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

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

Procedure: A mixture of 304 mg of (S)-2-tert-butoxycarbonylamino-3-(4-hydroxy-phenyl)-propionic acid methyl ester, 314 mg 2,3-dimethylpyridine-4-boronic acid, 374 mg cupric acetate, and 2 grams of powdered 4 Å molecular seives in 50 mL dry DCM and 0.75 mL TEA was stirred vigorously at rt under an O2 atmosphere for 40 h. The mixture was then poured into water-EtOAc. The organic layer was washed with water and saturated brine, dried over Na2SO4 and concentrated under reduced pressure. The residue was purified by column chromatography (DCM-EtOAc) to provide (S)-2-tert-Butoxycarbonylamino-3-[4-(2,3-dimethyl-pyridin-4-yloxy)-phenyl]-propionic acid methyl ester (18 mg). LCMS (m/z) 401. The organic layer was washed with water and saturated brine dried over Na2SO4 concentrated under reduced pressure The residue was purified by column chromatography (DCM-EtOAc)

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

Procedure: 13.39 g of N-tert-butoxycarbonyltyrosine methyl ester was dissolved in 65 ml of tetrahydrofuran and 65 ml of dimethylformamide, and to the solution was added 1.9 g of 60% sodium hydride with stirring in an ice bath. After removing from the ice bath, the mixture was stirred at a room temperature for 30 minutes, and after addition of 5.4 g of methoxyethoxymethyl chloride with ice cooling, stirred for 15 hours allowing to warm to a room temperature. The reaction mixture was poured on ice, saturated with sodium chloride and extracted twice with 800 ml of chloroform. The extract was dried over magnesium sulfate and the solvent was evaporated under a reduced pressure, and resulting residue was applied to a silica gel column and eluted with hexane/ethyl acetate (4:1) to obtain 13.85 g of the title compound in a colorless amorphous form. After removing from the ice bath the mixture was stirred at a room temperature for 30 minutes after addition of 5.4 g of methoxyethoxymethyl chloride with ice cooling stirred for 15 hours The reaction mixture was poured on ice, saturated with sodium chloride extracted twice with 800 ml of chloroform The extract was dried over magnesium sulfate the solvent was evaporated under a reduced pressure resulting residue eluted with hexane/ethyl acetate (4:1)

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

Procedure: A mixture of N-Boc-L-tyrosine methyl ester (11.95 g, 40.57 mmol), 3,5-dichloro-4-bromethyl pyridine (see International Patent Application No. PCT/GB99/00589; 10.74 g, 44.56 mmol) and caesium carbonate (14.52 g, 44.56 mmol) in DMF (100 ml) was stirred at room temperature overnight. The solvent was removed in vacuo and the residue partitioned between ethyl acetate and aqueous NaHCO3. The organic layer was washed with citric acid (10%×2), aqueous NaHCO3 (×2) and brine, dried (MgSO4) and concentrated in vacuo to give the title compound as a brown solid (18.0 g, 98%). δH (d6 DMSO) 8.72 (2H, s), 7.25 (1H, d, J 8.2 Hz), 7.19 (2H, d, 18.5 Hz), 6.97 (2H, d, 18.5 Hz), 5.20 (2H, s), 4.13 (1H, m), 3.61 (3H, s), 2.95 (1H, dd, J 13.7, 5.0 Hz), 2.82 (1H, m), 1.32 (9H, s) m/z (ESI, 60V) 477 (M++H). The solvent was removed in vacuo the residue partitioned between ethyl acetate and aqueous NaHCO3 The organic layer was washed with citric acid (10%×2), aqueous NaHCO3 (×2) and brine dried (MgSO4) concentrated in vacuo

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

Procedure: A mixture of N-Boc-L-tyrosine methyl ester (11.95 g, 40.57 mmol), 3,5-dichloro-4-bromethyl pyridine (see International Patent Application No. PCT/GB99/00589; 10.74 g, 44.56 mmol) and caesium carbonate (14.52 g, 44.56 mmol) in DMF (100 ml) was stirred at room temperature overnight. The solvent was removed in vacuo and the residue partitioned between ethyl acetate and aqueous NaHCO3. The organic layer was washed with citric acid (10%×2), aqueous NaHCO3 (×2) and brine, dried (MgSO4) and concentrated in vacuo to give the title compound as a brown solid (18.0 g, 98%). δH (d6 DMSO) 8.72 (2H, s), 7.25 (1H, d, J 8.2 Hz), 7.19 (2H, d, 18.5 Hz), 6.97 (2H, d, 18.5 Hz), 5.20 (2H, s), 4.13 (1H, m), 3.61 (3H, s), 2.95 (1H, dd, J 13.7, 5.0 Hz), 2.82 (1H, m), 1.32 (9H, s) m/z (ESI, 60V) 477 (M++H). The solvent was removed in vacuo the residue partitioned between ethyl acetate and aqueous NaHCO3 The organic layer was washed with citric acid (10%×2), aqueous NaHCO3 (×2) and brine dried (MgSO4) concentrated in vacuo

