Hydrogen Bromide → HCID 86739414, compound
Reaction equation
[NH2:1][C@H:2]([C:8]([O:10]CC1C=CC=CC=1)=[O:9])[CH2:3][CH2:4][C:5]([O-:7])=[O:6].[NH2:18][C@H:19]([C:25]([O:27][CH2:28][CH3:29])=[O:26])[CH2:20][CH2:21][C:22]([O-:24])=[O:23].N[C@H](C(O)=O)CCC(O)=O.C(N[C@H](C([O-])=O)CCC([O-])=O)C.Br>>[NH2:1][C@H:2]([C:8]([OH:10])=[O:9])[CH2:3][CH2:4][C:5]([OH:7])=[O:6].[NH2:18][C@H:19]([C:25]([O:27][CH2:28][CH3:29])=[O:26])[CH2:20][CH2:21][C:22]([O-:24])=[O:23]Participants
Procedure
The HBr concentration in the debenzylating step can be used to control the final copolymer composition, even though a large molar excess of HBr is used and its concentration does not significantly change during reaction. For example, if the HBr concentration is 0.07 g/ml, the final composition of the copolymer is 29/71; whereas when the HBr concentration is 0.05 g/ml, the composition is 26/74. In the selective debenzylation of the benzyl glutamate portion of the intermediate some de-ethylation will always occur. However, it is possible to obtain the desired final copolymer composition by beginning with the appropriate intermediate. For example, 15/85 benzyl glutamate/ethyl glutamate can be deesterified (at anHBr concentration of 0.05 g/ml for 12 hours) to a 20/80 glutamic acid/ethylglutamate product containing a residual benzyl content of 0.68 mole %. In contrast, a 10/90 intermediate can be treated with 0.05 g/ml HBr for 24 hours to yield 20/80 glutamic acid/ethyl glutamate with an approximate residual of 0.03 mole % benzyl.
Workup
- customfor 12 hours
Sources & evidence
- ORD record
- ord-812a67e51e6d4e959c9b3eab0d8d7c26
- Source dataset
- uspto-grants-1984_05
- Patent number
- US04450150
Reaction notes
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