Gyrinidal

Captive fish, Micropterus slamoides, rejected both the beetle Dineutes hornii and mealworms after topical treatment with gyrinidal. The fish also exhibited an intensive and dose dependent oral flushing behaviour to get rid of gyrinidal [109]. 

Decomposition rates of some organic substrates are reduced. Substantial changes in the species composition of primary producers occur. The richness of phytoplankton species is reduced, while biomass and productivity of phytoplankton are not reduced by acidification. The biomass of herbivorous and predaceous zooplankton is probably reduced because of reductions in numbers of organisms and/or reduction in their average size. Many benthic invertebrates such as species of snails, clams, crayfish, amphipods, and various aquatic insects are intolerant of low pH and are seldom found in acidic lakes. However, certain large aquatic insects such as water boatmen and gyrinids are very acid tolerant and may become the top predators in some acidified lakes. Acidification of aquatic systems has major effects on fish population. 

Oxidation reactions of this nature are common in the literature.For example, selenium dioxide in refluxing ethanolic solution brought about the allylic oxidative rearrangement of geranyl acetate, which was further functionalized in a synthesis of the norsesquiterpenoid gyrinidal (equation 46). This transformation was also used in a tot synthesis of phytol. Similarly, an a,p-unsaturated aldehyde was obtained under similar conditions in studies of a synthesis of pentalenic acid derivatives (equation 47). ... 

AllyUc oxidation. The reaction was used by Meinwald and co-workers in the first step of a synthesis of gyrinidal (9), a norsesquiterpenoid from gyrinid beetles, from geranyl acetate (5). 

A component of the defensive secretion of gyrinid beetles has been identified as the nor-sesquiterpenoid aldehyde gyrinidal (21). The odour... 

Gyrinidal. C,4)1,303, Mr 234.30. Defence substance of water beetles (Carabidae) of the genera Gyrinus and Dineutes produced in the so-called pygidial glands... 

Gyrinidal and gyrinidone are compounds from the defensive glands of whirligig water beetles Gyrinus sp.). Suggest schemes for their biosynthesis from farnesol. Note the resemblance to iridoids. 

Q7. The ring closure from gyrinidal to gyrinidone is as for iridoids. 

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