Ethyl chloroformate → (5-Bromo-3-pyridinyl)methanol

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The manner in which certain 5-substituted-3-pyridyl compounds of the present invention can be synthetically produced can vary. For example, 3-(5-bromo-3-pyridyl)- containing compounds can be prepared using a combination of synthetic techniques known in the art. 2-[3-(5-bromopyridiyl)]- substituted analogs of the 1-azatricyclo[3.3.1.13,7]decanes can all be prepared starting from 5-bromonicotinic acid, which is commercially available from Aldrich Chemical Co. The 5-bromonicotinic acid is converted to the mixed anhydride with ethyl chloroformate and reduced with lithium aluminum hydride/tetrahydrofaran (THF) at −78° C., to afford 5-bromo-3-hydroxymethylpyridine, as reported by Ashimori et al., Chem. Pharm. Bull. 38:2446 (1990). Alternatively, the 5-bromonicotinic acid is esterified in the presence of sulfuric acid and ethanol, and the intermediate ester is reduced with sodium borohydride to yield 5-bromo-3-hydroxymethylpyridine, according to the techniques reported in C. F. Natatis, et al., Org. Prep. and Proc. Int. 24:143 (1992). The resulting 5-bromo-3-hydroxymethylpyridine can then be converted to the 5-bromo-3-aminomethylpyridine utilizing a modification of the techniques of O. Mitsunobu, Synthesis 1 (1981), or via treatment of 5-bromo-3-hydroxymethylpyridine with tionyl chloride and reaction of the resulting 5-bromo-3-chloromethylpyridine with aqueous ammonia/ethanol, according to North et al., WO 95/28400. 5-Bromo-3-aminomethylpyridine can be converted to 1-aza-2-[5-bromo-(3-pyridyl)]tricyclo[3.3.1.13,7]decane using procedures analogous to those described hereinbefore for the preparation of 1-aza-2-(3-pyridyl)tricyclo[3.3.1.13,7]decane.

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