Sodium Carbonate → 2-Methanesulfonyl-thieno[2,3-h]quinazoline-8-carboxylic acid tert-butyl ester

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Reaction Steps

2-Methylsulfanyl-thieno[2,3-h]quinazoline-8-carboxylic acid tert-butyl ester (6.50 g, 19.55 mmol) was suspended/dissolved in DCM (150 mL) and cooled in an ice-bath. 3-chloroperbenzoic acid (22.49 g, 97.76 mmol, 75% pure) was added in one portion and the resultant suspension was stirred at 0° C. for 5 minutes and at room temperature for a further 55 minutes. This mixture was then carefully added to a 1:1:1 mixture of saturated Na2CO3, saturated Na2S2O3 and brine (˜500 mL). The organic layer was separated and the aqueous layer was further extracted with DCM (3×200 mL). The combined organics were washed with brine (1×100 mL), dried over Na2SO4, filtered and concentrated under reduced pressure. The yellow solid obtained was redissolved in acetone, silica (˜80 mL) was added and the suspension was concentrated under reduced pressure. The solid obtained was subjected to column chromatography (gradient elution, 5-10% EtOAc in DCM, ˜600 mL silica) to give a yellow solid (6.25 g, 88% yield). MS (ES+) 365. δH (CDCl3) 1.7 (9H, s), 3.5-3.6 (3H, s), 8.0 (1H, d), 8,2 (1H, d), 8,9 (1H, s), 9.6 (1H, s)

Provenance & Evidence