Monomorine from Monomorium pharaonis

The structure of monomorine I (16a), isolated from the extract of workers of the thief ant, Monomorium pharaonis, by gas-liquid chromatography (Table II), has been revealed to be 3-butyl-5-methyloctahydroindolizidine on the basis of mass and H-NMR spectra. The mass spectmm shows characteristic peaks at m/z 180 (345 M - CH3) and m/z 138 (346 M - Bu, a base peak), indicating the presence of methyl and butyl group attached to the a carbons of an amine, in addition to a molecular ion at m/z 195. The fact that the (M — 1) peak is higher than the M peak indicates a cyclic amine. The H-NMR spectmm shows two methyl groups (triplet at 8 0.88, CH3—CH2 doublet at 8 1.18, CH3CH—N) and three methines adjacent to nitrogen (8 2.13, 2.27, and 2.52). 

We end with an example that includes methods from this chapter as well as some revision and a reminder of stereochemistry. Monomorine I 71 is the trail pheromone of Pharaoh s ant (Monomorium pharaonis). These ants are pests in hospitals as they spread infections and they follow a trail of monomorine as they go about their evil work. Synthetic monomorine might be... 

All the currently known indolizidine and quinolizidine alkaloids isolated from ants are illustrated in Fig. 6. (+ )-Monomorine I (427), the well-studied trail pheromone constituent of the Pharaoh ant Monomorium pharaonis), and the analogs 428-431 were described in the earlier volumes in this series. These five compounds are 3,5-disubstituted indolizidines bearing short saturated or mono-unsaturated hydrocarbon chains. The relative stereochemistry in monomorine VI (430) still remains unknown, while that of 431 was atypical for the class at the time of its isolation 380). The structural resemblance of fiiis group of alkaloids to the... 

Monomorine (664), isolated from the cosmopolitan ant Monomorium pharaonis (L.) as a major component displaying attracting and trail-initiating activity, is another example in which stereoselective hydride addition to a prochiral ketone creates easy access to cmcial stereogenic centers. L-Selectride reduction of 647 affords, with high syn selectivity, alcohol 662 (98 2). This is similarly converted in six steps to the (25, 5i )-pyrroline 663 which, after... 

From the above survey of results the synthetic potential of the oxazinolactam intermediate 46 in hand, we envisaged to synthesize monomorine I (62) which constitutes of an extension of the methodology based on intramolecular nitroso Diels-Alder cycloaddition. The relative stereochemistry of this substance, isolated as one of the trail pheromones from Pharaoh ants (Monomorium pharaonis L.) (ref. 19), has been determined its relative stereochemistry by nonstereoselective synthesis (ref. 20). More recently, a stereospecific synthesis of racemic 62 (ref. 21) and a chiral synthesis of the (-)-enantiomer of natural 62 (ref. 22) were reported. 

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