methyl (2S)-3-(4-aminophenyl)-2-[(2-methylpropan-2-yl)oxycarbonylamino]propanoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 4-amino-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester (127.6 mmol, 37.57 g) and 2,6-dichlorobenzoyl chloride (140.6 mmol, 29.45 g) in dichloromethane (350 mL) was added diisopropylethylamine (192 mmol, 33.4 mL) at room temperature. The brown solution was stirred for 15 h at room temperature to afford a white suspension. At this time, TLC analysis of the mixture indicated the absence of starting material. The solids were collected by filtration and were washed with dichloromethane (150 mL) and air dried to obtain 52.75 g (88.4%) of a white solid: mp 192-194° C. 1H NMR (DMSO-d6) (400 MHz) δ 10.68 (s, 1H), 7.47-7.6 (m, 5H), 7.2-7.29 (m, 3H), 4.12-4.17 (m, 1H), 3.62 (s, 3H), 2.79-2.99 (m, 2H), 1.33 (s, 9H), 13C NMR, CDCl3 (100 Mhz) d 172.49, 161.82, 155.37, 136.99, 136.36, 131.28, 131.16, 129.48, 128.19, 119.31, 78.27, 55.3, 51.76, 35.9, 27.77. HR MS: Obs. mass, 466.1069. Calcd. mass, 466.1062). to afford a white suspension The solids were collected by filtration were washed with dichloromethane (150 mL) and air dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a mixture of of N-[(1,1-dimethylethoxy)carbonyl]-4-nitro-L-phenylalanine methyl ester (222 mmol, 72 g), zinc dust (˜325 mesh, 2.2 mol, 145.2 g, 10 equiv) and ammonium chloride (3.3 mol, 178.1 g, 15 equiv) was added methanol (1 L) and water (500 mL) at room temperature. After addition of water, an exothermic reaction ensued and the internal temperature rose to 45 to 50° C. The suspension was stirred for 30 min to 1 h at room temperature, at which time TLC analysis of the mixture indicated the absence of starting material, and the reaction mixture was filtered through a pad of celite and the filtered cake was washed with methanol (1 L) and water (500 mL). Concentration to remove most of the methanol afforded white solid which was collected by filtration and washed with water. After air drying, 65.5 g of a white solid, mp 86-89° C. was obtained. 1H-NMR (DMSO-d6) (400 MHz) δ 6.9 (d, 2H, J=20 Hz), 6.62 (d, 2H, J=20 Hz), 7.39 (d, 1H, J=22 Hz), 4.26-4.28 (m, 1H), 3.68 (s, 3H), 2.96-3.19 (m, 2H), 1.25 (s, 9H). HR MS: Obs. mass, 294.1614. Calcd. mass, 294.1621 (M+). an exothermic reaction rose to 45 to 50° C the reaction mixture was filtered through a pad of celite the filtered cake was washed with methanol (1 L) and water (500 mL) Concentration to remove most of the methanol afforded white solid which was collected by filtration washed with water After air drying

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 4-amino-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester (6.78 mmol, 1.99 g) in dichloromethane (90 mL) was added a solution of 4-bromophthalic anhydride (6.78 mmol, 1.54 g) in dichloromethane (30 mL) and 1,1′-carbonyldiimidazole (6.78 mmol, 1.1 g) at room temperature. The resulting solution was stirred for 15 h at which time TLC analysis of the mixture indicated the absence of starting material. The mixture was diluted with water (100 mL) and layers were separated. The aqueous layer was extracted with dichloromethane (2×100 mL) and the combined extracts were washed with brine solution and dried over anhydrous magnesium sulfate. Filtration of the drying agent and concentration of the solvent under vacuum gave a crude product which was purified by silica gel column chromatography to obtaine 2.4 g (70%) of a white solid: mp 168-170° C. HR MS C23H23BrN2O6): Obs mass, 525.0656. Calcd mass, 525.0637 (M+Na). were separated The aqueous layer was extracted with dichloromethane (2×100 mL) the combined extracts were washed with brine solution dried over anhydrous magnesium sulfate Filtration of the drying agent and concentration of the solvent under vacuum

