32570-09-5Relevant articles and documents
Crystalline salicylic acid as an efficient catalyst for ultrafast Paal–Knorr pyrrole synthesis under microwave induction
Aghapoor, Kioumars,Mohsenzadeh, Farshid,Darabi, Hossein Reza,Sayahi, Hani
, (2021/04/19)
Abstract: In this study, the viability of a wide range of crystalline aromatic and aliphatic carboxylic acids as organocatalysts has been investigated for solvent-free Paal–Knorr pyrrole synthesis under microwave activation. Among these potential catalysts, crystalline salicylic acid proved to be a remarkable catalyst because its efficiency remained high even under low microwave power irradiation or a shorter reaction time for the model reaction. The outstanding catalytic activity of salicylic acid allowed the Paal–Knorr cyclocondensation with a turnover frequency up to 1472?h?1 which is unique in the context of a metal-free homogeneous catalysis. The attractive feature of this organocatalyst is its assistance in ultrafast pyrrole synthesis with no risk of metal contamination. Graphic abstract: [Figure not available: see fulltext.] Synopsis: A green and expeditious protocol for the synthesis of 2,5-dimethylpyrroles via combination of salicylic acid as catalyst (in its solid state) and microwaves has been introduced.
A New FXR Ligand Chemotype with Agonist/Antagonist Switch
Helmst?dter, Moritz,Vietor, Jan,Sommer, Jana,Schierle, Simone,Willems, Sabine,Kaiser, Astrid,Schmidt, Jurema,Merk, Daniel
supporting information, p. 267 - 274 (2021/02/20)
Therapeutic modulation of the bile acid-sensing transcription factor farnesoid X receptor (FXR) is an appealing strategy to counteract hepatic and metabolic diseases. Despite the availability of several highly potent FXR agonists structural diversity of FXR modulators is limited, and new ligand scaffolds are needed. Here we report structure-activity relationship elucidation of a new FXR modulator chemotype whose activity can be tuned between agonism and antagonism by two minor structural modifications. Starting from a weak FXR/PPAR agonist, we have developed selective FXR activators and antagonists with nanomolar to low-micromolar potencies and binding affinities. The new FXR ligand chemotype modulates the FXR activity in the native cellular setting, is endowed with favorable metabolic stability, and lacks cytotoxicity. It valuably expands the collection of FXR modulators as a new scaffold for FXR-targeted drug discovery.
Method for preparing N-aryl pyrrole compound
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Paragraph 0021; 0049, (2020/09/09)
The present invention relates to a method for preparing an N-aryl pyrrole compound. Furan containing different substituents, aromatic amine containing different substituents and a solid Lewis acid catalyst are mixed and placed in a closed reactor, and an N-aryl pyrrole compound with different substituents is prepared under certain catalytic conditions. The reaction temperature of the catalytic reaction condition is 140-210 DEG C. The solid Lewis acid catalyst is prepared by a sol-gel method, Hf is used as a core metal element, and a mesoporous molecular sieve SBA-15 is used as a carrier. According to the method, the catalyst is simple to prepare, low in cost, high in reaction activity, good in water resistance and structural stability and high in catalytic reaction yield; meanwhile, the Lewis acid type catalyst does not generate acid protons, the corrosion of the catalyst to equipment at high temperature is avoided, the post-reaction treatment is convenient, and the catalyst is renewable and environment-friendly.
