Seed-germination stimulant

The compound (I) was given the trivial name strigol and it has been shown to be a very potent witchweed seed germination stimulant. 

Galindo, J.C.G., de Luque, A.P., Jorrin, J., Macias, F.A. SAR studies of sesquiterpene lactones as Orobanche cumana seed germination stimulants. J Agric Food Chem 2002 50 1911-1917. 

Eplee, R.E. 1975. Ethylene a witchweed seed germination stimulant. Weed Sci. 23, 433-436... 

Formation of the 3j8-acetoxyeti-5-enic esters has been used to obtain optically pure samples of (+)- and (—)-tran5-verbenoP and to resolve an alcohol intermediate in the synthesis of the witchweed seed germination stimulant (+)-strigol. A general synthesis of thiol esters from carboxylic acids, exemplified by the formation of the n-propylthio-, isopropylthio-, and t-butylthio-esters of cholic acid, comprises reaction with diethyl chlorophosphate-triethylamine, followed by the thallium(i) salt of the appropriate thiol. 

Other Syntheses of Strigol Analogs. In 1979, Cook and Co-workers reported the synthesis the aromatic analog 75 (42), which contains all but one of the carbon atoms of strigol. It was about 2% as active as strigol as a seed germination stimulant. The diastereomeric compound 76 exhibited one-hundredth of the activity of 75. 

An improved total synthesis of ( )-strigol (1), a potent seed germination stimulant for Striga and other related parasitic plants, is described along with the determination of the absolute configuration of natural (+)-strigol. 

Scheme 3. Some Synthetic Strlga Seed Germination Stimulants...

A lettuce seed germination stimulant, graphinone, isolated from Graphium fungus culture has been attributed the structure (114). This compound appears to be identical to ovalicin, isolated from Pseudeurotium ovalis. ... 

Notable natural product syntheses in this area include an improved route to the seed germination stimulant strigol, in which the butenolide unit is introduced by 0-alkylation using... 

Kim HI, Xie X, Kim HS, Chun JC, Yoneyama K, Nomura T, Takeuchi Y, Yoneyama K (2010) Structure-activity relationship of naturally occurring sbigolactones in Orobanche minor seed germination stimulation. J Pestic Sci 35 344—347. doi 10.1584/jpestics.G10-17... 

---