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To the solution of 4-amino-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester (5.09 g, 17 mmol) in DMF (60 mL) was added Fmoc-D-Phenylalanine (8.70 g, 22.5 mmol), DIPEA (12 mL, 69 mmol) and HBTU (8.50 g, 22.5 mmol). The mixture was then stirred at room temperature for 4 h. The reaction mixture was diluted with water (150 mL) and the light yellow solid which precipitated was collected by filtration. This solid was then redissolved in 60 mL of acetone and the solution was treated with 100 mL of water. The solid was collected by filtration and was washed with 1N HCl, H2O. After drying at 60° C. under vaccum overnight, a light yellow solid was obtained (13.2 g). A portion of this solid (2.51 g, 3.78 mmol) was dissolved in 15 mL of DMF and to the solution was added 1.5 mL of piperidine. The above solution was stirred at room temperature for 45 min. After removal of the solvent, the residue was recrystillized from ethyl acetate-hexane to give N-[(1,1-dimethylethoxy)carbonyl]-4-[[(2R)-2-amino-1-oxo-3-phenylpropyl]amino]-L-phenylalanine methyl ester (1.36 g, 3.0 mmol) in 81.5% yield. LR MS 442 (M+H). the light yellow solid which precipitated was collected by filtration This solid was then redissolved in 60 mL of acetone the solution was treated with 100 mL of water The solid was collected by filtration was washed with 1N HCl, H2O After drying at 60° C. under vaccum overnight a light yellow solid was obtained (13.2 g) The above solution was stirred at room temperature for 45 min After removal of the solvent

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a mixture of 4-amino-N-[(1,1-dimethylethoxy)carbonyl)-L-phenylalanine methyl ester (20 mmol, 5.88 g), 2-chloro-5-bromobenzoic acid (22 mmol, 5.18 g) and HBTU (22 mmol, 8.34 g) in DMF (70 mL) was added diisopropylethylamine (50 mmol, 8.7 mL) at room temperature. The suspension was stirred for 48 h at which time TLC analysis of the mixture indicated the absence of starting material. Then, the mixture was diluted with water (100 mL) and the solids were collected by filtration and washed with water (150 mL). After air drying, the crude product was purified by silica gel column chromatography to obtain 1.02 g (10%) of a white solid: mp 158-161° C. HR MS (C22H24BrClN2O5): Ob, 533.0442. Calcd mass, 533.0455 (M+Na). the solids were collected by filtration washed with water (150 mL) After air drying the crude product was purified by silica gel column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 4-(amino)-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester (2.6 g, 8.6 mmol) in dichloromethane (20 mL) were added diisopropylethylamine (2.3 mL, 13 mmol) followed by 2,6-dichlorobenzoyl chloride (1.99 g, 9.5 mmol) at room temperature. The mixture was stirred for 15 h at which time a white precipitate was formed. The mixture was diluted with 30 mL of dichloromethane and 50 mL of water. The layers were separated and the aqueous layer was extracted with 100 mL (2×50 mL) of dichloromethane. The combined organic extracts were washed with brine and dried over anhydrous magnesium sulfate. Filtration and concentration of the solvent gave 4.03 g (quantitative) of 4-[[(2,6-dichlorophenyl)carbonyl]amino]-N-[(1,1-dimethylethoxy)-carbonyl]-L-phenylalanine methyl ester as a white solid, mp 148-151° C. was formed The layers were separated the aqueous layer was extracted with 100 mL (2×50 mL) of dichloromethane The combined organic extracts were washed with brine dried over anhydrous magnesium sulfate Filtration and concentration of the solvent

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (S)-3-(4-Amino-phenyl)-2-tert-butoxycarbonylamino propionic acid methyl ester (574 mg, 1.95 mmol), 1-Chloro-2,6-naphthyridine (350 mg, 2.13 mmol) (prepared according to the method of Van der Plas, H. C. et al J. Heterocyclic Chem. 1981, 18, 1349) and DIPEA (372 μl, 2.13 mmol) in 2-ethoxyethanol (0.5 ml) were stirred at 130° C. under N2 overnight. The reaction mixture was partitioned between EtOAc (70 ml) and saturated aqueous NaHCO3 (30 ml). The phases were separated and the aqueous layer re-extracted with EtOAc (3×30 ml). The combined organic extracts were dried (MgSO4) and the solvents eliminated in vacuo. The residue was purified by flash chromatography (5:1 to 1:1 hexanes/EtOAc) to give (S)-2-tert-butoxycarbonylamino-3-[4-([2,6]naphthyridin-1-ylamino)phenyl] propionic acid methyl ester (385 mg, 47%) as an orange foam. The reaction mixture was partitioned between EtOAc (70 ml) and saturated aqueous NaHCO3 (30 ml) The phases were separated the aqueous layer re-extracted with EtOAc (3×30 ml) The combined organic extracts were dried (MgSO4) The residue was purified by flash chromatography (5:1 to 1:1 hexanes/EtOAc)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of (S)-3-(4-Aminophenyl)-2-tert-butoxycarbonylaminopropionic acid methyl ester (0.25 g, 0.84 mmol), 2-chloro[1,6]naphthyridine-3-carbonitrile (0.15 g, 0.77 mmol) (prepared according to the method of E. M. Hawes et