Sodium triacetoxyborohydride → 2-{3-[1-tert-Butoxycarbonyl-5-(4-trimethylstannanyl-benzylamino)-pentyl]-ureido}-pentanedioic acid di-tert-butyl ester

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Reaction Conditions

Reaction Steps

To a solution of 2-[3-(5-Amino-1-tert-butoxycarbonyl-pentyl)-ureido]-pentanedioic acid di-tert-butyl ester (150 mg, 0.31 mmol) in DCE (10 mL) was added 4-Trimethylstannanyl-benzaldehyde (82 mg, 0.31 mmol) followed by sodium triacetoxyborohydride (98 mg, 0.47 mmol) and the reaction was stirred overnight at 40° C. The reaction was concentrated and purified by column chromatography using hexanes/ethyl acetate as eluent to afford the desired product (88 mg, 38%) as a thick syrup which begins to solidify upon standing. 1H NMR (400 MHz, DMSO-d6) δ 7.48 (d, J=7.4 Hz, 2H), 7.30 (d, J=7.4 Hz, 2H), 6.27 (m, 2H, NH's), 3.96 (m, 4H), 2.74 (bm, 2H), 2.21 (m, 2H), 1.87 (m, 2H), 1.65-1.19 (m, 7H), 1.35 (m, 27H, t-Bu's), 0.23 (s, 9H). ESMS m/z: 742 (Sn-cluster).

Provenance & Evidence