Background: 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%. The ratio of the yield of the dibenzyl product to the yield of the monobenzyl product was 1:1.66. Hypothesis: The reaction conducted on electron-rich aromatic aldehydes may produce higher yields of N,N-diaryl-N-methylamines and lower yields of N-aryl-N-methylformamides. In this work the hypothesis was tested by conducting the reaction on 9-anthracenecarboxaldehyde. Methods: The reaction was conducted on 10 mmol scale at 186°C. Column chromatography was used for the isolation of the products. NMR-spectroscopy and elemental analysis were used to determine the structures of the products. Results: The reaction was fully completed in 10 minutes. N-(9-anthrylmethyl)-N-methylformamide was still produced as the main product but with a lower isolated yield of 43.3%. N,N-di-(9-anthrylmethyl)-N-methylamine was also produced with a slightly lower isolated yield of 30.1%. The ratio of the yield of the dibenzyl product to the yield of the monobenzyl product was 1:1.44. Conclusions: The results of the reaction tend to support the initial hypothesis. The reaction provides a new method for the synthesis of N-(9-anthrylmethyl)-N-methylformamide and N,N-di-(9-anthrylmethyl)-N-methylamine. Both products of the reaction are new compounds. Support: The project was supported by NIH grant 8 P20 GM103442-12 from the National Institute of General Medical Sciences of the National Institutes of Health.

Rapid synthesis of N-(9-anthrylmethyl)-N-methylformamide

255th National Meeting (2018)

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