DI-TERT-BUTYLPHOSPHATE, TETRABUTYLAMMONIUM SALT

Method 2: Tetrabutylammonium di-t-butyl phosphate is prepared by dissolving di-t-butyl phosphate [2Og, 94 mmol (obtained from di-t-butyl phosphite by the method of Zwierzak and Kluba, Tetrahedron, Vol. 27, 3163 (1971)] in methanolic tetrabutylammonium hydroxide (47 mL of IM solution, 47 mmol) . The reaction mixture has a temperature of 23°C and pH of 4.33. The pH of the reaction mixture is adjusted to 6.5-7.0 by addition of methanolic tetrabutylammonium hydroxide (48 mL of IM solution, 48 iranol) over 0.2 h. The reaction mixture is stirred for 0.5 h at approximately 2β°C and then is concentrated under reduced pressure at a bath temperature below 40°C. The crude residue is azeotroped three times by adding toluene (3x100 mL) and then the mixture is concentrated under reduced pressure. The crude residue is then triturated in cold hexanes (0°C) for 1 h and then the solid is collected by filtration, washed with a minimum amount of cold hexanes and dried to give a first crop of tetrabutylammonium di-t-butyl phosphate as a white- solid.(24.0 g) . The mother liquor is concentrated under reduced pressure and then triturated in cold hexanes (20 mL) for Ih.The solid is collected by filtration, washed with a minimum amount of cold hexanes and dried to give a second crop of tetrabutylammonium di-t-butyl phosphate as a white solid. [(8.5g), 32.5 g total (77percent)]. A solution of tetrabutylammonium di-t-butyl phosphate (218 g, 480 mmol) in benzene (200 mL) is added dropwise to stirred chloroiodomethane (800 g, 4535 mmol) over 1.5 h at rt. The reaction mixture is stirred an additional 1.5 h at rt and then is concentrated under reduced pressure. The oily residue is dissolved in Et2O and filtered to remove white solids that precipitates. The organic layer is washed with saturated NaHCO3 and H2O/brine (1/1) . The organic layer is then dried over magnesium sulfate, filtered and concentrated under reduced pressure to yield a red brown oil (320 g) . The red brown oil is subjected to chromatography on silica gel (800 g) eluted with 20percent EtOAc/Hexanes, 25percent EtOAc/Hexanes then 30percent EtOAc/Hexanes. The product containing fractions are concentrated under reduced pressure to yield a golden oil. The oil is diluted with CH2C12 (30 mL) , concentrated under reduced pressure and then dried under vacuum to yield the compound 3 (61.3g, 49percent yield). IH NMR (Benzene-dβ) δ5.20 (2H, d, J=15), 1.22 (18H, s) .b) Tetrabutylammonium di-tert-butylphosphate [0935] 41.9 ml of tetra-n-butylammonium hydroxide (20percent solution in water) dissolved in 50 ml of water, and 6.8 g of di-tert-butyl phosphate (75percent), dissolved in 5 ml of acetone, added dropwise with stirring and ice-cooling. The solution obtained is lyophilised; yield: 14.6 g (99percent) of tetrabutylammonium di-tert-butylphosphate (content about 40percent).Intermediate 69tetrabutyl ammonium di-tert-butyl phosphateA solution of di-tert-butyl hydrogen phosphate (Intermediate 68, 7.2 g, 34.2 mmol) in acetone (60 mL) was cooled in an ice/salt bath to -5 to -10° C. To this was added dropwise a solution of tetrabutylammonium hydroxide (40percent in water, 22.2 mL, 34.2 mmol). The mixture was stirred 30 min after addition then the solvents were removed by evaporation and the material was dried under vacuum to a semi-solid. The product was triturated with ether and filtered to give 13.6 g (37percent) of product as a white solid.Di-tert-butyl phosphate tetrabutylammonium salt (0.826 g, 1.83 mmol) was combined with chloroiodomethane (1.6 mL, 18.3 mmol) and was stirred at r.t. for 4 h during which time a precipitate formed. Tert-butyl methyl ether was then added and the mixture was vigorously stirred for 20 min resulting in the formation of a white precipitate. The precipitate was removed by