N,N-Dimethylbenzamide → N-Propyl-N-methyl-benzamide

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Reaction Steps

Table 1 lists the addition products of some typical small molecule amides. In the case of N,N-dimethylformamide (DMF), the double bond content nearly completely disappeared, after stirring for 3 days in the presence of DTBP at 125° C. to give a mixture of products 2a and 2b. Abstraction of the carbonyl-bonded hydrogen atom results in the formation of the N,N-dimethyl amide 2b (13C NMR: 171 ppm; IR: 1655 cm−1; >N—CO—CH2—). However, abstraction of the hydrogen atom of the nitrogen-bonded methyl group also yields N-propyl-N-methyl formamide 2a (13C NMR: 161 ppm; IR: 1684 cm−1; >N—CO—H). Solid state 13C NMR shows an approximately 1:1 ratio of a mixture which is consistent with the results reported for the similar small molecules [ ] Friedman and Schecter y1961 ibid]. Similarly, addition of N,N-dimethylacetamide and N,N-dimethylbenzamide to (vinyl)polystyrene gave only N-propyl-N-methylacetamide 3a and N-propyl-N-methylbenzamide 4a, respectively. Cyclic N-methylamide N-methylpyrrolidione (NMP) also gave good yields of the possible addition products 7a-c although the exact proportions could not be determined.20 N-methylacetamide, acetamide and formamide showed none of the addition products 5a and 8a respectively. Substituted ureas such as N,N,N′,N′-tetramethylurea and DMPU were succesful in adding to the residual vinyl groups although in moderately low yeilds of 6a and 9a and 9b. The addition of an N-acetyl α-amino acids was also performed (22).

Provenance & Evidence