Journal of Medicinal Chemistry points for further structure-based drug design. The hit-to-lead development of the 3,4-dihydroquinazoline inhibitor series is summarized in Figure 6. ’ EXPERIMENTAL SECTION Chemicals and solvents were purchased from the Aldrich Chemical Co., Fluka, ABCR, VWR, Acros, Fisher Chemicals, and Alfa Aesar and were used as received unless otherwise stated. Air- and moisture- sensitive reactions were carried out under an inert atmosphere of argon in oven-dried glassware. Analytical thin-layer chromatography (TLC) was performed on precoated TLC plates (layer 0.20 mm silica gel 60 with ﬂuorescent indicator UV254, from Merck). Developed plates were air-dried and analyzed under a UV lamp (UV254/365 nm). Flash column chromatography was performed using prepacked silica gel cartridges (230 400 mesh, 40 63 μm, from SiliCycle) using a Tele- dyne ISCO Combiﬂash Companion, or Combiﬂash Retrieve. 1H NMR, 13C NMR, 19F NMR, and 2D-NMR spectra were recorded on a Bruker Avance DPX 500 spectrometer (1H at 500.1 MHz, 13C at 125.8 MHz, 19F at 470.5 MHz). Chemical shifts (δ) are expressed in ppm recorded using the residual solvent as the internal reference in all cases. Signal splitting patterns are described as singlet (s), doublet (d), triplet (t), quartet (q), multiplet (m), broad (br), or a combination thereof. Coupling constants (J) are quoted to the nearest 0.5 Hz. LC-MS analyses were performed with either an Agilent HPLC 1100 series connected to a Bruker Daltonics MicrOTOF or an Agilent Technologies 1200 series HPLC connected to an Agilent Technologies 6130 quad- rupole LC/MS, where both instruments were connected to an Agilent diode array detector. LCMS chromatographic separations were con- ducted with a Waters Xbridge C18 column, 50 mm 2.1 mm, 3.5 μm particle size; mobile phase, water/acetonitrile +0.1% HCOOH, or water/acetonitrile +0.1% NH3; linear gradient 80:20 to 5:95 over 3.5 min, and then held for 1.5 min; ﬂow rate 0.5 mL min 1. All assay compounds had a measured purity of g95% as determined using this analytical LC-MS system (TIC and UV). High resolution electrospray measurements were performed on a Bruker Daltonics MicrOTOF mass spectrometer. Microwave-assisted chemistry was performed using a Biotage Initiator microwave synthesizer. Method A (Compounds 3a e). Pyridine (1.2 equiv) was added to a solution of the relevant 2-aminobenzophenone analogue, DMAP (cat.), and the relevant acid chloride in anhydrous CH2Cl2 and stirred at 25 C for 16 h. The reaction mixture was then added to a solution of NaOH (2.0M, aq), the layers separated, and the aqueous extracted with CH2Cl2. The organic layers were combined, dried over MgSO4, filtered, and the solvent removed under reduced pressure to give the crude amide product. Method B (Compounds 4a k, 7a e). The required amine (1.2 equiv) was added to a solution of the relevant benzophenone analogue in EtOH and the reaction mixture heated at 160 C for 1 h in a microwave reactor. Method C1 (Compounds 5a c,h,i, 8a,b). NaBH4 (20 equiv) was added to a solution of the appropriate imine in anhydrous DMF (2 mL) and heated at 60 C for 16 h. The reaction was then quenched by the addition of water (1 mL) and subsequently extracted into Et2O (3 5 mL). The workup was completed as outlined in method A. Note that the amine products were observed to slowly convert to the cyclic amidines when in solution. Method C2 (Compounds 6d g,j,k 9a,c e). NaBH4 (20 equiv) was added to a solution of the appropriate imine in EtOH and heated at 78 C for 16 48 h. The reaction was then quenched by the addition of an aqueous solution of citric acid (10% w/v), the EtOH removed under reduced pressure, and the pH of the remaining aqueous adjusted to ∼10 before being extracted with CH2Cl2. The workup was completed as outlined in method A. ARTICLE Method D (Compounds 6a c,h,i, 9a,b). POCl3 (5 equiv) was added to a solution of the relevant amine in CHCl3 and