Diisopropylethylamine → 5-[(9-Fluorenylmethoxyformamido)methyl]-3,6-dimethoxy-9,9-dimethylxanthene-4-acetic acid

Participants

Reaction Steps

1.58 g (34.35 mmol) of 5-aminomethyl-3,6-dimethoxy-9,9-dimethylxanthene-4-acetic acid trifluoroacetate were suspended in a mixture of 7 ml of dioxan and 7 ml of water together with 1.13 g (3.35 mmol) of N-(9-fluorenylmethoxycarbonyl)-succinimide, whereupon 0.9 ml (5.03 mmol) of ethyldiisopropylamine was added at 0°. The mixture was stirred at 0° for 2 hours and thereafter at room temperature for 4 hours. The solid obtained was filtered off, washed with water, dried and chromatographed on silica gel with chloroform/methanol. The fractions containing the desired product were combined, washed with dilute potassium hydrogen sulphate solution and thereafter with water, dried over magnesium sulphate and concentrated, whereby 1.17 g of 5-[(9-fluorenylmethoxyformamido)methyl]-3,6-dimethoxy-9,9-dimethylxanthene-4-acetic acid were obtained as a colourless powder of m.p. 134°-136°; IR 1727, 1703, 1606, 1495 cm-1.

Provenance & Evidence