Triethylamine → 3,5-Bis(1,1-dimethylethyl)-2-hydroxybenzenecarboxamide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Thionyl chloride (5.95 g, 50 mmol) was added to a mixture of 3,5-bis(1,1-dimethylethyl)-2-hydroxybenzoic acid (alternatively named 3,5-di-tert-butylsalicylic acid) (2.50 g, 10 mmol) and N,N-dimethylformamide (10 drops) in dry toluene (50 mL) at 60° C. After 1 hour at 60° C., the light yellow solution was evaporated in vacuo to leave a thick oil and then diluted with dry tetrahydrofuran (THF) (40 mL). After heating to 50° C., a solution of (1S,2S)-(+)-1,2-cyclohexanediamine (0.560, 4.90 mmol) in 10 mL of dry THF was added followed by triethylamine (1.01 g, 10 mmol). After 1 h at 50° C., the reaction mixture was quenched with water (25 mL) and then poured into ethyl acetate/water. The organic phase was separated, and the aqueous phase extracted with additional ethyl acetate (35 mL). The combined organic phase was washed once more with water and then evaporated onto silica gel. Purification by flash chromatography (hexanes-ethyl acetate, 0 to 20% ethyl acetate over 1 hour) and evaporation of the chromatography solvent in vacuo afforded the product as a foamy off-white solid (1.18 g). The product was further purified by stirring the white solid in methanol (5 mL) and then decanting the mother liquor from a small amount of insoluble, gummy solids. Evaporation of the methanol mother liquor afforded the title product as an off-white solid (1.15 g). 1H NMR (CDCl3) δ 1.29 (s, 18H), 1.38 (s, 18H), 1.82 (s, 2H), 2.22 (br s, 2H), 3.96 (br s, 2H), 6.95 (br s, 2H), 7.16 (d, J=2 Hz, 2H), 7.41 (d, J=2 Hz, 2H), 12.70 (s, 2H). MS ESI Positive: 579 (M+1), ESI Negative: 577 (M−1).

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