Dialkylamino-methyl -indole

Substituted indoles may be used, but must be protected (e.g. methoxy instead of hydroxy). Substitutions on the phenyl ring will result in the formation of substituted 3-(dialkylamino-methyl)-indoles such as 4-methoxy-gramine. 

Figure 2. Formulas of selected D-A compounds which contain 4-dialkylamino group as an electron donor and reveal dual fluorescence behaviour. Top /)-cyano-A,A-dimethylaniline (I, CDMA) and its model derivatives p-cyano-2,A,A-trimethylaniline (II), p-cyano-2,6,A.A-tetramethylaniline (III, CTMA)./)-aminobenzonitrile (IV, ABN) and l-ethyl-2,3-dihydro-indole-5-carbonitrile (V. BIN). Middle 4-(dimethylamino)pyrimidine (VI), 4-(diethylamino)pyrimidine (VTI), 4-(dimethylamino)-5-methylpyrimidine (VIII), 4-(diethylamino)-5-methylpyrimidine (IX) and 4-(dimethylamino)-pyridine (X). Bottom methyl 4-(dimethylamino)benzoate (XI, DMAMB), ethyl 4-(dimethylamino)benzoate (XII, DMAEB), p-(dimethylamino)-benzaldehyde (XIll) and />-(dimethylamino)acetophenone (XIV).

An important use of H CHO has been found in amino[ " C]methylations of nucleophiles in the presence of primary and secondary amines (Mannich reaction). Nucleophilic substrates include C—H acidic aliphatic compounds (e.g. aldehydes, ketones, esters, nitroalkanes and nitriles), and reactive aromatic and heteroaromatic substrates such as indoles, furans and phenols. The amino[ C]methylations of some C—H acidic methyl, methylene and methine substrates are exemplified in Figure 5.44. The immediate products, alkyl- or dialkylamino[ C]methylene derivatives ( Mannich bases ), can undergo a number of useful synthetic transformations. Condensation of H CHO with acetophenone and dimethylamine provided the carbon- 14-labeled /3-aminoketone 147 in 51 % yield. /3-Aminocarbonyl compounds such as 147. whQe stable at room temperature, can eliminate... 

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