Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C-H functionalization of pyridine N-oxides

Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C-H functionalization of pyridine N-oxides

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02556K, Paper

Valentin A. Rassadin, Dmitry P. Zimin, Gulnara Z. Raskil’dina, Alexander Yu. Ivanov, Vadim P. Boyarskiy, Semen S. Zlotskii, Vadim Yu. Kukushkin

A solvent- and halide-free atom-economical synthesis of practically useful pyridine-2-yl substituted ureas utilizes pyridine N-oxides and dialkylcyanamides.

Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C–H functionalization of pyridine N-oxides

 *Corresponding authors

aInstitute of Chemistry, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia

bUfa State Petroleum Technological University, Kosmonavtov 1, Ufa, Bashkortostan, Russia

cResearch Park SPbSU, Center for Magnetic Resonance, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02556K

A novel solvent- and halide-free atom-economical synthesis of practically useful pyridine-2-yl substituted ureas utilizes easily accessible or commercially available pyridine N-oxides (PyO) and dialkylcyanamides. The observed C–H functionalization of PyO is suitable for the good-to-high yielding synthesis of a wide range of pyridine-2-yl substituted ureas featuring electron donating and electron withdrawing, sensitive, or even fugitive functional groups at any position of the pyridine ring (63–92%; 19 examples). In the cases of 3-substituted PyO, the C–H functionalization occurs regioselectively providing a route for facile generation of ureas bearing a 5-substituted pyridine-2-yl moiety.

1,1-Dimethyl-3-(pyridin-2-yl)urea

1,1-Dimethyl-3-(pyridin-2-yl)urea (4a)3 : From pyridine 1-oxide (1a) (95.0 mg, 1.00 mmol) and dimethylcyanamide (2a) (105 mg, 1.50 mmol), compound 4a (147 mg, 89%) was obtained according to GP1 as a yellow oil, which was then crystalized in the freezer to give pale yellow solid, m.p. = 42.6–43.5 °C, lit.4 m.p. = 44–47 °C (EtOAc/hexane), Rf = 0.25 (EtOAc). 1H NMR (400 MHz, CDCl3): δ = 3.00 (s, 6 H, NCH3), 6.88 (ddd, J = 7.3, 5.0, 0.9 Hz, 1 H), 7.30 (br. s, 1 H), 7.60 (ddd, J = 8.5, 7.3, 1.9 Hz, 1 H), 8.02 (dt, J = 8.5, 0.9 Hz, 1 H), 8.14 (ddd, J = 5.0, 1.9, 0.9 Hz, 1 H) ppm. 13C NMR (101 MHz, CDCl3): δ = 36.3 (2 С, CH3), 113.0 (CH), 118.1 (CH), 138.0 (CH), 147.3 (CH), 152.8 (C), 154.8 (C) ppm. NMR data are consistent with previously reported.3 HRMS (ESI), m/z: [M + H]+ calcd. for C8H12N3O+ : 166.0975; found: 166.0977.

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A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles: an easy access to five-ring-fused tetrahydroisoquinolines

A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles: an easy access to five-ring-fused tetrahydroisoquinolines

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02517J, Communication

Xihong Liu, Dongxu Yang, Kezhou Wang, Jinlong Zhang, Rui Wang

A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles has been reported under mild conditions.

A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles: an easy access to five-ring-fused tetrahydroisoquinolines

Xihong Liu,a   Dongxu Yang,a   Kezhou Wang,a  Jinlong Zhanga and   Rui Wang*ab  

*Corresponding authors

aSchool of Life Sciences, Institute of Biochemistry and Molecular Biology, Lanzhou University, Lanzhou 730000, P. R. China

bState Key Laboratory of Chiroscience, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, P. R. China

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02517J

We have reported herein a catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles by which a series of five-ring-fused tetrahydroisoquinolines featuring an indoline scaffold were obtained as single diastereomers in moderate to high yields without any additives under mild conditions. Moreover, the current method provides a novel and convenient approach for the efficient incorporation of two biologically important scaffolds (tetrahydroisoquinoline and indoline).

