
TY  - JOUR
A1  - Crow, W 
A1  - Osawa, T 
A1  - Platz, K 
A1  - Sutherland, D 
T1  - Root Inhibitors in <I>Eucalyptus grandis</I>. 2. Synthesis of the Inhibitors and Origin of the Peroxide Linkage
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1976
VL  - 29
IS  - 11
SP  - 2525
EP  - 2531
KW  - 
UR  - https://doi.org/10.1071/CH9762525 
N2  - Syntheses are described for the three inhibitors G3 (1-hydroxy- 4,4,8,8,10,10-hexamethyl-2,3-dioxabicyclo[4,4,0]dec-5-ene-7,9-dione), G1 and G2 (the diastereoisomers 4-ethyl-1-hydroxy-4,8,8,10,10-pentamethyl- 2,3-dioxabicyclo[4,4,0]dec-5-ene-7,9-dione). Knoevenagel condensation of syncarpic acid with 2-methylpropanal or 2-methylbutanal respectively is followed by slow spontaneous uptake of atmospheric oxygen and cyclization to give the products named.     Isolation of the naturally occurring inhibitors from Eucalyptus grandis in an atmosphere of 18O2 results in no incorporation of isotopic oxygen into the peroxide linkage; this indicates that this structural feature was present in the inhibitors in vivo. 
ER  -

