N-Carbobenzyloxy-L-threonine methyl ester

white to off-white powder

The In a 2L beaker, 100 g of L-threonine methyl ester hydrochloride, 600 ml of water and adjusted to pH of sodium bicarbonate were added dropwise, and z-cl 110 g was added dropwise and the pH was adjusted with 2 moc / l sodium hydroxide 8-9 reaction. The reaction was terminated, 1L of ethyl acetate was added, 500ML washed with water, washed with 500ml of saturated brine, dried over 100g of anhydrous sodium sulfate, filtered and evaporated to a solid solution under reduced pressure. The granite was crystallized at 600Ml, filtered and dried to obtain z-thr-ome 140 g, yield 89.1percent;General procedure: A solution of N-benzyloxycarbonyl-L-amino acid S5 (7.9 mmol) in DMF (20 ml) was added methyliodide (1.1 g, 7.9 mmol) and potassium carbonate (1.2 g, 8.7 mmol). The reaction mixture waskept at room temperature for 3 hours. The methylated products were purified by column chromatographyin the yields of 50percent (1.0 g, colorless-oil) for serine and 92percent (1.9 g, white-solid) for threonine.The methylated amino acid (4.0 mmol) in DMF (10 ml) was mixed with TBDPSCl (2.2 g, 7.9mmol), imidazole (810 mg, 11.9 mmol) and catalytic amount of DMAP. The reaction was processedat 45 °C for 7 hours. The desired products were purified by column chromatography in theyields of 90percent (1.7 g, colorless-oil) for serine and 90percent (1.8 g, white-solid) for threonine. The silylproduct (500 mg, 1.0 mmol) in DMF (1 ml) was reacted with 15percent NaOH (5 ml) for 2 hours. Thereaction mixture was quenching by 1 N HCl(aq) and 6 was extracted by ethyl acetate. The desiredamino acid 6 was obtained after removal of ethyl acetate in the quantitative yields (470 mg, white-solid for serine; 486 mg, colorless-oil for threonine).[00283] To a stirring solution of 6S-X (60 g, 353 mmol) in water/1, 4 dioxane (150 m l. 300 ml.) The reaction mixture was cooled to 0 To a stirring solution of 4S-H (60 g, 353 mmol) in water/1, 4 dioxane (150 mL/300 mL) The reaction mixture was cooled to 0 °C added NaHCO3 (88.9 g, 1.059 mol) at 0 C and stirred for 1 min. Cbz-Cl (60.7 mL. 426 mmol) was added drop wise and stirred for 1 h. The reaction mixture was stirred to RT and stirred for 12 h. After completion of starting material (by TLC), diluted the reaction mass with EtOAc (300 ml). The separated organic layer was washed with (2x200 mL) of saturated NaHCO3 solution followed by brine solution (2x100 mL). The organic layer was dried over anhydrous NaPlus 99. 5percent of the 125 kg of methanol, A saturated solution of sodium carbonate was added dropwise, Adjusting the pH of the solution to 7-8;50 kg of benzyl chloroformate was added dropwise, Reaction 3-5h, filtration, To give 105 kg of β-hydroxy N-formyl benzyl ester threonine methyl ester

Molecular Weight:267.28
XLogP3:1.1
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:7
Exact Mass:267.11067264
Monoisotopic Mass:267.11067264
Topological Polar Surface Area:84.9
Heavy Atom Count:19
Complexity:301
Defined Atom Stereocenter Count:2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes