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US 2006/0287534 A1Published application
Method of obtaining urethane-protected n-carboxyanhydrides of alpha amino acids
AssigneeIsochem
InventorsHerve Lhermitte, Julien Grima, Antoine Paris
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Abstract
The invention relates to a method of preparing urethane-protected N-carboxyanhydrides of alpha amino acids. The inventive method enables the synthesis of urethane-protected N-carboxyanhydrides of alpha amino acids in the presence of a catalytic quantity of triethylene diamine without the addition of a tertiary amine-type base.
Claims21
A method for obtaining urethane-protected N-carboxyanhydrides of alpha amino acids (UNCAs), of formula I
- in which R1 and R2 are either identical or different, and selected from the group consisting of hydrogen and a side-chain of a natural or synthetic alpha-amino acid, and R3 is selected from the group consisting of a saturated or unsaturated, linear or branched C1-C10 alkyl radical, an aralkyl radical with 7 to 14 carbon and an alkylaryl radical with 7 to 14 carbon atoms, comprising the step of reacting an N-carboxyanhydride of alpha-amino acid (NCA) of formula II,
- in which R1 and R2 have the same meaning as for the formula I, with at least one equivalent, relatively to the molar amount of the N-carboxyanhydride of alpha-amino acid (NCA) of formula II, of a dicarbonate of formula III
- in which R3 has the same meaning as for the formula I, in the presence of a catalytic amount of triethylene diamine (TEDA), relatively to the molar amount of the N-carboxyanhydride of alpha-amino acid (NCA) of formula II, in an organic solvent with a melting point less than about −20° C.
(canceled)
A method for obtaining urethane-protected N-carboxyanhydrides of alpha amino acids, of formula I
- in which R1 and R2 are either identical or different and selected from the group consisting of hydrogen and a side-chain of a natural or synthetic alpha-amino acid, and R3 is selected from the group consisting of a saturated or unsaturated, linear or branched C1-C10 alkyl radical, an aralkyl radical with 7 to 14 carbon atoms, and an alkylaryl radical with 7 to 14 carbon atoms, comprising the step of reacting an N-carboxyanhydride of alpha-amino acid (NCA), of formula II
- in which R1 and R2 have the same meaning as for the formula I with 1.1 to 1.5 equivalents, based on the molar amount of the N-carboxyanhydrides of alpha amino acids (NCA) of formula II, of a dicarbonate of formula III
- in which R3 has the same meaning as for the formula I, in the presence of 0.1% to 5% molar, based on the molar amount of the N-carboxyanhydrides of alpha amino acids (NCA) of formula II, of triethylene diamine (TEDA) in a solvent selected from the group consisting of C4-C10 ethers and chlorinated C1-C5 alkanes.
Dependencies are inferred from the claim text.