A new synthesis of o-prenyl phenols

Abstract

Phenylthiyl radicals add regiospecifically to isoprenoid chrom-3-enes to yield 3-phenylthiochromans which open to o-prenylphenols on electron transfer from metal naphthalenides or a mercury cathode; the two-step process is tolerant of free phenol and carbonyl functions, and trisubstituted double bonds.

Synthesis, photooxygenation, and characterization of new angular furoquinolinone derivatives, a new furocoumarin bioisoster

“…Hydroxyquinolinones 1–3 were synthesized according to the literature procedure by condensing ethyl acetoacetate with m‐aminophenol, 26 o‐anisidine, 27 and p‐anisidine, 28 respectively, while 4‐hydroxyquinolinone 4 was formed by condensing N‐methylaniline with diethyl malonate 29 . Williamson reaction of 1–4 with 3‐chloro‐2‐butanone in acetone and in the presence of K 2 CO 3 at reflux temperature gave keto ethers 5 , 9 , 12 , and 13 in 60, 42, 60, and 54% yield, respectively (Scheme 1).…”

Phytoalexins

“…The mechanism of this process is not yet known, but Scheme 12 is in accord with the known facts. In a recent investigation, 2',4,4'-trihydroxy-[carbonyl,a-I 3Cz]chalcone (1 58a) was fed to seedlings of Trifolium pratense that had been stimulated (by treatment with CuCl,) to produce the phytoalexins formononetin (1 57), ( -)medicarpin (163), and (-)-maackiain (161). The I3C2 unit was found to be incorporated intact into all three metabolites, indicating that aryl migration had occurred, and not a rearrangement of the C3 chain of the chalcone.…”

“…The metabolic grid that is involved in the biosynthesis of (-)medicarpin (163) in T. pratense is indicated in Scheme 18. Feeding 2',4,4'-trihydroxy[P,3,5-ZH3]cha1cone (1 58b) to CuC1,treated seedlings yielded formononetin (1 57) and (-)-medicarpin (163), both retaining all three deuterium atoms. (-)-Maackiain was also isolated, and consisted of 50% dideuteriated and 50% trideuteriated molecules.…”

“…Confirmation of the metabolic grid that is outlined in Scheme 18 was obtained by feeding (-)-7-hydroxy-4'methoxy[2,2-2H,]isoflavanone (1 82a) to CuC1,-treated T. pratense. The compound was incorporated into ( -)-medicarpin (163)largely with retention of both deuterium atoms, i.e. (182a) was incorporated into medicarpin via a route that does not involve its conversion into formononetin, with consequent loss of label.151…”