No abstract

14,15,17-Trinorlabdan-8,13-dione 6 was efficiently synthesized via ozonolysis of (+)-manool (4) followed by treatment with aqueous NaOH in the presence of tetra- n-butylammonium bromide as catalyst. This protocol has the advantages of high yield, mild conditions and simple procedure. Utilizing this strategy, the first enantiospecific synthesis of 13,14-dihydroxy-8,11,13-podocarpatrien-7-one (1), a constituent of Taiwania cryptomerioides and Celastrus paniculatus, was achieved starting from (+)-manool (4) after a four-step sequence in 24% overall yield.

A series of novel podocarpa-8,11,13-triene-7- and 13-nitriles were prepared from the naturally occurring labdane diterpenoid (+)-manool, using podocarp-8(14)-en-13-one and 13-methoxypodocarpa-8,11,13-trien-7-one as key intermediates and TMSCN and acetonitrile as source of the nitrile. The synthesised compounds were screened for cytotoxicity against mouse macrophage cell line (RAW 264.7), human colon adenocarcinoma cell lines (HT-29) and human prostate adenocarcinoma cell lines (PC3) and for anti-inflammatory, as measured by the inhibition of nitric oxide (NO) production by RAW cells. 7-Oxopodocarpa-8,11,13-triene-13-nitrile exhibited significant inhibition of NO production (IC50 = 6 μM) and was not cytotoxic.

Facile and Simple Synthesis of Ring C Aromatic Diterpenes: Synthesis of (+)-13-Hydroxypodocarpa-8,11,13-triene (IV) and (+)-7-Deoxynimbidiol (VIII) -[starting from (+)-manool (I)]. -(VILLAMIZAR*, J. E.; GAMEZ, C.; ALCALA, A.; SALAZAR, F.; TROPPER, E.; ANGARITA, A.; CANUDAS, N.; Synth. Commun. 41 (2011) 12, 1733-1741, http://dx.