filtration through a pad of Celite and the filtrate was concentrated. The resulting yellow oil was then taken up in tert-butyl methyl ether (16 mL) to precipitate additional salts. The mixture was filtered through a pad of Celite and the filtrate was concentrated and dried under vacuum to afford di-tert-butyl (chloromethyl) phosphate (0.457 g, 97% yield) as an oil: 1H NMR (500 MHz, CHLOROFORM-d) delta 5.62 (d, J=14.5 Hz, 2H), 1.50 (s, 18H).Compound 2 was prepared by using an alternative method. To a solution of compound (1) (11.1 mmol) in benzene (0.9 mL/mmol) was added chloroiodomethane (111 mmol). The reaction mixture was stirred at room temperature for 20 hours in the dark. The crude mixture was concentrated under reduced pressure and the oily residue was dissolved in diethyl ether. The precipitate was filtered off and the organic layer was washed with a saturated NaHCO3 solution and brine. The organic layer was dried over Na2SO4, concentrated under reduced pressure and purified by chromatography on silica (cyclohexane/EtOAc 9:1 then 8:2) to afford the expected compound as a colorless oil in 61% yield. 'H NMR (CDC13, 400MHz) oe (ppm) 5.64 (d, J=l2Hz, 2H), 1.51 (s, 18H).Method 2: Tetrabutylammonium di-t-butyl phosphate is prepared by dissolving di-t-butyl phosphate [2Og, 94 mmol (obtained from di-t-butyl phosphite by the method of Zwierzak and Kluba, Tetrahedron, Vol. 27, 3163 (1971)] in methanolic tetrabutylammonium hydroxide (47 mL of IM solution, 47 mmol) . The reaction mixture has a temperature of 23C and pH of 4.33. The pH of the reaction mixture is adjusted to 6.5-7.0 by addition of methanolic tetrabutylammonium hydroxide (48 mL of IM solution, 48 iranol) over 0.2 h. The reaction mixture is stirred for 0.5 h at approximately 2betaC and then is concentrated under reduced pressure at a bath temperature below 40C. The crude residue is azeotroped three times by adding toluene (3x100 mL) and then the mixture is concentrated under reduced pressure. The crude residue is then triturated in cold hexanes (0C) for 1 h and then the solid is collected by filtration, washed with a minimum amount of cold hexanes and dried to give a first crop of tetrabutylammonium di-t-butyl phosphate as a white- solid.(24.0 g) . The mother liquor is concentrated under reduced pressure and then triturated in cold hexanes (20 mL) for Ih.The solid is collected by filtration, washed with a minimum amount of cold hexanes and dried to give a second crop of tetrabutylammonium di-t-butyl phosphate as a white solid. [(8.5g), 32.5 g total (77%)]. A solution of tetrabutylammonium di-t-butyl phosphate (218 g, 480 mmol) in benzene (200 mL) is added dropwise to stirred chloroiodomethane (800 g, 4535 mmol) over 1.5 h at rt. The reaction mixture is stirred an additional 1.5 h at rt and then is concentrated under reduced pressure. The oily residue is dissolved in Et2O and filtered to remove white solids that precipitates. The organic layer is washed with saturated NaHCO3 and H2O/brine (1/1) . The organic layer is then dried over magnesium sulfate, filtered and concentrated under reduced pressure to yield a red brown oil (320 g) . The red brown oil is subjected to chromatography on silica gel (800 g) eluted with 20% EtOAc/Hexanes, 25% EtOAc/Hexanes then 30% EtOAc/Hexanes. The product containing fractions are concentrated under reduced pressure to yield a golden oil. The oil is diluted with CH2C12 (30 mL) , concentrated under reduced pressure and then dried under vacuum to yield the compound 3 (61.3g, 49% yield). IH NMR (Benzene-dbeta) delta5.20 (2H, d, J=15), 1.22 (18H, s) .Phosphate ester A (45.1 g, 0.1 mol) and chloroiodomethane B (200 g, 1.14 mol) were combined in 100 ml of benzene and the mixture was stirred at room temperature for four hours before benzene was removed under vacuum. Then, 500 ml of ethyl ether was