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Figure 9.8 Substitited pyrrolidines from the venom of a slave-making ant and its slaves.

The compounds are arranged from the one in greatest quantity on the left to the least on the right

Figure 9.8 Substitited pyrrolidines from the venom of a slave-making ant and its slaves.

The compounds are arranged from the one in greatest quantity on the left to the least on the right very small, 10 ng down to 5 pg, but there is more in the slave-maker than in the slaves. The alkyl groups certainly suggest amino-acid origins (leucine, methionine, phenylalanine and isoleucine).

The coccinellid beetles (ladybirds) evidently have enzymic resources to make a variety of alkaloidal defenses. The coccinellines, adaline and epilachnine have already been encountered, since their biosynthetic origin is known. Another ladybird, Hyperaspis campestris produces hyper-aspine (Figure 9.9), which has a partly constructed precoccinelline (see Figure 3.22) with pyrrole carboxylic acid esterified to it. Exochomus quadripustulatus produces a more complex compound, exochomine (Figure 9.9), which has an azaacenaphthalene linked to hippodamine (see Figure 3.22). Yet another coccinellid Chilocorus cacti produces the complex alkaloid chilocorine (Figure 9.9), which has hippodamine linked by two bonds to the same azaacenaphthalene as that in exochomine. An amino-acid amide of quinaldinic acid occurs in Subcoccinella vigintiquatuorpunctata. For a series of eight coccinellid alkaloids, some met previously, see Attygalle, Xu, McCormick, Meinwald, Blankspoor and Eisner (Tetrahedron, 1993, 49, 9333). Finally the fatty acid derivative (Z)-l,17-diamino-9-octadecene is found in several species. Its structure indicates an origin in oleic acid but it has no obvious relationship to the wealth of polycyclic coccinellid amines. These compounds have been relegated to this section because their biosynthesis is incompletely known.

Some ants make products reminiscent of the coccinellid alkaloids. Three indolizidines are known from the venom gland of Monomorium pharaonis (Figure 9.10), and a pyrrolizidine from a Solenopsis ant has been known for some time. They would appear to be formed from polyketides or fatty acids as in the case of the coccinellines. More pyr-rolizidines and indolizidines with two alkyl and alkenyl groups have been found in Monomorium and Solenopsis species. Tetraponerine ants smear the venom of their poison glands onto prey. The venom consists of tricyclic alkaloids called tetraponerines (Figure 9.10). They are divided rv-/

\hyperaspine

\hyperaspine

exochomine

1,17-diamino-9-octadecene

Figure 9.9 Some alkaloids with bridge-head nitrogen and a diamine from ladybirds. The biosynthetic scheme for hyperaspine is the author's present suggestion only. No scheme for the formation of the azanaphthacene part is offered exochomine

1,17-diamino-9-octadecene

Figure 9.9 Some alkaloids with bridge-head nitrogen and a diamine from ladybirds. The biosynthetic scheme for hyperaspine is the author's present suggestion only. No scheme for the formation of the azanaphthacene part is offered

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