(2S)-4-methyl-2-[methyl-[(2-methylpropan-2-yl)oxycarbonyl]amino]pentanoic acid

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: This was prepared by the method of Cheung and Benoitin (1977). In brief, Boc-L-leucine (5 g, 21.6 mmol) and methyl iodide (24.6 g, 172.8 mmol) were dissolved in anhydrous tetrahydrofuran (30 ml) and chilled to 0° C. Sodium hydride (0.26 g, 32.4 mmol) was added slowly with vigorous stirring to the solution over a period of 10 minutes. The reaction was allowed to proceed for a further 24 hours at room temperature. Ethyl acetate (50 ml) followed by water (20 ml) was added and the solution was reduced to dryness in vacuo. The residue was partitioned between diethyl (50 ml) and water (50 ml). The aqueous layer was removed and the organic layer was washed with 5% NaHCO3 (50 ml). The aqueous extracts were combined and acidified by the addition of 5% NaHSO4. The product was extracted into ethyl acetate (100 ml) and washed successively with water (2×50 ml), 10% Na2S2O3 (2×50 ml) and water (100 ml). The organic layer was dried over magnesium sulphate and reduced to dryness. The product was obtained as a pale yellow oil which solidified at -20° C. Yield 4.69 g (88%), m.p. 53°-55° C. (lit. 56°-57° C., Cheung and Benoiton, 1977). The product was homogeneous as judged by tlc in chloroform/methanol (4:1) (Rf 0.375) or chloroform/methanol (1:1) (Rf 0.683). (Found: C, 58.47; H, 9.19; N, 5.71. C12H23O4N1 requires C, 59.77; H, 9.38; N, 5.71%). 1H n.m.r. (p.p.m) CDCl3 δ 0.98 (6H, α, (CH3)2), 1.5 (9H, s, C(CH3)3), 1.82 (3H, m, CH2CH), 2.84 (3H, s, N--CH3), 9.94 (1H, s, COOH). This was prepared by the method of Cheung and Benoitin (1977) to proceed for a further 24 hours at room temperature was added The residue was partitioned between diethyl (50 ml) and water (50 ml) The aqueous layer was removed the organic layer was washed with 5% NaHCO3 (50 ml) acidified by the addition of 5% NaHSO4 The product was extracted into ethyl acetate (100 ml) washed successively with water (2×50 ml), 10% Na2S2O3 (2×50 ml) and water (100 ml) The organic layer was dried over magnesium sulphate The product was obtained as a pale yellow oil which solidified at -20° C Yield 4.69 g (88%), m.p. 53°-55° C. (lit. 56°-57° C., Cheung and Benoiton, 1977)

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

Procedure: 2,2-Bis(4-fluorophenyl)-N-[(3aR,4S,6aS)-octahydrocyclopenta[c]pyrrol-4-yl]acetamide (30 mg, 0.084 mmol) and (S)-2-(tert-butoxycarbonyl(methyl)amino)-4-methylpentanoic acid (22.71 mg, 0.093 mmol) were dissolved in dichloromethane (0.5 mL) and then treated with 1-hydroxybenzotriazole hydrate (14.18 mg, 0.093 mmol). After 10 minutes, N1-((ethylimino)methylene)-N3,N3-dimethylpropane-1,3-diamine (0.016 mL, 0.093 mmol) was added, and the reaction mixture was stirred at ambient temperature overnight followed by quenching with water. The material in the organic layer was purified with a 4 g silica gel cartridge eluting with 1-10% methanol (2 N ammonia)/dichloromethane to give tert-butyl(S)-1-((3aR,4S,6aS)-4-(2,2-bis(4-fluorophenyl)acetamido)hexahydrocyclopenta[c]pyrrol-2(1H)-yl)-4-methyl-1-oxopentan-2-yl(methyl)carbamate: 1H NMR (400 MHz, pyridine-d5) δ ppm 8.25 (s, 1H), 7.46 (td, J=8.5, 5.5, 4H), 7.08-6.96 (m, 4H), 5.08 (s, 2H), 4.29-4.18 (m, 1H), 3.80 (s, 2H), 3.69 (s, 1H), 3.43 (dd, J=11.7, 3.5, 1H), 2.93 (s, 3H), 2.63 (s, 2H), 2.10 (td, J=12.9, 6.9, 1H), 1.91-1.69 (m, 3H), 1.63 (dt, J=13.2, 6.5, 2H), 1.51 (s, 9H), 1.40-1.26 (m, 1H), 0.97 (d, J=6.5, 3H), 0.92 (d, J=6.6, 3H); MS (ESI+) m/z 584 (M+H)+. by quenching with water The material in the organic layer was purified with a 4 g silica gel cartridge eluting with 1-10% methanol (2 N ammonia)/dichloromethane

