Saturday 29 April 2017

Visible-light-induced and iron-catalyzed methylation of N-arylacrylamides with dimethyl sulphoxide: a convenient access to 3-ethyl-3-methyl oxindoles

Visible-light-induced and iron-catalyzed methylation of N-arylacrylamides with dimethyl sulphoxide: a convenient access to 3-ethyl-3-methyl oxindoles

Org. Biomol. Chem., 2017, Advance Article
DOI: 10.1039/C7OB00779E, Paper
Zuguang Xie, Pinhua Li, Yu Hu, Ning Xu, Lei Wang
An efficient synthesis of 3-ethyl-3-methyl oxindoles by visible-light promoted and iron-catalyzed difunctionalization of N-arylacrylamides with dimethyl sulphoxide was developed

Visible-light-induced and iron-catalyzed methylation of N-arylacrylamides with dimethyl sulphoxide: a convenient access to 3-ethyl-3-methyl oxindoles

Abstract

A visible-light-induced and iron-catalyzed methylation of arylacrylamides by dimethyl sulphoxide (DMSO) is achieved, leading to 3-ethyl-3-methyl indolin-2-ones in high yields. This reaction tolerates a series of functional groups, such as methoxy, trifluoromethyl, cyano, nitro, acetyl and ethyloxy carbonyl groups. The visible-light promoted radical methylation and arylation of the alkenyl group are involved in this reaction.
Graphical abstract: Visible-light-induced and iron-catalyzed methylation of N-arylacrylamides with dimethyl sulphoxide: a convenient access to 3-ethyl-3-methyl oxindoles
str1 str2
 
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N-Methyl-3-Bromo-5-Methyl Pyrazole

N-Methyl-3-Bromo-5-Methyl Pyrazole

3·HCl as a white solid in 27% yield; sublimes at 40 °C; 1H NMR (500 MHz, DMSO-d6) δ 11.88 (s, 1 H), 6.07 (s, 1 H), 3.62 (s, 3 H), 2.16 (s, 3 H); 13C NMR (125 MHz, DMSO-d6) δ 141.7, 123.0, 107.5, 36.5, 10.9; HRMS-ESI (m/z) calcd for C5H8N2Br [M + H]+ 174.9864, found 174.9864.
3·TfOH as an off-white solid; mp = 145 °C; 1H NMR (400 MHz, DMSO-d6) δ 11.73 (s, 1 H), 6.06 (s, 1 H), 3.62 (s, 3 H), 2.16 (s, 3 H); 13C NMR (100 MHz, DMSO-d6) δ 141.9, 123.2, 121.2 (q, J = 320 Hz), 107.6, 36.5, 10.9; HRMS-ESI (m/z) calcd for C5H8N2Br [M + H]+ 174.9864, found 174.9865.

Development of Scalable Processes for the Preparation of N-Methyl-3-Bromo-5-Methyl Pyrazole

Chemical & Synthetic Development, Bristol-Myers Squibb Company, P.O. Box 191 New Brunswick, New Jersey 08903-0191, United States
Org. Process Res. Dev., Article ASAP
DOI: 10.1021/acs.oprd.7b00091
 
Abstract Image
The development and optimization of two scalable routes to N-methyl-3-bromo-5-methyl pyrazole is described. The initial Sandmeyer route entailed a three-step sequence from crotonitrile and methyl hydrazine, proceeding through the 3-amino pyrazole intermediate. Due to the GTI liability of the 3-amino pyrazole intermediate, a tedious steam-distillation, and <30% overall yield, we developed a second-generation Sandmeyer-free approach from methyl crotonate and methyl hydrazine which leveraged a condensation, bromination, and oxidation sequence. Process development led to the improved preparation of N-methyl-3-bromo-5-methyl pyrazole with increased efficiency and overall yield. The isolation, handling, and storage of the final product was greatly improved through the generation of the triflic acid salt, and salt form studies are also discussed.
str1 str2 str3 str4
Org. Process Res. Dev., Article ASAP
DOI: 10.1021/acs.oprd.7b00091
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Asymmetric synthesis of ent-fragransin C1

Asymmetric synthesis of ent-fragransin C1

Org. Biomol. Chem., 2017, Advance Article
DOI: 10.1039/C7OB00749C, Paper
Santikorn Chaimanee, Manat Pohmakotr, Chutima Kuhakarn, Vichai Reutrakul, Darunee Soorukram
The first asymmetric synthesis of ent-fragransin C1 bearing 2,3-anti-3,4-syn-4,5-anti stereochemistries is reported.

