Ant repellant

A certain species of grasshopper secretes an allenic substance of molecular formula C13H20O3 that acts as an ant repellent The carbon skeleton and location of various substituents in this substance are indicated in the partial structure shown Complete the structure adding double bonds where appropriate... 

Okunade and Wiemer reported isolation of a potent ant-repellent compound, (-)-loliolide (Fig. 7) from Xanthoxyllum setulosum. The plant is one of the many native Costa Rican plants found to escape attack of the highly polyphagous leafcutter ants Atta cephalotes. Additional leafcutter ant repellent constituents have been isolated from Piper tuberculatum ... 

Okunade AL, Wiemer DF, (-)-Loholide, an ant-repellent compound from Xan-thoxyllum setulosum. J Nat Prod 48 472 73, 1985. 

Capron MA, Wiemer DF, Piplaroxide, an ant-repellent piperidine epoxide from Piper tuberculatum. J Nat Prod 59 794—795, 1996. 

As part of our investigations (1,2) of the psychotropic Mexican labiate. Salvia divinorum Epling Jativa-M., we report the presence of loliolide (1), previously isolated from Lolium perenne (3), Gramineae, Digitalis purpurea L. (4), Scrophulariaceae, and several other species (5). The compound has recently been described to be a potent ant-repellent (8). 

The important piece of information that allows us to complete the structure properly is that the ant repellent is an allenic substance. The allenic unit cannot be incorporated into the ring, because the three carbons must be collinear. The only possible constitution is therefore... 

Other functions of carotenoids are briefly mentioned here. These include phototropism and phototaxis, reproduction, camouflage colour, precursor role of neoxanthin (38, Fig. 16) for the plant growth hormone abscisic acid and the ant repellent grasshopper ketone [18,41], and cell-cell communication [49], In recent years the function of zeaxanthin (15) and lutein (25) in the human retina has received much attention, cf. the section on Health aspects. 

The salvinorins are a class of non-nitrogenpus diterpenes isolated from a little-known Mexican entheogenic plant. Salvia divinorum, a member of the Labiatae or Lamiaceae, the mint fitmily. Similar diterpenes such as salviarin and splendidin have been isolated from Salvia splendens and other Salvia species (Savona etal. 1978 Savona etal. 1979), and these Salvia diterpenes represent a novel class of psycho-active compounds. Loliolide, an ant repellent, has recendy been isolated from Salvia divinorum (Valdes 19S6). Salvia occidentalis is reportedly used for analgesia by Panamanian Cuna Indians (Duke 1975). Salviapersepolitana was once proposed... 

The dyestuff, which is also called scarlet or carmine, may be obtained from the dried female kermes scale-insects (various species, e.g. Kermes ver-milio and Kermococcus ilicis L.) by extraction with ethanol (Fig. 2.19). Ker-mesic acid serves as an ant repellent to these insects living on Kermes oaks Quercus coccifera) in the Mediterranean. [50] The Polish cochineal (Por-phyrophora polonica L.), which lives on the roots of a member of the carnation family (Perennial knawel, Scleranthusperennis), was first mentioned in 812 in Charlemagne s Capitulare. It was also known as Saint John s blood , because harvesting began by tradition on the feast-day of St John the Baptist (June 24) (Fig. 2.20). 

Wiemer, D. F. and D. C. Ales, Lasidiol angelate Ant repellent sesquiterpenoid from Lasianthaea fruticosa, J. Org. Chem., 46, 5449-5450 (1981). 

Hubert, T.D., D.F. Wiemer Ant-repellent terpenoids from Melampodium divaricatum, Phytochem. 24, 1197 (1985). 

The large, flightless grasshopper, Romalea microptera excretes a novel sesquiterpenoid allenic ketone in its defensive secretionsJ Meinwald and Hendry confirmed the proposed structure and stereochemistry of this ant-repellant substance by stereospecific synthesis from isophorone. 

---