128266-21-7Relevant academic research and scientific papers
Pyrimidin-4-one compounds
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, (2008/06/13)
Compound of formula (I): wherein: R1, R2, R3 and R4, which may be the same or different, each represent a hydrogen atom, a halogen atom or a group selected from alkyl, alkoxy, polyhaloalkyl, hydroxy, cyano, nitro and amino, ?or R1 with R2, R2 with R3, or R3 with R4, together with the carbon atoms carrying them, form an optionally substituted benzene ring or an optionally substituted heteroaromatic ring, X represents an oxygen atom or a methylene group, A represents an alkylene chain, ?represents an optionally substituted, unsaturated, nitrogen-containing heterocycle and R5 represents an alkyl group, its enantiomers and diastereoisomers, and addition salts thereof with a pharmaceutically acceptable acid. a medicinal products containing the same are useful as a double α2/5-HT2c antagonist.
4. Synthese von Plectranthonen, diterpenoiden Phenanthren-1,4-chinonen
Kaliakoudas, Dimitrios,Eugster, Conrad Hans,Rueedi, Peter
, p. 48 - 62 (2007/10/02)
The following phenanthrene-1,4-diones have been synthesized by using the photocyclization of the corresponding highly substituted stilbenes as the key step: 3-hydroxy-5,7,8-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (1), (RS)-, (R)-, and (S)-2--1-methylethyl)acetate (2, 31, and 32, resp.), 3-hydroxy-7,8-dimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (3), 3-hydroxy-7,8,10-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (4), 5,7,8-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (17) and 3-hydroxy-2-methylphenanthrene-1,4-dione (42).The quinones 1 and 3 proved to be identical with recently isolated plectranthons A and C.Compounds 2, 31, and 32 exhibited the same UV/VIS, IR, 1H-NMR and mass spectra as natural plectranthon B, but had different melting points.This might be due either to crystal modifications or to diastereoisomerism caused by the helical structure of the phenanthrene-1,4-dione skeleton.The spectral data of synthetic 4 were not compatible with those of natural plectranthon D for which structure 4 had been proposed based mainly on 1H-NMR arguments concerning the chemical shifts of H-C(9) and H-C(10) in 1-3.Extensive 1H-NMR investigations have now revealed that the currently stated assignments of the H-C(9)/H-C(10) AB system have to be reversed for highly substituted phenanthrene-1,4-diones: in the model compounds 2-methylphenanthrene-1,4-dione (41) and 2, H-C(10) resonates at lower field as expected (peri-position), whereas in the highly substituted congeners 1, 2, 3, 31, and 32, H-C(9) is shifted paramagnetically, a fact which had lead to the erroneous assignment of structure 4 for natural plectranthon D.
