Rf 0.5 SRT 1720 Hydrochloride (Hexane/EtOAc: 8/2). chlorinated derivative 2 being the most potent. Table 2 Results of PHGDH inhibition for compounds 1C11. All experiments were performed with at least triplicates and IC50 values were determined in two or more independent experiments. * Compounds previously published in Ravez et al. . Open in a separate window position by a chlorine atom resulted in an improvement in PHGDH inhibition (Figure 3B). The most promising compounds (1, 2, 23, 38, 37, and 39) were validate in a counter screen against PSAT1 and the diaphorase. Based on the preliminary study reported earlier and the present work, the following SARs can be highlighted (Figure 3A). Open in a separate window Figure 3 Overview of the structure?activity relationships. Color code: green yellow red, for decreasing PHGDH activity (A). Influence of the position on the most promising molecules resulted in the discovery of novel micromolar range inhibitors (38 and 39). Target engagement was confirmed in cellular thermal shift assay (CETSA) SRT 1720 Hydrochloride and the anticancer potential was validated in cell-based experiments. Interestingly, the identification of the sulfonohydrazide motif as a new series of inhibitors of this enzyme offers interesting prospects in the development of future PHGDH inhibitors, this function being reported in several works as non-toxic [29,30]. It should be noted that recent mass spectrometry studies suggest that some of the inhibitors discussed here would interact at the c-terminal end of PHGDH. This will be detailed in a forthcoming publication. 4. Materials and Methods 4.1. General Chemistry All reagents were purchased from chemical suppliers and used without purification. Thin-layer chromatography (TLC) was performed using silica gel 60 F254 plates, with observation under UV when necessary. Melting points were recorded on an Electrothermal IA9000 melting point system. 1H NMR spectra were recorded on an AVANCE II 400 MHz Bruker spectrometer with CDCl3 or DMSO-d6 as the solvent. 13C NMR spectra were recorded at 100 MHz. All coupling constants were measured in hertz (Hz), and the chemical shifts (H and C) were quoted in parts per million (ppm) relative to TMS (0), which was used as the internal standard. Data were reported as follows: chemical shift, multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, br = broad, m = multiplet), integration, and coupling constant (Hz). High-resolution mass spectroscopy (HRMS) analyses were carried out on an LTQ-Orbitrap XL hybrid mass Efnb2 spectrometer (Thermo Fisher Scientific, Bremen, Germany). Data were acquired in positive ion mode using full-scan MS with a mass range of 100C1000 0.2 (cyclohexane/EtOAc: 8/2). M.p.: 110C112 C. 1H NMR (400 MHz, CDCl3): = 4.8 Hz), 3.69C3.71 (t, 2H, = 4.8 Hz), 3.90C3.92 (t, 2H, = 4.8 Hz), SRT 1720 Hydrochloride 4.33C4.35 (t, 2H, = 4.8 Hz), 7.48C7.52 (m, 2 ArH), 7.59C7.65 SRT 1720 Hydrochloride (m, 1 ArH), 7.99C8.01 (d, 2 ArH, = 8.2 Hz). 13C NMR (100 MHz, CDCl3): calcd for C12H13NO2S [M + H]+ 236.0739, found 236.0737. 1-(4-Chlorophenyl)-2-morpholino-2-thioxoethan-1-one (2). This compound was synthesized according to General Procedure I using 2-bromo-1-(2-chlorophenyl)ethanone (0.50 g, 2.14 mmol), morpholine (0.56 mL, 6.42 mmol), and sulfur (0.10 g, 3.21 mmol) in DMF (10 mL). Acetonitrile was used for recrystallization to afford the title compound as a yellow solid (0.22 g, 38%). R0.2 (cyclohexane/EtOAc: 8/2). M.p.: 135C137 C. 1H NMR (400 MHz, CDCl3): = 4.8 Hz), 4.31C4.33 (t, 2H, = 4.8 Hz), 7.46C7.48 (d, 2 ArH, =.