23731-66-0Relevant academic research and scientific papers
The Quinones of Nepenthes rafflesiana. The Crystal Structure of 2,5-Dihydroxy-3,8-dimethoxy-7-methylnaphtho-1,4-quinone (Nepenthone-E) and a Synthesis of 2,5-Dihydroxy-3-methoxy-7-methylnaphtho-1,4-quinone (Nepenthone-C)
Cannon, Jack R.,Lojanopiwatna, Vitchu,Raston, Colin L.,Sinchai, Wannee,White, Allan H.
, p. 1073 - 1093 (2007/10/02)
Plumbagin (1), droserone (2), hydroxydroserone (4) and four new quinones, nepenthone-A, nepenthone-B, nepenthone-C (17) and nepenthone-E (9), have been isolated from the roots of Nepenthes rafflesiana Jack.A fifth quinone--nepenthone-D-has been detected in the extract and has been assigned the tentative structure (29) from its spectroscopic properties. The crystal structure of nepenthone-E (9) was determined by X-ray diffraction; diffractometer data at 295 K were refined by full-matrix least squares to a residual of 0.061 (1040 'observed' reflections).Crystals of nepenthone-E (9) are triclinic, P1 a 7.579 (4), b 7.764 (5), c 10.806 (7) Angstroem, α 70.86 (4), β 101.40 (5), γ 91.70 (5) deg, Z 2. The structure of nepenthone-C (17) has been confirmed by an unambiguous synthesis.A synthesis of 2,7,8,-trimethoxy-3-methyl-5,6-methylenedioxynaphtho-1,4-quinone (49) has revealed that this substance (49) is not identical with the O,O-dimethyl ether of nepenthone-A, and it is suggested that nepenthone-A is either the 5- or 8-O-methyl ether of 2,5,8-trihydroxy-3-methyl-6,7-methylenedioxynaphtho-1,4-quinone .
