Ethyl Acetate → 2-({4-[(2-Chloro-4-nitrophenyl)diazenyl]phenyl}ethylamino)ethyl (5S,3R)-5-{[bis(4-methoxyphenyl)phenylmethoxy]methyl}-3-hydroxypyrrolidinecarboxylate

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Reaction Steps

To a solution of 3 (9.1 g, 18.53 mmol) in 130 ml of anhydrous pyridine was added 6.26 g of dimethoxytrityl chloride. The solution was stirred for 3 h. at room temperature and then poured into 300 ml of 5% sodium bicarbonate solution. The mixture was extracted with ethyl acetate (2×300 ml) and the combined extracts were dried over sodium sulfate, filtered and evaporated. The residue was purified by silica gel chromatography eluting with a gradient of 20-0% hexane in ethyl acetate followed by a gradient of 0-2% methanol in ethyl acetate. The chromatography eluent also contained 1% triethylamine. The pure product fractions were combined affording an amorphous solid: 12.66 g (86%); TLC (ethyl acetate), Rf=0.44. 1H NMR (DMSO-d6) δ8.45 (1H, s), 8.26 (1H, d, J=8.9 Hz), 7.82 (3H, m), 7.27 (4H, m), 7.16 (5H, m), 6.95-6.79 (6H, m), 4.95 (1H, m), 4.32 (1H, m), 4.14 (1H, m), 3.99 (2H, m), 3.73 (1H, m), 3.69 (6H, s), 3.56 (1H, m), 3.40-3.30 (2H, m), 3.14 (1H, m), 2.10-1.82 (2H, m), 1.16 (3H, m), 1.06 (3H, t, J=6.5 Hz). Anal. Calcd for C43H44ClN5O8*0.2 H2O: C, 64.73; H, 5.61; N, 8.78. Found: C, 65.08; H, 5.70; N, 8.31.

Provenance & Evidence