scholarly journals A chiral “Siamese-Twin” calix[4]pyrrole tetramer

2016 ◽  
Vol 7 (9) ◽  
pp. 5976-5982 ◽  
Author(s):  
Albano Galán ◽  
Gemma Aragay ◽  
Pablo Ballester
Keyword(s):  
Coupling Reaction ◽  
Starting Material ◽  
Reaction Conditions ◽  
Siamese Twin

We describe our results in the attempted template syntheses of oligomacrocycle calix[4]pyrrole dimer 4, using Hay coupling reaction conditions, tetraalkynyl calix[4]pyrrole 5 as starting material and two bipyridyl N-oxides of different length as templates.

An Unprecedented Cyano-Induced Sodium Nitrite-Catalyzed C(sp3)-H and C(sp2)-H Coupling Reaction

2018 ◽  
Vol 15 (7) ◽  
pp. 989-994 ◽  
Author(s):  
Ling Li ◽  
Bo Su ◽  
Yuxiu Liu ◽  
Qingmin Wang
Keyword(s):  
Sodium Nitrite ◽  
Oxidative Coupling ◽  
High Resolution Mass Spectrometry ◽  
Coupling Reaction ◽  
13C Nmr Spectroscopy ◽  
Coupling Reactions ◽  
Reaction Conditions ◽  
1H And 13C Nmr ◽  
Oxidative Coupling Reaction ◽  
Oxidative Coupling Reactions

Aim and Objective: During the investigation of sodium nitrite-catalyzed oxidative coupling reaction of aryls, an unprecedented C(sp2)-H and C(sp3)-H coupling of substituted 2-aryl acetonitrile was found. Materials and Methods: The structure of the coupled product was confirmed by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry (HRMS), and comparison of its derivatives with known compounds. The effects of methoxy group in the benzene ring on the reaction were evaluated. Results: The optimized reaction conditions are summarized as follows: CF3SO3H/substrate = 1.5 equiv., NaNO2/substrate = 0.3 equiv., CH3CN as solvent. 2-(4-Methoxyphenyl)acetonitrile and 2-(3,4,5- trimethoxyphenyl)acetonitrile could also generate C(sp2)-H and C(sp3)-H coupling. The coupling reaction occurred as a typical radial mechanism. Conclusion: An unprecedented cyano-induced, NaNO2-catalyzed oxidative C(sp3)-H and C(sp2)-H coupling was reported. The reaction proceeded under very mild conditions, using O2 in the air as terminal oxidant. The unique oxidative manner might provide more inspiration for the development of intriguing oxidative coupling reactions.

Nickel-Catalyzed Multicomponent Coupling Reaction of Alkyl Halides, Isocyanides and H2O: An Expedient Way to Access Alkyl Amides

Synthesis ◽  
2020 ◽  
Vol 52 (22) ◽  
pp. 3466-3472
Author(s):  
Yunkui Liu ◽  
Bingwei Zhou ◽  
Qiao Li ◽  
Hongwei Jin
Keyword(s):  
Functional Group ◽  
Coupling Reaction ◽  
Alkyl Halides ◽  
Previous Literature ◽  
Catalytic Cycle ◽  
Reaction Conditions ◽  
Multicomponent Coupling ◽  
Easy Operation

We herein describe a Ni-catalyzed multicomponent coupling reaction of alkyl halides, isocyanides, and H2O to access alkyl amides. Bench-stable NiCl2(dppp) is competent to initiate this transformation under mild reaction conditions, thus allowing easy operation and adding practical value. Substrate scope studies revealed a broad functional group tolerance and generality of primary and secondary alkyl halides in this protocol. A plausible catalytic cycle via a SET process is proposed based on preliminary experiments and previous literature.

scholarly journals Grignard coupling-based synthesis of vinyl-substituted hydridopolycarbosilane: effect of starting material and polymerization behavior

RSC Advances ◽  
2021 ◽  
Vol 11 (19) ◽  
pp. 11771-11778
Author(s):  
Minji Jeong ◽  
Moon-Gun Choi ◽  
Yoonjoo Lee
Keyword(s):  
Coupling Reaction ◽  
Starting Material ◽  
Polymerization Behavior