added to the residue and insoluble solid was filtered away. Concentration of the filtrate provided di-tert-butyl chloromethyl phosphate, which was utilized in the next step without any purificationDi-tert-butyl phosphate potassium salt (5 g, 20.14 mmole) is dissolved in methanol (15 g): to this solution at 0 C. a slight excess of concentrated HCl is slowly added with efficient stirring at 0 C. The addition of acid causes the precipitation of potassium chloride. The solid is then filtered and washed with methanol. The compound in the mother liquor is then converted to the ammonium form by adding an equal molar amount of tetrabuthylammonium hydroxide 1 M in methanol (20.14 mmole) while keeping the reaction cooled at 0 C. with efficient stirring. The resulting clear solution is placed under reduced pressure to give the intermediate product. The Di-tert-butyl phosphate potassium salt (5 g, 20.14 mmole)Was dissolved in methanol (15 g) and to this solution at 0 C., Slowly add a slight excess of concentrated HCl and perform efficient stirring at 0 C.The addition of acid causes the precipitation of potassium chloride.The solids are then filtered and washed with methanol.By adding an equimolar amount of tetrabutylammonium hydroxide 1 M (20.14 mmole) in methanol, Converting the compound in the mother liquor to the ammonium form, Meanwhile, the reaction is cooled to 0 C. and efficient stirring is carried out.The resulting clear solution is placed under reduced pressure to provide the intermediate product.Thereafter, 53.3 grams of chloroiodomethane (302.1 mmole)Tetrabutylammonium di-tert-butylphosphate dissolved in acetone was added dropwise, And stir at 40 C. for 1-2 hours.The solvent and excess chloroiodomethane were distilled off, The reaction mass is suspended in TBME and then filtered.The filtrate is washed with a saturated solution of sodium bicarbonate and water, then placed under reduced pressure and the solvent is replaced with acetone, ie the solvent is removed, Replace it with acetone.7 to 20% of chloromethyl di-tert-butyl phosphate in acetone is used in the next step without further purification (70 to 80% yield):To a stirred solution of 3-(7-(bromomethyl)-5-fluoro-1H-indol-4-yl)-2-(2, 6-diethylphenyl)-5-(5-(trifluoromethyl)pyrimidin-2-yl)-4, 5, 6, 7-tetrahydro-2H-pyrazolo[4, 3-c]pyridine (85 mg, 1.24 mmol) in THF (4 mL) was added A mixture of (3ri)-l-(((ri)-2-(((chloromethoxy)carbonyl)amino)-3- methylbutanoyl)oxy )-2-methy lpropyl-3 -(4-(dii sobuty lamino)-3 -(3 -(p- tolyl)ureido)phenyl)pentanoate (0.550 g, 0.767 mmol), tetra-n-butylammonium d-tert- butylphosphate (1.039 g, 2.300 mmol) and sodium iodide (0.345 g, 2.300 mmol) in dry tetrahydrofuran (5 mL) was stirred at room temperature for 24 h. The mixture was diluted with water and extracted with DCM (3 x 50 mL). The organic layer was dried over anhydrous sodium sulphate and concentrated under vacuum at ~30 C to give light yellowish oil. The crude product was purified by RP HPLC (Kinetex Cl 8 [250 x 21.2 mm]; mobile phase A: 10 mM ammonium acetate in water; mobile phase B: acetonitrile; flow rate: 18 mL/min) gave (3ri)-l-(((ri)-2-(((((di-/er/-butoxyphosphoryl)oxy) methoxy)carbonyl)amino)-3-methylbutanoyl)oxy)-2-methylpropyl 3-(4- (diisobutylamino)-3-(3-(p-tolyl)ureido)phenyl)pentanoate (0.160 g, 0.177 mmol, 23.07%) as an off-white solid. NMR (400 MHz, DMSO-i) d ppm = 9.31 (s, 1H), 8.07 - 8.01 (m, 1H), 7.87 (dd, =4.3, 2.4 Hz, 2H), 7.37 (d, J=8.0 Hz, 2H), 7.16 - 7.04 (m, 3H), 6.79 (d, =8.0 Hz, 1H), 6.52 - 6.44 (m, 1H), 5.51 - 5.39 (m, 2H), 4.00 - 3.88 (m, 1H), 2.94 - 2.75 (m, 1H), 2.72 - 2.54 (m, 6H), 2.26 (s, 3H), 2.11 - 1.96 (m, 1H), 1.94 - 1.76 (m, 1H), 1.70 - 1.44 (m, 4H), 1.40 (s, 18H), 0.88 (d, =7.0 Hz, 6H), 0.84 (d, =6.5 Hz, 12H), 0.80 (t, J=1.3 Hz, 3H), 0.77 - 0.69 (m, 6H); LC-MS (ES): w/z=892.4 [M+H]+.A mixture of