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Study on synthesis of some new derivatives of Malloapelta B isolated from Mallotus apelta

Six new benzopyran derivatives were synthesized by reduction reaction and Michael reaction from malloapelta B. Their structures were determined as 8-(1’-oxo-butyl)-5,7-dimethoxy-2,2- dimethyl-2H-1-benzopyran (2), 8-(1’-oxo-3’(R)-methyl-4’-acetyl-5’-oxo-hexyl)-5,7-dimethoxy2,2-dimethyl-2H-1-benzopyran (3), 8-(1’-oxo-3’(R)-methyl-4’(S/R)-(methyl fomiate)-5’-oxohexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (4,4’), 8-(1’-oxo-3’(R)-methyl-4’(S/R)-(ethyl formiate)-5’-oxo-hexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (5,5’) by spectroscopic data, including two-dimensional NMR techniques and ESI spectrum. | Journal of Chemistry, Vol. 45 (2), P. 250 - 254, 2007 Study on the synthesis of some new Derivatives of malloapelta B isolated from Mallotus apelta Received 6 June 2006 Nguyen Hoai Nam, Nguyen Huu Tung, Nguyen Xuan Nhiem, Chau Van Minh, Phan Van Kiem Institute of Natural Products Chemistry, Vietnamese Academy of Science and Technology summary Six new benzopyran derivatives were synthesized by reduction reaction and Michael reaction from malloapelta B. Their structures were determined as 8-(1’-oxo-butyl)-5,7-dimethoxy-2,2dimethyl-2H-1-benzopyran (2), 8-(1’-oxo-3’(R)-methyl-4’-acetyl-5’-oxo-hexyl)-5,7-dimethoxy2,2-dimethyl-2H-1-benzopyran (3), 8-(1’-oxo-3’(R)-methyl-4’(S/R)-(methyl fomiate)-5’-oxohexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (4,4’), 8-(1’-oxo-3’(R)-methyl-4’(S/R)-(ethyl formiate)-5’-oxo-hexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (5,5’) by spectroscopic data, including two-dimensional NMR techniques and ESI spectrum. Keywords: Malloapelta B; Michael reaction; reduction reaction; 5,7-dimethoxy-2,2-dimethyl2H-1-benzopyran. I - introduction Malloapelta B (1), a new benzopyran derivative was isolated from the Vietnamese traditional medicinal plant Mallotus apelta (Lour.) Muell.-Arg. [1]. It shows strong cytotoxic effect as well as strong activity against NF- B activation with IC50 value 0.54±0.05 µM. This compound is continued studying further for cancer treatment [2, 3]. To investigate the relations between the structures and their bioactivities as well as probably find new derivatives having stronger bioactivities, we have synthesized a series of its derivatives. As a part of our research, we report herein six new derivatives synthesized by reduction reaction and Michael reaction. Their structures were determined as 8-(1’-oxo-butyl)-5,7dimethoxy-2,2-dimethyl-2H-1-benzopyran (2), 8-(1’-oxo-3’(R)-methyl-4’-acetyl-5’-oxohexyl)-5,7-dimethoxy-2,2-dimethyl-2H-1benzopyran (3), 8-(1’-oxo-3’(R)-methyl-4’(S/R)250 (methyl .