tert-butyl 2-oxoacetate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: (3R,4R)-3-Phenylacetamido-4-[(RS)-tetrahydropyran-2-yl-carbonylmethylthio]azetidin-2-one (1.7g) in 1,2-dichloroethane (20ml) was successively treated with 0.5M t-butyl glyoxylate in 1,2-dichlorethane (10ml) and triethylamine (50mg, 70μl) and monitored by t.l.c. (ethyl acetate) until no starting material remained. The reaction mixture was concentrated and flash chromatography (70% ethyl acetate in hexane, ethyl acetate) to afford the title compound as a yellow foam (1.9g, 82%); vmax (CH2Cl3) 3400 (w), 1780, 1736, 1687cm-1 ; δH (CDCl3) 1.49 (9H, s) overlapping 1.44-1.61 (4H, m), 1.8-2.0 (2H, m), 3.35-3.58 (3H, m), 3.65 (2H, s), 3.81-3.92 (1H, m), 4.01-4.06 (1H, m), 4.28-4.43 (1H, m), 4.99, 5.00, 5.07 (together 1H, 3d, J4.7Hz), 5.21, 5.32, 5.33 (together 1H, 3d, J6.8, 7.7, 7.6Hz), 5.42, 5.50 (together 1H, 2dd, J4.8, 8.7Hz, 6.35, 6.36, 6.61 (together 1H, 3d, J8.7Hz) and 7.27-7.38 (5H, m). The reaction mixture was concentrated

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

Procedure: 3-(Triphenylmethylamino)-4-(but-2-ynylthio)azetidin-2-one (1.03g) and t-butyl glyoxalate (3.3g) were refluxed in dry benzene (50ml) with provision for the removal of water. After one hour the benzene solution was washed 5 times with water, dried and evaporated. Chromatography of the residue on silica --H gave 1-(1-hydroxy-1-t-butoxycarbonylmethyl)-3-(triphenylmethylamino)-4-(but-2-ynylthio)azetidin-2-one as an amorphous white solid (0.978 g). After one hour the benzene solution was washed 5 times with water dried evaporated

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

Procedure: 3-(Triphenylmethylamino)-4-(3-p-fluorophenylprop-2-ynylthio)azetidin-2-one (1.02g) and t-butyl glyoxalate (2.76g) were refluxed in dry benzene (50ml) with provision for the removal of water. After 1 hour the benzene solution was washed 5 times with water, dried and evaporated. The residue was chromatographed on silica to give 1-(1-Hydroxy-1-t-butoxycarbonylmethyl)-3-(triphenylmethylamino)-4-(3-p-fluorophenylprop-2-ynylthio)azetidin-2-one as an amorphous solid (.969g). After 1 hour the benzene solution was washed 5 times with water dried evaporated The residue was chromatographed on silica

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

Procedure: A suspension of Fmoc-Lys-OH.HCl (6.07 g, 15 mmol) and thiazole-2-carbaldehyde (1.697 g, 15 mmol) in DCE (100 mL) was refluxed for 30 min under nitrogen. The reaction mixture was cooled to 0° C., and treated sequentially with NaBH(OAc)3 (7.95 g, 37.5 mmol) and crude tert-butyl glyoxalate (3.53 g). The reaction mixture was stirred at room temperature for overnight and decomposed with water. The reaction mixture was extracted with DCM. The organic layer was dried and concentrated under reduced pressure. The residue was purified by flash chromatography over silica gel to afford (S)-1-(9H-fluoren-9-yl)-14,14-dimethyl-3,12-dioxo-10-(thiazol-2-ylmethyl)-2,13-dioxa-4,10-diazapentadecane-5-carboxylic acid (1.85 g, 21%). MS (ESI), 580 (M+H)+. was refluxed for 30 min under nitrogen The reaction mixture was extracted with DCM The organic layer was dried concentrated under reduced pressure The residue was purified by flash chromatography over silica gel

