Syntheses of n-heterocyclic carbenes and intermediates therefor
AssigneeUmicore AG & Co. KG
InventorsSteven P. Nolan, Sebastien Meiries
Life of this patent
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Abstract
A method of preparing a 2,6 disubstituted anilines includes, reacting a 2-amino isophthalic acid diester with sufficient Grignard reagent R2CH2MgX to form the corresponding diol product, dehydrating the diol product to the corresponding dialkene; and hydrogenating the diol product to form the corresponding aniline. The 2,6 disubstituted anilines can be used to produce N-Heterocyclic Carbenes (NHCs). The NHCs can find application in various fields such as organic synthesis, catalysis and macromolecular chemistry. Palladium catalysts containing the NHCs are also described.
Claims17
1-13. (canceled)
A method of preparing an N-heterocyclic carbene, the method comprising:
- reacting an aniline of general formula I:
- wherein each group R2 is the same;
- and is selected from H, methyl, ethyl, n-propyl and
- wherein either R3 is H and R4 is an alkyl that may be substituted;
- or
- each of R3, R4 are an independently selected alkyl that may be substituted;
- and
- each group Z1, Z2 and Z3 is independently selected from the group consisting of —H, —I, —CF3, —OR5—R6 and —NR72, wherein each group R5, R6 or R7 is independently selected from the group consisting of alkyl that may be unsaturated, substituted alkyl that may be unsaturated, aryl, substituted aryl, aralkyl and substituted aralkyl;
- with glyoxal to form a diimine of general formula II:
- cyclizing the diimine of structure II with paraformaldehyde to form an imidazolium salt of structure III:
- wherein X− is an anion;
- and
- reacting the imidazolium salt of structure III with a base to form the N-heterocyclic carbene.
17-23. (canceled)
A method of preparing an N-Heterocyclic Carbene, the method comprising:
- reacting an aniline of general formula XV:
- wherein each group R2 is the same and is selected from H, methyl, ethyl, n-propyl and
- wherein either R3 is H and R4 is alkyl that may be substituted, or
- each of R3, R4 are an independently selected alkyl that may be substituted;
- and wherein the groups Z1, Z2, and Z3 are H or a substituent independently selected from the group consisting of:
- —I, —CF3, —OR6, —R6 and —NR72;
- wherein each group R5, R6 or R7 is independently selected from the group consisting of:
- alkyl that may be unsaturated, substituted alkyl that may be unsaturated, aryl, substituted aryl, aralkyl and substituted aralkyl, with glyoxal to form a diimine of general formula XVI:
- cyclizing the diimine of structure XVI with paraformaldehyde, to form an imidazolium salt of structure XVII:
- wherein X− is an anion;
- and
- reacting the imidazolium salt of structure XVI with a base to form the corresponding N-Heterocyclic Carbene.
25-30. (canceled)
Dependencies are inferred from the claim text.