Diethylamine → (3S)-3-amino-4-oxobutyric acid tert-butyl ester semicarbazone
Reaction equation
[C:1]([O:5][C:6](=[N:29][NH:30][C:31]([NH2:33])=[O:32])[CH2:7][C@H:8]([NH:11]C(OCC1C2CC3C(=CC=CC=3)C=2C=CC=1)=O)[CH:9]=[O:10])([CH3:4])([CH3:3])[CH3:2].C(NCC)C>CN(C=O)C>[C:1]([O:5][C:6](=[N:29][NH:30][C:31]([NH2:33])=[O:32])[CH2:7][C@H:8]([NH2:11])[CH:9]=[O:10])([CH3:4])([CH3:2])[CH3:3]Participants
Procedure
(3S)-3-(1-Fluorenylmethyloxycarbonylamino)-4-oxobutyric acid tert-butyl ester semicarbazone (210 mg, 0.45 mol, Prepared in a similar manner to the benzyloxycarbonyl analog in Graybill et al., Int. J. Protein Res. , 44, pp. 173-82 (1994).) was dissolved in 10 ml of DMF and 2 ml of diethylamine and stirred for 2 h. The reaction was concentrated in vacuo to give (3S)-3-amino-4-oxobutyric acid tert-butyl ester semicarbazone. The 0° C. solution of the above residue and 603a (200 mg, 0.42 mmol) in 5 ml of DMF and 5 ml of CH2Cl2 was treated with 1-hydroxybenzotriazole (57 mg, 0.42 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (98 mg, 0.51 mmol). The reaction was stirred at RT for 18 h, poured onto EtOAc (75 ml) and washed with aq. 0.3 N KHSO4, sat. aq. NaHCO3 and sat. aq. NaCl, dried over Na2SO4 and concentrated in vacuo. Chromatography 2 (flash, SiO2, 0% to 4% MeOH/0.1% NH4OH/CH2Cl2) to give 240 mg (83%) of 604a.
Workup
- concentrationThe reaction was concentrated in vacuo
Sources & evidence
- ORD record
- ord-0a1a927927ac45788c48c1e72b9b229f
- Source dataset
- uspto-grants-1999_12
- Patent number
- US06008217
Reaction notes
Loading…