Of pheromones

Construction of the carbon frameworks by using the activating property of the nitro group followed by denitration provides a useful tool for the preparation of various naniral products as shovm in Schemes 3 5-3 7 For example, fZ -jasmone and dihydrojasmone, constinients of the essential oilof jasmone flowers, have been prepared as shown in Scheme 3 5 Schemes 3 6 and 3 7 present a synthesis of pheromones via denitration of ct-nitro ketones " ... 

The addition of the lithium azaenolate of the SAMP hydrazone of propanal to methyl (E)-2-butenoate to furnish the (S,S,S)-adduct in 58% yield with > 96% ee and de is illustrative for the efficiency of this asymmetric Michael addition10°. Only the anti-isomer (an / adduct) is found. This methodology was used in the synthesis of pheromones of the small forest and red wood ant200. 

The Chemistry of Pheromones and Other Semiochemicals I Volume Editor Schulz, S. 

This procedure has been used with good results to prepare certain long-chain ketones that are precursors of pheromones.204... 

Central/Tertiary structures The fish olfactory bulb is a fourlayered structure much as in higher vertebrates. Within the 2nd layer, the first synapse for olfactory input is on the dendrites of the mitral cells (MC). About 1000 ORN axons converge on one MC, a ratio similar to mammals. The MC output, from cells at various levels, leads into several glomeruli and receives (inhibitory) input from granule cells. The latter also innervate a distinct cell type in the MC layer of teleosts — the ruffed cells (RC), with which they have reciprocal synapses [Fig. 2.18(a)] both relay cells send ascending fibres to forebrain centres (Kosaka and Hama, 1982). The RC are unlike the MC since they are not stimulated by the ORNs directly. Their interactions (Chap. 5) may contribute to the processing of pheromonal stimuli (Zippel, 2000). The main bulbar pathways project to several nuclei in the forebrain via two ipsilateral tracts, the lateral and medial [Fig. 2.18(b)], the latter mediates sexual behaviour and the former probably other behaviours (Hara,... 

Behavioural testing of protein fractions has not kept pace with semiochemical studies. Belcher et al. (1990) found that the mixed scent marks of the Saddle-backed Tamarin (S. fusicollis) comprise urine and genital/suprapubic gland secretions. Both sexes deposit mixtures of pheromonally active large molecules at, for example, exudate feeding... 

Belluscio L., Koentges G., Axel R. and Dulac C. (1999). A map of pheromone receptor activation in the mammalian brain. Cell 97, 209-220. 

Dulac C. (2000). Sensory coding of pheromone signals in mammals. Curr Opin Neurobiol 10, 511-518. 

Duvall D. (1986). A new question of pheromones Aspects of possible chemical signalling and reception in the mammal-like reptiles. In Ecology and Biology of Mammal-like Reptiles (Hotton N., et al., eds.). Smithsonian Institution, Washington D.C., pp. 219-238. 

Fadem B.H. (1989). The effects of pheromonal stimuli on estrus and peripheral plasma estradiol in female gray short-tailed opossums. Biol Reprod 41, 213-217. 

Goodrich B.S. and Myktowycz R. (1972). Individual and sex-differences in chemical composition of pheromone-like substances from skin giands of rabbit. J Mammal 53, 540-548. 

Inamura K., Matsumoto Y., Kashiwayanagi M. and Kurihara K. (1999). Laminar distribution of pheromone-receptive neurons in rat vomeronasal epithelium. J Physiol 517, 731-739. 

Iwata T., Umezawa K., Toyoda F., Takahashi N., et al. (1999). Molecular cloning of newt sex pheromone precursor cDNAs evidence for the existence of species-specific forms of pheromones. FEBS Lett 457, 400-404. 

Kelliher K Chang Y., Wersinger S. and Baum M. (1998). Sex difference and testosterone modulation of pheromone-induced neuronal fos in the Ferret s main olfactory bulb and hypothalamus. Biol Reprod 59, 1454-1463. 

Meredith M. (1983). Sensory physiology of pheromone communication. In Pheromones and Reproduction in Mammals (Vandenbergh J.G., ed.). Academic Press, New York, pp. 200-252. 

Regier F. and Goodwin M. (1977). On the chemical and environmental modulation of pheromone release from vertebrate scent marks. In Chemical Signals in Vertebrates 1 (Muller-Schwarze D. and Mozell M.M., eds.), pp. 115-134. 

Sorensen P., Christensen T. and Stacey N. (1998). Discrimination of pheromonal cues in fish emerging parallels with insects. Curr Opin Neurobiol 8, 458-467. 

Tirindelli R., Mucignat-Caretta C. and Ryba J. (1998). Molecular aspects of pheromonal communication via the vomeronasal organ of mammals. Trends Neurosci 21, 482-486. 

Golden, J.W. and Riddle, D.L. (1984) The Caenorhabditis elegans dauer larva developmental effects of pheromone, food, and temperature. Developmental Biology 102, 368—378. 

The other major class of extracellular LBPs of mammals is the lipocalins (Flower, 1996). These are approximately 20 kDa, P-sheet-rich proteins, performing functions such as the transport of retinol in plasma or milk, the capture of odorants in olfaction, invertebrate coloration, dispersal of pheromones, and solubilizing the lipids in tears (Flower, 1996). The retinol-binding protein (RBP) of human plasma is found in association with a larger protein, transthyretin, the complex being larger than the kidney threshold and thus not excreted, although the RBP itself may dissociate from the complex to interact with cell surface receptors in the delivery of retinol (Papiz et al., 1986 Sundaram et al., 1998). 

Many different functions of pheromones have been found since Butenandt. Aggregation pheromones attract both sexes to a special location, while sex pheromones are offered by one sex only to attract or arouse the other one. Trail pheromones used by ants mark food trails and alarm pheromones change the state of alertness of conspecifics. These are only some of the functions pheromones can have, and similar different functions can be found in allelochemicals as well. 

F. Sato developed titanium (Il)-based c/s-reduction of alkynes as shown in Scheme 5 [14], and the method was applied to the synthesis of pheromones by Kitching (Scheme 6) [15]. This titanium (Il)-based reaction gives pure (Z)-alkenes. Kitching summarized the contemporary methods for the synthesis of skipped polyynes and their reduction to skipped polyenes [15]. 

Various enzymes, especially esterases and lipases, are employed in the enan-tioselective syntheses of pheromones [16,17]. Examples will be given later. 

By synthesizing pure enantiomers of pheromones, various stereochemistry-pheromone activity relationships could be clarified. For example, in the case of sulcatol (6-methyl-5-hepten-2-ol),both the enantiomers are necessary for bioactivity. For other relationships, please refer to [4-9]. 

Mori K (2000) Chemoenzymatic synthesis of pheromones, terpenes, and other bioregulators. In Patel RN (ed) Stereoselective biocatalysis. Marcel Dekker, New York, p 59... 

---