p-Toluenesulfonic acid → [2,5-Bis-(4-tert-butyl-phenyl)-pyrrol-1-yl]-carbamic acid 2-trimethylsilanyl-ethyl ester

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Reaction Steps

A solution of 1,4-bis-(4-tert-butyl-phenyl)-butane-1,4-dione (377 mg, 1.08 mmol) in toluene (3 mL) was treated with hydrazinecarboxylic acid 2-trimethylsilanyl-ethyl ester (212 mg, 1.18 mmol) and p-toluene sulfonic acid (11.3 mg). The resulting solution was heated to reflux under Ar for 1.5 h, then cooled to rt and concentrated in vacuo to provide crude [2,5-Bis-(4-tert-butyl-phenyl)-pyrrol-1-yl]-carbamic acid 2-trimethylsilanyl-ethyl ester. The residue was not purified, but was deprotected immediately as follows.

Provenance & Evidence