41833-57-2

The invention belongs to the field of organic synthesis, and particularly relates to synthesis of aromatic halogens, in particular to arylamine. The invention discloses a synthesis method of a corresponding ortho-halogenated product from aromatic compounds such as carbazole and phenol. The method comprises the following steps: adding a metal sulfonate salt catalyst, aromatic amine, carbazole, phenol and other hydrogen - heteroatom-containing aromatic compound reaction substrates, a halogenation reagent and a reaction solvent at a specific reaction temperature. After the drying agent is dried, the yield of the reaction product and the nuclear magnetic characterization determining structure are determined by column chromatography. The reaction product yield is determined by gas chromatography. By adopting the method, under the cheap metal salt catalyst, a plurality of ortho-substituted brominated and chloro products can be obtained with moderate to excellent yield.

Abstract: This paper reports an efficient protocol for the synthesis of coumarins via Pechmann reaction, and β-amino carbonyl compounds via aza-Michael reaction using catalytic amount of solid Lewis acid catalyst, C@TiO2–SO3–SbCl2. Six different catalysts were prepared by covalent immobilization of homogeneous Lewis acids onto sulfonated carbon@titania composite derived from amorphous carbon and nano-titania. Among various catalysts tested, C@TiO2–SO3–SbCl2 showed superior catalytic activity. The catalyst could be recycled without significant loss of its catalytic activity and demonstrated versatile catalysis for a wide range of substrates. Graphical abstract: [Figure not available: see fulltext.]

A polyacrylamide coated magnetite (PAM@MNP) catalyst was synthesized by following a two step approach involving the reaction of magnetite (Fe3O4) particles with coupling agent 3-(trimethoxysilyl)propyl methacrylate followed by grafting of acrylamide and subsequent polymerization via surface initiated radical polymerization technique. The synthesized organocatalyst was used for a one-pot aza-Michael addition reaction of amines with electron deficient alkenes to give β-amino carbonyls. The magnetic properties of the synthesized organocatalyst provide it a facile recovery by external magnet which eliminates the problems arising during catalyst separation by conventional filtration.

Abstract: MCM-41 immobilized phenanthrolinium dibromide (phen-MCM-Br2) was easily prepared and applied as an efficient heterogeneous catalyst for aza-Michael addition of aromatic amines to α,β-unsaturated nitriles and nitro compounds in water. The catalyst was characterized by CHN, TGA, FT-IR, SEM, EDAX, XRD, BET, and TEM. It could be simply recovered and reused several times without significant loss of catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]

Thiomorpholine 1,1-dioxides were prepared with double Michael addition reaction of aromatic amines to divinyl sulfone catalyzed by boric acid/glycerol in water. This catalyst system was also used for the Michael addition reaction of aromatic amines to electron-deficient alkenes. The reaction is simple and green and gives good to excellent yields.

Reaction of the chiral bis-diketiminate complex rac- or (R,R)-C 6H10(nacnacXyl)2ZrCl2 with AgOTf yielded the corresponding bis-triflate complex. The complex geometry changes from distorted octahedral in the dichloride complex to a pseudotetrahedral coordination involving π coordination of the diketiminate ligands. The bis-triflate complex is highly active for aza-Michael additions with turnover frequencies of 20000/h for the addition of morpholine to acrylonitrile and 1000/h for the addition of morpholine to methacrylonitrile. The enantioselectivities of the latter reaction in various solvents were low, never surpassing 19% ee. The reaction is first-order in olefin concentration and second order in amine concentration, which is explained by its participation as a base in the reaction mechanism. The presence of catalytic amounts of triethylamine slightly increases the observed rate constants and reduces the reaction order in amine to first order. Other activated alkenes such as methacrylonitrile, crotonitrile, methyl acrylate, and cyclohexenone can be employed, but no reactivity is observed toward styrene or vinyl ethers. Primary amines, secondary amines, and anilines can be employed as nucleophiles with activities correlating with their nucleophilicity, but the catalyst is unstable in the presence of alcohols.

Lithium tetrafluoroborate has been demonstrated for the first time to be an efficient catalyst in intermolecular aza-Michael addition aromatic amines to electron deficient alkenes. Suitability of the same catalyst in intramolecular aza-Michael addition leading 2-aryl-2,3-dihydroquinolin-4(1H) ones has also been described.

