Carbon=nitrogen double bonds, sodium borohydride

The 2,3-, 2,5- and 3,4-dihydropyridines all contain a highly polarized carbon-nitrogen double bond and should be reactive toward nucleophilic reagents. From the limited information in the literature, this appears to be the situation. The 2,3-dihydropyridine is readily reduced by sodium borohydride (equation 58) (64JHC13). Hydride addition occurs in a 1,2 rather than 1,4 sense. 

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