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Metallation of BF3-pyridine complex with lithium tetramethylpiperidide (LTMP) in ether at -78 "C, followed by reaction with carbonyl compounds, affords a-pyridyl alcohols in good yields. a-Pyridyl alcohols, which are intermediates of some pharmacological interest ,132 are often synthesised from halogen derivatives or N-oxides of pyridine because direct metallation of this heterocycle is deemed impractical.3-5 It was, therefore, of interest to see if Lewis acid complexation can be used for this purpose (Scheme 1).6Our attempts to obtain the alcohol 3a through deprotonation of pyridine with the highly hindered base lithium tetramethylpiperidide (LTMP) furnished only 2,2'-bipyridy17 at -78"C, while no reaction was observed at -120°C. However, treatment of an ether solution? of the BF3-complex 1 with LTMP at -78 "C, followed by addition of benzaldehyde afforded 3a8 in 85% yields.$ The alcohol 3b9 (87%) was t Use of tetrahydrofuran (THF) as solvent gave inferior yields. Also reactions with methyl iodide and benzyl chloride proceeded poorly.

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The diffusion of iron in copper and nickel in silver is studied in the temperature range of 790 to 1000 °C and 750 to 920 °C, respectively, by the resistometric technique. An Arrhenius relation is found to be obeyed in both the cases within the limit of experimental error. The values of the activation energy and the diffusion coefficient are consistent with previous studies in the case of diffusion of iron in copper. This shows the applicability of the resistometric technique for the study of diffusion of iron in copper under the existing experimental conditions. For the diffusion of nickel in silver previous data are inconsistent amongst themselves and the data obtained are expected to be more reliable. Attempts are made to interpret the data by using the electrostatic theory of Le Claire using both the Thomas‐Fermi and oscillating potentials.

Impurity diffusion of Zn in similar metals like Cu and Ag have been studied by resistometric method and the values of diffusion coefficient D2 and activation energy Q2 have been determined in both the cases. The values of D2 and Q2 thus found agree fairly well with the earlier values determined by radioactive tracer techniques. Attempts have been made to interpret the date in the light of LeClaire's electrostatic theory incorporating in it the effect of impurities of equal valence which belong to different periods of the periodic table for zinc diffusing in silver.