2-Methyl-1H-indole-3-ethylamine → (S)-2-[1-(6-Chloroimidazo[2,1-b]thiazole-5-sulfonyl)-1H-indol-3-yl]-1-methylethylamine Hydrochloride

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Reaction Steps

A mixture of (S)-2-(1H-Indol-3-yl)-1-methylethylamine (0.43 g, 2.5 mmol) and di-t-butyl dicarbonate (0.60 g, 2.75 mmol) in acetone is treated dropwise with aqueous K2CO3 (3.5 g, 25 mmol) at 0° C., allowed to warm to room temperature for 16 h, concentrated to an aqueous residue and extracted with EtOAc. The extracts are combined, dried over MgSO4 and concentrated in vacuo to dryness. This residue is chromatographed (silica gel, 10%-50% EtOAc in hexanes as gradient eluent) to give the protected®-2-methyl tryptamine. A mixture of the protected tryptamine (0.17 g, 0.62 mmol) and 6-chloroimidazo[2,1-b]thiazole-5-sulfonyl chloride (0.16 g, 0.62 mmol) in THF is treated with potassium t-butoxide (77 mg, 0.68 mmol) at room temperature, stirred for 1 H, poured into saturated NaHCO3 and extracted with EtOAc. The extracts are combined, dried over Na2SO4 and concentrated in vacuo. The resultant residue is dispersed in THF and 4N HCl in dioxane, stirred for 16 h, concentrated in vacuo and purified by HPLC1 to afford the title product as a beige solid, 0.62 mg (35% yield), identified by NMR and mass spectral analyses.

Provenance & Evidence