al., J. Med. Chem. 1973,16, 849) and diisopropylethylamine (0.11 g, 0.84 mmol) in EtOH (1 ml) were heated under reflux for 3 h. The solvent was removed under reduced pressure and the resulting crude was purified by flash chromatography (CH2Cl2;AcOEt, 1:1) to yield (S)-2-tert-Butoxycarbonylamino-3-[4-(3-cyano[1,6]naphthyridin-2-ylamino)phenyl]propionic acid methyl ester (0.12 g, 34%) as a yellow solid. under reflux for 3 h The solvent was removed under reduced pressure the resulting crude was purified by flash chromatography (CH2Cl2;AcOEt, 1:1)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of (S)-3-(4-Aminophenyl)-2-tert-butoxycarbonylaminopropionic acid methyl ester (0.25 g, 0.84 mmol), 2-chloro[1,6]naphthyridine-3-carbonitrile (0.15 g, 0.77 mmol) (prepared according to the method of E. M. Hawes et al., J. Med. Chem. 1973,16, 849) and diisopropylethylamine (0.11 g, 0.84 mmol) in EtOH (1 ml) were heated under reflux for 3 h. The solvent was removed under reduced pressure and the resulting crude was purified by flash chromatography (CH2Cl2;AcOEt, 1:1) to yield (S)-2-tert-Butoxycarbonylamino-3-[4-(3-cyano[1,6]naphthyridin-2-ylamino)phenyl]propionic acid methyl ester (0.12 g, 34%) as a yellow solid. under reflux for 3 h The solvent was removed under reduced pressure the resulting crude was purified by flash chromatography (CH2Cl2;AcOEt, 1:1)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methyl (2S)-3-(4-aminophenyl)-2-[(tert-butoxycarbonyl)amino]propanoate (1.0 g, 3.22 mmol) and N-chlorosuccinimide (474 mg, 3.55 mmol) were dissolved in DMF (20 mL) and allowed to stir under an atmosphere of nitrogen for 24 h. The reaction was quenched with water and diluted with ethyl acetate (100 mL). The organic phase was separated, dried over sodium sulfate, filtered and concentrated in vacuo. The crude material was purified by silica gel column (5–20% ethyl acetate/hexanes) to afford the product as a clear oil (645 mg, 61%). 1H NMR (400 MHz, CD3OD): δ 7.05 (s, 1H), 6.90–6.87 (m, 1H), 6.76–6.74 (m, 1H), 4.27–4.23 (m, 1H), 3.68 (s, 3H), 2.97–2.92 (m, 1H), 2.78–2.72 (m, 1H), 1.39 (s, 9H); LCMS found for C10H14ClN2O2 (M+H)+: m/z=229. The reaction was quenched with water diluted with ethyl acetate (100 mL) The organic phase was separated dried over sodium sulfate filtered concentrated in vacuo The crude material was purified by silica gel column (5–20% ethyl acetate/hexanes)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Methyl (2S)-2-[(tert-butoxycarbonyl)amino]-3-(4-nitrophenyl)propanoate (44.0 g, 136 mmol) in methanol (750 mL) and water (75 mL) was treated with ammonium chloride (10.9 g, 203 mmol) and then zinc (71 g, 1.1 mol). The solution was stirred at reflux for 1 h. The solution was filtered through celite, the residue concentrated under vacuum to remove methanol, the water solution extracted with ethyl acetate (500 mL) and dried over sodium sulfate. The product was a yellow foam (38.2 g, 96%). 1H NMR (400 MHz, CD3OD): δ 6.91 (d, J=8.4 Hz, 2H), 6.65 (d, J=8.3 Hz, 2H), 4.28–4.22 (m, 1H), 3.66 (s, 3H), 2.98–2.90 (m, 1H), 2.86–2.78 (m, 1H), 1.39 (s, 9H). LCMS found for C15H22N2O4Na (M+Na)+: m/z=317. at reflux for 1 h The solution was filtered through celite the residue concentrated under vacuum to remove methanol the water solution extracted with ethyl acetate (500 mL) dried over sodium sulfate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 4-amino-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester (127.6 mmol, 37.57 g) and 2,6-dichlorobenzoyl chloride (140.6 mmol, 29.45 g) in dichloromethane (350 mL) was added diisopropylethylamine (192 mmol, 33.4 mL) at room temperature. The brown solution was stirred for 15 h at room temperature to afford a white suspension. At this time, TLC analysis of the mixture indicated the absence of starting material. The solids were collected by filtration and were washed with dichloromethane (150 mL) and air dried to obtain 52.75 g (88.4%) of a white solid: mp 192-194° C. 1H NMR (DMSO-d6) (400 MHz) δ 10.68 (s, 1H), 7.47-7.6 (m, 5H), 7.2-7.29 (m, 3H), 4.12-4.17 (m, 1H), 3.62 (s, 3H), 2.79-2.99 (m, 2H), 1.33 (s, 9H), 13C NMR, CDCl3 (100 Mhz) d 172.49, 161.82, 155.37, 136.99, 136.36, 131.28, 131.16, 129.48, 128.19, 119.31, 78.27, 55.3, 51.76, 35.9, 27.77. HR MS: Obs. mass, 466.1069. Calcd. mass, 466.1062). to afford a white suspension The solids were collected by filtration were washed with dichloromethane (150 mL) and air dried