Polymerization of VHPCS by the Grignard coupling reaction depended on the type of starting material. In the case of Cl3SiCH2Cl starting material, a stepwise growth manner was shown, due to a coupling between –CH2Cl and the Si–Cl sites.

scholarly journals The Eschenmoser coupling reaction under continuous-flow conditions

2011 ◽  
Vol 7 ◽  
pp. 1164-1172 ◽  
Author(s):  
Sukhdeep Singh ◽  
J Michael Köhler ◽  
Andreas Schober ◽  
G Alexander Groß
Keyword(s):  
Continuous Flow ◽  
Elevated Temperatures ◽  
Reaction Times ◽  
Coupling Reaction ◽  
Flow Chemistry ◽  
Flow Conditions ◽  
Reaction Conditions ◽  
Bond Forming ◽  
Carbon Carbon Bond ◽  
Reaction Proceeds

The Eschenmoser coupling is a useful carbon–carbon bond forming reaction which has been used in various different synthesis strategies. The reaction proceeds smoothly if S-alkylated ternary thioamides or thiolactames are used. In the case of S-alkylated secondary thioamides or thiolactames, the Eschenmoser coupling needs prolonged reaction times and elevated temperatures to deliver valuable yields. We have used a flow chemistry system to promote the Eschenmoser coupling under enhanced reaction conditions in order to convert the demanding precursors such as S-alkylated secondary thioamides and thiolactames in an efficient way. Under pressurized reaction conditions at about 220 °C, the desired Eschenmoser coupling products were obtained within 70 s residence time. The reaction kinetics was investigated and 15 examples of different building block combinations are given.

HYDROGENOLYSIS OF CARBOHYDRATES: V. ISOMERIZATION OF METHYL β-L-ARABOPYRANOSIDE

1958 ◽  
Vol 36 (6) ◽  
pp. 921-925 ◽  
Author(s):  
A. S. Perlin ◽  
E. Von Rudloff ◽  
A. P. Tulloch
Keyword(s):  
Chromium Oxide ◽  
Oxide Catalyst ◽  
Starting Material ◽  
Reaction Conditions ◽  
Copper Chromium ◽  
Cis And Trans

Treatment of methyl β-L-arabopyranoside under hydrogenolytic conditions with copper chromium oxide catalyst induces extensive isomerization. Products formed include glycosides of D-ribose, D-xylose, D-lyxose, and L-lyxose which together represent about an 80–90% conversion of starting material. Isolation of these compounds shows that carbons 2, 3, and 4 undergo isomerization, but no evidence has been obtained of anomerization. These findings possibly explain the formation of an optically inactive mixture of cis- and trans-tetrahydropyran-3,4-diol under slightly more drastic reaction conditions.

Ligand free copper(i)-catalyzed synthesis of diaryl ether with Cs2CO3via a free radical path

2015 ◽  
Vol 44 (27) ◽  
pp. 12086-12090 ◽  
Author(s):  
Hong-Jie Chen ◽  
Mei-Chun Tseng ◽  
I-Jui Hsu ◽  
Wei-Ting Chen ◽  
Chien-Chung Han ◽  
...  
Keyword(s):  
Free Radical ◽  
Catalytic Reaction ◽  
Coupling Reaction ◽  
Reaction Conditions ◽  
Esi Ms ◽  
Ms Analysis ◽  
Diaryl Ether ◽  
Ligand Free

Complexes [Cu(i)(2,4-dimethylphenoxy)2]− (A) and [Cu(ii)(2,4-dimethylphenoxy)2(p-tolyl)]− (B) were observed by in situ ESI-MS analysis of the ligand free copper(i)-catalyzed C–O coupling reaction using Cs2CO3 under the catalytic reaction conditions.