ethyl 13b-nitro-8-tosyl-8,8a,13b,13c-tetrahydro-5H-indolo[2′,3′:3,4]pyrazolo[5,1- a]isoquinoline-9(6H)-carboxylate

ethyl 13b-nitro-8-tosyl-8,8a,13b,13c-tetrahydro-5H-indolo[2′,3′:3,4]pyrazolo[5,1- a]isoquinoline-9(6H)-carboxylate:

White solid, m.p. 153 – 154 oC; 94% yield; 1H NMR (300 MHz, CDCl3) δ 7.86 (d, J = 8.2 Hz, 2H), 7.78 (d, J = 7.9 Hz, 1H), 7.30 – 7.13 (m, 5H), 7.1 (s, 1H), 7.05 – 6.94 (m, 1H), 6.94 – 6.87 (m, 1H), 6.59 (t, J = 7.6 Hz, 3H), 6.28 (d, J = 7.6 Hz, 1H), 4.78 (s, 1H), 4.37 (q, J = 7.1 Hz, 2H), 2.80 – 2.58 (m, 2H), 2.33 (s, 3H), 2.31 – 2.11 (m, 2H), 1.41 (t, J = 7.1 Hz, 3H) ppm;

13C NMR (75 MHz, CDCl3) δ 152.1, 144.6, 142.6, 134.0, 132.1, 129.3, 129.0, 128.7, 128.3, 127.5, 127.3, 126.2, 122.8, 121.1, 115.5, 104.5, 84.9, 70.7, 62.8, 48.5, 29.1, 21. 6, 14.3 ppm;

HRMS (ESI): C27H26N4NaO6S [M + Na]+ calcd: 557.1465, found: 557.1476.

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Simultaneous rapid reaction workup and catalyst recovery

Simultaneous rapid reaction workup and catalyst recovery

Green Chem., 2016, 18,5769-5772

DOI: 10.1039/C6GC02448C, Communication

Zhichao Lu, Zofia Hetman, Gerald B. Hammond, Bo Xu

By combining reaction work-up and catalyst recovery into a simple filtration procedure we have developed a substantially faster technique for organic synthesis.

By combining reaction work-up and catalyst recovery into a simple filtration procedure we have developed a substantially faster technique for organic synthesis. Our protocol eliminates the time-consuming conventional liquid–liquid extraction and is capable of parallelization and automation. Additionally, it requires only minimal amounts of solvent.

Simultaneous rapid reaction workup and catalyst recovery

Zhichao Lu,a   Zofia Hetman,a   Gerald B. Hammond*a and  Bo Xu*b  

 *Corresponding authors

aDepartment of Chemistry, University of Louisville, Louisville, USA

bCollege of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China

E-mail: bo.xu@dhu.edu.cn

Green Chem., 2016,18, 5769-5772

DOI: 10.1039/C6GC02448C

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC02448C?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

. General procedure for a reaction Step 1. Reaction setup. The reaction is conducted in the usual way with the supported catalyst. Porelite® (typically 1 mL for every 0.1 gram of product) is added to the reaction mixture under stirring, Step 2. Reaction quench and rigid solvent extraction. If needed, the reaction is quenched with a suitable aqueous solution (e.g. NaHCO3 solution). • If the solvent used in the reaction is water-miscible (eg., DMF, methanol, etc.), a minimum amount of water immiscible solvent (e.g. 3 mL ether for every 1 g of product) is added to help organic material become entrenched in Porelite. • If the reaction is conducted in a water immiscible solvent (e.g. toluene, DCM), no extra solvent is needed in most cases. The excess amount of solvent is removed by rotavapor or by nitrogen/air purging (no need to remove the water from the mixture). The reaction mixture is filtered to remove aqueous-soluble components (starting materials, by-products, etc.) and washed with water (or HCl or Na2CO3 solution to remove basic or acidic byproducts. Vacuum is applied to dry the filtrate for 2 minutes to remove any remaining aqueous and volatile solvents. (For automatic flash chromatographic separation, an empty loading cartridge can be used, which can be directly attached to the commercial system. For manual chromatographic separation, a regular Büchner filter can be used). Step 3. Sample loading to chromatographic system. • The loading cartridge can be directly attached to the commercial flash chromatographic system (e.g., CombiFlash Rf series). • For manual chromatographic separation, the polymer powder is loaded directly onto a manual flash silica gel column (dry loading).