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

Procedure: A suspension of Fmoc-Lys-OH.HCl (4.859 g, 12 mmol) and 2-pyridinecarboxaldehyde (1.285 g, 12 mmol) in DCE (100 mL) was refluxed for 30 min under nitrogen. The reaction mixture was cooled to 0° C., and treated sequentially with NaBH(OAc)3 (6.36 g, 30 mmol) and crude tert-butyl glyoxalate (2.34 g, 18 mmol) The reaction mixture was stirred at room temperature for overnight and decomposed with water. The reaction mixture was extracted with DCM. The organic layer was dried and concentrated under reduced pressure. The residue was purified by flash chromatography over silica gel to afford ((S)-1-(9H-fluoren-9-yl)-14,14-dimethyl-3,12-dioxo-10-(pyridin-2-ylmethyl)-2,13-dioxa-4,10-diazapentadecane-5-carboxylic acid (1.924 g, 28%). 1H NMR (400 MHz, CDCl3) 8.89 (d, J=4.4 Hz, 1H), 8.06 (d, J=8.0 Hz, 1H), 8.02 (d, J=7.6 Hz, 2H), 7.88 (t, J=5.8 Hz, 2H), 7.81 (d, J=7.6 Hz, 1H), 7.66 (t, J=7.4 Hz, 2H), 7.60-7.53 (m, 4H), 6.03 (d, J=7.2 Hz, 1H), 4.67-4.22 (m, 8H), 3.64-3.53 (m, 2H), 3.12 (t, J=6.8 Hz, 2H), 2.19-2.08 (m, 2H), 1.92-1.79 (m, 2H), 1.73 (s, 9H); MS (ESI), 564 (M+H)+. was refluxed for 30 min under nitrogen The reaction mixture was extracted with DCM The organic layer was dried concentrated under reduced pressure The residue was purified by flash chromatography over silica gel

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

Procedure: A suspension of Fmoc-Lys-OH.HCl (4.859 g, 12 mmol) and 2-pyridinecarboxaldehyde (1.285 g, 12 mmol) in DCE (100 mL) was refluxed for 30 min under nitrogen. The reaction mixture was cooled to 0° C., and treated sequentially with NaBH(OAc)3 (6.36 g, 30 mmol) and crude tert-butyl glyoxalate (2.34 g, 18 mmol) The reaction mixture was stirred at room temperature for overnight and decomposed with water. The reaction mixture was extracted with DCM. The organic layer was dried and concentrated under reduced pressure. The residue was purified by flash chromatography over silica gel to afford ((S)-1-(9H-fluoren-9-yl)-14,14-dimethyl-3,12-dioxo-10-(pyridin-2-ylmethyl)-2,13-dioxa-4,10-diazapentadecane-5-carboxylic acid (1.924 g, 28%). 1H NMR (400 MHz, CDCl3) 8.89 (d, J=4.4 Hz, 1H), 8.06 (d, J=8.0 Hz, 1H), 8.02 (d, J=7.6 Hz, 2H), 7.88 (t, J=5.8 Hz, 2H), 7.81 (d, J=7.6 Hz, 1H), 7.66 (t, J=7.4 Hz, 2H), 7.60-7.53 (m, 4H), 6.03 (d, J=7.2 Hz, 1H), 4.67-4.22 (m, 8H), 3.64-3.53 (m, 2H), 3.12 (t, J=6.8 Hz, 2H), 2.19-2.08 (m, 2H), 1.92-1.79 (m, 2H), 1.73 (s, 9H); MS (ESI), 564 (M+H)+. was refluxed for 30 min under nitrogen The reaction mixture was extracted with DCM The organic layer was dried concentrated under reduced pressure The residue was purified by flash chromatography over silica gel

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

Procedure: (3R,4R)-3-Phenylacetamido-4-[(RS)-tetrahydropyran-2-yl-carbonylmethylthio]azetidin-2-one (1.7g) in 1,2-dichloroethane (20ml) was successively treated with 0.5M t-butyl glyoxylate in 1,2-dichlorethane (10ml) and triethylamine (50mg, 70μl) and monitored by t.l.c. (ethyl acetate) until no starting material remained. The reaction mixture was concentrated and flash chromatography (70% ethyl acetate in hexane, ethyl acetate) to afford the title compound as a yellow foam (1.9g, 82%); vmax (CH2Cl3) 3400 (w), 1780, 1736, 1687cm-1 ; δH (CDCl3) 1.49 (9H, s) overlapping 1.44-1.61 (4H, m), 1.8-2.0 (2H, m), 3.35-3.58 (3H, m), 3.65 (2H, s), 3.81-3.92 (1H, m), 4.01-4.06 (1H, m), 4.28-4.43 (1H, m), 4.99, 5.00, 5.07 (together 1H, 3d, J4.7Hz), 5.21, 5.32, 5.33 (together 1H, 3d, J6.8, 7.7, 7.6Hz), 5.42, 5.50 (together 1H, 2dd, J4.8, 8.7Hz, 6.35, 6.36, 6.61 (together 1H, 3d, J8.7Hz) and 7.27-7.38 (5H, m). The reaction mixture was concentrated

