N-tert-Butoxycarbonyl-L-threonine

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Preparation 52 N-Boc-L-threonine To a solution of L-threonine (400 mg, 3.36 mmol) in MeOH (5 mL) was added NaHCO[00118] Di-tert-butyl dicarbonate (56.7 g, 59.7 mL, 0.23 mol, Aldrich) was added dropwise to a solution of L-threonine 1_6_1 (23.8 g, 0.2 mol) in THF (200 mL) and a 2 N aqueous sodium hydroxide solution (120 mL) at 0°C. The resulting mixture was stirred at 0°C to room temperature overnight and concentrated under reduced pressure to remove the solvent. The residue was saturated with solid ammonium chloride, cooled to 0°C, acidified with 1 N hydrochloric acid to pH 3, and extracted with ethyl acetate (3 x 100 mL). The combined organic layers were washed with water (200 mL) and brine (200 mL), dried over sodium sulfate and concentrated under reduced pressure. The residue was treated with hexane (300 mL) and filtered to give 1_6_2 (39.7 g, 91 percent) as a colorless solid. [00119] NMR (400 MHz, DMSO-dThe L-threonine 10mmol join flask, water 10 ml, acetone 20 ml, stirring, add 2.08 ml of Et3N, controlling the temperature in the 25 °C under stirring di-tert-butyl dicarbonate to 20mmol, and to continue stirring 4.5h, decompression evaporate acetone, the water layer is extracted with ethyl ether 3 times, each 10 ml, with dilute HC1 the aqueous layer to adjust pH value to 2-3 rear, ethyl acetate extraction 3 times, each 15 ml, combined with the organic layer, saturated salt for washing 2 times, each 10 ml, anhydrous NaTo a stirred solution of L-threonine (SMI) (100 g, 0.84 mol) in 1, 4-dioxane (500 mL) and water (800 mL) was added NaTo a stirring solution of L-threonine (50 g, 420 mol) in THF/water (500 mL/500 mL) were added NaHCOTo a solution of SM-2 (50 g, 0.420 mol) in l, 4-dioxane:water (500 mL, 1 : 1) was added NaHCCb (133 g, 1.255 mol) portion wise at RT and stirred for 15 min. Then Boc-anhydride (0183) (144 mL, 0.629 mol) was added drop wise to the reaction mixture and stirring was continued at RT for 16 h. After consumption of the starting material (by TLC), the reaction mixture was concentrated under reduced pressure and obtained residue was diluted with water (200 mL) and acidified by using IN HCl (pH~2). The aqueous layer was extracted with EtOAc (2 x 300 mL). The combined organic layer was washed with brine (1 x 200 mL), dried over anhydrous (0184) Na2SC>4, filtered and concentrated under reduced pressure to afford Al (80 g, 87percent) as colorless syrup. To a solution of SM-2 (50 g, 0.420 mol) in 1, 4-dioxane:water (500 mL, 1:1) was addedNaHCO3 (133 g, 1.255 mol) portion wise at RT and stirred for 15 mm. Then Boc-anhydride(144 mL, 0.629 mol) was added drop wise to the reaction mixture and stirring was continued at RT for 16 h. After consumption of the starting material (by TLC), the reaction mixture was concentrated under reduced pressure and obtained residue was diluted with water (200 mL) and acidified by using iN HC1 (pH2). The aqueous layer was extracted with EtOAc (2 x 300 mL).The combined organic layer was washed with brine (1 x 200 mL), dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure to afford compound A (80 g, 87percent) as colorless syrup. ‘H-NMR: (500 MHz, DMSO-d6): ö 12.5 (br s, 1H), 6.30 (d, J= 8.5 Hz, 1H), 4.50 (br s, 1H), 4.05-4.02 (m, 1H), 3.88-3.86 (m, 1H), 1.39 (s, 9H), 1.08 (d, J= 6.0 Hz, 3H); LCMS (m/z): 218.1 [MtljTo a solution of SM-2 (50 g, 0.420 mol) in 1, 4-dioxane and water (500 mL, 1 : 1) was added NaHCC^ (133 g, 1.255 mol) portion wise at RT and stirred for 15 min. Then B0C2O (144 mL, 0.629 mol) was added drop wise to the reaction mixture and stirring was continued at RT for 16 h. After consumption of the starting material (by TLC), the reaction mixture was concentrated under reduced pressure and obtained residue was diluted with water (200 mL) and acidified by using IN HC1 (pH~2). The aqueous layer was extracted with EtOAc (2 x 300 mL). The combined organic layer was washed with brine (1 x 200 mL), dried over anhydrous NaTo a stirring solution of SM-2 (300 g, 2.52 mol) in water (2 L) was added NaHCON-Boc-L-threonine: The L-threonine amine was protected in the same manner as the tyrosine with some modifications. 10g (0.08mol) of l-threonine were stirred in 240mL dioxane and water mixture (1:1) and 80mL of 1M sodium hydroxide solution was added until all the solid dissolved. L-Threonine (1.00 g, 8.40 mmol) and NaHCOGeneral procedure: l-lysine, l-alanine, l-leucine, l-isoleucine, l-phenylalanine, l-threonine (5g, 1 equiv) was dissolved in H[00108] To a stirring solution of (25, 3R)-2-amino-3-hydroxybutanoic acid (SM-2) (30 g, 0.25 mol) in THF (150 mL) and water (150 mL) was added NaHC0To a solution of SM-1 (100 g, 456 mmol) in 1, 4 dioxane (450 mL_ and H

Molecular Weight:219.23
XLogP3:0.3
Hydrogen Bond Donor Count:3
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:5
Exact Mass:219.11067264
Monoisotopic Mass:219.11067264
Topological Polar Surface Area:95.9
Heavy Atom Count:15
Complexity:245
Undefined Atom Stereocenter Count:2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes