Bredereck imidazole synthesis, related terms:
Chemical substances, components, reactions, process design
N-Methylimidazole is a promising catalyst for aza-Michael reactions. Lin, Synthesis, Chetcuti, Synthesis, EvansPavel Nagorny, and Risheng Xu.
Benzoxazolewhere the oxazole is fused to another aromatic ring. The reaction has later been expanded to a two-step synthesis in which the aldimine is generated in situ: LeyChristoper D.
Thus, l- butyl-aminocarbonylmethoxycarbonylamino benzimidazole and 2- thiazolyl benzimidazole are widely used as fungicides, the latter additionally as a preservative for fruits E Starting from acylated 2-azidomethylbenzimidazolesan additional imidazole ring can be condensed by transformation of the azido group with tri-n-butylphosphane into Emotional abuse in dating relationships appropriate iminophosphorane intermediate Pyrrolean analog without the oxygen atom.
The Cornforth rearrangement of 4-acyloxazoles is a thermal rearrangement reaction with the organic acyl residue and the C5 substituent changing positions. The only difference is the nature of the iminophosphorane generation: Elimination of p-toluenesulfinic acid TosH from the intermediate 4-tosylimidazoline provides a 1,5-disubstituted imidazole:: When simple substituted benzimidazoles such as 2-azidomethyl benzimidazole are employed, their iminophosphoranes react with isocyanate to give carbodiimide Srinivasan, Tetrahedron,61, A simple and efficient approach allows the preparation of biologically active 2,4 5 -diarylimidazoles by parallel synthesis.
The 2-imidazolines were smoothly oxidized to the corresponding imidazoles in good yields using diacetoxyiodo benzene at room temperature.
Benzimidazoles occurring as constituents of vitamin B12 in nature are of preparative interest due to their high biological activity.
In the balanced half-reaction three equivalents of water are consumed for each equivalent of oxazoline, generating 4 protons and 4 electrons the latter derived from CeIV.
Cycloheptylamine, benzylamine, dodecylamine, and 4-dimethylaminoaniline can be employed as amines. A number of new reactions of IBX with heteroatom-containing substrates were discovered and their utility was demonstrated.
The aldimine can also be generated in situ by condensation of an amine with an aldehyde in approximately half an hour. Reactive 1,2-diketones include benzil, 4-chlorobenzil, and 9,phenanthrenequinones 90H Ullmann's Encyclopedia of Industrial Chemistry.
N-Arylation of azoles and amines with arylboronic acids was efficiently carried out with heterogeneous copper I oxide in methanol at room temperature under base-free conditions.
Base-induced cycloaddition of sulfonylmethyl isocyanides to carbon,nitrogen double bonds. Electrophilic aromatic substitution takes place at C5 requiring activating groups.
Bratulescu, Synthesis, Togo, Synlett, In both cases, intramolecular cyclization occurs. A one-pot, four-component synthesis of 1,2,4-trisubstituted 1H-imidazoles was achieved in very good yields by heating a mixture of a 2-bromoacetophenone, an aldehyde, a primary amine, and ammonium acetate under solvent-free conditions.
Various arylboronic acids and amines were converted to the corresponding N-arylazoles and N-arylamines in very good yields, demonstrating the versatility of the reaction.
Fused bicyclic imidazole rings have been prepared in good yields by a sequence of the van Leusen three-component reaction and the ring-closing metathesis reaction. Oxadiazoles with two nitrogens instead of one e.
The competing intramolecular azide-alkyne click reaction, although likely also catalyzed by gold, is minimized by using AuCl3 as the catalyst. However, despite the name, the vL-3CR is not a true multicomponent reactionas the components react stepwise.
This one-pot methodology offers excellent isolated yields, simple work up procedures and efficient recovery and recycling of the ionic liquid. An improved and rapid one-pot synthesis of 2,4,5-triaryl imidazoles in a room temperature ionic liquid does not need any added catalyst. OxazolineBredereck imidazole synthesis has one double bond reduced.
Synthesis of 1,5-disubstituted and 1,4,5-trisubstituted imidazoles from aldimines and imidoyl chlorides A. Diels—Alder reactions with oxazole dienes can be followed by loss of oxygen to form pyridines.