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

Procedure: (3R,4R)-3-Phenylacetamido-4-[(RS)-tetrahydropyran-2-yl-carbonylmethylthio]azetidin-2-one (1.7g) in 1,2-dichloroethane (20ml) was successively treated with 0.5M t-butyl glyoxylate in 1,2-dichlorethane (10ml) and triethylamine (50mg, 70μl) and monitored by t.l.c. (ethyl acetate) until no starting material remained. The reaction mixture was concentrated and flash chromatography (70% ethyl acetate in hexane, ethyl acetate) to afford the title compound as a yellow foam (1.9g, 82%); vmax (CH2Cl3) 3400 (w), 1780, 1736, 1687cm-1 ; δH (CDCl3) 1.49 (9H, s) overlapping 1.44-1.61 (4H, m), 1.8-2.0 (2H, m), 3.35-3.58 (3H, m), 3.65 (2H, s), 3.81-3.92 (1H, m), 4.01-4.06 (1H, m), 4.28-4.43 (1H, m), 4.99, 5.00, 5.07 (together 1H, 3d, J4.7Hz), 5.21, 5.32, 5.33 (together 1H, 3d, J6.8, 7.7, 7.6Hz), 5.42, 5.50 (together 1H, 2dd, J4.8, 8.7Hz, 6.35, 6.36, 6.61 (together 1H, 3d, J8.7Hz) and 7.27-7.38 (5H, m). The reaction mixture was concentrated

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

Procedure: A suspension of Fmoc-Lys-OH.HCl (6.07 g, 15 mmol) and thiazole-2-carbaldehyde (1.697 g, 15 mmol) in DCE (100 mL) was refluxed for 30 min under nitrogen. The reaction mixture was cooled to 0° C., and treated sequentially with NaBH(OAc)3 (7.95 g, 37.5 mmol) and crude tert-butyl glyoxalate (3.53 g). The reaction mixture was stirred at room temperature for overnight and decomposed with water. The reaction mixture was extracted with DCM. The organic layer was dried and concentrated under reduced pressure. The residue was purified by flash chromatography over silica gel to afford (S)-1-(9H-fluoren-9-yl)-14,14-dimethyl-3,12-dioxo-10-(thiazol-2-ylmethyl)-2,13-dioxa-4,10-diazapentadecane-5-carboxylic acid (1.85 g, 21%). MS (ESI), 580 (M+H)+. was refluxed for 30 min under nitrogen The reaction mixture was extracted with DCM The organic layer was dried concentrated under reduced pressure The residue was purified by flash chromatography over silica gel

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

Procedure: A suspension of Fmoc-Lys-OH.HCl (4.859 g, 12 mmol) and 2-pyridinecarboxaldehyde (1.285 g, 12 mmol) in DCE (100 mL) was refluxed for 30 min under nitrogen. The reaction mixture was cooled to 0° C., and treated sequentially with NaBH(OAc)3 (6.36 g, 30 mmol) and crude tert-butyl glyoxalate (2.34 g, 18 mmol) The reaction mixture was stirred at room temperature for overnight and decomposed with water. The reaction mixture was extracted with DCM. The organic layer was dried and concentrated under reduced pressure. The residue was purified by flash chromatography over silica gel to afford ((S)-1-(9H-fluoren-9-yl)-14,14-dimethyl-3,12-dioxo-10-(pyridin-2-ylmethyl)-2,13-dioxa-4,10-diazapentadecane-5-carboxylic acid (1.924 g, 28%). 1H NMR (400 MHz, CDCl3) 8.89 (d, J=4.4 Hz, 1H), 8.06 (d, J=8.0 Hz, 1H), 8.02 (d, J=7.6 Hz, 2H), 7.88 (t, J=5.8 Hz, 2H), 7.81 (d, J=7.6 Hz, 1H), 7.66 (t, J=7.4 Hz, 2H), 7.60-7.53 (m, 4H), 6.03 (d, J=7.2 Hz, 1H), 4.67-4.22 (m, 8H), 3.64-3.53 (m, 2H), 3.12 (t, J=6.8 Hz, 2H), 2.19-2.08 (m, 2H), 1.92-1.79 (m, 2H), 1.73 (s, 9H); MS (ESI), 564 (M+H)+. was refluxed for 30 min under nitrogen The reaction mixture was extracted with DCM The organic layer was dried concentrated under reduced pressure The residue was purified by flash chromatography over silica gel