Because the polymer pad may contain some trapped air, it is recommended to start with the least polar solvent (e.g., hexane) during chromatographic separation to remove the trapped air.

1-(biphenyl-4-yl)ethanone

1-(biphenyl-4-yl)ethanone

Han, W.; Liu, C.; Jin, Z.-L. Organic Letters 2007, 9, 4005-4007

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CO2-Catalysed aldol condensation of 5-hydroxymethylfurfural and acetone to a jet fuel precursor

CO2-Catalysed aldol condensation of 5-hydroxymethylfurfural and acetone to a jet fuel precursor

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01697A, Communication
Roland Lee, Jesse R. Vanderveen, Pascale Champagne, Philip G. Jessop
CO2 can act as a catalyst for the production of bio-jet fuel precursors through aldol condensation.

CO2-Catalysed aldol condensation of 5-hydroxymethylfurfural and acetone to a jet fuel precursor

 *Corresponding authors
aDepartment of Chemistry, Queen’s University, Kingston, Canada K7L 3N6
E-mail: Philip.jessop@queensu.ca
bDepartment of Civil Engineering, Queen’s University, Kingston, Canada K7L 3N6
Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC01697A, http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01697A?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

CO2 can act as a catalyst for the production of bio-jet fuel precursors through aldol condensation. CO2-Catalysed aldol condensation of HMF with acetone gives a >95% yield of [4-(5-hydroxymethyl-2-furyl)-3-butenone] mono-aldol condensate, while direct conversion of glucose to the same mono-aldol condensate gave a yield of 11%
Method Single step dehydration, aldol condensation, and hydrogenation was carried out in a Parr 31 mL high pressure vessel (T316SS, Parr no. N4742, modified to 31 mL). Glucose/5-HMF, hydrogenation catalyst (Pt (nominally 50 %), Ru (nominally 25 %) on high surface area advanced carbon support supplied by Alfa Aesar (stock# 12100) and reaction solvents were added to the Parr vessel equipped with a stir bar. The vessel was then closed and heated in an oil bath to the required temperature and allowed to equilibrate for 30 min. Following equilibration, the reactor was pressurized with CO2 and H2 to operating conditions. Following reaction (both for conversion of 5-HMF to aldol condensation product or direct conversion from glucose) and dilution, the samples were analyzed with the use of GC-MS (Perkin Elmer Clarus 680 gas chromatograph (GC)), using an Elite-5MS column (30 m, 250 µm i.d., 0.25 µm film of 5% diphenyl 95% dimethyl polysiloxane). Initially the temperature was held at 30 °C for 0 min, followed by a ramp to 125 °C at a rate of 2.5 °C /min held for 1 min, ramp to 260 °C at a rate of 20 °C /min held for 1 min and, finally, ramp to 300 °C at a rate of 20 °C /min held for 3 min. The injector temperature was held at 250 °C and the detector at 200 °C for the duration of the analysis. Carrier gas (helium) flow rate was maintained at 1 mL/min. Aldol condensation products were independently prepared by a literature method17 and utilized for calibration and determination of retention time. Chromatograms and data were collected precisely with the use of Perkin Elmer TurboMass, version 5.4.2.1617 chromatography software.
Image result for bio-jet fuel precursors
Scheme 1 Proposed conversion of cellulose to biomass derived jet fuel.
Image result for bio-jet fuel precursors
Image result for bio-jet fuel precursors
///////////CO2-Catalysed,  aldol condensation, -hydroxymethylfurfural, jet fuel precursor

Visible-light induced oxidative Csp3-H activation of methyl aromatics to methyl esters

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01880G, Communication
Lingling Zhang, Hong Yi, Jue Wang, Aiwen Lei
A mild and catalytic oxidative Csp3-H activation of methyl aromatics using O2via photocatalysis has been achieved. A lot of methyl aromatics can be tolerated, providing a route for aromatic methyl carboxylates. In addition, this protocol can be performed on a gram scale
Visible-light induced oxidative Csp3-H activation of methyl aromatics to methyl esters

Visible-light induced oxidative Csp3–H activation of methyl aromatics to methyl esters

