Recently, we developed a rapid procedure for the Leuckart reaction and successfully applied it for the synthesis of substituted N-benzyl-N-methylformamides. Interestingly, in the reaction conducted on 4-chlorobenzaldehyde, a large amount of a by-product, N,N-di-(4-chlorobenzyl)-N-methylamine was produced with an isolated yield of 31.3%. N-(4-chlorobenzyl)-N-methylformamide was produced with an isolated yield of 52.0%. It was interesting to determine what results the reaction will produce with 2-chlorobenzaldehyde. We hypothesized that the ratio of the products depends on the nature of the substituents and that the yields of both of the 2-chlorobenzyl products will be similar to the yields of the respective 4-chlorobenzyl products. The reaction was conducted on 10 mmol scale at 187°C. Column chromatography was used for the isolation of the products of the reaction. NMR-spectroscopy and elemental analysis were used to determine the structures of the products. The reaction was fully completed in 10 minutes. Surprisingly, the ratio of the products changed and the isolated yield of N,N-di-(2-chlorobenzyl)-N-methylamine (42.5%) appeared to be larger than the isolated yield of N-(2-chlorobenzyl)-N-methylformamide (37.3%). The reaction comprises a new method for the synthesis of N-(2-chlorobenzyl)-N-methylformamide and N,N-di-(2-chlorobenzyl)-N-methylamine.

Rapid synthesis of N-(2-chlorobenzyl)-N-methylformamide

253rd National Meeting (2017)

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