Triethylamine → 4-(4-Pyridin-3-yl-buta-1,3-diynyl)-benzamide

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Reaction Steps

Resin 1 (142 mg, 0.109 mmol) was swelled in DCM (2 mL) for 1 h and drained. A solution of 3-ethynylpyridine 2 (38 mg, 0.368 mmol) and Et3N (200 μL 1.4 mmol) in DMF (2 mL) was added and the resin agitated for 5 min. A mixture of PdCl2(PPh3)2 (22 mg, 0.031 mmol) and CuI (25 mg, 0.131 mmol) was added and the resin was agitated for 72 h. The resin was drained, washed with DMF (3×2 mL), DCM (3×2 mL) and cleaved with 10% TFA/DCM (1.5 mL) for 20 min. The solution was collected and the resin was rinsed with additional 10% TFA/DCM (1.0 mL). The cleavage fractions were combined, treated with neat TFA (2.0 mL), stirred for 1 h at rt and concentrated by rotary evaporation to give a crude brown residue. Purification by RP-HPLC (C18 column, CH3CN gradient 5-65%, 0.1% TFA, UV analysis 300 nm, 24 min) and lyophilization of the collected fractions afforded 4.4 mg (11% yield) of N-(2R)-hydroxy-(1S)-hydroxycarbamoyl-propyl)-4-(4-pyridin-3-yl-buta-1,3-diynyl)-benzamide. LRMS (ES+) m/z 364.0 (C20H17N3O4+H requires 364.13); RP-HPLC (300 nm, 24 min run) 11.2 min.

Provenance & Evidence