Solid-phase process for making indole compounds

A solid-phase process for the synthesis of indole compounds comprising the steps:

• (a) treating an amino resin with diketene to provide a resin-bound acetoacetamide:
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• (b) treating the resin-bound acetoacetamide from Step (a) with a primary amine, R-NH2, in the presence of a dehydrating agent to provide a resin-bound enaminone:
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• wherein R is selected from the group consisting of alkyl, aryl, and heterocyclyl;
• (c) treating the resin-bound enaminone from Step (b) with a 1,4-benzoquinone:
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• to provide resin-bound product:
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• wherein each of R1, R2 and R3 are independently selected from the group consisting of hydrogen, halo, nitro, cyano, alkyl, aryl, heterocyclyl, and any of the following unsubstituted or substituted with alkyl, aryl or heterocyclyl:
• hydroxy, thio, amino, formyl, formoyl, formylamino, aminoformyl, sulfo, sulfonyl, phospho, phosphonyl, carboxy;
• (d) optionally treating the resin-bound product from Step (c) with an alcohol, R4-OH, or a halide, R4-Cl, to provide resin-bound product:
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• wherein R4 is alkyl;
• (e) treating the resin-bound product from Step (c) or from Step (d) to release indole product from the resin:
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• wherein B is H or R4, respectively.