Pyridine → 2-{[5-(bis{[4-(tert-butyl)phenyl]sulfonyl}amino)-1-{2-([tert-butyl(dimethyl)silyl]oxy}ethyl}4-{4-methylphenyl}-1H-pyrazol-3-yl]oxy}ethyl acetate

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Reaction Steps

A solution of 2-{[5-amino-1-(2-{[tert-butyl(dimethyl)silyl]oxy}ethyl)-4-(4-methylphenyl)-1H-pyrazol-3-yl]oxy}ethyl acetate (0.35 g) (Preparation 30), 4-(tert-butyl)phenylsulfonyl chloride (0.25 g) and 4-(N,N-dimethyl)aminopyridine (98 mg) in pyridine (4 ml) was stirred at room temperature overnight. Tlc (30:70 ethyl acetate/hexane) indicated a new less polar product had formed, but the reaction appeared to have proceeded only 50% to completion. A further aliquot of the sulfonyl chloride (0.25 g) was added to the reaction mixture and stifling at room temperature was continued for a further 4 days. Tlc analysis then indicated complete disappearance of the starting materials and a single new product was observed. The reaction mixture was poured into saturated copper (II) sulfate solution (100 ml) and the aqueous mixture was extracted with ether (2×5 ml). The combined ether extracts were washed with saturated copper (II) sulfate solution (30 ml). The organic extract was dried over magnesium sulfate, filtered and concentrated under reduced pressure to leave a yellow/brown gum. The gum was recrystallised from methanol/water to give the title compound as yellow crystals (325 mg).

Provenance & Evidence