This report describes the catalytic activity of the pincer-type complex {κP,κC,κP-2,6-(Ph 2PO)2C6H3}Ni(OSO2CF 3) (1) in the anti-Markovnikov addition of aliphatic and aromatic amines and alcohols to acrylonitrile, crotonitrile, and methacrylonitrile. The influence of additives on the catalytic activities was investigated, and it was found that substoichiometric quantities of water promoted the C-N bond forming reactions catalyzed by 1, especially the reactions involving aromatic amines; in comparison, NEt3 had a less dramatic impact. The opposite pattern was observed for the alcoholysis of acrylonitrile promoted by 1: water had no beneficial effect on these reactions, while NEt3 proved to be a potent promoter. Another important difference between these reactions is that hydroamination works better with more nucleophilic amines, whereas the alcoholysis reactions work well with ArOH, CF3CH2OH, and ArCH2OH but not at all with the more nucleophilic aliphatic alcohols methanol, ethanol, and 2-propanol. Both hydroamination and alcoholysis proceed much better with acrylonitrile in comparison to its Me-substituted derivatives crotonitrile and methacrylonitrile. Under optimized conditions, precatalyst 1 promotes conjugate additions to acrylonitrile with catalytic turnover numbers of up to 100 (hydroamination) or higher (alcoholysis). Spectroscopic studies have established that the main Ni-containing species in the hydroamination reactions is a cationic adduct in which the olefinic substrate is bound to the Ni center via its nitrile moiety; this binding activates the double bond toward an outer-sphere nucleophilic attack by the amine (Michael addition). The solid-state structures of the cationic nitrile adducts [{κP, κC,κP-2,6-(Ph2PO)2C 6H3}Ni(NCR)][OSO2CF3] (R = Me (2a), CH2CH2N(H)Ph (2e)), which can be regarded as model complexes for the species involved in the hydroamination catalysis, have been elucidated. Also reported are the solid-state structures of the charge-neutral compound {κP,κC,κP-2,6-(i- Pr2PO)2C6H3}Ni(OSO 2CF3) and an octahedral Ni(II) species resulting from the aerobic/hydrolytic oxidation of 1.

A simple, green, and environmentally benign protocol for squaric acid (5 mg) catalyst conjugate addition of aromatic amines and thiols to unsaturated carbonyl compounds in water in good to excellent yields is developed. The advantages of low sensitivity toward moisture and oxygen, high tolerance of different functional groups, green reaction media and efficient recyclability make this organocatalyst suitable for both laboratory and industrial scale synthesis of β-substituted carbonyls under very mild conditions.

Aza-Michael addition of aromatic or aliphatic amines with various electron-deficient alkenes was performed using alkaline Al2O 3 as solid media at room temperature afforded the corresponding Michael addition products in good to excellent yields.The alkaline Al 2O3 can be easily recovered and reused.

A functionalized ionic liquid, 3-(N,N-dimethyldodecylammonium) propanesulfonic acid hydrogen sulphate ([DDPA][HSO4]) has been used as catalyst for the aza-Michael reactions of aromatic amines with α,β-unsaturated compounds at room temperature to produce β-amino compounds in good yields. The catalyst can be reused for several times without obvious loss of the catalytic activity.

The efficient and very simple conjugate addition of aromatic and aliphatic amines to α,β-unsaturated carbonyl compounds under solvent-free conditions in the presence of catalytic amount of silicon tetrachloride is reported. The reaction of aryl and alkyl amines with different Michael acceptors gave the corresponding Michael adducts with simple catalyst and good to excellent yields. Georg Thieme Verlag Stuttgart New York.

Nucleophilic attack of cyanide ion on the 5-position of 2-oxazolidinones in the presence of 18-crown-6 gave 3-aminopropionitriles.

Aliphatic and aromatic amines undergo smooth nucleophilic addition to α,β-unsaturated compounds in the presence of a catalytic amount of silica-supported aluminum chloride at 60°C and under solvent-free conditions to produce the corresponding β-amino compounds in excellent yields. This method is simple and convenient and works efficiently under mild conditions. This catalyst can used again without losing its activity three times. Copyright Taylor & Francis Group, LLC.

The invention provides compounds of formula I: or pharmaceutically salts thereof where R1, R2, and the A, B, and C-rings are as defined herein. Compounds of formula I are useful in treating or preventing cognitive disorders, such as Alzheimer's disease. The invention also encompasses pharmaceutical compositions comprising compounds or salts of formula I, methods of preparing the desired compounds, and methods of treating cognitive disorders, such as Alzheimer's disease, using the compounds or salts of formula I.

12-Tungstophosphoric acid (H3PW12O40) has been found to be an efficient and recyclable catalyst in promoting room temperature Michael additions of amines and aryl thiols to α,β- unsaturated esters and acrylonitrile in water to afford the corresponding saturated amines in good to excellent yields. Georg Thieme Verlag Stuttgart.

An efficient and environmentally benign tandem bis-aza-Michael addition of amines catalyzed by polystyrenesulfonic acid (PSSA) is described. This operationally simple high yielding microwave assisted synthetic protocol proceeded in water in the absence of any organic solvent.

Catalytic amount of indium (III) trichloride efficiently catalyzed Michael reaction between amines and α,β-ethylenic compounds in water and under mild conditions. Indium trichloride can be recovered and reused without decrease in yield.