Selective Methylation of NH-Containing Heterocycles and Sulfonamides Using N,N-Dimethylformamide Dimethylacetal Based on Calculated pKa Measurements
摘要:
The use of N,N-dimethylformamide dimethylacetal (DMF-DMA) as a suitable methylating agent for the methylation of NH-containing groups and heterocycles has been investigated. Use of ReactArray and calculated pK(a) measurements have allowed additional helpful information to be collated to determine optimum reaction conditions for a variety of substrates.
The synthesis of N-alkyl-1H-1,2,4-triazoles from N,N-dialkylhydrazones and nitriles via formal [3+2] cycloaddition including the C-chlorination/nucleophilic addition/cyclisation/dealkylation sequence was developed. This sequential reaction utilising the in situ generation of hydrazonoyl chloride based on the ambiphilic reactivity of hydrazones afforded a variety of multi-substituted N-alkyl-triazoles