Palladium-catalyzed coupling of azoles with 1-aryltriazenes via C–H/C–N cleavage

 

Palladium-catalyzed coupling of azoles with 1-aryltriazenes via C–H/C–N cleavage

Wei-Can Daia  and  Zhong-Xia Wang*ab 

*Corresponding authors

aCAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, P. R. China
E-mail: zxwang@ustc.edu.cn
Tel: +86 551 63603043

bCollaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P. R. China

Abstract

In the presence of CuCl and ButOLi, PdCl2/dppe catalyzes the reaction of (benzo)oxazoles or (benzo)thiazoles with 1-aryltriazenes to yield arylated products of (benzo)oxazoles or (benzo)thiazoles. Functional groups including F, Cl, CF3, COOEt, CN, OMe, NMe2, Py, and thienyl groups can be tolerated.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

    

3a (11.2 mg, 38%) were obtained along with unreacted 1 (1.1 mg, 4%).

1H NMR (400 MHz, CS2/CDCl3) δ 8.39 (d, J = 8.0 Hz, 2H), 7.60 (t, J = 7.4 Hz, 1H), 7.50 (t, J = 7.7 Hz, 2H), 7.41 (d, J = 7.8 Hz, 1H), 7.29 (s, 1H), 7.04 (d, J = 7.8 Hz, 1H), 5.95 (s, 1H), 2.76 (s, 3H), 2.52 (s, 3H);

13C NMR (100 MHz, CS2/CDCl3, all 1C unless indicated) δ 196.06 (C=O), 167.78 (C=O), 152.39, 152.08, 151.38, 150.04, 149.83, 149.22, 148.81, 148.52, 148.26, 147.93, 147.86, 147.73, 147.36, 147.18, 147.14 (2C), 146.91, 146.86, 146.41, 146.40, 145.99 (2C), 145.95, 145.92, 145.53, 145.37, 145.33, 144.82 (2C), 144.80, 144.72, 144.54, 144.42, 144.31, 144.14, 143.84, 143.65, 143.42, 143.31, 143.05, 142.13, 141.93, 141.79, 141.72 (2C), 141.69, 141.55, 141.35, 141.24, 141.10, 140.63, 140.14, 139.93 (aryl C), 138.84, 137.70, 137.54 (aryl C), 137.47, 137.38, 135.44 (aryl C), 133.14 (aryl C), 129.16 (2C, aryl C), 128.72 (2C, aryl C), 128.61 (aryl C), 125.80 (aryl C), 125.42 (aryl C), 115.11 (aryl C), 83.58 (sp3 -C of C60), 69.89 (sp3 -C of C60), 62.42 (sp3 -C of C60), 56.81 (sp3 -C of C60), 26.84, 22.25;

UV-vis (CHCl3) λmax nm (log ε) 251.0 (5.1), 318.5 (4.6), 403.5 (4.0), 440.0 (3.9), 525.5 (3.2), 703.5 (2.5);

FT-IR ν/cm-1 (KBr) 2922, 2860, 1668, 1599, 1499, 1439, 1366, 1304, 1236, 1180, 1086, 1020, 964, 858, 802, 748, 691, 604, 528;

MALDI-TOF MS m/z calcd for C76H16NO2 [M+H]+ 974.1176, found 974.1165.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

Hao-Sheng Lin,a  Yutaka Matsuo,a  Jun-Jie Wanga  and  Guan-Wu Wang*ab 

Author affiliations

Abstract

A regioselective and highly efficient electrochemical method for direct acylation and carboxylation of a [60]fulleroindoline has been developed. By using inexpensive and readily available acyl chlorides and chloroformates, both keto and ester groups can be easily attached onto the fullerene skeleton to afford 1,2,3,16-functionalized [60]fullerene derivatives regioselectively. In addition, a plausible mechanism for the formation of fullerenyl ketones and esters is proposed, and their further transformations under basic and acidic conditions have been investigated.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

    

3a (11.2 mg, 38%) were obtained along with unreacted 1 (1.1 mg, 4%).

