From Four or More Synthons

The primary synthesis of 1,6-naphthyridines has been accomplished by condensation of two or more aliphatic substrates by cycbzation of a single pyridine substrate by condensation of a pyridine substrate with an aliphatic synthon that provides one, two, three, or even four ring atoms by condensation of a pyridine substrate with two or more synthons or from other heterocyclic substrates by degradation, rearrangement, or other elaborative processes. 

The products from oxidation of halobenzenes with P. putida 39/D or the recombinant E. coli JM109 expressing TDO activity have been used as starting materials for many chemical syntheses, with more recent examples including the preparations of the fluoro-inositols 41 and 42 [52], 2-deoxy-2-fluoro-D-glucose (43) [53], and the protected 5-deoxy-5-fluoro-manno-7-lactol (44) [53], shown in Fig. 32. The cis-diol obtained from chlorobenzene has also been used as starting materials for the syntheses of all four stereoisomers of sphingosine (45) (Fig. 33) [54], and cw-diols derived from 2-phenylethyl bromides (Fig. 34) have potential applications as chiral synthons in the preparation of morphine [55,56]. 

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