A series of new piperidinomethylphenoxypropylamine‐type histamine H2 receptor (H2R) antagonists with different substituted “urea equivalents” was synthesized and characterized in functional in vitro assays. Based on these data as selection criteria, radiosynthesis of N‐[6‐(3,4‐dioxo‐2‐{3‐[3‐(piperidin‐1‐ylmethyl)phenoxy]propylamino}cyclobut‐1‐enylamino)hexyl]‐(2,3‐3H2)propionic amide ([3H]UR‐DE257) was performed. The radioligand (specific activity: 63 Ci mmol?1) had high affinity for human, rat, and guinea pig H2R (hH2R, Sf9 cells: Kd, saturation binding: 31 nM , kinetic studies: 20 nM ). UR‐DE257 revealed high H2R selectivity on membranes of Sf9 cells, expressing the respective hHxR subtype (Ki values: hH1R: >10 000 nM , hH2R: 28 nM , hH3R: 3800 nM , hH4R: >10 000 nM ). In spite of insurmountable antagonism, probably due to rebinding of [3H]UR‐DE257 to the H2R (extended residence time), the title compound proved to be a valuable pharmacological tool for the determination of H2R affinities in competition binding assays. 相似文献
So far, the direct C−H alkenylation of aromatic nitriles with alkynes has not been achieved. Herein, we discribe the first manganese‐catalyzed C−H alkenylation of aromatic N−H imidates to access mono‐alkenylated aromatic nitriles. The reaction is accelerated by the presence of a catalytic amount of sodium pivalate. This protocol is also highlighted by the simple catalytic system, good compatibility of functional groups, and excellent mono‐/dialkenylation selectivity as well as E/Z stereoselectivity.
An efficient ligand‐free copper‐manganese (Cu‐Mn) spinel oxide‐catalyzed direct tandem C−H oxygenation and N‐arylation of benzylamines has been developed. The method has been utilized for the synthesis of medicinally important 2‐arylquinazolin‐4(3H)‐ones. Salient features of this method include recyclable catalyst, no ligand, excellent product yields, shorter reaction times and a broad substrate scope.
Histamine mediates its various functions through four histamine receptor subtypes. The H3 subtype is mainly found in the central nervous system, where it modulates the release of histamine and other neurotransmitters, whereas the H4 subtype plays a crucial role in inflammatory and immunological processes. Herein, the synthesis and characterization of a conveniently accessible tritiated radioligand is reported that proved to be a versatile pharmacological probe.
Palladium‐catalyzed cycloaromatization of N‐acyl‐2‐aminobiaryls, through a sequence of ortho C−H bond activation/alkyne insertion/meta C−H bond activation/alkyne insertion, was developed. An efficient synthesis of multiaryl‐substituted naphthalenes, N‐[2‐(5,6,7,8‐tetraarylnaphthalen‐1‐yl)aryl]acetamides, was demonstrated using molecular oxygen as the sole oxidant. Furthermore, through Buchwald's synthetic protocol, two compounds were converted into corresponding fluorescent carbazoles in 30–40% yield by intramolecular C−N bond formation.
A method for copper‐catalyzed aryltrifluoromethylation of N‐phenylcinnamamides is reported. This method provides a straightforward route to a variety of CF3‐containing 3,4‐dihydroquinolin‐2(1 H)‐ones with excellent regioselectivity and diastereoselectivity.
A copper‐mediated oxidative radical addition/cyclization cascade of o‐cyanoarylacrylamides with sodium trifluoromethanesulfonate (Langlois’ reagent) has been achieved. The reaction proceeds through radical addition, cyclization, and imine hydrolysis, in which the cyclization was accomplished by an intramolecular addition of the carbon radical to the nitrile. This transformation exhibits a wide substrate scope and good functional group tolerance, thus providing a highly efficient and practical access to a variety of trifluoromethylated quinoline‐2,4(1H,3H)‐diones. Furthermore, using other sulfinic acid sodium salts as sulfonylating agents, sulfonated quinolinediones were also obtained through a similar radical cascade.
The first example of a nickel‐catalyzed C–H trifluoromethylation of electron‐rich heteroarenes, including imidazopyridines, indoles and thiophenes, has been developed with the commercially available and relatively inexpensive industrial raw material iodotrifluoromethane (CF3I) as the trifluoromethylating reagent. The synthetic potential of this method is demonstrated by its successful application to the direct trifluoromethylation of the biologically active molecules melatonin and zolmitriptan.
A copper‐catalysed multicomponent coupling reaction between readily available (Z)‐3‐iodoacrylic acids, terminal alkynes, and primary amines was developed to smoothly access a small library of 5‐hydroxy‐1H‐pyrrol‐2(5H)‐ones in good yields. This practical and general process was applied to a short‐steps synthesis of the natural product pulchellalactam.
The first highly enantioselective intramolecular N−H bond insertion was realized by using copper catalysts modified with chiral spirobisoxazoline ligands, which provides a novel strategy for the synthesis of chiral 2‐carboxytetrahydroquinolines. This reaction features fast reaction rate, high yield, high enantioselectivity, and mild reaction conditions.
The copper‐catalyzed reaction of 5‐substituted penta‐1,4‐diyn‐3‐yl acetates with P(O)H compounds to efficiently give a new class of phosphonyl diynes is reported. The reaction may take place through a regioselective nucleophilic attack of phosphorus nucleophiles on Cu‐allenylidene intermediates to form allenyl intermediates followed by a rapid allene‐alkyne isomerization process. The synthetic utility of the obtained products is demonstrated.
An efficient avenue for the facile and atom‐economic synthesis of (1H)‐isochromen‐1‐imines has been developed, and a broad spectrum of substrates can participate in the process effectively to produce the desired products in good yields. Significantly, this is the first report of the synthesis of (1H)‐isochromen‐1‐imines that involves a silver(I)‐catalyzed, regiocontrolled intramolecular addition of the carbonyl group of the amide moiety towards an alkyne. 相似文献
A facile and efficient one‐pot synthesis of isoxazol‐3(2H)‐ones has been developed starting from α‐acyl cinnamides and tosyliminophenyliodinane catalyzed by copper(II) acetate [Cu(OAc)2] under very mild conditions involving a tandem aza‐Michael addition and intramolecular cyclization sequence.
A facile one‐pot, catalyst‐free reaction has been developed for the synthesis of 2,3,6,7‐tetrahydro‐1H‐pyrrolo[3,2‐c]pyridin‐4(5H)‐ones from readily available 1‐acryloyl‐1‐N‐arylcarbamylcyclopropanes and amines using a domino ring‐opening/cyclization/aza‐addition sequence.
A new water‐soluble monomeric agent for the aminisation of lyocell has been designed and synthesised. The agent, which contains a sulphatoethylsulphonyl group, an s‐triazinyl keto–enol tautomeric system and a primary aromatic amine was prepared in acidic media, in good yield from cyanuric chloride, p‐aminophenyl‐β‐sulphatoethylsulphone and p‐phenylenediamine, via a triazinyl betaine intermediate. 相似文献