Umbelliferone synthesis

Stanjek, V., Piel, J., Boland, W. (1999a) Synthesis of furanocoumarins mevalonate-independent prenylation of umbelliferone in Apium graveolens (Apiaceae). Phytochemistry, 50,1141-5. 

Geiparvarin (898) isolated from Geijera parviflora, reported to have antitumor properties, was first synthesized by Smith et al., who thereby also established the stereochemistry of the double bond. The synthesis consisted of the aldol addition of the aldehyde 899 (R = CH2CHO), prepared from umbelliferone (899, R = H), to 5-ethyl-2,2-dimethyl-2/f-furan-3-one (900) when both isomers of 898 were obtained, the ( )-isomer being identical to the natural product. The synthesis of Jackson and Raphael (Scheme 67) starts with the acetylenic alcohol 901, once readily available, but no longer, because of the hazards associated with its handling (cf. Vol. 4, p. 558, Ref. 733). The... 

Skimmtn. 7-(0-D-Glucopyrano ytoxy -2H-I-ben-zopyran-2-ane 7-(glucosyloxy)coumarin 7 -hydroxycouma-rin -7 -glucoside umbelliferone glucoside. C,sH]403 mo] wt 324.28. C 55.55%, H 4.97%, O 39,47%. In bark and wood of Skimmia japonica Thunb., Rutaceae. lsoln, structure and synthesis Spath. Neufeld, Rec. Trav. Chim. ST, 535 (1938). 

Eicosanoid inhibition Umbelliferone (I) Inhibitor of prostaglandin synthesis [213]... 

In the field of organic synthesis, it was reported that the catalytic hydrolysis of umbelliferone esters (7-acetoxycoumarin) to 7-hydroxycoumarinby porcine pancreatic lipase covalently immobilized on microchannel reactors almost completed within 1 min, to be compared with 4 min in a normal batch reaction [86]. The same group demonstrated an improvement in the yield of trypsinmicrochannel reactor with a lower enzyme concentration but a 20-fold higher reaction rate than in a batch reactor [87]. 

Environmentally benign synthesis routes for umbelliferone (I), 7-hydroxy-4-methylcoumarin (II), 3,4-dihydrocoumarin (III), and tricyclic coumarin (IV) (Figure 10.2) were developed using zeolite-H-p or Amberlyst-15 as solid catalysts. This resulted in the minimization of harmful mineral acid wastes. The reactions of resorcinol with acrylic acid, propynoic acid, and ethyl acetoacetate were investigated in toluene and p-chlorotoluene under reflux conditions to obtain coumarins in 60%-80% yield (Hoefnagel et al. 1995 Gunnewegh et al. 1995). 

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