Diisopropylethylamine → Methyl 2-[4-((2S)-2-[(benzyloxy)carbonyl]amino-3-[3-bromo-4-(1,1-dioxido-3-oxoisothiazolidin-5-yl)phenyl]propanoylamino)butoxy]-6-hydroxybenzoate

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Reaction Steps

(2S)-2-[(Benzyloxy)carbonyl]amino-3-[3-bromo-4-(1,1-dioxido-3-oxoisothiazolidin-5-yl)phenyl]propanoic acid (10.2 mg, 0.020 mmol) in DMF (2.00 mL) was treated with benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (10.6 mg, 0.0240 mmol). After five minutes methyl 2-(4-aminobutoxy)-6-hydroxybenzoate hydrochloride (8.27 mg, 0.030 mmol) and N,N-diisopropylethylamine (17.4 μL, 0.100 mmol) were added and the solution stirred at rt for 2 h. Purification by preparative LCMS afforded product as a white solid (8.9 mg, 61%). 1H NMR (400 MHz, CD3OD): δ 8.07 (brs, 1H), 7.63 (s, 1H), 7.41 (d, J=8.1 Hz, 1H), 7.31–7.23 (m, 7H), 6.49–6.46 (m, 2H), 5.43 (t, J=6.1 Hz, 1H), 5.02 (s, 2H), 4.33–4.29 (m, 1H), 3.97–3.92 (m, 2H), 3.85 (s, 3H), 3.47–3.36 (m, 2H), 3.29–2.82 (m, 4H), 1.68–1.60 (m, 4H); LCMS found for C32H35BrN3O10S (M+H)+: m/z=734.

Provenance & Evidence