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

Procedure: To a solution of N-Boc-(L)tyrosine, methyl ester (500 mg) and potassium carbonate (467 mg) in dimethylformamide (5 mL) was added dropwise 1-fluoro-2-nitrobenzene (189 μL). The yellow solution was stirred for 3 days at room temperature. The mixture was diluted with ether which was subsequently washed with 1N hydrochloric acid, water, saturated salt solution and dried over anhydrous magnesium sulfate. After filtration, the solvent was removed by rotoevaporation to yield the title compound (700 mg) which was used in the subsequent reaction without further purification. was subsequently washed with 1N hydrochloric acid, water, saturated salt solution dried over anhydrous magnesium sulfate After filtration the solvent was removed by rotoevaporation

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

Procedure: To a solution of N-Boc-(L)tyrosine, methyl ester (500 mg) and potassium carbonate (467 mg) in dimethylformamide (5 mL) was added dropwise 1-fluoro-2-nitrobenzene (189 μL). The yellow solution was stirred for 3 days at room temperature. The mixture was diluted with ether which was subsequently washed with 1N hydrochloric acid, water, saturated salt solution and dried over anhydrous magnesium sulfate. After filtration, the solvent was removed by rotoevaporation to yield the title compound (700 mg) which was used in the subsequent reaction without further purification. was subsequently washed with 1N hydrochloric acid, water, saturated salt solution dried over anhydrous magnesium sulfate After filtration the solvent was removed by rotoevaporation

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

Procedure: A solution of N-BOC-L-tyrosine methyl ester (2.95 g, 10 mmol) in THF (10 ml) was added to a suspension of NaH (60% in oil, 11 mmol, 440 mg) in THF (30 ml) at 0°. After 10 min, a solution of 3,5-dichloroisonicotinoyl chloride (11 mml, 2.32 g) in THF (10 ml) was added and the mixture stirred at RT for 4 h. NH4Cl (aq) was added and the mixture extracted with DCM. The DCM extracts were dried (Na2SO4) and concentrated in vacuo. Recrystallisation (EtOAc/hexane) gave the title compound as white crystals (3.61 g, 77%). δH (DMSO d6) 8.89 (2H, s), 7.39 (2H, d, J 8.5 Hz), 7.32 (1H, d, J 8.2 Hz), 7.23 (2H, d, J 8.5 Hz), 4.21 (1H, m), 3.62 (3H, s), 3.05 (1H, dd, J 13.8, 4.9 Hz), 2.89 (1H, dd, J 13.8, 10.5 Hz), 1.31 (9H). m/z (ES+, 70V) 410 (M++Na). the mixture extracted with DCM The DCM extracts were dried (Na2SO4) concentrated in vacuo Recrystallisation (EtOAc/hexane)

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

Procedure: A solution of N-BOC-L-tyrosine methyl ester (2.95 g, 10 mmol) in THF (10 ml) was added to a suspension of NaH (60% in oil, 11 mmol, 440 mg) in THF (30 ml) at 0°. After 10 min, a solution of 3,5-dichloroisonicotinoyl chloride (11 mml, 2.32 g) in THF (10 ml) was added and the mixture stirred at RT for 4 h. NH4Cl (aq) was added and the mixture extracted with DCM. The DCM extracts were dried (Na2SO4) and concentrated in vacuo. Recrystallisation (EtOAc/hexane) gave the title compound as white crystals (3.61 g, 77%). δH (DMSO d6) 8.89 (2H, s), 7.39 (2H, d, J 8.5 Hz), 7.32 (1H, d, J 8.2 Hz), 7.23 (2H, d, J 8.5 Hz), 4.21 (1H, m), 3.62 (3H, s), 3.05 (1H, dd, J 13.8, 4.9 Hz), 2.89 (1H, dd, J 13.8, 10.5 Hz), 1.31 (9H). m/z (ES+, 70V) 410 (M++Na). the mixture extracted with DCM The DCM extracts were dried (Na2SO4) concentrated in vacuo Recrystallisation (EtOAc/hexane)

