Di-tert-butyl dicarbonate → HCID 22219740, compound

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Reaction Steps

A solution of a-methyltryptamine methane sulfonate (5.0 g, 18.5 mmol) in a 1:1 mixture of acetone:water is treated with di-t-butyl dicarbonate (7.7 g, 55.5 mmol, 3 eq.), stirred at room temperature for 16 h, concentrated to an aqueous mixture and extracted with EtOAc. The extracts are combined, dried over MgSO4 and concentrated in vacuo. A mixture of a portion of the resultant residue (2.0 g, 7.3 mmol, 1.1 eq.) and 6-chloroimidazo[2,1-b]thiazole-5-sulfonyl chloride (1.7 g, 6.6 mmol, 1.0 eq.) in THF is treated portionwise with potassium t-butoxide (820 mg, 7.3 mmol, 1.1 equiv.) 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. This resultant residue is chromatographed (silica gel, 20%-50% EtOAc in hexanes as gradient eluent) to give the free base of the title product as a brown oil, 1.7 g (50% yield). Treatment with 4N HCl in dioxane and THF, followed by filtration and recrystallization of the filtercake from ethanol affords the title product as a light brown solid 1.0 g (40% yield), identified by NMR and mass spectral analyses.

Provenance & Evidence