benzyl (2S)-4-amino-2-[(2-methylpropan-2-yl)oxycarbonylamino]-4-oxobutanoate

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

Procedure: A 1-L round bottom flask was charged with (S)-benzyl 4-amino-2-(tert-butoxycarbonylamino)-4-oxobutanoate (10.0 g, 31.0 mmol), Lawesson's reagent (6.58 g, 16.3 mmol), and tetrahydrofuran (155 mL). Hydrazine (7.8 mL, 0.248 mol) was added and the resulting mixture was stirred at room temperature for 72 h. The resulting mixture was then concentrated in vacuo and the residue purified via flash silica gel chromatography (Analogix IF-280, SF40-400 g column, gradient 90:10-60:40 Heptane:EtOAc) to yield-(S)-tert-butoxycarbonylamino-3-thiocarbamoyl-propionic acid benzyl ester. MS (ES+) 339 (M+1). The resulting mixture was then concentrated in vacuo the residue purified via flash silica gel chromatography (Analogix IF-280

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

Procedure: A 1-L round bottom flask was charged with (S)-benzyl 4-amino-2-(tert-butoxycarbonylamino)-4-oxobutanoate (10.0 g, 31.0 mmol), Lawesson's reagent (6.58 g, 16.3 mmol), and tetrahydrofuran (155 mL). Hydrazine (7.8 mL, 0.248 mol) was added and the resulting mixture was stirred at room temperature for 72 h. The resulting mixture was then concentrated in vacuo and the residue purified via flash silica gel chromatography (Analogix IF-280, SF40-400 g column, gradient 90:10-60:40 Heptane:EtOAc) to yield-(S)-tert-butoxycarbonylamino-3-thiocarbamoyl-propionic acid benzyl ester. MS (ES+) 339 (M+1). The resulting mixture was then concentrated in vacuo the residue purified via flash silica gel chromatography (Analogix IF-280

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

Procedure: A 1-L round bottom flask was charged with (S)-benzyl 4-amino-2-(tert-butoxycarbonylamino)-4-oxobutanoate (10.0 g, 31.0 mmol), Lawesson's reagent (6.58 g, 16.3 mmol), and tetrahydrofuran (155 mL). Hydrazine (7.8 mL, 0.248 mol) was added and the resulting mixture was stirred at room temperature for 72 h. The resulting mixture was then concentrated in vacuo and the residue purified via flash silica gel chromatography (Analogix IF-280, SF40-400 g column, gradient 90:10-60:40 Heptane:EtOAc) to yield-(S)-tert-butoxycarbonylamino-3-thiocarbamoyl-propionic acid benzyl ester. MS (ES+) 339 (M+1). The resulting mixture was then concentrated in vacuo the residue purified via flash silica gel chromatography (Analogix IF-280