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

Procedure: A solution of N-BOC-L-tyrosine methyl ester (3.0 g, 10.2 mmol) in DMF (5 ml) was added to a suspension of NaH (60% in oil, 11.2 mmol, 447 mg) in DMF (10 ml). After 10 min, a solution of 2-chloropyrimidine (11.2 mmol, 1.28 g) in DMF (3 ml) was added and the mixture stirred overnight. The reaction was quenched with water, diluted EtOAc and washed with water and brine. The EtOAc layer was dried (Na2SO4) and concentrated in vacuo. Purification by column chromatography [SiO2, EtOAc/hexane, 1:1] gave the title compound. δH (DMSO d6) 8.62 (2H, d, J 4.8 Hz), 7.37 (1H, d, J 8.1 Hz), 7.28 (2H, d, J 8.4 Hz), 7.24 (1H, t, J 4.8 Hz), 7.09 (2H, d, J 8.4 Hz), 4.18 (1H, m), 3.01 (1H, dd, J 13.8, 4.6 Hz), 1.33 (9H, s). The reaction was quenched with water, diluted EtOAc washed with water and brine The EtOAc layer was dried (Na2SO4) concentrated in vacuo Purification by column chromatography [SiO2, EtOAc/hexane, 1:1]

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

Procedure: To N-(t-butyloxycarbonyl)tyrosine methyl ester (1.42 g, 4.82 mmol) in dry DMF (10 ml) was added 1-chloro-2,6 naphthyridine (0.79 g, 4.82 mmol) and cesium carbonate (1.65 g, 5.06 mmol) and the reaction stirred at 45° under N2 for 2 days. The DMF was evaporated, EtOAc added and washed (3×) with water, dried (MgSO4), and evaporated in vacuo. The residue was chromatographed (SiO2; 40 to 100% EtOAc/isohexane) to afford the title compound as white foam (1.61 g, 82%). δH (CDCl3) 9.29 (1H, s), 8.76 (1H, d, J 5.74 HZ), 8.17 (1H, d, J 5.74 Hz), 8.11 (1H, d, J 5.8 Hz), 7.43 (1H, d, J 5.8 Hz), 7.22-7.18 (3H, m), 5.03 (1H, br s), 4.61 (1H, br s), 3.75 (3H, s), 3.15-3.05 (2H, m), 1.44 (9H, s); m/z (ES+, 70V) MH+424. The DMF was evaporated EtOAc added washed (3×) with water dried (MgSO4) evaporated in vacuo The residue was chromatographed (SiO2; 40 to 100% EtOAc/isohexane)

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

Procedure: A stirred solution of (S)-methyl 2-((tert-butoxycarbonyl)amino)-3-(4-hydroxyphenyl)propanoate (1.257 g, 4.26 mmol), DMAP (26 mg, 0.213 mmol), and triethylamine (0.71 mL, 0.51 g, 5.11 mmol) in anhydrous DCM (15 mL) was cooled to 0° C. Then nonafluorobutanesulfonyl fluoride (0.82 mL, 1.41 g, 4.68 mmol) was added in one portion. The mixture was allowed to warm and stirred at room temperature. After 18 hours, the mixture was poured into water (80 mL) and extracted with DCM (2×100 mL). The combined organic layers were washed with brine (50 mL), dried over sodium sulfate, and concentrated under reduced pressure. The resultant residue was chromatographed using a Biotage™ 50 g silica gel cartridge by eluting with 0-10% EtOAc in 1:1 Hexane/DCM over 10 column volumes. The product fractions were combined and concentrated under reduced pressure to give the desired product as a clear, colorless oil. LC-MS: calculated for C19H20F9NO7S 577.08, observed m/e: 478.14 (M+H with loss of BOC)+ (Rt 2.67/4 min). to warm extracted with DCM (2×100 mL) The combined organic layers were washed with brine (50 mL) dried over sodium sulfate concentrated under reduced pressure The resultant residue was chromatographed by eluting with 0-10% EtOAc in 1:1 Hexane/DCM over 10 column volumes concentrated under reduced pressure

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

Procedure: To a solution of N-(tert-butoxycarbonyl)-L-tyrosine methyl ester (5.64 g) in THF (10 ml) was added NH4NO3 (3 g) and concentrated HNO3 (3 ml). After 30 sec., the reaction mixture turned to dark red with reflux occurring. The reaction mixture was quenched with solid NaHCO3 and H2O, and extracted with AcOEt. The extract was dried over Na2SO4 and the solvent was removed in vacuo. The residue was purified by column chromatography on silica gel (eluent; Hexane→1:1, Hexane/AcOEt) to give N-(tert-butoxycarbonyl)-3-nitro-L-tyrosine methyl ester (3.42 g). The obtained compound was treated in a similar manner as described in R. Example 4 to give 3-Nitro-L-tyrosine methyl ester, hydrochloride salt. with reflux The reaction mixture was quenched with solid NaHCO3 and H2O extracted with AcOEt The extract was dried over Na2SO4 the solvent was removed in vacuo The residue was purified by column chromatography on silica gel (eluent; Hexane→1:1, Hexane/AcOEt)