Synthesis of 1-(2-Methyl-1,2,3,4-tetrahydroquinolin-4-yl) pyrrolidin-2-ones from Anilines and N-Vinyl Pyrrolidin-2-one Through Imino Diels–Alder Reaction Using 4-Nitro Phthalic Acid as Catalyst

Aryl amines react smoothly and efficiently with N-vinyl pyrrolidin-2-one in the presence of 4-nitro phthalic acid in acetonitrile to afford the corresponding 1-(2-methyl-1,2,3,4-tetrahydroquinolin-4-yl)pyrrolidin-2-ones in good yields.     

One-Pot,Three-Component Coupling Reaction: Catalyst-Free Green Synthesis of Novel N-Heteroaryl α-Naphthylglycines

A series of novel N-heteroaryl α-arylglycines containing naphthol rings has been prepared by one-pot, three-component condensation reaction of glyoxalic acid, heteroaryl amines and naphthols in water at ambient temperature and under reflux conditions in moderate to high yields. The promising advantages such as removal of organic solvent, no need to catalyst, simplicity of the reaction procedure and easy product separation will be discussed in this article.     

Mild and Convenient Synthesis of Organic Carbamates from Amines and Carbon Dioxide using Tetraethylammonium Superoxide

A safe and simple method of preparing organic carbamates has been achieved from amines and carbon dioxide using tetraethylammonium superoxide generated in situ.     

N-Nitrosation of Secondary Amines Using p-TSA-NaNO2 as a Novel Nitrosating Agent Under Mild Conditions

A combination of p-toluenesulfonic acid (p-TSA) and sodium nitrite was used as a novel effective nitrosating agent for the N-nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in moderate to excellent yields.     

Synthesis of N,N‐Dimethylamines via Barbier–Grignard‐Type Electrophilic Amination

Aryl Grignard reagents react with N,N‐dimethyl O‐(mesitylenesulfonyl)hydroxylamine in THF under Barbier conditions at room temperature and give N,N‐dimethylanilines with high yields in a 2‐h reaction. The amination yield of in situ Grignard reagents were not lower than those of preformed aryl Grignard reagents. In situ cycloalkyl‐, allyl‐, and benzylmagnesium bromides did not react with N,N‐dimethyl O‐(mesitylenesulfonyl)hydroxylamine, except that amination of in situ n‐hexylmagnesium bromide resulted in a medium yield. Grignard–Barbier‐type amination of aryl bromides with N,N‐dimethyl O‐(mesitylenesulfonyl)hydroxylamine provides a new alternative route for the synthesis of N,N‐dimethylanilines.     

ZrOCl2·8H2O: An Efficient Catalyst for One-Pot Synthesis of α-Amino Phosphonates Under Solvent-Free Conditions

A highly efficient protocol has been developed for the three-component reaction of an amine, an aldehyde, and diethyl phopshite catalyzed by ZrOCl₂·8H₂O, an environmentally friendly catalyst, at ambient temperature. The catalyst exhibited remarkable activity and tolerated a wide variety of functional groups, providing the desired amino phosphonates in excellent yields under solvent-free conditions. Alternatively, the reaction rate can be significantly enhanced by carrying out the reaction in a monomode microwave reactor as a promoter.     

Synthesis of Some Novel α-Cyanoketene-N,S-acetals Derived from Secondary Aliphatic Amines and Their Use in Pyrazole Synthesis

New α-cyanoketene-N,S-acetals 2(a–g) and β-dialkylamine-α-cyanoacrylates 3(g–i) were synthesized in good to excellent yields by the reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate 1 with secondary aliphatic amines (i.e., N-methylalkyl- and N-ethylalkylamines), and pyrrolidine, in the presence of triethylamine, under reflux in ethanol, for 1–16 h, depending on the amine used. Five N-methylalkyl amines and pyrrolidine yielded exclusively mono-substituted N,S-acetals 2(a–f) in good yields. On the other hand, N-ethylbenzylamine gave a mixture of monosubstituted products including N,S-acetal 2g in 35% yield and the unexpected product ethyl 3-[benzyl(ethyl)amino]-2-cyanoacrylate 3g in 50% yield. N-Ethylcyclohexylamine and N-ethylbutylamine did not produce N,S-acetals and gave only the unexpected products ethyl 2-cyano-3-[cyclohexyl(ethyl)amino]acrylate 3h and ethyl 3-[butyl(ethyl)amino]-2-cyanoacrylate 3i in good yields. The α-cyanoketene-N,S-acetals 2(a–f), 2j, and 2k underwent cyclization with the binucleophile hydrazine in ethanol under reflux to afford substituted pyrazoles 4(a–f), 4j, and 4k in good yields.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]     

Convenient,Cost‐Effective,and Mild Method for the N‐Acetylation of Anilines and Secondary Amines

Abstract

An efficient, cost‐effective, and mild method for the N‐acetylation of anilines and secondary amines with ammonium acetate in acetic acid media at reflux temperature in good yield is described.     

Synthesis and characterization of new selective Zn fluorescent probes for functionalization: in vitro Cell imaging applications

Herein the synthesis and characterization of new, lipophilic highly Zn²⁺-selective fluorescent probes are reported. High affinity for zinc (K_d 1.1–8.0 nM) over other biologically relevant metals and mixtures of metals was observed. Excitation at 360 nm afforded an emission spectrum with maximum at 530 nm for the zinc bound complex. The linear relationship between fluorescence intensity and zinc concentration indicates that FZnA-probes can be used for quantification. The probes have been synthesized in 28–45% overall yield and the feasibility for further functionalization with biologically relevant side chains has been demonstrated. In vitro studies using PC12 cells and 10 μM of one of the novel probes (FZnA-Ada) visualized endogenous labile Zn²⁺ after 45 min incubation time.     

Synthesis and Crystal Structures of Antimony(III) Complexes With a Bis(amino)silane Ligand

Bis(amino)silane bearing bulky substituents on nitrogen, LH₂ [L = Me₂Si(NDipp)₂, Dipp = 2, 6‐diisopropylphenyl] was reacted with nBuLi (ratio 1:1 and 1:2) in toluene. The Me₂Si(LiNDipp)₂ was treated with SbCl₃ in a 1:1 ratio to yield the four‐membered SiN₂Sb ring compound of composition [η²(N,N)‐Me₂Si(NDipp)₂SbCl] ( 1 ). The mono lithiated bis(amino)silane was used to synthesize the monodentate heterotetraatomic complex [(η¹‐Me₂SiNDipp)NHDippSbCl₂] ( 2 ) by the reaction with SbCl₃. The complexes were characterized by ¹H and ¹³C NMR, elemental analysis, IR, and single‐crystal X‐ray structural analysis.