Reaktion #1090807

Reaktionsgleichung

imidazole

triisopropylsilyl chloride

water

6-methyl-7-hydroxychroman-4-one

→

6-methyl-7-triisopropylsilyloxychroman-4-one

Ausbeute 100.0%

Lösungsmittel

dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with ether (2×)
2. 2
   WaschenThe combined organic layer was washed with 1 N lithium chloride (2×)
3. 3
   Trocknendried over magnesium sulfate
4. 4
   Einengenconcentrated

Vorschrift

A mixture of 6-methyl-7-hydroxychroman-4-one (the compound of Preparation 32, 1.50 g, 8.42 mmol), imidazole (1.15 g, 16.9 mmol), and triisopropylsilyl chloride (2.0 mL, 9.2 mmol) in dimethylformamide (30 mL) was stirred overnight at ambient temperature. The reaction was poured into water and extracted with ether (2×). The combined organic layer was washed with 1 N lithium chloride (2×), dried over magnesium sulfate, and concentrated to afford 3.01 g (100%) of 6-methyl-7-triisopropylsilyloxychroman-4-one as a dull yellow oil which had: NMR δ 7.64 (s, 1 H), 6.30 (s, 1 H), 4.45 (t, J=6.4 Hz, 2 H), 2.70 (t, J=6.4 Hz, 2 H), 2.14 (s, 3 H), 1.40-1.25 (m, 3 H), 1.09 (d, J=7.3 Hz, 18 H). The product also had a small silyl impurity and residual dimethylformamide present but was suitable for subsequent reaction.

Quelle