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.
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.
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.
