ethyl 4-methyl-2-oxopentanoate

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

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

Procedure: To a stirred and cooled (0° C.) solution of 9.1 parts of 4-[(3-chlorophenyl)(1H-imidazol-1-yl)methyl]-1,2-benzenediamine in 80 parts of acetic acid and 20 parts of water were added portionwise 5.8 parts of ethyl 4-methyl-2-oxopentanoate. Upon completion, stirring was continued for 4 hours at room temperature. The reaction mixture was poured into 100 parts of water and the whole was neutralized with a sodium hydroxide solution 3N. The product was extracted with dichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of 2-propanone and 1,1'-oxybisethane. The product was filtered off (the filtrate was set aside) and dried, yielding 1.5 parts (12.6%) of 6-[(3-chlorophenyl) (1H-imidazol-1-yl)methyl]-3-(2-methylpropyl)-2(1H)-quinoxalinone; mp. 209.7° C. (comp. 178) Upon completion, stirring The product was extracted with dichloromethane The extract was dried filtered evaporated The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (95:5 by volume) as eluent The pure fractions were collected the eluent was evaporated The residue was crystallized from a mixture of 2-propanone and 1,1'-oxybisethane The product was filtered off (the filtrate dried

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

Procedure: Ethyl 4-methyl-2-oxopentanoate and L-isoleucyl-N-(3-pyridyl)-glycine were condensed in the presence of sodium cyanoborohydride to yield N-[1-(S)-ethoxycarbonyl-3-methylbutyl]-L-isoleucyl-N-(3-pyridyl)glycine.

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

Procedure: Ethyl 4-methyl-2-oxopentanoate and L-isoleucyl-N-(3-pyridyl)-glycine were condensed in the presence of sodium cyanoborohydride to yield N-[1-(S)-ethoxycarbonyl-3-methylbutyl]-L-isoleucyl-N-(3-pyridyl)glycine.

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

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

Procedure: Ethyl 4-methyl-2-oxopentanoate and L-isoleucyl-N-(3-pyridyl)-glycine were condensed in the presence of sodium cyanoborohydride to yield N-[1-(S)-ethoxycarbonyl-3-methylbutyl]-L-isoleucyl-N-(3-pyridyl) glycine.

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

Procedure: To a stirred and cooled (0° C.) solution of 9.1 parts of 4-[(3-chlorophenyl)(1H-imidazol-1-yl)methyl]-1,2-benzenediamine in 80 parts of acetic acid and 20 parts of water were added portionwise 5.8 parts of ethyl 4-methyl-2-oxopentanoate. Upon completion, stirring was continued for 4 hours at room temperature. The reaction mixture was poured into 100 parts of water and the whole was neutralized with a sodium hydroxide solution 3N. The product was extracted with dichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of 2-propanone and 1,1'-oxybisethane. The product was filtered off (the filtrate was set aside) and dried, yielding 1.5 parts (12.6%) of 6-[(3-chlorophenyl) (1H-imidazol-1-yl)methyl]-3-(2-methylpropyl)-2(1H)-quinoxalinone; mp. 209.7° C. (comp. 178) Upon completion, stirring The product was extracted with dichloromethane The extract was dried filtered evaporated The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (95:5 by volume) as eluent The pure fractions were collected the eluent was evaporated The residue was crystallized from a mixture of 2-propanone and 1,1'-oxybisethane The product was filtered off (the filtrate dried

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

Procedure: A solution of phenylhydrazine (1.0 g, 6.92 mmol) in absolute ethanol (50 mL) was placed in an oil bath at 60° C. and a reflux condenser attached. Ethyl 4-methyl-2-oxopentanoate (1.0 g, 6.33 mmol) (prepared according to Singh, J; Kissick, T. P.; Mueller, R. H. Organic Preparations and Procedures International (1989), 21(4), 501-4.) was added dropwise. The reaction mixture was heated to reflux and stirred for 18 h. Water (25 mL) and EtOAc (25 mL) were added and the layers separated. The aqueous layer was extracted with EtOAc (2×25 mL), the organic layers combined, dried over sodium sulfate, filtered and concentrated. Purification was accomplished by column chromatography (hexanes/EtOAc) and RPHPLC. Neutralization and extraction of the desired fractions with EtOAc afforded ethyl 3-propyl-1H-indole-2-carboxylate (0.250 g) as a yellow solid. 1H NMR (400 MHz, DMSO-d6): δ ppm 11.39 (s, 1H) 7.82 (d, 1H) 7.42 (d, 1H) 7.22 (t, 1H) 7.01 (t, 1H) 4.33 (q, 2H) 4.01-4.09 (m, 1H) 1.39 (d, 6H) 1.35 (t, 3H). MS: m/z 232.0 (M+1). a reflux condenser attached The reaction mixture was heated to reflux the layers separated The aqueous layer was extracted with EtOAc (2×25 mL) dried over sodium sulfate filtered concentrated Purification Neutralization and extraction of the desired fractions with EtOAc

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

Procedure: To a stirred and cooled (0° C.) solution of 9.1 parts of 4-[(3-chlorophenyl)(1H-imidazol-1-yl)methyl]-1,2-benzenediamine in 80 parts of acetic acid and 20 parts of water were added portionwise 5.8 parts of ethyl 4-methyl-2-oxopentanoate. Upon completion, stirring was continued for 4 hours at room temperature. The reaction mixture was poured into 100 parts of water and the whole was neutralized with a sodium hydroxide solution 3N. The product was extracted with dichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of 2-propanone and 1,1'-oxybisethane. The product was filtered off (the filtrate was set aside) and dried, yielding 1.5 parts (12.6%) of 6-[(3-chlorophenyl) (1H-imidazol-1-yl)methyl]-3-(2-methylpropyl)-2(1H)-quinoxalinone; mp. 209.7° C. (comp. 178) Upon completion, stirring The product was extracted with dichloromethane The extract was dried filtered evaporated The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (95:5 by volume) as eluent The pure fractions were collected the eluent was evaporated The residue was crystallized from a mixture of 2-propanone and 1,1'-oxybisethane The product was filtered off (the filtrate dried

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

Procedure: Ethyl 4-methyl-2-oxopentanoate and L-isoleucyl-N-(3-pyridyl)-glycine were condensed in the presence of sodium cyanoborohydride to yield N-[1-(S)-ethoxycarbonyl-3-methylbutyl]-L-isoleucyl-N-(3-pyridyl)glycine.