Lingling Zhang,a   Hong Yi,a   Jue Wanga and   Aiwen Lei*ab  
*Corresponding authors
aCollege of Chemistry and Molecular Sciences, the Institute for Advanced Studies, Wuhan University, Wuhan, P. R. China
E-mail: aiwenlei@whu.edu.cn
bNational Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, P. R. China
Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC01880G. http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01880G?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Direct functionalization of readily available hydrocarbons under mild conditions fulfills the requirements of green and sustainable chemistry. In this work, a mild and green catalytic oxidative Csp3–H activation of methyl aromatics using O2 via photocatalysis has been achieved. A lot of methyl aromatics can be tolerated, providing a green route for aromatic methyl carboxylates. In addition, this protocol can be performed on a gram scale.
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Methyl 4-methylbenzoate (2a): [1] 32.9 mg (yield: 73%, light yellow oil). 1H NMR (400 MHz, CDCl3) δ 7.78 (d, J = 8.1 Hz, 2H), 7.06 (d, J = 8.0 Hz, 2H), 3.73 (s, 3H), 2.22 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 167.0, 143.5, 129.6, 129.0, 127.4, 51.8, 21.5.
Liu, H.; Chen, G.; Jiang, H.; Li, Y.; Luque, R., ChemSusChem. 2012, 5 , 1892-1896.
///////Visible-light,  induced oxidative,  Csp3-H activation,  methyl aromatics, methyl esters

High Throughput Enzymatic Enantiomeric Excess: Quick-ee

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High throughput screening techniques (HTS) are fast and efficient alternatives to evaluate enzymatic activities. Here, this technique is applied to obtain enantiomeric excess and conversions values with chiral fluorogenic probes and a non fluorogenic competitor, which was named Quick-ee. The fluorescent signal reveals of the enantioselectivity of the enzyme. Details are presented in the Article High Throughput Enzymatic Enantiomeric Excess: Quick-ee by Maria L. S. de O. Lima, Caroline C. da S. Gonçalves, Juliana C. Barreiro, Quezia Bezerra Cass and Anita Jocelyne Marsaioli on page 319.

http://dx.doi.org/10.5935/0103-5053.20140282

Cover Article

J. Braz. Chem. Soc. 2015, 26(2), 319-324

High Throughput Enzymatic Enantiomeric Excess: Quick-ee

Maria L. S. O. Lima; Caroline C. S. Gonçalves; Juliana C. Barreiro; Quezia B. Cass; Anita J. Marsaioli

Lima MLSO, Gonçalves CCS, Barreiro JC, Cass QB, Marsaioli AJ. High Throughput Enzymatic Enantiomeric Excess: Quick-ee.J. Braz. Chem. Soc. 2015;26(2):319-324

/////////////High Throughput,  Enzymatic,  Enantiomeric Excess,  Quick-ee

http://jbcs.sbq.org.br/imagebank/pdf/v26n2a14.pdf

http://jbcs.sbq.org.br/imagebank/pdf/v26n2a14-Sup01.pdf

Flow Grignard and Lithiation: Screening Tools and Development of Continuous Processes for a Benzyl Alcohol Starting Material

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Abstract Image

Efficient continuous Grignard and lithiation processes were developed to produce one of the key regulatory starting materials for the production of edivoxetine hydrochoride. For the Grignard process, organometallic reagent formation, Bouveault formylation, reduction, and workup steps were run in continuous stirred tank reactors (CSTRs). The lithiation utilized a hybrid approach where plug flow reactors (PFRs) were used for the metal halogen exchange and Bouveault formylation steps, while the reduction and workup steps were performed in CSTRs. Relative to traditional batch processing, both approaches offer significant advantages. Both processes were high-yielding and produced the product in high purity. The two main processes were directly compared from a number of perspectives including reagent and operational safety, fouling potential, process footprint, need for manual operation, and product yield and purity.

Flow Grignard and Lithiation: Screening Tools and Development of Continuous Processes for a Benzyl Alcohol Starting Material

Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
D&M Continuous Solutions, LLC, Greenwood, Indiana 46143, United States
Org. Process Res. Dev., Article ASAP

//////////Flow Grignard,  Lithiation, Screening Tools,  Development, Continuous Processes,  Benzyl Alcohol, Starting Material

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