1H NMR (400 MHz, CS2/CDCl3) δ 8.39 (d, J = 8.0 Hz, 2H), 7.60 (t, J = 7.4 Hz, 1H), 7.50 (t, J = 7.7 Hz, 2H), 7.41 (d, J = 7.8 Hz, 1H), 7.29 (s, 1H), 7.04 (d, J = 7.8 Hz, 1H), 5.95 (s, 1H), 2.76 (s, 3H), 2.52 (s, 3H);

13C NMR (100 MHz, CS2/CDCl3, all 1C unless indicated) δ 196.06 (C=O), 167.78 (C=O), 152.39, 152.08, 151.38, 150.04, 149.83, 149.22, 148.81, 148.52, 148.26, 147.93, 147.86, 147.73, 147.36, 147.18, 147.14 (2C), 146.91, 146.86, 146.41, 146.40, 145.99 (2C), 145.95, 145.92, 145.53, 145.37, 145.33, 144.82 (2C), 144.80, 144.72, 144.54, 144.42, 144.31, 144.14, 143.84, 143.65, 143.42, 143.31, 143.05, 142.13, 141.93, 141.79, 141.72 (2C), 141.69, 141.55, 141.35, 141.24, 141.10, 140.63, 140.14, 139.93 (aryl C), 138.84, 137.70, 137.54 (aryl C), 137.47, 137.38, 135.44 (aryl C), 133.14 (aryl C), 129.16 (2C, aryl C), 128.72 (2C, aryl C), 128.61 (aryl C), 125.80 (aryl C), 125.42 (aryl C), 115.11 (aryl C), 83.58 (sp3 -C of C60), 69.89 (sp3 -C of C60), 62.42 (sp3 -C of C60), 56.81 (sp3 -C of C60), 26.84, 22.25;

UV-vis (CHCl3) λmax nm (log ε) 251.0 (5.1), 318.5 (4.6), 403.5 (4.0), 440.0 (3.9), 525.5 (3.2), 703.5 (2.5);

FT-IR ν/cm-1 (KBr) 2922, 2860, 1668, 1599, 1499, 1439, 1366, 1304, 1236, 1180, 1086, 1020, 964, 858, 802, 748, 691, 604, 528;

MALDI-TOF MS m/z calcd for C76H16NO2 [M+H]+ 974.1176, found 974.1165.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

Hao-Sheng Lin,a  Yutaka Matsuo,a  Jun-Jie Wanga  and  Guan-Wu Wang*ab 

Author affiliations

Abstract

A regioselective and highly efficient electrochemical method for direct acylation and carboxylation of a [60]fulleroindoline has been developed. By using inexpensive and readily available acyl chlorides and chloroformates, both keto and ester groups can be easily attached onto the fullerene skeleton to afford 1,2,3,16-functionalized [60]fullerene derivatives regioselectively. In addition, a plausible mechanism for the formation of fullerenyl ketones and esters is proposed, and their further transformations under basic and acidic conditions have been investigated.

1,5-bis-(2-furanyl)-1,4-pentadien-3-one (FAF)

A catalytic aldol condensation system enables one pot conversion of biomass saccharides to biofuel intermediates

Huixiang Li,ab  Zhanwei Xu,a  Peifang Yana  and  Z. Conrad Zhang*a 

Author affiliations

*Corresponding authors

aState Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
E-mail: zczhang@yahoo.com

bDepartment of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China

Abstract

Producing bio-intermediates from lignocellulosic biomass with minimal process steps has a far-reaching impact on the biofuel industry. We studied the metal chloride catalyzed aldol condensation of furfural with acetone under conditions compatible with the upstream polysaccharide conversions to furfurals. In situ far infrared spectroscopy (FIR) was applied to guide the screening of aldol condensation catalysts based on the distinguishing characteristics of metal chlorides in their coordination chemistries with carbonyl-containing compounds. NiCl2, CoCl2, CrCl3, VCl3, FeCl3, and CuCl2 were selected as the potential catalysts in this study. The FIR results further helped to rationalize the excellent catalytic performance of VCl3 in furfural condensation with acetone, with 94.7% yield of biofuel intermediates (C8, C13) in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) solvent. Remarkably, addition of ethanol facilitated the acetal pathway of the condensation reaction, which dramatically increased the desired product selectivity over the furfural pathway. Most significantly, we demonstrate for the first time that VCl3 catalyzed aldol condensation in acidic medium is fully compatible with upstream polysaccharide hydrolysis to monosaccharide and the subsequent monosaccharide isomerization and dehydration to furfurals. Our preliminary results showed that a 44% yield of biofuel intermediates (C8, C13) can be obtained in one-pot conversion of xylose catalyzed by paired metal chlorides, CrCl2 and VCl3. A number of prior works have shown that the biofuel intermediates derived from the one-pot reaction of this work can be readily hydrogenated to biofuels.

