L-Methionine → tert-Butyloxycarbonyl-L-glutaminyl-L-methionine
Reaction equation
[NH:1]([C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12])[C@H:2]([C:8]([OH:10])=O)[CH2:3][CH2:4][C:5](=[O:7])[NH2:6].CN1CCOCC1.C(OC(Cl)=O)C(C)C.[NH2:33][C@H:34]([C:39]([OH:41])=[O:40])[CH2:35][CH2:36][S:37][CH3:38]>C1COCC1.O>[C:14]([O:13][C:11]([NH:1][C@H:2]([C:8]([NH:33][C@H:34]([C:39]([OH:41])=[O:40])[CH2:35][CH2:36][S:37][CH3:38])=[O:10])[CH2:3][CH2:4][C:5](=[O:7])[NH2:6])=[O:12])([CH3:17])([CH3:16])[CH3:15]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 2
Procedure
A solution of Boc-L-Gln (Bachem, 4.92 g, 20 mmole) in THF (45 ml) was cooled to -15°, neutralized with N-methylmorpholine (2.2 ml, 20 mmole) and treated with isobutylchlorocarbonate 2.74 g (20 mmole). After 5 min a solution of L-methionine (4.48 g, 30 mmole) and N-methylmorpholine (3.3 ml. 30 mmole) in H2O (45 ml) was added. (Some warming was necessary to obtain a clear solution of the methionine salt). The mixture was stirred and allowed to warm up to room temperature; gradually a clear solution formed. After 1.5 hr the solution was concentrated in vacuo to remove most of the THF and then acidified with a 20% solution of citric acid in H2O. Saturation with NaCl and extraction with EtOAc (3×50 ml), was necessary to isolate the desired material. The organic layer was washed with H2O and evaporated with a stream of N2. The solid residue was suspended in warm EtOAc (100 ml), stirred for 1 hr, filtered, washed with EtOAc and dried. The product (4.75 g, 63%) melted at 149°-150°; [α]D20 -11.8° (c 2, DMF); RfB, 0.60; RfE, 0.73, Glu, 1.0; Met, 1.0. The proton nmr spectrum, in CD3COOD, showed the expected resonances.
Sources & evidence
- ORD record
- ord-9c9f67b33ae643d9a7d09266cb58101e
- Source dataset
- uspto-grants-1980_12
- Patent number
- US04237046
Reaction notes
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