Nanoscale graphene oxide sheets (NGO), as activated carbocatalysts, were synthesized by a reduction size strategy and used in chemoselective oxidative conversion of benzylic C–H to the corresponding carboxylic acid. On the basis of the results of the optimization process of different parameters, 3 equiv of H2O2 for each C–H group, 100 wt % of NGO in aqueous medium, acetone as a cosolvent, and a reaction temperature of 100 °C were selected as optimum parameters.

In this optimum condition, xylenes and toluene over 24 h with good yield were converted to the corresponding carboxylic acid, and in the case of diphenylmethane and ethylbenzene, these substrates with excellent yield were converted to benzophenone and acetophenone.

Selective Oxidation of Benzylic C–H Using Nanoscale Graphene Oxide as Highly Efficient Carbocatalyst: Direct Synthesis of Terephthalic Acid

Masoud Heidari, Alireza Sedrpoushan* , and Farajollah Mohannazadeh

Institute of Industrial Chemistry, Iranian Research Organization for Science and Technology (IROST), P.O. Box 33535-111, Tehran, Iran

Org. Process Res. Dev., Article ASAP

DOI: 10.1021/acs.oprd.7b00056

http://pubs.acs.org/doi/full/10.1021/acs.oprd.7b00056

 

*Tel.: +98 21 56276031. E-mail address: sedrpoushan1395@gmail.com (Alireza Sedrpoushan).

 

  

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A Brønsted acid catalysed enantioselective Biginelli reaction

A Bronsted acid catalysed enantioselective Biginelli reaction

Green Chem., 2017, 19,1529-1535
DOI: 10.1039/C6GC03274E, Paper

Margherita Barbero, Silvano Cadamuro, Stefano Dughera
A chiral derivative of 1,2-benzenedisulfonimide, namely (-)-4,5-dimethyl-3,6-bis(o-tolyl)-1,2-benzenedisulfonimide is herein proven to be an efficient chiral catalyst in a one pot three-component Biginelli reaction.

 

A Brønsted acid catalysed enantioselective Biginelli reaction

Margherita Barbero,a   Silvano Cadamuroa and  Stefano Dughera*a  

*Corresponding authors

aDipartimento di Chimica, Università di Torino, C.so Massimo d'Azeglio 48, 10125 Torino, Italy
E-mail: stefano.dughera@unito.it

Green Chem., 2017,19, 1529-1535

DOI: 10.1039/C6GC03274E

A chiral derivative of 1,2-benzenedisulfonimide, namely (−)-4,5-dimethyl-3,6-bis(o-tolyl)-1,2-benzenedisulfonimide is herein proven to be an efficient chiral catalyst in a one pot three-component Biginelli reaction. In fact the yields of the target dihydropyrimidines were very high (25 examples; average 91%) and enantiomeric excesses were always excellent (14 examples; average 97%). Ultimately, we herein propose a procedure that displays a number of benefits and advantages including the total absence of solvents, mild reaction conditions, relatively short reaction times and stoichiometric reagent ratios. Target dihydropyrimidines are obtained in adequate purity, making further chromatographic purification unnecessary. Moreover, the chiral catalyst was easily recovered from the reaction mixture and reused, without the loss of catalytic activity.

 

