3582-26-1Relevant academic research and scientific papers
Partial Synthesis of 9,10-Syn Diterpenes via Tosylhydrazone Reduction: (-)-(9β)-Pimara-7,15-diene and (-)-(9β)-Isopimaradiene
Chu, Min,Coates, Robert M.
, p. 4590 - 4597 (2007/10/02)
(9β)-Pimara-7,15-diene (3), a proposed intermediate in the biosynthesis of the momilactone phytoalexins (1 and 2) from rice, and its C-13 epimer, (9β)-isopimara-7,15-diene (4), were synthesized from methyl pimara- and isopimara-8,15-dien-18-oates (8b and 8a, respectively).Allylic oxidation of 8a and 8b as well as the derived diterpene hydrocarbons 15a and 15b with chromium trioxide-dipyridine complex afforded 8,15-dien-7-ones 9a, 9b, 16a, and 16b (35-54percent).Lithium-ammonia reduction of 9a, 16a, and 16b gave predominantly trans,anti,trans-isopimara- and -pimara-15-en-7-ones 10, 17a, and 17b.In contrast, catecholborane reduction of the tosylhydrazones of 9a and 9b provided methyl (9β)-isopimara- and (9β)-pimara-7,15-dien-20-oates (23a and 23b) having the 9,10-syn stereochemistry.The parent diterpenes, 3 and 4, were obtained by carboxyl-to-methyl conversions.In a collaborative investigation 3 was tentatively identified as one of five diterpene hydrocarbons produced upon incubation of (E,E,E)-geranylgeranyl pyrophosphate with a crude enzyme extract from UV-treated rice plants.
CYCLIZATION OF TRICYCLIC DITERPENOIDS INTO TETRACYCLIC DITERPENOIDS BY THE ACTION OF SUPERACIDS
Shmidt, E. N.,Gatilov, Yu. V.,Bagryanskaya, I. Yu.,Korchagina, D. V.,Bardina, N. M.,et al.
, p. 718 - 725 (2007/10/02)
The cyclization of pimaradienes - the methyl esters of isopimaric (I), pimaric (II), and Δ8,9-isopimaric (III) acids - into tetracyclic diterpenes was realized for the first time by the action of superacids (HSO3F-SO2FCl, SbF5-HSO3F-SO2FCl at -120 deg C), followed by "quenching" of the acid solutions with methanol.
PART I. EPOXYDES DITERPENIQUES : SYNTHESE ET REACTIVITE D'EPOXYDES DERIVES D'ACIDES RESINIQUES
Papillaud, B.,Tiffon, F.,Taran, M.,Miguel, B. Arreguy-San,Delmond, B.
, p. 1845 - 1858 (2007/10/02)
Epoxidation of methyl esters of resin acids with the pimarane skeleton with p-nitroperbenzoic acid has permitted the isolation of epoxides of the intracyclic double bond.Allylic diterpenic alcohols were obtained by acid-catalysed isomerisation of diterpene epoxides, and the action of Collins reagent on these allylic alcohols has been studied.