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

Procedure: A mixture of Ia (0.535 g, 1.65 mmol), N-Methyl-N-Boc-L-Leucine (0.405 g, 1.65 mmol), HBTU (0.625 g, 1.65 mmol), and diisopropylethylamine (0.516 g, 6.6 mmol) was stirred in CH3CN (30 mL) for 15 hours. The reaction mixture was concentrated, redissolved in EtOAc, washed 3 times with saturated sodium bicarbonate solution and once with brine, then concentrated to give 1.2 g of the desired product. The reaction mixture was concentrated redissolved in EtOAc washed 3 times with saturated sodium bicarbonate solution once with brine, then concentrated

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

Procedure: N-tert-butoxycarbonyl-N-methyl-L-leucine (5.0 g, 20.4 mmol) was dissolved in DMF (100 mL), treated with treated with N,N-diisopropylethylamine (28 mL, 163 mmol), N,N-dimethylhydroxylamine hydrochloride salt (2.0 g, 20.4 mmol), and HBTU (7.73 g, 20.4 mmol), then stirred overnight at room temperature. The reaction was diluted with EtOAc (500 mL), washed with saturated bicarbonate solution and brine, dried over Na2SO4, and concentrated to give the desired product as an oil; MS: 289.2 (M+1 for C14H28N2O4); TLC (SiO2) Rf 0.39 (8% MeOH/CH2Cl2), visualized with ninhydrin. treated washed with saturated bicarbonate solution and brine dried over Na2SO4 concentrated

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-tert-Butoxycarbonyl-N-methyl-L-leucine (0.42 g, 1.7 mmol, Bachem Inc., Torrance, Calif.) was dissolved in dry DMF (5 mL) under nitrogen atmosphere and cooled to 0° C. in an ice-water bath. To this solution were added, in succession, N,N-diisopropylethylamine (0.90 mL, 5.2 mmol) and solid O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (0.66 g, 1.7 mmol). The resulting reaction mixture was stirred at that temperature for 30 minutes; 4,4-bis-(4-fluoro-phenyl)-butylamine monohydrochloride (0.51 g, 1.7 mmol) was then added. After additional 30 minutes stirring at 0° C., reaction mixture was mixed with 60 mL of diethyl ether; the resulting mixture was successively washed with 5% aqueous HCl solution, brine, saturated aqueous NaHCO3 solution, brine, and was dried over Na2SO4. Concentration in vacuo followed by drying under vacuum afforded the crude desired product which was used in the subsequent reaction without further purification. The resulting reaction mixture After additional 30 minutes stirring at 0° C. reaction mixture the resulting mixture was successively washed with 5% aqueous HCl solution, brine, saturated aqueous NaHCO3 solution, brine was dried over Na2SO4 Concentration in vacuo by drying under vacuum

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-tert-Butoxycarbonyl-N-methyl-L-leucine (0.42 g, 1.7 mmol, Bachem Inc., Torrance, Calif.) was dissolved in dry DMF (5 mL) under nitrogen atmosphere and cooled to 0° C. in an ice-water bath. To this solution were added, in succession, N,N-diisopropylethylamine (0.90 mL, 5.2 mmol) and solid O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (0.66 g, 1.7 mmol). The resulting reaction mixture was stirred at that temperature for 30 minutes; 4,4-bis-(4-fluoro-phenyl)-butylamine monohydrochloride (0.51 g, 1.7 mmol) was then added. After additional 30 minutes stirring at 0° C., reaction mixture was mixed with 60 mL of diethyl ether; the resulting mixture was successively washed with 5% aqueous HCl solution, brine, saturated aqueous NaHCO3 solution, brine, and was dried over Na2SO4. Concentration in vacuo followed by drying under vacuum afforded the crude desired product which was used in the subsequent reaction without further purification. The resulting reaction mixture After additional 30 minutes stirring at 0° C. reaction mixture the resulting mixture was successively washed with 5% aqueous HCl solution, brine, saturated aqueous NaHCO3 solution, brine was dried over Na2SO4 Concentration in vacuo by drying under vacuum

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

Procedure: To (S)-2-(tert-butoxycarbonyl(methyl)amino)-4-methylpentanoic acid in DMF was added EDC, DMAP and isoquinolin-7-amine. This mixture was stirred for 4 hours and the reaction was washed with NaHCO3 (sat), extracted with EtOAc, dried (Na2SO4), filtered and evaporated. Column chromatography (SiO2, Hexanes/EtOAc) gave pure (S)-tert-butyl 1-(isoquinolin-7-ylamino)-4-methyl-1-oxopentan-2-yl(methyl)carbamate (E87). the reaction was washed with NaHCO3 (sat) extracted with EtOAc dried (Na2SO4) filtered evaporated

