3- nitro-4- nitromethylene -2-azetine, m. p. (-39)-(-35) C. Reagent 1: 5-(N,N-dimethylaminomethyl)-furfuryl alcohol. Reagent 2: cysteamine hydrochloride. Process conditions: in the presence of acid, at temperature from room one to boiling point of reaction medium. Reagent 3: inorganic base followed by treatment of reaction mixture with excess of 1-nitro-2,2-di- (methylthio) -ethene at boiling and removal of unreacted 1-nitro -2,2-di- (methylthio)-ethene and addition of zinc salt to the residue in the medium of C₁-C₄-alkanol in the presence of base. Ranitidine is synthesized by a single stage, yield is 100% Ranitidine is used in medicine as an antagonist of H2-receptors. EFFECT: improved method of synthesis, increased yield of product. 6 cl