scholarly journals Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

2018 ◽  
Vol 14 ◽  
pp. 1871-1884 ◽  
Author(s):  
Siva Sankar Murthy Bandaru ◽  
Darinka Dzubiel ◽  
Heiko Ihmels ◽  
Mohebodin Karbasiyoun ◽  
Mohamed M A Mahmoud ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Binding Constants ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Sonogashira Coupling ◽  
Reaction Conditions ◽  
Quadruplex Dna ◽  
Cross Coupling Reactions ◽  
Sonogashira Coupling Reaction

9-Arylbenzo[b]quinolizinium derivatives were prepared with base-free Suzuki–Miyaura coupling reactions between benzo[b]quinolizinium-9-trifluoroborate and selected benzenediazonium salts. In addition, the Sonogashira coupling reaction between 9-iodobenzo[b]quinolizinium and the arylalkyne derivatives yielded four novel 9-(arylethynyl)benzo[b]quinolizinium derivatives under relatively mild reaction conditions. The 9-(N,N-dimethylaminophenylethynyl)benzo[b]quinolizinium is only very weakly emitting, but the emission intensity increases by a factor >200 upon protonation, so that this derivative may operate as pH-sensitive light-up probe. Photometric and fluorimetric titrations of duplex and quadruplex DNA to 9-(arylethynyl)benzo[b]quinolizinium derivatives revealed a significant binding affinity of these compounds towards both DNA forms with binding constants ofKb= 0.2–2.2 × 105M−1.

Efficient Halogenation of 2-Aminopyrazine

Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 2000-2003
Author(s):  
Enric Lizano ◽  
Josep Grima ◽  
M. Dolors Pujol
Keyword(s):  
Nitrogen Heterocycles ◽  
Starting Material ◽  
Reaction Conditions ◽  
Microwave Assistance

2-Aminopyrazine was halogenated with NIS, NCS, and NBS under different reaction conditions. Chlorination and bromination were achieved with good yields by using acetonitrile as the solvent. However, iodination was only obtained in poor yields. Undoubtedly, the best conditions for both mono- and dihalogenation were the use of NBS, acetonitrile, and microwave assistance for short periods. 3,5-Dibromo-2-aminopyrazine is an excellent functionalized starting material for the synthesis of nitrogen heterocycles.

Regiospecific Palladium-Catalyzed Cross-Coupling Reactions Using the Operational Equivalent of 1,3-Dilithiopropyne

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2387-2394 ◽  
Author(s):  
Jorge A. Cabezas ◽  
Natasha Ferllini
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Terminal Alkyne ◽  
Copper Iodide ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
High Yields

A regiospecific palladium-catalyzed cross-coupling reaction using the operational equivalent of the dianion 1,3-dilithiopropyne, with aromatic iodides is reported. This reaction gives high yields of 1-propyn-1-yl-benzenes and 2-(propyn-1-yl)thiophenes in the presence of catalytic amounts of palladium(0) or (II) and stoichiometric amounts of copper iodide. No terminal alkyne or allene isomers were detected. Reaction conditions were very mild and several functional groups were tolerated.

scholarly journals High Yielding, Base Catalyzed C6 Regioselective Amination and N9 Alkylation in Purine Nucleotide

2019 ◽  
Vol 31 (12) ◽  
pp. 2871-2874
Author(s):  
Gautamkumar Dhuda ◽  
Khushal Kapadiya ◽  
Paresh Ladwa ◽  
Bhavna Godhaniya ◽  
Jayesh Modha
Keyword(s):  
Coupling Reaction ◽  
Purine Nucleoside ◽  
Regioselective Synthesis ◽  
Secondary Amines ◽  
Purine Nucleotide ◽  
Reaction Conditions ◽  
Simple Reaction ◽  
Amine Coupling

2,6-Dichloropurine is an interesting new nucleoside which gave regioselectively various 2-derivatized or 6-derivatized purines by using a secondary amines. An efficient, simple and regioselective synthesis of C6 morpholine, N9 alkylated purine nucleoside derivatives were attained via chloro-amine coupling reaction between 2,6-dichloropurine with morpholine followed by commercial alkylation method using DMF and K2CO3. Over the traditionally used protocols and procedure, it have been exhibited advance benefits such as admirable yield, simple reaction conditions and modest influence.

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