dihydropyrimidine-2-thiones 5

(R)-(-)-Ethyl 6-methyl-4-phenyl-2-thioxo-3,4-dihydropyrimidine-5-carboxylate (5a): pale grey solid (135 mg, 98% yield); mp 201–202 °C ( from EtOH; lit17 200–202 °C). 96.4% Ee (GC connected to a J&W Scientific Cyclosil-B column; stationary phase: 30% heptakis (2,3-di-Omethyl-6-O-t-butyldimethylsilyl)-β-cyclodextrin in DB-1701), tR= 12.11 min (major), tR= 12.54 min (minor); [a]D -65.4 (c 0.1 in MeOH). 1H NMR (200 MHz, DMSO-d6): δ = 10.24 (br s, 1H), 9.55 (br s, 1H), 7.31–7.12 (m, 5H), 5.09 (d, J = 3.9 Hz, 1H), 3.92 (q, J = 7.0 Hz, 2H), 2.21 (s, 3H), 1.01 (t, J = 7.0 Hz, 3H); 13C NMR (50 MHz, DMSO-d6): δ = 174.9, 165.8, 145.7, 129.3, 128.3, 127.0, 101.3, 60.2, 54.7, 17.8, 14.7. MS (m/z, EI): 276 [M+ ] (45), 247 (40), 199 (100). IR (neat) ν (cm−1): 3311 (NH), 3112 (NH), 1665 (CO), 1195 (CS).

 

 

 

Dughera Dott. Stefano

Tel: 0116707645
Email: stefano.dughera@unito.it
address: Department of Chemistry

Dipartimento di Chimica, Università di Torino, C.so Massimo d'Azeglio 48, 10125 Torino, Italy

R. Fu, Y. Yang, W. Lai, Y. Ma, Z. Chen, J. Zhou, W. Chai, Q. Wang, and R. Yuan, Synth. Comm., 2015, 45, 477.

 

//////////////Brønsted acid,  catalysed,  enantioselective,  Biginelli reaction, dihydropyrimidine-2-thiones

5-chloro-6-morpholinonicotinic acid

Preparation of 5-chloro-6-morpholinonicotinic acid (18)1
A solution of ethyl 5,6-dichloronicotinate (A-1, 1.1 g, 5.0 mmol), N,N-diisopropylethylamine (DIPEA, 0.97
g, 7.5 mmol) in acetonitrile (3.0 mL) was treated with morpholine (0.48 g, 6.0 mmol). The mixture was
stirred for 6 hours at 95 °C. The complete conversion of the starting material could be detected by
observing a change of the color from yellowish to deep orange. After complete conversion, the mixture was
evaporated to dryness, the residue diluted with water (20 mL), and extracted with dichloromethane (3x20
mL). The combined organic layer was dried over sodium sulfate and evaporated under reduced pressure to
yield 1.31 g (97 %) of A-2 as a red oil. The product was identified by LC/ESI-MS analysis and used for the
next synthetic step without further purification.
The ester A-2 (1.31 g, 4.83 mmol) was dissolved in a tetrahydrofurane/water mixture (1:1, 4.0 mL) and
treated with 2.0 M sodium hydroxide (0.33 g, 5.80 mmol). The reaction mixture was stirred for 5 h at 55 °C.
After complete conversion, the mixture was cooled to room temperature, diluted with water (20 mL) and
extracted with ethyl acetate (3x20 mL). The water layer was neutralized with an aqueous solution of
hydrochloric acid (2.0 N) until a white precipitate was observed. The product was collected by repeated
filtration and evaporation. The combined product fractions were dried at 70 °C yielding 1.17 g (100 %) of
18 as a white solid,

m.p. 185.2–186.2;

1H NMR (500 MHz, DMSO-d6) δ (ppm) 3.45 (t, J = 5.04 Hz, 2xCH2,4H), 3.72 (t, J = 4.41 Hz, 2xCH2, 4H), 8.08 (d, J = 1.89 Hz, CH, 1H), 8.66 (d, J = 1.90 Hz, CH, 1H), 13.01(s, CO2H, 1H). 13C (125 MHz, DMSO-d6) δ (ppm) 48.9 (2xCH2), 66.1 (2xCH2), 119.4, 139.7, 147.5, 159.3,
165.4;

LC/ESI-MS (m/z): 243.28 [M+H]+; Purity: 100.0 % (N).

Colandrea, V. J.; Doherty, G. A; Hale, J. J.; Huo, P.; Legiec, I. E.; Toth, L.; Vachal, P.; Yan, L. (3,4-
Disubstituted)propanoic carboxylates as S1P (EDG) receptor agonists. PCT Int. Appl. WO2005058848A1, 2005 (Merck & Co., Inc.).