heated at 61 C for 16 24 h. The reaction mixture was added to a solution of NaOH (2.0M, aq), the layers separated, and the aqueous extracted with CH2Cl2. The workup was completed as outlined in method A. Method E (Compounds 11b h and 13b h). HCl (4.0 M in dioxane, 40 equiv) was added to a solution of Boc protected amine 11a or 13a in anhydrous THF and stirred at 25 C for 2.5 h before removal of the solvent under reduced pressure. The crude amine was then redis- solved in CH2Cl2/pyridine (4:1), to which was added DMAP (cat.) and the relevant benzoyl chloride (2 equiv). The reaction was subsequently heated at 40 C for 16 h, after which the reaction mixture was added to a solution of NaOH (2.0M, aq), the layers separated and the aque- ous extracted with CH2Cl2. The workup was completed as outlined in method A. Method F (Compounds 18, 19a f). Pd(PPh3)4 (0.03 equiv) was added to a degassed solution consisting of the relevant aryl bromide, the relevant boronic acid, and K3PO4 (2 equiv) in dioxane/water (10:1). Subsequently, the reaction was heated at 120 C for 30 min in a microwave reactor, followed by evaporation of the solvents under reduced pressure. Method G (Compounds 26b e). n-BuLi (19.4 mmol, 1.6 M in hexanes, 12.1 mL) was added to a solution of the relevant aryl bromide (17.6 mmol) in anhydrous Et2O (20 mL) at 78 C. Subsequently, the reaction was allowed to warm to 0 C over 2 h, after which a solution of 5-chloro anthranilate (23) (4 mmol, 686 mg) in dry THF (30 mL) was added to the resultant aryl lithium and the reaction stirred for a further 2 h at 0 C. Work up was initiated by the addition of TMSCl (10 mL), and the reaction was allowed to warm to 25 C over 15 min. Subsequently, 1N HCl (aq, 30 mL) was added and the mixture stirred at 25 C for a further 15 min. The biphasic mixture was then separated and the aqueous layer neutralized and extracted into Et2O (3 50 mL). The workup was completed as outlined in method A. Method H (Compounds 31a g). The appropriate Grignard reagent (8 mmol) was added to a solution of quinazolinone (30) (2 mmol, 612 mg) in anhydrous THF (10 mL) at 0 C. The reaction was then allowed to warm to 25 C over 2 h before workup was initiated by the addition of NaCl solution (satd aq 20 mL). The resultant mixture was filtered and the solids washed with EtOAc (2 10 mL). Subse- quently, the biphasic filtrate was separated and the pH of the aqueous layer adjusted to 10 prior to further extraction with EtOAc (3 50 mL). The workup was completed as outlined in method A. Method I (Compounds 32b d,g). BF3 3 OEt2 (40 equiv) and HSiEt3 (40 equiv) were sequentially added to a solution of the relevant alcohol in CH2Cl2 and the reactions stirred at 25 C for 60 h. Workup was initiated by the addition of NaCl solution (satd aq), the pH of which was adjusted to 10 prior to the layers being separated and the aqueous further extracted with CH2Cl2. The workup was completed as outlined in method A. Synthesis and Analysis of Selected Compounds. N-(2- Benzoyl-4-chlorophenyl)acetamide (3a). Prepared according to method A from 2-amino-5-chlorobenzophenone (2a) (23.2 g, 100 mmol) and acetyl chloride (9.42 g, 120 mmol). The crude product was purified by recrystallization from EtOAc/hexane to give a white solid (21.5 g, 79%). 1H NMR (500 MHz, CDCl3): δ 10.63 (br s, 1H, NH), 8.61 (d, 1H, J = 9.0 Hz, H-6), 7.71 7.69 (m, 2H, 2 ArH), 7.66 7.62 (m, 1H, ArH), 7.54 7.50 (m, 4H, 4 ArH), 2.22 (s, 3H, CH3). 13C NMR (125 MHz, CDCl3): δ 198.5 (C), 169.2 (C), 138.9 (C), 137.9 (C), 134.0 (CH), 133.1 (CH), 132.6 (CH), 129.9 (CH), 128.6 (CH), 127.3 (C), 124.6 (C), 123.1 (CH), 25.3 (CH3). LRMS (ES+): m/z (%) 232 (67) [35Cl M Ac + H]+, 234 (22) [37Cl M Ac + H]+, 274 (100) [35Cl M + H]+, 276 (42) [37Cl M + H]+. N-(2-((Benzylimino)(phenyl)methyl)-4-chlorophenyl)acetamide (4a). Prepared according to method B from benzylamine (129 mg, 6525 dx.doi.org/10.1021/jm200312v |J. Med. Chem. 2011, 54, 6514–6530