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

Procedure: To (S)-2-(tert-butoxycarbonyl(methyl)amino)-4-methylpentanoic acid in DMF was added EDC, DMAP and isoquinolin-7-amine. This mixture was stirred for 4 hours and the reaction was washed with NaHCO3 (sat), extracted with EtOAc, dried (Na2SO4), filtered and evaporated. Column chromatography (SiO2, Hexanes/EtOAc) gave pure (S)-tert-butyl 1-(isoquinolin-7-ylamino)-4-methyl-1-oxopentan-2-yl(methyl)carbamate (E87). the reaction was washed with NaHCO3 (sat) extracted with EtOAc dried (Na2SO4) filtered evaporated

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

Procedure: 23.3 ml (18.9 g=157 mMol) pivaloyl chloride and 48 ml (28.9 g=286 mMol) triethylamine are added to a solution of 35 g (143 mMol) BOC-MeLeu-OH in 500 ml chloroform and the mixture stirred for 2 hrs. at room temperature under a nitrogen atmosphere. 30.7 g (171 mMol) H-Ala-Bzl dissolved in 300 ml chloroform are then added and the reaction mixture stirred for a further 2 hrs. at room temperature, again under a nitrogen atmosphere. The product is purified in accordance with the technique of example 1a) to yield the title compound: at room temperature are then added the reaction mixture stirred for a further 2 hrs at room temperature The product is purified in accordance with the technique of example 1a)

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: This was prepared by the method of Cheung and Benoitin (1977). In brief, Boc-L-leucine (5 g, 21.6 mmol) and methyl iodide (24.6 g, 172.8 mmol) were dissolved in anhydrous tetrahydrofuran (30 ml) and chilled to 0° C. Sodium hydride (0.26 g, 32.4 mmol) was added slowly with vigorous stirring to the solution over a period of 10 minutes. The reaction was allowed to proceed for a further 24 hours at room temperature. Ethyl acetate (50 ml) followed by water (20 ml) was added and the solution was reduced to dryness in vacuo. The residue was partitioned between diethyl (50 ml) and water (50 ml). The aqueous layer was removed and the organic layer was washed with 5% NaHCO3 (50 ml). The aqueous extracts were combined and acidified by the addition of 5% NaHSO4. The product was extracted into ethyl acetate (100 ml) and washed successively with water (2×50 ml), 10% Na2S2O3 (2×50 ml) and water (100 ml). The organic layer was dried over magnesium sulphate and reduced to dryness. The product was obtained as a pale yellow oil which solidified at -20° C. Yield 4.69 g (88%), m.p. 53°-55° C. (lit. 56°-57° C., Cheung and Benoiton, 1977). The product was homogeneous as judged by tlc in chloroform/methanol (4:1) (Rf 0.375) or chloroform/methanol (1:1) (Rf 0.683). (Found: C, 58.47; H, 9.19; N, 5.71. C12H23O4N1 requires C, 59.77; H, 9.38; N, 5.71%). 1H n.m.r. (p.p.m) CDCl3 δ 0.98 (6H, α, (CH3)2), 1.5 (9H, s, C(CH3)3), 1.82 (3H, m, CH2CH), 2.84 (3H, s, N--CH3), 9.94 (1H, s, COOH). This was prepared by the method of Cheung and Benoitin (1977) to proceed for a further 24 hours at room temperature was added The residue was partitioned between diethyl (50 ml) and water (50 ml) The aqueous layer was removed the organic layer was washed with 5% NaHCO3 (50 ml) acidified by the addition of 5% NaHSO4 The product was extracted into ethyl acetate (100 ml) washed successively with water (2×50 ml), 10% Na2S2O3 (2×50 ml) and water (100 ml) The organic layer was dried over magnesium sulphate The product was obtained as a pale yellow oil which solidified at -20° C Yield 4.69 g (88%), m.p. 53°-55° C. (lit. 56°-57° C., Cheung and Benoiton, 1977)

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

Procedure: To (S)-2-(tert-butoxycarbonyl(methyl)amino)-4-methylpentanoic acid in DMF was added EDC, DMAP and isoquinolin-7-amine. This mixture was stirred for 4 hours and the reaction was washed with NaHCO3 (sat), extracted with EtOAc, dried (Na2SO4), filtered and evaporated. Column chromatography (SiO2, Hexanes/EtOAc) gave pure (S)-tert-butyl 1-(isoquinolin-7-ylamino)-4-methyl-1-oxopentan-2-yl(methyl)carbamate (E87). the reaction was washed with NaHCO3 (sat) extracted with EtOAc dried (Na2SO4) filtered evaporated

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

Procedure: Methylation of BocLeuOH (12.5 g.) using sodium hydride and methyl iodide gave BocMeLeuOH in 73% yield. Condensation of BocMeLeuOH (3.7 g.) and HMetNH2 hydrochloride salt (2.8 g.) by the mixed anhydride method using isobutyl chloroformate gave BocMeLeu-MetNH2 in 56% yield. De-t-butoxycarbonylation of BocMeLeu-MetNH2 (3.3 g.) using hydrogen chloride in ethyl acetate gave MeLeu-MetNH2 in 64% yield.