Synthesis and derivatization of 8-acetylpsoralens. Acetyl migrations during Claisen rearrangement

Abstract

We have synthesized a series of 8-acetylpsoralens in which methyl and hydrogen substitutions were systematically varied at the 4-and S'-positions. Claisen rearrangement was employed in developing the furano ring, and acetyl migration during the rearrangement was identified as a major side reaction. This migration was circumvented by applying a diethylaluminum chloride catalyzed Claisen rearrangement to the pyrone ring-opened compound.

Highly sensitive cyanide anion detection with a coumarin–spiropyran conjugate as a fluorescent receptor

“…1,3,3-Trimethyl-2-methylideneindole (161 mg, 0.93 mmol) and 8-formyl-7-hydroxy-4methylcoumarin (200 mg, 0.98 mmol) [3] were refluxed in MeOH (5 mL)…”

Interactions of a series of novel spiropyranocoumarin derivatives with reactive oxygen species

“…The preparation of the target derivatives is depicted in F igures 1 and 2. We used 8-acetyl-7-hydroxycou marin (3) as starting material, which was obtained together with its regioisom er 4, according to known procedur es starting from commercial 7-hydr oxycouma rin (1) through a F ries rearrangement of the intermediate acetate 2 (F igure 1) (Bender et al 1983;Prashant et al 2001). A solution of compoun d 3 in toluene was then treated at reflux with the appropriate carbocyclic ketone in the presence of pyrrolidine (Kabbe 1978) to provide the spiropyra nobenzop yranodion es 5a-c in very good yield.…”

Psoralens as Photoactive Probes of Nucleic Acid Structure and Function: Organic Chemistry, Photochemistry, and Biochemistry

“…The final substituents at the 5 and 8 positions of the psoralen or isopsoralen are those present on the resorcinol used in the initial step. When proceeding from the coumarin, the presence or absence of substituents at the 6 and 8 position of the coumarin determine if a psoralen, isopsoralen, or a mixture of the two is obtained (61)(62)(63). Substituents at the position of the coumarin direct furan ring closure to the 6 position giving a psoralen, while substituents at the 6 position of the coumarin have just the opposite effect and are precursors of isopsoralens.…”