62640-05-5Relevant academic research and scientific papers
NEO-CLERODANE DITRPENOIDS FROM TEUCRIUM MASSILIENSE
Savona, Giuseppe,Bruno, Maurizio,Piozzi, Franco,Servettaz, Orietta,Rodriguez, Benjamin
, p. 849 - 852 (1984)
From the aerial part of Teucrium massiliense three new neo-clerodane diterpenoids, deacetylajugarin-II, teumassilin and 6,19-diacetylteumassilin, have been isolated, besides the previously known diterpenes montanin C and teucjaponin A.The structures of deacetylajugarin-II (4α,18-epoxy-6α,19-dihydroxy-neo-clerodan-13-en-15,16-olide), teumassilin (4α,18:15,16-diepoxy-6α,12S,19-trihydroxy-neo-cleroda-13(16),14-diene) and 6,19-diacetylteumassilin (6α,19-diacetoxy-4α,18:15,16-diepoxy-12S-hydroxy-neo-cleroda-13(16),14-diene) were established by chemical and spectroscopic means.In addition, the previously known flavones salvigenin and cirsimaritin have also been obtained from the same source.Key Word Index - Teucrium massiliense; Labiatae; diterpenoids; neo-clerodane derivatives; teumassilin; 6,19-diacetylteumassilin; deacetylajugarin-II; montanin C; teucjaponin A.
Hydrogenation derivatives of neo-clerodanes and their antifeedant activity
Bruno, Maurizio,Rosselli, Sergio,Pibiri, Ivana,Piozzi, Franco,Simmonds, Monique S. J.
, p. 599 - 612 (2007/10/03)
Hydrogenation of some natural neo-clerodanes on 10percent Pd/C resulted in the saturation of the furan ring and in some cases hydrogenolysis of the epoxide system and or γ-lactone ring. Overall, reduction of the furan ring found in the natural compounds resulted in a decrease in the antifeedant activity of the compounds against the lepidopteran pests, Heliocoverpa armigera and Spodoptera frugiperda. However, two of the most active derivatives had both the furan ring and the lactone ring hydrogenated but the epoxide intact.
TOTAL SYNTHESIS OF THE INSECT ANTIFEEDANT AJUGARIN I AND DEGRADATION STUDIES OF RELATED CLERODANE DITERPENES
Jones, Philip S.,Ley, Steven V.,Simpkins, Nigel S.,Whittle, Alan J.
, p. 6519 - 6534 (2007/10/02)
The first total synthesis of the diterpene clerodane insect antifeedant ajugarin I (1) has been achieved.The key step of the synthesis discloses the use of the 1,3-dithiolane unit to stereochemically direct the conjugate addition of a but-3-enyl cuprate to set in place the C-10 sp3 carbon centre.The trans-fused ring geometry was obtained by conjugate addition of a vinyl cuprate to an enone and regio and stereoselectively trapping the resulting enolate with formaldehyde.Introduction of the necessary butenolide side chain was achieved by conjugate addition of a sulphone stabilised anion to ethyl-4-(t-butyldimethylsilyloxy)but-2-ynoate followed by work-up with fluoride.Final hydroxyl directed epoxidation was not specific giving both the natural product ajugarin I and its 4-epi isomer.Chemical modification of the insect antifeedant clerodin hemiacetal afforded a series of side chain modified structures for biological evaluation.
INVESTIGATIONS INTO THE TOTAL SYNTHESIS OF INSECT ANTIFEEDANT CLERODANES THE TOTAL SYNTHESIS OF +/- 4-EPI AJUGARIN
Luteijn, J. M.,Groot, Ae. de
, p. 3421 - 3424 (2007/10/02)
Starting from alcohol 3, a stereospecific synthesis of carboxylic acid 2 is described.This acid 2 is a key intermediate in the total synthesis of ajugarins and its conversion into +/- 4-epi ajugarin is reported.
