4-Bromo-2-iodoaniline → 4-Bromo-2-[4-(2-methyl-pyrrolidin-1-yl)-but-1-ynyl]-phenylamine

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Reaction Steps

The compound of formula (43) can be prepared from 3-butynyl p-toluenesulfonate (42) and 2(R)-methylpyrrrolidine L-tartrate (40) as shown in Scheme 5. 2(R)-Methylpyrrolidine L-tartrate (40) is treated with potassium carbonate in acetonitrile to provide 2(R)-methylpyrrolidine (41), which is combined with 3-butynyl p-toluenesulfonate (42) to give 1-but-3-ynyl-2-methyl-pyrrolidine (43). Compound (43) is reacted with 4-bromo-2-iodo-phenylamine (44) to provide 4-bromo-2-[4-(2-methyl-pyrrolidin-1-yl)-but-1-ynyl]-phenylamine (45). Compound (45) undergoes cyclization to compound (46) in the presence of a strong base, such as potassium t-butoxide. Compound (46) then is subjected to the Suzuki reaction conditions with an aryl or heteroaryl boronic acid, such as 4-cyanophenylboronic acid, to give compound (47) and (47a). Alternatively, in the presence of base and an alkylating agent, compounds (45) and (46) are alkylated with an alkyl halide such as methyl iodide to give an N-alkyl indole compounds, such as compound (48). Compound formula (48) is then subjected to the Suzuki reaction conditions with an aryl or heteroaryl boronic acid, such as 4-cyanophenylboronic acid, to give compounds such as compound (49) and (49a). Similarly, the compounds (40) and (41) can be substituted with any other suitable amine to provide the corresponding amine-substituted indole compound. In addition, the 4-cyanophenylboronic acid can be substituted with other boronic acids of the formula RcB(OH)2, wherein Rc is aryl or heteroaryl, to provide compounds of general structures (47a) and (49a), wherein R1 is aryl, heteroaryl, or heterocycle.

Provenance & Evidence