1429651-50-2

HPOB is a histone deacetylase 6 inhibitor used in the enhancement of anti-cancer drugs.

HPOB is a very potentselective inhibitor of HDAC6. HPOB inhibits proliferation of normal and transformed cell lines but does not induce cell death. The compound HPOB potentiates the effects of DNA-damaging cytotoxic anti-cancer drugs.

4-(2-((((tert-butyldimethylsilyl)oxy)ethyl)(phenyl)amino)-2-oxoethyl)-N-hydroxybenzamide (16 mg, 0.037 mmol) was used as a starting material, which was dissolved in a solution (3 mL) of dichloromethane (CH2Cl2) containing 5% trifluoroacetic acid (TFA) and the reaction was stirred for 5 minutes. After completion of the reaction, the organic phase was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with the eluent dichloromethane/methanol (10:1, v/v) to afford the target compound N-hydroxy-4-(2-((2-hydroxyethyl)(phenyl)amino)-2-oxoethyl)benzamide in a yield of 8 mg and 68%. Thin layer chromatography (TLC) Rf value was 0.23 (unfolding agent: dichloromethane/methanol, 10:1). Nuclear magnetic resonance hydrogen spectrum (1H NMR, CD3OD, 400 MHz): δ 7.64 (d, J = 8.4 Hz, 2H), 7.45 (m, 3H), 7.29 (d, J = 8.0 Hz, 2H), 7.14 (d, J = 8.0 Hz, 2H), 3.86 (t, J = 6.0 Hz, 2H), 3.68 (t, J = 6.0 Hz. 2H), 3.55 (s, 2H). NMR carbon spectrum (13C NMR, CD3OD, 100 MHz): δ 172.0, 166.9, 142.7, 139.7, 130.9, 129.9, 129.4, 128.7, 128.5, 127.1, 58.8, 51.8, 41.0. mass spectra (APCI+): [M + H]+ m/z = 315.26 .

HDAC6: 0.056 μM (IC₅₀); HDAC3/NCOR2: 1.7 μM (IC₅₀); HDAC8: 2.8 μM (IC₅₀); HDAC1: 2.9 μM (IC₅₀); HDAC10: 3.0 μM (IC₅₀); HDAC2: 4.4 μM (IC₅₀)

[1] Patent: WO2013/52110, 2013, A1. Location in patent: Page/Page column 46; 48