[Synthesis]
Example A73 Preparation of Ar2-acetyl-L-lysinyl-L-valinyl-A-carbamoyl-Ar-[4-({[(2-{[(3i,51S',7i,8i)-8-hydroxy-7-{(1£,3£)-5-[(21S,35',5i',6i')-5-{[(2Z,41S)-4-hydroxy-2-enoyl]amino }-3,6-dimethyltetrahydro-2H-pyran-2-yl]-3-methylpenta-1,3-dien-1-yl}-1,6-dioxaspiro[2.5]oct-5-yl]acetyl}hydrazinyl)carbonyl]oxy}methyl)phenyl]-L-ornithinamide, acetate (B222). B227 Step 1. Synthesis of N2-acetyl-N6-(tert-butoxycarbonyl)-L-lysine (B223). To a mixture of N6-(tert-butoxycarbonyl)-L-lysine (22.5 g, 91.5 mmol, 1 eq.) and K2CO3 (63.1 g, 0.457 mol, 5 eq.) in tetrahydrofuran/water (200 mL/200 mL) was added acetochloride (8.62 g, 0.109 mol, 1.2 eq.) at 0 °C and the mixture was at room temperature The mixture was stirred for 4 hours. The mixture was concentrated in vacuum to remove the tetrahydrofuran and the aqueous layer was adjusted to pH=1 with 2M HCl and extracted three times with EtOAc (100 mL). The extract was washed with brine (100 mL), dried over sodium sulfate and concentrated in vacuum to give B223 (23.1 g, 87.7%) as a yellow oil. Step 2.Synthesis of N2-acetyl-L-lysine hydrochloride (B224). To a solution of B223 (23.1 g, 0.080 mmol, 1 eq.) in ethyl acetate (400 mL) was added HCl (g) in ethyl acetate (250 mL) under nitrogen at 0 °C. The mixture was stirred at room temperature for 4 hours and filtered. The solid was washed with ethyl acetate and dried under vacuum to give B224 (18.5 g, >100%) as a white solid which was used without further purification. Step 3.Synthesis of N2-acetyl-N6-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-lysine (B225). To a mixture of B224 (8 g, 35.6 mmol, 1 eq.) and NaHCO3 (5.99 g, 71.3 mmol, 2 eq.) in acetone/water (80 mL/80 mL) was added a solution of Fmoc-Cl (9.41 g, 36.3 mmol, 1.02 eq.) in acetone (80 mL) at 0 °C, and the mixture was at room temperature stirred for 2 hours. The mixture was adjusted to pH=3-4 with 2N HCl and extracted three times with ethyl acetate (100 mL). The extract was washed with brine (100 mL), dried over sodium sulfate and concentrated in vacuum to give the crude product (7 g) as a yellow oil. Dichloromethane and tert-butyl methyl ether (100 mL) were added to the crude product, and the suspension was stirred for 30 min and then filtered. The filter cake was vacuum dried to give B225 (3.25 g, 22.2%) as a white solid. Step 4.Synthesis of N2-acetyl-N6-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-lysinyl-L-valinyl-N5-carbamoyl-N-[4-(hydroxymethyl)phenyl]-L-ornithinamide (B226). To a mixture of B225 (1.04 g, 2.54 mmol, 1 eq.) in N2-dimethylformamide (20 mL) was added N-methylmorpholine (769 mg, 7.61 mmol, 3 eq.), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-HCl (632 mg, 3.30 mmol, 1.3 eq.) at 0 °C. 1-hydroxybenzotriazole hydrate (445 mg, 3.30 mmol, 1.3 eq.) and L-valyl-N5-carbamoyl-N-[4-(hydroxymethyl)phenyl]-L-ornithine amide (from WO04010957,1.01 g, 2.66 mmol, 1.05 eq.) and the mixture was stirred for 2 hours at room temperature. The mixture was poured into tert-butyl methyl ether (300 mL) and filtered. The solid was washed with dichloromethane (50 mL) and water (50 mL) and dried under vacuum to give B226 (1.87 g, 95.6%) as a white solid. Step 5.N2-acetyl-N6-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-lysinyl-L-valinyl-N5-carbamoyl-N-[4-({[(4-nitrophenoxy)carbonyl]oxy}methyl)phenyl]-L-ornithinamide (B227). To a mixture of B226 (1.87 g, 2.43 mmol, 1 eq.) and bis-(4-nitrophenyl) carbonate (2.21 g, 7.28 mmol, 3 eq.) in NN-dimethylformamide (30 mL) at 0 °C was added under nitrogen, NN-diisopropylethylamine (313 mg, 2.43 mmol, 1 eq.) and the mixture was stirred at room temperature overnight. The mixture was poured into tert-butyl methyl ether (50 mL) and filtered. The solid (1.95 g) was purified by preparative HPLC to afford B227 (580 mg, 25.7%) as a white solid.1H NMR (400 Hz, DMSO-dg): 10.1 (s, 1H), 8.29 (d, 2H), 8.00 (d, 1H), 7.86 (d, 1H), 7.65 (d, 2H), 7.64 (d, 1H). 1H), 7.61 (m, 4H), 7.40 (m, 2H), 7.38 (m, 4H), 7.30 (m, 3H), 6.01 (br, 1H), 5.21 (s, 2H), 4.35 (br, 1H), 4.27-4.15 (m, 5H), 2.96 (m, 4H), 1.98 (m, 1H), 1.82 (s, 3H ), 1.65 (br, 3H), 1.43-1.24 (m, 7H), 0.83 (m, 6H). Step 6.N2-acetyl-N6-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-lysyl-L-valyl-N5-carbamoyl-N-[4-({[(2-{[(3R,5S,7R,8R)-8-hydroxy-7-{(1£',3£')-5-[(2S,3S,5R,6R)-5-{[(2Z,4S)-4- hydroxy-2-enoyl]amino}-3,6-dimethyltetrahydro-2H-pyran-2-yl]-3-methylpenta-1,3-dien-1-yl}-1.6-dioxaspiro[2.5]oct-5-yl]acetyl}hydrazinyl)carbonyloxy}methyl)phenyl]-L-ornithinamide (B228). To a solution of B209 (8.1 mg, 0.016 mmol, 1 eq.) in NN-dimethylformamide (0.4 mL) was added 2,6-dimethylpyridine (7.5 μL, 0.064 mmol, 4 eq.), N,N-diisopropylethylamine (11.3 L, 0.064 mmol, 4 eq.) and 4-NN-dimethylaminopyridine ( 2 mg, 0.016 mmol, 1 eq.), then B227 (17.8 mg, 0.019 mmol, 1.2 eq.) was added, and the reaction was purified by reversed-phase chromatography (Method A) by stirring the reactants for 5 h. The reaction afforded B228 as a white solid. Yield: 5.5 mg, 0.004 mmol, 26%. lCMS (Scheme D): m/z 1306.1 [M+H]+, retention time = 0.81 minutes |