1,5-bis-(2-furanyl)-1,4-pentadien-3-one (FAF)

FAF is a yellow solid.1H NMR (400 MHz, CDCl3, TMS) δ 7.51 – 7.46 (m, 4H), 6.92 (d, J = 15.6 Hz, 2H), 6.69 (d, J = 3.4 Hz, 2H), 6.50 – 6.49 (m, 2H);13C NMR (100 MHz, CDCl3) δ 188.1, 151.6, 144.9, 129.2, 123.2, 115.8, 112.6

2-({3-Methyl-6-[(3R)-3-piperidinylamino]-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl}methyl)-4-fluorobenzonitrile

 

2-({3-Methyl-6-[(3R)-3-piperidinylamino]-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl}methyl)-4-fluorobenzonitrile (8)

Mp: 90 °C decomposed.

 

1H NMR (400 MHz, CD3OD) δ (ppm): 7.85–7.89 (m, 1H), 7.25–7.28 (m, 1H), 6.96–6.99 (m, 1H), 5.37–5.51 (m, 2H), 4.84 (s, 1H), 3.42–3.49 (m, 1H), 3.28 (s, 3H), 3.11–3.15 (m, 1H), 2.89–2.93 (m, 1H), 2.46–2.58 (m, 2H), 1.92–1.95 (m, 1H), 1.48–1.70 (m, 3H).

 

MS (ESI+): m/z, 358.06 ([M + H]+).

Synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions at room temperature

Synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions at room temperature

Green Chem., 2017, Advance Article
DOI: 10.1039/C6GC03494B, Paper

Zheng Fang, Wen-Li Hu, De-Yong Liu, Chu-Yi Yu, Xiang-Guo Hu
A procedure for the synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions has been developed.

An efficient and green procedure for the synthesis of tetrazines has been developed based on an old chemistry reported by Carboni in 1958. Both symmetric and asymmetric 3,6-disubstituted 1,2,4,5-tetrazines can be obtained in moderate to high yields from the corresponding gem-difluoroalkenes under aerobic conditions at room temperature. This work represents a rare example that ambient air is utilized as an oxidant for the synthesis of tetrazines.

Synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions at room temperature

Zheng Fang,^a   Wen-Li Hu,^a   De-Yong Liu,^a  Chu-Yi Yu^ab and   Xiang-Guo Hu*^a  

Hide Affiliations

*

Corresponding authors

^a

National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, P. R. China
 E-mail: huxiangg@iccas.ac.cn

^b

Beijing National Laboratory for Molecular Science (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China

Green Chem., 2017, Advance Article

DOI: 10.1039/C6GC03494B

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C6GC03494B?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

3,6−bis([1,1'−biphenyl]−4−ylmethyl)−1,2,4,5−tetra zine (3a). (41 mg, 83%). purple solid;

m.p. 200−202°C;

IR(KBr) nmax/cm−1 2924, 2850, 1488, 1451, 1432, 1388, 851, 750;

1 H NMR (400 MHz, CDCl3) 7.55−7.33 (m, 18H), 4.65 (s, 4H).

 13C NMR (100 MHz, CDCl3) δ 169.2, 140.6, 140.4, 134.8, 129.7, 128.8, 127.6, 127.4, 127.1, 40.9;

HRMS (ESI): calcd. for C28H22N4 [M+H]+ 415.19172, found 415.19124.



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One-Pot Reductive Cyclisations of Nitroanilines to Imidazoles

Hana and co-workers ( Synlett 2010, 18, 2759−2764) from Genentech have developed a single-step procedure for conversion of 2-nitro aromatic amines to benzimidazoles. Addition of ammonium chloride proved necessary as Fe powder and formic acid alone was ineffective for nitro reduction. These conditions were compatible with a variety of functional groups on the aromatic, including boronate esters. The methodology was also extended to nitro aminopyridines but failed to deliver the desired product with isoxazole or pyrazole reactants.

Mild and General One-Pot Reduction and Cyclization of Aromatic and Heteroaromatic 2-Nitroamines to Bicyclic 2H-Imidazoles

Emily J. Hanan*, Bryan K. Chan, Anthony A. Estrada, Daniel G. Shore, Joseph P. Lyssikatos

*Discovery Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA, Email: hanan.emilygene.com

E. J. Hanan, B. K. Chan, A. A. Estrada, D. G. Shore, J. P. Lyssikatos, Synlett, 2010, 2759-2764.

DOI: 10.1055/s-0030-1259007

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see article for more reactions

Abstract

A one-pot procedure for the conversion of aromatic and heteroaromatic 2-nitroamines into bicyclic 2H-benzimidazoles employs formic acid, iron powder, and NH₄Cl as additive to reduce the nitro group and effect the imidazole cyclization with high-yielding conversions generally within one to two hours. The compatibility with a wide range of functional groups demonstrates the general utility of this procedure.

see article for more examples

//////////One-Pot, Reductive Cyclisations,  Nitroanilines,  Imidazoles

 

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