Process for the preparation of methylated cyclodextrin derivatives, and their use as solubilizers
AssigneeConsortium fur Elektrochemische Industrie GmbH
InventorThomas Wimmer
Life of this patent
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Abstract
A process in which .alpha.-, .beta.- and/or .gamma.-cyclodextrin are reacted in a suitable base, with a suitable O-alkylating agent and, where appropriate, following neutralization of the reaction mixture, the resulting alkylated cyclodextrin derivatives are subsequently separated, out of the reaction mixture, wherein .alpha.-, .beta.- and/or .gamma.-cyclodextrin are initially dissolved in a portion of the base and the O-alkylation agent and further base are added subsequently.
Claims16
A process for the preparation of a methylated cyclodextrin selected from the group consisting of a methylated .alpha.-cyclodextrin, a methylated .beta.-cyclodextrin, a methylated .gamma.-cyclodextrin and the mixtures thereof, which process has a total reaction time of about 5-30 hours, comprising
- initially dissolving an .alpha.-, .beta.-, or .gamma.-cyclodextrin or mixture thereof in a portion of a base and subsequently adding methyl chloride as an O-alkylation agent and additional base simultaneously and continuously during a period of time up to two-thirds of the total reaction time;
- reacting the .alpha.-, .beta.-, or .gamma.-cyclodextrin or mixture thereof in said base with said methyl chloride O-alkylating agent to produce a reaction mixture;
- and
- separating the resulting methylated cyclodextrin derivatives out of the reaction mixture.
A process for the preparation of a methylated cyclodextrin selected from the group consisting of a methylated .alpha.-cyclodextrin, a methylated .beta.-cyclodextrin, a methylated .gamma.-cyclodextrin and the mixtures thereof, which process has a total reaction time of about 5-30 hours, comprising
- initially dissolving an .alpha.-cyclodextrin, a .beta.-cyclodextrin, or a .gamma.-cyclodextrin or mixture thereof in from 1 to 5 mol portion of an aqueous solution of a base in a concentration of 5-20% (w/w) per mol of cyclodextrin, and from 15 to 25 mol of methyl chloride as an O-alkylating agent, up to a maximum base concentration of from 15 to 25 mol per mol of cyclodextrin;
- subsequently adding additional base and said methyl chloride O-alkylating agent simultaneously and continuously during a period of time up to two-thirds of the total reaction time;
- reacting the .alpha.-cyclodextrin, .beta.-cyclodextrin or .gamma.-cyclodextrin in said base with said methyl chloride O-alkylating agent to produce a reaction mixture;
- and
- separating the resulting methylated cyclodextrin derivatives out of the reaction mixture.
Methyl cyclodextrin having an average degree of substitution (DS), measured by means of .sup.1 H-NMR spectroscopy, between 1.7 and 1.9 and the O6 position is methylated to the extent of from 55 to 75%.
Methyl-.beta.-cyclodextrin having an average degree of substitution (DS), measured by means of .sup.1 -NMR spectroscopy, between 1.7 and 1.9 and having an average degree of methylation of the O2 and O6 positions of from 60 to 70%.
Methyl-.gamma.-cyclodextrin having an average degree of substitution (DS), measured by means of .sup.1 H-NMR spectroscopy, of between 1.7 and 1.9 and having an average degree of methylation of the O2 and the O6 positions of from 60 to 70%.
Methyl-.alpha.-cyclodextrin having an average degree of substitution (DS), measured by means of .sup.1 H-NMR spectroscopy, of between 1.7 and 1.9 and having an average degree of methylation of the O2 position of from 70 to 80% and having an average degree of methylation of the O6 position of from 60 to 70%.
Dependencies are inferred from the claim text.