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With pyridinium hydrobromide perbromide; hydrogen bromide; acetic acid; In water; at 0 - 20℃; for 1h; |
Production Example 2; Synthesis of N-{4-[4-(2-[amino(imino)methyl]amino}ethyl)phenyl]-5-[4-(methylsulfonyl)benzyl]-., 3-thiazol-2-yl}acetamidehydrochloride; Step 1; Ethyl 4-acetylbenzoate (10 g) was dissolved in AcOH(80 ml), and then 90 % pyridinium tribromide (22.2 g) and33 % hydrobromic acid in AcOH (30 ml) were added to thesolution at 0 C. The reaction mixture was stirred at r.t.for 1 hour, and poured into ice-water. The precipitate wascollected in vacuo to give ethyl 4-(bromoacetyl)benzoate(15.1 g) as an off-white solid |
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With bromine; In chloroform; |
(a) Ethyl (4-bromoacetyl)benzoate A solution of ethyl 4-acetylbenzoate (1.586 g) in chloroform (50 ml) was stirred at ambient temperature and treated with bromine (0.43 ml). After two hours the resulting solution was evaporated to a solid, which was crystallized from ethanol to give the title benzoate (960 mg); m.p. 73-75. |
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With bromine; In tetrachloromethane; |
Example 40 (S)-N-[2-(Benzo[b]thiophen-5-ylmethanesulfonyl)-1-(4-ethoxycarbonylphenyl)ethyl]-N-hydroxyformamide. A stirred solution of ethyl 4-acetylbenzoate (1.92 g) in carbon tetrachloride (20 ml) was treated with bromine (0.51 ml) and heated to 40 C. until the reaction initiated. Heating was then removed and the mixture was stirred for a further 1 h. Removal of the solvent afforded a crude product which was chromatographed (silica gel, 10% EtOAc/hexane) to give ethyl 4-(2-bromoacetyl)-benzoate as a white solid (2.04 g). |
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With aluminum (III) chloride; bromine; In diethyl ether; at 0 - 20℃; for 7.36667h; |
A mixture containing ethyl 4-acetylbenzoate (502 mg, 2.61 mmol), AlCl3 (50 mg, 0.37 mmol) in anhydrous ether (5 mL) was cooled in an ice bath under an inert atmosphere of argon. Bromine (0.17 mL, 3.31 mmol) was then added as a solution in ether ( 15 mL) over a period of 10 min. The reaction mixture was slowly allowed to warm to room temperature and stirred for 18 h. The reaction mixture was carefully poured into saturated aqueous NaHCO3 solution and stirred for 30 min. The organic layer was separated and washed successively with dilute aqueous NaHCO3 and H2O. It was then dried (Na2SO4) and concentrated under reduced pressure to afford crude ethyl 4-(2-bromoacetyl) benzoate as a white solid (650 mg). 1H NMR (400MHz, CDCl3) delta: 1.45 (3H, t, J= 7.2 Hz), 4.44 (2 H, q, J= 7.2 Hz), 8.06-8.00 (5H, m). |
| 0.44 g |
With bromine; In chloroform; at 20℃; for 3h; |
To a solution of precursor 18a (0.86 g, 4.48 mmol, 1 equiv) in CHCl3 (30 mL) bromine (0.24 mL, 4.70 mmol, 1.05 equiv) was added dropwise and the reaction mixture stirred 3 h at room temperature. The product was partially purified by washing the organic layer with a saturated Na2S2O3 solution. The solvent was removed under reduced pressure. The crude product was recrystallized in EtOH and the resulting solid (0.44 g, 1.62 mmol, 1 equiv) was dissolved in methanol (25 mL). Thiourea (0.19 g, 2.43 mmol, 1.5 equiv) was added and the reaction was stirred 3 h at room temperature. The solvent was evaporated under reduced pressure. The crude product was suspended in a 5% NaHCO3 solution ande xtracted with dichloromethane (3 × 25 mL). The combined organic layers were dried over anhydrous MgSO4 and the solvent was evaporated under reduced pressure. The crude product was further purified by column chromatography on silica gel (n-hexane-ethyl acetate) to obtain ethyl4-(2-amino-1,3-thiazol-4-yl)benzoate as a slightly yellow solid; overall yield 13 % (0.14 g). 1H-NMR (400.13 MHz, (CD3)2SO) delta: 1.32 (t, 3H, -O-Ethyl-CH3, J = 7.12Hz), 4.31 (q, 2H, -O-Ethyl-CH2, J = 7.10Hz), 7.14 (s, 2H, -NH2), 7.23 (s, 1H, Thiazole-H5), 7.91-7.96 (m, 4H, Ph-H2/3/5/6). 13C-NMR (100.61 MHz, (CD3)2SO) delta: 14.19(-O-Ethyl-CH3), 60.60 (-O-Ethyl-CH2), 104.43 (Thiazole-C5), 125.55 (Ph-C3/5),128.11 (Ph-C1), 129.46 (Ph-C2/6), 139.09 (Ph-C4), 148.74 (Thiazole-C4),165.53 (-COOEt), 168.36 (Thiazole-C2). MS(ESI+): m/e= 249.14 [M+H]+ |
| 4.40 g |
With bromine; In tetrachloromethane; at -10 - 20℃; for 1h; |
To the stirred solution of <strong>[38430-55-6]4-acetyl-benzoic acid ethyl ester</strong> (3.0 g, 15.6 mmol) in dry Cd4(150 ml) was added bromine (0.75 ml, 14.8 mmol, in 15 ml Cd4) very slowly at -10 C to 0C. After addition temperature of the reaction mixture was slowly raised to RT and stirred at RT for 1 h. The reaction was monitored by TLC and after completion of the reaction aqueous sodium thiosulphate solution was added to the reaction mixture and was subjected to astandard CH2C12 work up to give 4.40 g of the desired product as a liquid. |
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With N-Bromosuccinimide; trimethylsilyl trifluoromethanesulfonate; In acetonitrile; at 40℃; for 5h; |
General procedure: Ketone (1 eq) and N-bromosuccinimide (NBS) (2 eq) were solved in acetonitrile and trimethylsilyl trifluoromethanesulfonate (TMS-OTf) (1 eq) was added. The reactions were stirred at T=40C until completeness, diluted with diethyl ether (2ml), washed with H2O (3×2ml), dried over Na2SO4 and concentrated under reduced pressure. This procedure provided bromoketones intermediates in 70-90% overall yield, with purities generally>90% as determined by HPLC-MS. The compounds were used without further purification. |
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