We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Synthese der Phoracantholide K, O und M.
- Authors
Gerlach, Hans; Künzler, Peter
- Abstract
Synthesis of Phoracantholide K, O and M Two 14membered ring lactones 3 and 4 and a 12membered ring lactone 5 isolated from the metasternal secretion of the eucalypt longicorn Phoracantha synonyma have been synthesized as racemic mixtures by the following method. Reaction of the dilithium derivative of 5-hexynoic acid (6) with threo-8-bromo-2,4-isopropylidenedioxyoctane (7), followed by removal of the protecting group and esterification with diazomethane gave methyl- threo-11, 13-dihydroxy-5-tetradecy-noate (8) (s. Scheme 2). Partial hydrogenation of the triple bond in 8 with Lindlar Pd-catalyst, followed by saponification lead to ( threo, Z)-11, 13-dihydroxy-5-tetra-decenoic acid (10). The dihydroxy acid 10 was converted into the S-(2-pyridyl) thioate and cyclized in diluted benzene solution under the influence of silver ions to yield the corresponding 12- and 14-membered lactones in approximately equal amounts. Isomerization of the mixture with p-toluenesulfonic acid in methylene chloride yielded the 14-membered lactone ( cis-11, 13-5 Z)-11-hydroxy-5-tetradecen-13-olide almost exclusively. It proved to be identical in its properties with natural phoracantholide K (3). With 5-hexynoic acid and 7-tetrahydropyranyloxy-octyl bromide or 5-tetrahydropyranyloxy-hexyl bromide as starting materials (±)-phoracantholide O (4) and M (5) have been synthesized in an analogous manner.
- Publication
Helvetica Chimica Acta, 1980, Vol 63, Issue 8, p2312
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/hlca.19800630821