Boc-L-2,4-diaminobutyric acid

To a solution of (S)-5-amino-2-(tert-butoxycarbonylamino)-5-oxopentanoic acid (2g, 8. lmmol) in DMF: water (l : l, v/v, 18ml) was added pyridine (1.3ml, 16.2mmol). The resulting reaction mixture was stirred at room temperature for 5-10 minutes. Iodobenzene diacetate (3.92g, 12. lmmol) was added and further stirred for 4 hours. After completion of reaction D.M. water (100ml) was added and the resulting mixture was extracted with ethyl acetate (3 x 100ml). The combined organic extracts was washed with D.M. water (100ml), brine (100ml), dried over sodium sulphate and concentrated under vacuo to get the desired crude product. The crude product was purified by triturating with diethyl ether. Evaporation of the product fractions gave l .lg (yield, 62percent) of desired compound as brown solid. LC-MS: m/z = 219.1(M+H). [[00383] Step 1 : Preparation of (S)-4-amino-2-(tert-butoxycarbonylamino)butanoic acid [00384] To a solution of (S)-5-amino-2-(tert-butoxycarbonylamino)-5-oxopentanoic acid (2g, 8. lmmol) in DMF: water (l : l, v/v, 18ml) was added pyridine (1.3ml, 16.2mmol). The resulting reaction mixture was stirred at room temperature for 5-10 minutes. Iodobenzene diacetate (3.92g, 12. lmmol) was added and further stirred for 4 hours. After completion of reaction D.M. water (100ml) was added and the resulting mixture was extracted with ethyl acetate (3 x 100ml). The combined organic extracts was washed with D.M. water (100ml), brine (100ml), dried over sodium sulphate and concentrated under vacuo to get the desired crude product. The crude product was purified by triturating with diethyl ether. Evaporation of the product fractions gave l .lg (yield, 62percent) of desired compound as brown solid. LC-MS: m/z = 219.1(M+H).To a solution of (S)-5-amino-2-(tert-butoxycarbo- nylamino)-5-oxopentanoic acid (2 g, 8.1 mmol) in DMF:water (1:1, v/v, 18 ml) was added pyridine (1.3 ml, 16.2 mmol). The resulting reaction mixture was stirred at room temperature for 5-10 minutes. Iodobenzene diacetate (3.92 g, 12.1 mmol) was added and further stirred for 4 hours. After completion of reaction D.M. water (100 ml) was added and the resulting mixture was extracted with ethyl acetate (3x1 00 ml). The combined organic extracts was washed with D.M. water (100 ml), brine (100 ml), dried over sodium sulphate and concentrated under vacuo to get the desired crude product. The crude product was purified by triturating with diethyl ether. Evaporation of the product fractions gave 1.1 g (yield, 62percent) of desired compound as brown solid. LC-MS:mlz=219.1 (M+H).Butyloxycarbonyl-L-glutamine 1.2KG, add ethyl acetate 8 liters, tetrahydrofuran 2 liters, water 5 liters, cooled to 0-5 ° C, add iodobenzene diacetate 4.5KG, at room temperature for 12-24 hours, The reaction was completed, the aqueous layer separated, the organic layer washed three times with water, the organic layer was iodobenzene recovery, the combined aqueous layer, vacuum distilled water and absolute ethanol stirred and filtered, washed twice with ethanol, drained, dried at 60 , To obtain N2-tert-butoxycarbonyl-L-2, 4-diaminobutyric acid 450 g.[00202] (S)-tert-Ruiy (2-Oxopyrrolidin-3-yl)carbamate (126) To a solution of 0.60 g (2.75 mmol) of BOC-L-DAB-OH in 275 mL of DMF at a 10 mM concentration were added 1.22 g (2.75 mmol) of BOP and 1.16 g (20.0 mmol) of sodium bicarbonate. After 12 h stirring at room temperature, the mixture was concentrated to a small volume (around 5 mL) under reduced pressure. The concentrated mixture was diluted with water and saturated sodium bicarbonate solution (1 : 1, 100 mL) and extracted with three 100- mL portions of EtOAc. The combined organic extracts were washed with 200 mL of water and 200 mL of brine, dried over Na2S04, filtered, and concentrated under reduced pressure to afford a residue that crystallized upon trituration in 100 mL of ether and filtered to afford 126 as a colorless solid: yield 296 mg (54percent); mp 161-164°C (lit/ 168 - 171 °C); silica gel TLC i' 0.55 (10: 1 DCM-MeOH); 'H NMR (CDC13) delta 1.42 (s, 9H), 1.93-2.01 (m, 1H), 2.60-2.70 (m, 1H), 3.28-3.42 (m, 2H), 4.05-4.20 (m, 1H), 5.25 (s, 1H) and 6.85 (br s, 1H); 1 C NMR (CDC13) delta 28.3, 30.0, 39.2, 51.7, 79.9, 155.9 and 176.1.

Molecular Weight:218.25
XLogP3:-2.3
Hydrogen Bond Donor Count:3
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:6
Exact Mass:218.12665706
Monoisotopic Mass:218.12665706
Topological Polar Surface Area:102
Heavy Atom Count:15
Complexity:235
Defined Atom Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes