Trimethyl borate → HCID 89466289, compound

Participants

Reaction Steps

13.2 ml (33 mmol) of n-butyllithium (2.5 M in hexane) are added dropwise with vigorous stirring to a solution, cooled to −78° C., of 13.2 g (30 mmol) of 10-bromo-3,6-di-tert-butyl-8,9-dimethyl-4,6a,11-triazabenzo[α]fluorene in 300 ml of THF, and the mixture is stirred for a further 30 min. 4.7 ml (42 mmol) of trimethyl borate are added to this solution in one portion, the mixture is stirred for a further 1 h and then allowed to warm to room temperature. The solvent is removed in vacuo, the residue is taken up in 1000 ml of ethyl acetate, the solution is cooled to 5° C., 19 ml of aqueous H2O2 solution (30% by weight) are added with vigorous stirring, and a solution of 825 mg of NaOH in 20 ml of water is then added dropwise. After stirring for 3 h, 300 ml of saturated ammonium chloride solution are added, the organic phase is separated off, washed twice with 200 ml of water each time, dried over magnesium sulfate, and the org. phase is then evaporated to a volume of about 50 ml in vacuo. 200 ml of methanol are added to the crystal slurry, the crystals are filtered off with suction and washed once with 50 ml of methanol and dried in vacuo.

Provenance & Evidence