Francisco Rodríguez-Luis

Allelochemicals fromPilocarpus goudotianus leaves.

The effect on germination, shoot, and root growth by bergapten, xanthotoxin, imperatorin, xanthyletin, xanthoxyletin, luvangetin, donatin and alloxanthoxyletol fromPilocarpus goudotianus leaves, onLactuca sativa var. nigra seedlings has been evaluated. A structure-activity correlation is discussed based on the bioassay results. Furanocoumarins appear to be the most active compounds in comparison with pyrano- and simple coumarins. The presence of an oxygenated function at C-8 decreases the germination effect in furano- and pyranocoumarins, while C-5 substituents do not cause significant changes on the activity.

Studies on the Stereostructure of Eudesmanolides from Umbelliferae: Total Synthesis of (+)-Decipienin A

Abstract The first total synthesis of (+)-decipienin A has been achieved in 4% overall yield in seven steps from (+)-dihydrocarvone, thus confirming the stereostructure proposed by Holub et al. (Holub, M.; Budesinsky, M. Phytochemistry 1986, 25, 2015–2026) for this lactone and the original assignments should be corrected as indicated in by formula (a) (6αH,7αH,10αmethyl-eudesman-6,12-olide). Two different strategies were used, the first one an attempt to build the α-hydroxy-γ-lactone moiety through functionalization of the C-6 position and the second involved the introduction of the C-11 hydroxyl group at the final steps of the synthetic scheme.

Study of photochemical addition of acyl radical to electron-deficient olefins

Abstract The photochemical addition of acyl radical to electron-deficient olefins is studied. The scope of the reaction, the mechanism, the role that molecular oxygen plays, the influence of steric effects, and the side reaction that take place are discussed. The reaction was carried out using a range of electron-withdrawing substituents (ketones, amides, lactones, nitrile and esters) with good yields of the corresponding photoadduct in all cases.

Meridinol, a lignan from Zanthoxylum fagara

Abstract The structure of a novel lignan, meridinol, isolated from Zanthoxylum fagara was determined by the evidence of its spectroscopic data and X-ray single crystal structure as (1 S, 2R)-1,2-bis (3,4-methylenedioxy benzyl)- 1-hydroxy butyrolactone.

“An efficient and mild entry to 1,4-dicarbonyl compounds via photochemical addition of acyl radical to electron-deficient olefins”

Abstract Photoehcmical addition of acetaldehyde to electron-deficient olefins in the presence of molecular oxygen provides an efficient and mild method for the synthesis of 1,4-functionallzed compounds. Some considerations about the mechanism and the substituent effects are outlined.

Synthesis of C-8 prenylated and angular 3-(1',1'-dimethylallyl)coumarins

The natural coumarins ramosinin and 3-(1,1-dimethylallyl)-8-(3,3-dimethylallyl)xanthyletin have been synthesized from umbelliferone. The synthesis of the angular derivatives 3-(1,1-dimethylallyl)columbianetin and 3-(1,1-dimethylallyl)lomatin was also achieved

Guaianolides and an ethylcyclohexane lactone from Andriala integrifolia

Abstract The reinvestigation of the aerial parts of Andriala integrifolia afforded three new lactones, a guaianolide, a guaianolide glucopyranoside and an ethylcyclohexane lactonic derivative with a quinol structure, together with five known compounds. Their structures were established by high field 1H NMR spectroscopy and chemical correlation.

Sesquiterpene lactones from Artemisia lanata

Abstract A reinvestigation of the aerial parts of Artemisia lanata afforded a new germacranolide, 11-epidihydroridentin and three new guaianolides, 6α-acetylferulidin, carmenin and andalucin. Furthermore, several known compounds were isolated. The structure of the new compounds were elucidated by spectroscopic methods, and chemical transformations. The structure of andalucin was confirmed by X-ray analysis of its benzoate.

A new and efficient route to 3-(1,1-dimethylallyl)coumarins

Abstract A new method for the synthesis of 3-(1,1 dimethylallyl) coumarias is described. The key step involves an lreland-Claisen rearrangement of an allyl ester.

Sigmatropic rearrangements in synthesis of C-8 prenylated 3-(1',1'-dimethylallyl)coumarins: 3-(1',1'-dimethylallyl)seselin

A partir dhydroxy-7 coumarine, synthese du compose du titre et de la dimethyl-1,1 allyl-3 xanthyletine