1.
Chem Pharm Bull (Tokyo)
; 53(9): 1088-91, 2005 Sep.
Artigo
em Inglês
| MEDLINE
| ID: mdl-16141573
RESUMO
We describe the synthesis of 2-[(4-hydroxyphenyl)thio]-7-isopropoxy-5,6-dimethoxy-4H-chromen-4-one 2 from 3,4,5-trimethoxyphenol 6 via the key intermediate, 3-iodo-7-isopropoxy-5,6-dimethoxy-4H-chromen-4-one 3. An important feature of this synthetic scheme involves selective alkylation, which can be achieved by two different routes. One route involves the selective isopropylation of a triacetate derivative 4 under basic conditions. The second route employs the selective demethylation of a trimethoxy derivative 5 under acidic conditions followed by isopropylation. The product of these alternative routes, compound 3, is then converted to a capillarisin sulfur analogue 2 in a one-pot reaction via the imidazolyl intermediate 22.