Water → N-Cbz4-(4-hydroxyphenyl)butylamine

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Reaction Steps

4-(4-Hydroxyphenyl)butylamine hydrobromide (4) (197 g, 0.80 mole), water (1 L), 1,4-dioxane (1 L) and sodium bicarbonate (336 g, 4 mole) were combined and stirred while cooled in an ice-methanol cooling bath. Benzyl chloroformate (141 mL, 0.96 mole) was dripped in over 5 min. at −2° C. with no appreciable exotherm observed. This was stirred and allowed to warm to room temperature as the cooling bath thawed overnight. An additional quantity of benzyl chloroformate (8 mL, 0.54 mol) was dripped in and this was allowed to stir for 2 h. The product mixture was then evaporated to approximately 500 mL and transferred to a 2 L separatory funnel with ethyl acetate while decanting away from the solids. The aqueous layer was extracted with ethyl acetate (3×1 L). The extracts were combined, washed with brine, dried over sodium sulfate, filtered and evaporated to afford 265 g of the crude product. A portion of the crude product (130 g) was chromatographed (silica gel, 5:1 hexanes/ethyl acetate) using toluene to load the column. The remaining crude material was crystallized from 1:1 toluene/heptane. This material was suction filtered to collect the solid and washed with 1:1 toluene/heptane. This material was vacuum desiccated at 45° C. for 2 h. The combined yield of compound (29) was 150 g (62%) of a white crystalline solid. 1H NMR (300 MHz, CDCl3) δ 1.43-1.65 (m, 4H), 2.52 (t, J=7.4 Hz, 2H), 3.19 (q, J=6.4 Hz, 2H), 4.78 (br s, 1H), 5.09 (s, 2H), 5.77 (s, 1H), 6.74 (d, J=8.5 Hz, 2H), 6.98 (d, J=8.5 Hz, 2H), 7.34 (s, 5). CI MS m/z=300 [C18H21NO3+H]+.

Provenance & Evidence