Synthesis of Totarane Diterpenes: Totarol, Maytenoquinone, 6-Deoxymaytenoquinone and 8,11,13-Totaratriene-12,13-diol

Syntheses of Carnosic Acid and Carnosol, Anti-oxidants in Rosemary, from Pisiferic Acid, the Major Constituent of Sawara

“…Crystallization from ethyl acetate-hexane gave light green crystals (7.3 g, 0.6% of the leaves) of 1. The isolated pisiferic acid; green solid; mp 174-180°C was found to be identical with authentic pisiferic acid by the 1 H-NMR (600 MHz, CDCl 3 ) and 13 C-NMR (150 MHz, CDCl 3 ).…”

“…Previously we reported an efficient orthooxidation of phenols with meta-chlorobenzoyl peroxide (mCBPO) 11) and the synthesis of an anti-microbial diterpene, abietaquinone methide, active against drug resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). 12,13) In this report, we describe the facile synthesis of the major antioxidant in rosemary, carnosic acid 2, from pisiferic acid 1, which is the major constituent of Sawara (Chamaecyparis pisifera). The other rosemary anti-oxidants, e.g., carnosol 3, rosmanol 4, and other antioxidant diterpenes were synthesized from carnosic acid 2.…”

Diterpenoids

“…A synthesis of totarol has been described. 142 A number of abietane lactones possessing the ent stereochemistry for the A-B ring junction have been reported, including 18-hydroxyhelioscoponolide A from the shrub Goldfussia yutwanensis, 143 as well as some further cytotoxic gelomulides from a Formosan species of Gelonium aequorum 144 and the ketone 36 from the roots of Suregada glomerulata 145 Inumakiol A from Podocarpus macrophyllus is a phenolic abietane 19-carboxylic acid in which the isopropyl group is at C-12 and the phenolic hydroxyl group at C-13. 146 The icetexanes are a series of rearrangement products which possess a seven-membered ring B.…”

A short and efficient synthesis of (+)-totarol

“…As anticipated, analogous treatment of (+)-13-epi-manool (10) led to diketone 7 as well. (9) and from (+)-13-epi-manool (10). Reagents and conditions: (a) KOH, H 2 O, EtOH, RT, 48 h, 60%; (b) NaHCO 3 , DMSO, 150°C, 6 h, 90% (mixture of isomers with 77% major product 9); (c) O 3 , toluene, 10% aq.…”