- Microwave-Assisted Cu(I)-Catalyzed Synthesis of Unsymmetrical 1,4-Diamino-2-butynes via Cross-A3-Coupling/Decarboxylative A3-Coupling
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1,4-Diamino-2-butynes display both chemical and physiological properties. Here a highly efficient synthesis avenue to generate unsymmetric 1,4-diamino-2-butynes has been developed by microwave-assisted Cu(I)-catalyzed cross-A3-coupling/decarboxylative coupling of two different amines, formaldehyde, and propiolic acid through a domino process. This multicomponent reaction provides a series of target products in moderate to good yields with high chemoselectivity.
- Xu, Xianjun,Feng, Huangdi,Van Der Eycken, Erik V.
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p. 14036 - 14043
(2021/05/29)
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- Catalytic Access to Functionalized Allylic gem-Difluorides via Fluorinative Meyer–Schuster-Like Rearrangement
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An unprecedented approach for efficient synthesis of functionalized allylic gem-difluorides via catalytic fluorinative Meyer–Schuster-like rearrangement is disclosed. This transformation proceeded with readily accessible propargylic fluorides, and low-cost B–F reagents and electrophilic reagents by sulfide catalysis. A series of iodinated, brominated, and trifluoromethylthiolated allylic gem-difluorides that were difficult to access by other methods were facilely produced with a wide range of functional groups. Importantly, the obtained iodinated products could be incorporated into different drugs and natural products, and could be expediently converted into many other valuable gem-difluoroalkyl molecules as well. Mechanistic studies revealed that this reaction went through a regioselective fluorination of alkynes followed by a formal 1,3-fluorine migration under the assistance of the B–F reagents to give the desired products.
- An, Rui,Li, Huimin,Liao, Lihao,Wu, Jin-Ji,Xu, Yang,Zhao, Xiaodan
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supporting information
p. 11010 - 11019
(2020/05/18)
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- N-Propargylation of secondary amines directly using calcium carbide as an acetylene source
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A one-pot N-propargylation of secondary amines has been achieved by heating the amine with formaldehyde and calcium carbide in DMSO in the presence of CuCl as a catalyst. Fifteen examples of propargylic tertiary amines, 12 of which are novel, were efficiently prepared in yields of 65-84%. The advantages of the method are broad substrate scope and a simple work-up procedure.
- Fu, Rugang,Li, Zheng
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p. 341 - 345
(2017/06/19)
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- Copper catalysed alkynylation of tertiary amines with CaC2: Via sp3 C-H activation
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A mild and easy-to-handle protocol to produce propargylamines with a terminal alkyne through catalytic cross-coupling of tertiary amines and calcium carbide has been developed. The reaction proceeds via sp3 C-H bond activation and C-C coupling. Good to excellent yields were obtained for the corresponding propargylamines with both alkyl and aryl substitutions. The development of these functionalized propargylamines with a terminal alkyne group will offer a wider application for the synthesis of natural or pharmaceutical products due to their unique sp C-H reactivity.
- Teong, Siew Ping,Yu, Dingyi,Sum, Yin Ngai,Zhang, Yugen
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supporting information
p. 3499 - 3502
(2016/07/06)
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- A 1,3-amino group migration route to form acrylamidines
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A novel 1,3-amino group migration strategy for the synthesis of acrylamidines is presented. Cu(i) catalyzed reaction of N,N-disubstituted propargylamine with tosylazide generates a highly reactive ketenimine intermediate which is trapped by a tethered amino group leading to the rearrangement reaction.
- Chauhan, Dinesh Pratapsinh,Varma, Sreejith Jayasree,Vijeta, Arjun,Banerjee, Pallavi,Talukdar, Pinaki
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supporting information
p. 323 - 325
(2014/01/06)
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- A gallium-catalyzed cycloisomerization/Friedel-Crafts tandem
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Under noble (Au, Pt, Ru) and group 13 (Ga, In) metals catalysis, 1,6-arenynes rearrange to give 1,2-dihydronaphthalenes in a high yielding, regiocontrolled fashion. When the reaction is carried out in the presence of electron-rich arenes (anisole, phenol, indole derivatives), Friedel-Crafts addition may follow the cycloisomerization step. Only GaX3 salts proved able to catalyze these two C-C bond formation events. This specificity of gallium has been exploited for the synthesis of valuable polycyclic compounds that would be very difficult to prepare otherwise. For instance, tetrahydroisoquinolines and tetrahydrobenzoazepines have been obtained by selective 6-exo-dig or 7-endo-dig cyclization of N-tethered 1,6-arenynes. DFT calculations were carried out to shed light on the mechanism and provide a rationale for this regiodivergency. Computations also reveal the fundamental role of the tether in the stabilization of carbocationic species. Differential reactivities of other types of substrates in gallium- and gold-catalyzed cascades are also exposed, showing that the two approaches are complementary. In particular, bimolecular Friedel-Crafts additions are facilitated under gallium catalysis.
- Li, Hui-Jing,Guillot, Regis,Gandon, Vincent
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supporting information; experimental part
p. 8435 - 8449
(2011/03/19)
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- 4-(2-Pyridyl) piperizines having 5HT7 receptor agonist activity
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The present invention relates to compounds of the formula I wherein R1, R2, R3, X and Y are defined as in the specification. Those compounds are 5HT7 partial agonists and are useful in the treatment of several disorders of the central nervous system.
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- A simple procedure for af-propenylation and af-propynylation of secondary amines
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A number of tertiary N-allyl- and N-propargyl-substituted amines have been prepared by alkylation of secondary amines under solid-liquid phase-transfer catalysis conditions.
- Crock, Piero Dalla,Ferraccioli, Raffaella,Rosa, Concetta L.A.
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p. 107 - 109
(2007/10/03)
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- Synthesis, biological evaluation and quantitative structure activity relationship analysis of nuclearsubstituted pargylines as competitive inhibitors of MAO-A and MAO-B
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A series of nuclear substituted derivatives of pargyline has been prepared and tested (under controlled conditions designed to measure the competitive component of the inhibition) as competitive inhibitors of MAO-A and -B. Adequate correlation of the biological data with the physicochemical constants of substituent groups was obtained only when the m- and p-substituted derivatives were considered separately. Due to the narrow range of activity displayed by the p-substituted derivates when inhibiting MAO-B, meaningful correlations were not found. However, the inhibition of MAO-B by the m-substituted derivatives required the inclusion of the Verloop L parameter for adequate correlation suggesting that the inhibitor binding site of MAO-B is present within a cavity of more limited lateral dimensions than that present on the MAO-A surface. Inhibition of both MAO-A and -B demonstrated a parabolic relationship between inhibitory activity and Π. Whereas this parabolic relationship showed a maximal value for inhibition of MAO-A (mean Π0 = 0.86), inhibition of MAO-B demonstrated a minimal value of Π(Π(min) = -0.5)i.e.the optimal value of Π for inhibition of MAO-B has not been achieved for this series of compounds but such would be greater than that demonstrated for MAO-A. The Hammett σ function was important or significant only in the inhibition of MAO-A by the p-substituted derivatives.
- Ali,Robinson
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p. 750 - 757
(2007/10/02)
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