3-Heptyl-5-methylpyrrolizidine

The venomous constituent of the cryptic thief ant, Solenopsis xenovenenum, has been identified as the 3-heptyl-5-methylpyrrolizidine (50) from its mass spectrum and the fact that a related pyrrolidine (51) has been isolated from another species of ant.47 This is the first reported occurrence of a 3,5-dialkyl-pyrrolizidine, and its structure was confirmed by synthesis. Reductive amination of the known triketone (52) with sodium cyanoborohydride and ammonium acetate gave a mixture of four isomers of 3-heptyl-5-methylpyrrolizidine, which were separated by preparative g.l.c. The stereochemistry of the ring-junction of each isomer was established from its i.r. and n.m.r. spectra. 

Z,8E)-3-heptyl-5-methylpyrrolizidine (V) for all species (Figure 2). The trans-Cj j piperidine (VI) was intermediate in repellency between the pyrrolidines III and IV, and the pyrrolizidine (V), but was not significantly different from either class of alkaloids... 

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