Supporting Information

https://s3-eu-west-1.amazonaws.com/pstorage-acs-6854636/.../jm500729a_si_001.pdf

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

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

white solid . Mp: 193–195 °C.

 

1H NMR (400 MHz, CDCl3) δ (ppm): 7.74–7.76(m, 1H), 7.14–7.17 (m, 1H), 6.95–6.97 (m, 1H), 6.05 (s, 1H), 5.51 (s, 2H), 3.40 (s, 3H).

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]+).

A two-step efficient preparation of a renewable dicarboxylic acid monomer 5,5[prime or minute]-[oxybis(methylene)]bis[2-furancarboxylic acid] from D-fructose and its application in polyester synthesis

 

Green Chem., 2017, 19,1570-1575
DOI: 10.1039/C6GC03314H, Paper

Ananda S. Amarasekara, Loc H. Nguyen, Nnaemeka C. Okorie, Saad M. Jamal
A renewable monomer 5,5[prime or minute]-[oxybis(methylene)]bis[2-furancarboxylic acid] from D-fructose.

A two-step efficient preparation of a renewable dicarboxylic acid monomer 5,5′-[oxybis(methylene)]bis[2-furancarboxylic acid] from D-fructose and its application in polyester synthesis

Ananda S. Amarasekara,*a   Loc H. Nguyen,a  Nnaemeka C. Okoriea and   Saad M. Jamala  

*Corresponding authors

aDepartment of Chemistry, Prairie View A&M University, Prairie View, USA
E-mail: asamarasekara@pvamu.edu
Fax: +1 936 261 3117
Tel: +1 936 261 3107

Green Chem., 2017,19, 1570-1575

DOI: 10.1039/C6GC03314H

D-Fructose was converted to the dialdehyde 5,5′-[oxybis(methylene)]bis[2-furaldehyde] by heating at 110 °C in DMSO with the Dowex 50 W X8 solid acid catalyst in 76% yield without the isolation of the intermediate 5-hydroxymethylfurfural. This dialdehyde was then converted to the dicarboxylic acid monomer, 5,5′-[oxybis(methylene)]bis[2-furancarboxylic acid], using oxygen (1 atm.) and 5% Pt/C catalyst in 1.5 M aqueous NaOH at room temperature in 98% yield. The new dicarboxylic acid monomer can be considered as a renewable resource based alternative to terephthalic acid as demonstrated by the preparation of polyesters with 1,2-ethanediol and 1,4-butanediol in 87–92% yield.

 

Synthesis of 5,5'-[oxybis(methylene)]bis[2-furancarboxylic acid]

 

pale yellow crystals. 260 mg, 98 % yield. M.pt. 207-209 °C, Lit. M. pt. 209-210 °C 37 .

 

IR (ATR) 761, 891, 951, 1029, 1059, 1159, 1208, 1283, 1342, 1424, 1525, 1674, 3128 cm-1

 

1 H NMR (DMSO-d6 ) δ 3.38 (2H, bs, 2XCOOH), 4.51 (4H, s, 2X-CH2O ), 6.61 (2H, d, J = 3.6 Hz, C-4,4'), 7.15 (2H, d, J = 3.6 Hz, C-3,3').

 

13C NMR (DMSO-d6 ) δ 63.8, 112.2, 118.8, 145.3, 155.5, 159.6

37. T. Iseki and T. Sugiura, J. Biochem., 1939, 30, 113-118.

 

NMR PREDICT

1H NMR PREDICT

 

 

 

13C NMR PREDICT

 

 

//////////////O=C(O)c2ccc(COCc1ccc(o1)C(=O)O)o2

5,6-dihydropteridin-7(8H)-one

5,6-dihydropteridin-7(8H)-one

 

Org. Process Res. Dev., 2017, 21 (1), pp 11–17

DOI: 10.1021/acs.oprd.6b00219

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