A Straightforward Entry into Polyketide Monoprenylated Furanocoumarins and Pyranocoumarins
作者:Giovanni Appendino、Giancarlo Cravotto、Giovanni B. Giovenzana、Giovanni Palmisano
DOI:10.1021/np990241o
日期:1999.12.1
A regioselective synthesis of 5-methyl- and 5-ethyl-4-hydroxycoumarin (Ib and Ic, respectively) is described. Starting from these compounds, several prenylated polyketide coumarins of limited availability from natural sources and important taxonomic relevance were prepared.
Synthesis of the reported structure of crassiflorone, a naturally occurring quinone isolated from the African ebony Diospyros crassiflora, and regioisomeric pentacyclic furocoumarin naphthoquinones
作者:Jalindar Padwal、William Lewis、Christopher J. Moody
DOI:10.1039/c0ob01231a
日期:——
The key steps are a Diels–Alder reaction to form 2-bromo-8-hydroxy-6-methylnaphthoquinone, followed by O-protection and copper(II) mediated coupling to 4-hydroxy-5-methylcoumarin to establish the pentacyclic framework whose structure was unambiguously confirmed by X-ray crystallography. Since the spectroscopic data of the synthetic material did not match those reported for the natural product, three