Transformation of Azadiradione to Nimbocinol and 17β‐Hydroxynimbocinol, and StructurePesticidal‐Activity Relationship of Triterpenoids isolated from Azadirachta indica A. Juss. (Neem)

Abstract

During studies on the structureÀpesticidal-activity relationship of Azadirachta indica constituents, azadiradione (1) was treated with methanolic K 2 CO 3 to obtain 7-deacetyl derivative nimbocinol (2). Unexpectedly, 17b-hydroxynimbocinol (3), reported earlier as a natural product, was also formed. The structureÀpesticidal-activity relationship of triterpenoids 1 ± 16 against Anopheles stephensi Liston is described towards understanding the active functionalities responsible for the pesticidal activity of triterpenoids having apoeuphane(apotirucallane) and gedunin skeleta. The pesticidal activities of triterpenoids 2 ± 8 are reported for the first time.

11β-HSD1 Inhibitors from Walsura cochinchinensis

“…Moreover, H-1, H-3, and H-7 were determined to be β-equatorially oriented on the basis of the small values of J 1,2β (2,4 Hz), J 2β,3 (2.8 Hz), and J 6,7 (3.2 Hz), respectively, thus leaving the 1-, 3-, and 7-substituents all α-oriented. Finally, 17β-OH was assigned via comparison of NMR data with other limonoids possessing the same C-, D-, and E-ring structural fragments. , While a limited amount of sample prevented us from elucidating the configuration of the 2-methylbutyryloxy moieties by chemical means, crystallization of 1 in methanol with a trace of water afforded high-quality crystals suitable for X-ray diffraction analysis. The X-ray data confirmed the relative configuration of 1 assigned by spectroscopic methods and also established its absolute configuration as 1 S , 3 R , 4 R , 5 R , 6 R , 7 S , 8 R , 9 R , 10 R , 13 R , 17 S , 2′ R , 2″ R [absolute structure parameter: −0.05(18)] .…”

“…* S Supporting Information ABSTRACT: A search for inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) from Walsura cochinchinensis yielded 10 new limonoids, cochinchinoids A−J (1−10), and two new triterpenoids, 3-epimesendanin S (11) and cochinchinoid K (12). Their structures were assigned on the basis of spectroscopic data, with the absolute configurations of 1 and 12 being established by X-ray diffraction analysis.…”

Biocatalysis: fungi mediated novel and selective 12β- or 17β-hydroxylation on the basic limonoid skeleton

“…It is known that chemically synthesized 17β-hydroxynimbocinol (15) (∼10% yield) from azadiradione (1) showed two-fold potency against Anopheles stephensi Liston compared to nimbocinol. 24 Herein, the biocatalyst M881 was able to oxidize nimbocinol ( 14) to a more potent insecticide 17β-hydroxynimbocinol ( 15) under mild and more ecofriendly conditions with much higher yields. Modifications in the skeletal functional groups didn't change the outcome (such as position and stereochemistry of hydroxylation) of bioconversion but did influence the selectivity between two regioisomers.…”

Synthesis of Chiral Cyclopentenones

“…Selection of synthetic bioactive and natural molecules containing a chiral cyclopentenone functionality, such as prostaglandins and prostanoid derivatives, pentenomycins, lathyranoic acid A, , untenone A, , sesquiterpene from Acorus calamus rhizomes, daphmacromines, kjellmanianone, litseaverticillols, terpestacin, , przewalskin B, azadiradione, minwanenone, jiadifenin, , rupestonic acid, (+)-achalensolide, guaiane, parthenin, didemnenones, , lanostanoid from Antrodia camphorate, hookerolides A–D, 4α-phorbol-12,13-didecanoate, lobocrasol, gochnatiolides A–C, ainsliadimer-B, 4α-4-deoxyphorbol, and guaiane glycosides …”