Asymmetric synthesis of ent-fragransin C1

Abstract

The first asymmetric synthesis of ent-fragransin C1 was reported. The key step involves an intramolecular C–O bond formation (furan ring formation) via chemoselective generation of the benzylic carbocation leading to the 2,3-anti-3,4-syn-4,5-anti-tetrahydrofuran moiety as a single diastereomer in good yield. Our synthesis confirms that ent-fragransin C1 possesses 2R,3R,4S,5S configurations.
4-[(2R,3R,4S,5S)-5-(4-Hydroxy-3-methoxyphenyl)-3,4- dimethyltetrahydrofuran-2-yl]-2,6-dimethoxyphenol (ent-1). A flame-dried.......................... in vacuo, the crude product was purified by column chromatography (60% EtOAc in hexanes) to afford ent-1 as a sticky brownish oil (15.3 mg, 99% yield) as a single diastereomer (400 MHz 1 H NMR analysis). Rf 0.18 (40% EtOAc in hexanes);
[α]27 D -6.97 (c 0.60, CHCl3 ) (lit. [α]D +3.8 (c 0.60, CHCl3 ); 4a
UV (MeOH) λmax (log ε) 208 (0.85), 233 (0.24), 279 (0.07) nm; CD (MeOH) 226 (Δε 2.23), 250 (Δε +0.12).
1 H NMR (400 MHz, acetone-d6 ): δ 7.51 (s, 1H, OH), 7.12 (s, 1H, OH), 7.10 (d, J = 1.8 Hz, 1H, ArH), 6.92 (d, J = 8.1, 1.8 Hz, 1H, ArH), 6.82 (d, J = 8.1 Hz, 1H, ArH), 6.77 (s, 2H, 2  ArH), 4.43 (d, J = 5.4 Hz, 1H, 2  xCH), 3.86 (s, 3H, OCH3 ), 3.83 (s, 6H, 2  xOCH3 ), 2.202.45 (m, 2H, 2  xCH), 1.03 (d, J = 6.7 Hz, 3H, CH3 ), 1.00 (d, J = 6.7 Hz, 3H, CH3 ).
13C NMR (100 MHz, acetone-d6 ): δ 149.0 (2  C), 148.7 (C), 147.3 (C), 136.6 (C), 135.5 (C), 134.7 (C), 120.4 (CH), 115.9 (CH), 111.2 (CH), 105.1 (2  CH), 88.7 (CH), 88.4 (CH), 57.0 (2  CH3 ), 56.6 (CH3 ), 46.1 (CH), 45.7 (CH), 13.7 (CH3 ), 13.5 (CH3 ).
IR (CHCl3 ): νmax 3542s, 1616m, 1517s, 1465s, 1117s cm−1 .
MS (ISCID): m/z (%) relative intensity 397 [(M + Na)+ , 100], 357 (1).
HRMS (ESI-TOF) calcd for C21H26O6Na [M + Na]+ : 397.1627, found: 397.1622.
4 (a) M. Hattori, S. Hada, Y. Kawata, Y. Tezuka, T. Kikuchi and T. Namba, Chem. Pharm. Bull., 1987, 35, 3315; (

Image result for Darunee Soorukram Mahidol University
Darunee Soorukram
Assistant Professor

Darunee Soorukram

Education
  • B.Sc. (Chemistry), Khon Kean University, Khon Kean, Thailand
  • M.Sc. (Organic Chemistry), Mahidol University, Bangkok, Thailand
  • Ph.D., Ludwig-Maximilians-University, Munich, Germany
Name :Darunee Soorukram 
 ดรุณี สู้รักรัมย์
Title :Assistant Professor Dr.
Education :Ph.D. (Ludwig-Maximilians-University), Germany
  
Expertise :-
  
Contact Address :Department : Chemistry
 Room : C418B
 Phone : (662) 201 5148 
 E-Mail : darunee.soo@mahidol.ac.th 
   
More Information :CV from Dept. Chemistry Website   
 รางวัลวิทยานิพนธ์ ระดับดีเยี่ยม (สาขาวิทยาศาสตร์เคมีและเภสัช) จากสภาวิจัยแห่งชาติ 

Most Recent Articles from Scopus : Soorukram D (Author ID: 6506453550)

Contact
Phone: +66.(0).2.201.5148
LAB Tel: +66.(0).2.201.5149
Fax: +66.(0).2.354.7151
E-mail:darunee.soo@mahidol.ac.th
Address:
Room C418B
Department of Chemistry,
Faculty of Science, Mahidol University,
Rama 6 Road, Ratchthewee
Bangkok 10400 Thailand
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Tuesday 4 April 2017

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

*Corresponding authors

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

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

    str5
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

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

    str5
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

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

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.
Graphical abstract: A catalytic aldol condensation system enables one pot conversion of biomass saccharides to biofuel intermediates
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