Phosphine → 3-(2-Azido-1-methyl-ethylamino)-5-phenyl-thiophene-2-carboxylic acid methyl ester

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Reaction Steps

A mixture of 3-(2-Hydroxy-1-methyl-ethylamino)-5-phenyl-thiophene-2-carboxylic acid methyl ester (213 mg, 0.257 mmol), diethyldiazodicarboxylate (250 μL, 1.59 mmol, 2 eq), diphenylphosphoryl azide (343 μL, 1.59 mmol, 2 eq) and trphenyl phosphine (417 mg, 1.59 mmol, 2 eq) was stirred at 21° until all starting alcohol was consumed. The reaction was evaporated to dryness and the crude residue purified on biotage with 5% EtOAc/hexane followed by 100% toluene as eluent. 3-(2-Azido-1-methyl-ethylamino)-5-phenyl-thiophene-2-carboxylic acid methyl ester was isolated as a solid (181 mg, 78%); 1H NMR (300 MHz, CDCl3) 1.33 (d, J=6.6 Hz, 3H), 3.38-3.46 (m, 2H), 3.78-3.81 (m, 1H), 6.82 (s, 1H), 7.36-7.41 (m, 3H), 7.60-7.62 (m, 2H).

Provenance & Evidence