S)-(2-(((chloromethoxy)carbonyl)(methyl)amino)acetoxy)methyl 3- (4-(diisobutylamino)-3-(3-(/ -tolyl)ureido)phenyl)pentanoate (0.540 g, 0.834 mmol), tetra-n-butylammonium di-/tv7-butyl phosphate (1.131 g, 2.503 mmol) and sodium iodide (0.375 g, 2.503 mmol) in dry tetrahydrofuran (5 mL) was stirred at room temperature for 24 h. The mixture was diluted with water and extracted with DCM (3 x 50 mL). The organic layer was dried over anhydrous sodium sulphate and concentrated under vaccum at ~30 C to give light yellowish oil. The crude product was purified by ISCO (silica gel 60-120 mesh; 24% ethyl acetate in hexane as eluent) to give ( S)-(2-(((((di-tert - butoxyphosphoryl)oxy)methoxy)carbonyl)(methyl)amino)acetoxy)methyl 3-(4- (diisobutylamino)-3-(3-(p-tolyl)ureido)phenyl)pentanoate (0.150 g, 0.150 mmol, 17.96%) as an off-white solid. NMR (300 MHz, DMSO-7e) d ppm = 9.34 (s, 1H), 7.90 (s, 1H), 7.43 - 7.32 (m, 2H), 7.16 - 7.02 (m, 4H), 6.83 - 6.72 (m, 1H), 5.76 - 5.59 (m, 2H), 5.46 (dd, .7=19.1, 13.0 Hz, 2H), 4.11 (d, 7=12.1 Hz, 2H), 2.91 (s, 3H), 2.88 - 2.70 (m, 3H), 2.63 (d, 7=6.8 Hz, 4H), 2.24 (s, 3H), 1.63 (dd, 7=13.3, 6.4 Hz, 3H), 1.56 - 1.45 (m, 1H), 1.43 - 1.37 (m, 18H), 0.83 (d, 7=6.8 Hz, 12H), 0.71 (t, 7=7.2 Hz, 3H); LC-MS (ES): m z 821 [M+H] +To a solution of ( )-((5-bromopentanoyl)oxy)methyl 3-(4-(diisobutylamino)-3-(3- (/i-tolyl )urei do)phenyl )pentanoate (0.350 g, 0.541 mmol) in dry acetonitrile (5 mL) were added tetra-//-butyl ammonium di-/er/-butyl phosphate (0.489 g, 1.082 mmol), sodium iodide (0.081 g, 0.541 mmol) and K2CO3 (0.112 g, 0.812 mmol) under nitrogen atmosphere. The reaction mixture was heated at 85 C for 5 h. The reaction mixture was partitioned between sodium bicarbonate solution and DCM. The organic layer was washed with water and brine, dried over anhydrous sodium sulphate and concentrated to get crude product as a light yellowish oil, which was purified by CombiFlash chromatography (60-120 silica gel; 10-30% ethyl acetate in pet. ether to get (, S)-((5-((di- /er/-butoxyphosphoryl)oxy)pentanoyl)oxy)methyl 3 -(4-(di isobutyl ami no)-3 -(3 -(/;- tolyl)ureido)phenyl)pentanoate (250 mg, 59.5%) as a colorless oil. NMR (400 MHz, methanol-) <7 ppm 7.82 (d, =2.5 l Hz, 1H), 7.26 - 7.35 (m, 2H), 7.13 (t, =8.78 Hz, 3H), 6.84 (dd, J=8.03, 2.01 Hz, 1H), 5.62 - 5.73 (m, 2H), 4.10 (q, =7.03 Hz, 1H), 3.87 - 3.99 (m, 2H), 2.87 - 3.04 (m, 1H), 2.55 - 2.76 (m, 5H), 2.38 (t, =7.03 Hz, 2H), 2..3 l(s, 3H), 1.57 - 1.80 (m, 8H), 1.44 - 1.50 (m, 18H), 0.88 (d, J=6.53 Hz, 12H), 0.76 - 0.84 (m, 3H); LCMS (ES): m/z 776.7 [M +H]+To a solution of (ri)-(5-(bromomethyl)-2-oxo-l, 3-dioxol-4-yl)methyl 3-(4- (diisobutylamino)-3-(3-(/;-tolyl)ureido)phenyl)pentanoate (550 mg, 0.853 mmol) in anhydrous acetonitrile (5 mL), was added tetra-//-butylammonium di-/c/7-butyl phosphate (771 mg, 1.706 mmol) under nitrogen atmosphere. The reaction mixture was stirred at room temperature for 5 h and partitioned between sodium bicarbonate solution and DCM. The organic layer was washed with water and brine , dried over anhydrous sodium sulphate and concentrated to get crude product as a light yellowish oil, which was purified by CombiFlash chromatography (60-120 silica gel; 10-50% ethyl acetate in pet. ether as eluent) to afford (ri)-(5-(((di-/er/-butoxyphosphoryl)oxy)methyl)-2-oxo-l, 3- dioxol-4-yl)methyl 3-(4-(diisobutylamino)-3-(3-( -tolyl)ureido)phenyl)pentanoate (380 mg, 0.491 mmol, 57.5%) as an off-white solid. NMR (300 MHz, MeOH-i) <7 ppm 7.83 (d, .7=1.89 Hz, 1H), 7.32 (d, .7=8.31 Hz, 2H), 7.13 (d, .7=8.31 Hz, 3H), 6.83 (dd, .7=8.12, 2.08 Hz, 1H), 4.96 (d, .7=4.15 Hz, 2H), 4.82 (s, 2H), 2.89 - 3.06 (m, 1H), 2.71 - 2.81 (m, 1H), 2.61 - 2.70 (m, 5H), 2.3 (s, 3H), 1.69 (dt, .7=13.13, 6.47 Hz, 4H), 1.44 - 1.53 (m, 18H), 0.90 (d, 7=6.42 Hz, 12H), 0.83 (t, 7=7.37 Hz, 3H); LCMS (ES): m/z 774.6 [M +H]+.