Reactions of N,3-diarylpropiolamides with arenes under superelectrophilic activation: synthesis of 4,4-diaryl-3,4-dihydroquinolin-2(1H)-ones and their derivatives

• Larisa Yu. Gurskaya,
• Diana S. Belyanskaya,
• Dmitry S. Ryabukhin,
• Denis I. Nilov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 950–956, doi:10.3762/bjoc.12.93

• yields of the target products. Thus, it is better to conduct the reaction in neat TfOH, which is a good weak nucleophilic medium for the stabilization of the intermediate cationic species. No concurrent formation of the corresponding 4-arylquinolinones 3 was observed, and in most cases the yields of the

Iridium/N-heterocyclic carbene-catalyzed C–H borylation of arenes by diisopropylaminoborane

• Mamoru Tobisu,
• Takuya Igarashi and
• Naoto Chatani

Beilstein J. Org. Chem. 2016, 12, 654–661, doi:10.3762/bjoc.12.65

• instability of 11-B during isolation (Table 2, entry 8). Our protocol was able to borylate non-benzofused five-membered heteroarenes. Pyrrole 12 was much less reactive than indoles, and required neat conditions to obtain a modest yield of the borylated product 12-B (Table 2, entry 9). Thiophene (13) afforded

• 1g afforded 17-B in 48% isolated yield even when the reaction was conducted under neat conditions (Table 3, entry 1) (see the Supporting Information File 1 for details on the optimization for the borylation of benzene). Borylation was relatively independent of the electronic nature of the arene

Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions

• José M. Andrés,
• Miriam Ceballos,
• Alicia Maestro,
• Isabel Sanz and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2016, 12, 628–635, doi:10.3762/bjoc.12.61

• the thiourea derived from (L)-valine and 1,6-hexanediamine. The catalysts can be used in only 2 mol % loading, and reused for at least four cycles in neat conditions. The ball milling promoted additions also worked very well. Keywords: bifunctional organocatalysts; organocatalysis; stereoselective

• nucleophile in neat conditions and in different solvents. For comparative purposes, the same reactions were studied in the presence of unsupported catalysts I and VI, and the results are summarized in Scheme 1 and Table 1. Initially, the reactions were carried out in neat conditions at rt with twofold excess

• ) reacted very well with 1a, leading to 5ae in excellent yield and enantioselectivity, but only moderate diastereoselectivity (dr 70:30, Table 3, entry 10). To test the recyclability of catalyst V we choose the reaction of 1a with 3a in neat conditions and 5 mol % of catalyst as model. Once the reaction had

Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

• Julia Wappel,
• Roland C. Fischer,
• Luigi Cavallo,
• Christian Slugovc and
• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17

• polymerization of DCPD is their outstanding solubility in the neat monomer. The main challenge of the polymerization of DCPD is to guarantee an adequate mixing of monomer and catalyst to obtain a homogenous reaction mixture and moreover a steady polymerization product. DCPD is also prone to undergo a retro-Diels

Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports

• Krzysztof Skowerski,
• Jacek Białecki,
• Stefan J. Czarnocki,
• Karolina Żukowska and
• Karol Grela

Beilstein J. Org. Chem. 2016, 12, 5–15, doi:10.3762/bjoc.12.2

• yet powerful procedure gives access to a modified complex with multitude of possible applications [43][44][45][46][47]. We have found that the introduction of an ammonium chloride tag into the NHC ligand results in catalysts with interesting properties such as solubility in neat water as well as

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• polyrotaxane compounds exhibit a granular morphology with lower dispersity and smaller roughness exponent of the film surfaces in comparison with those of the neat copolymer 3. Keywords: energy band gaps; fluorescence lifetimes; permethylated cyclodextrins; polyfluorene; polyrotaxanes; Introduction Over the

• γCD [43][44][45], or TMS-γCD [46]. Therefore, 3·TM-βCD and 3·TM-γCD polyrotaxanes were synthesized by Suzuki coupling of 1 being in the form of its IC (1·TM-βCD or 1·TM-γCD) with 2 followed by the termination of the growing chains by bromobenzene, Scheme 1. To have the reference the neat copolymer 3

• Table 1. Two things should be noted here concerning the lower Mn of 3·TM-βCD and 3·TM-γCD polyrotaxanes than that of the neat copolymer 3. Firstly, the less ability of ester groups from molecule 2 to partially penetrate the macrocyclic cavities in the condensation reaction due to the sterical hindrance

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• further development of 2ME. Results and Discussion Interaction between 2ME and native CDs Initial studies focused on possible isolation of solid inclusion complexes of 2ME with the native cyclodextrins α-, β- and γ-CD. Following neat co-grinding of each CD and 2ME (1 h, 1:1 molar ratios) and kneading (1 h

Cu(I)-catalyzed N,N’-diarylation of natural diamines and polyamines with aryl iodides

• Svetlana P. Panchenko,
• Alexei D. Averin,
• Maksim V. Anokhin,
• Olga A. Maloshitskaya and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2015, 11, 2297–2305, doi:10.3762/bjoc.11.250

• -aryldiamines using aryl iodides in the presence of CuCl under neat conditions [28], N,N’-diarylation of the simplest propane-1,3-diamine and butane-1,4-diamine was carried out using a CuI-metformin catalyst [29], monoarylation of mono- and diamines was studied using Cu2O and CuO nanoparticles and CuO

Self-assemblies of γ-CDs with pentablock copolymers PMA-PPO-PEO-PPO-PMA and endcapping via atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine

• Jing Lin,
• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2015, 11, 2267–2277, doi:10.3762/bjoc.11.247

• indicated that the entrapped γ-CDs restrict the central PEO segment from aggregating to form the crystalline phase [24]. The neat pentablock copolymer PR0CD30P gave rise to an endothermic peak for PEO at 44.2 °C. At the same time, weak endothermic peaks at 38.6°C and 37.9°C were observed in two PR samples

Evidencing an inner-sphere mechanism for NHC-Au(I)-catalyzed carbene-transfer reactions from ethyl diazoacetate

• Manuel R. Fructos,
• Juan Urbano,
• M. Mar Díaz-Requejo and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2015, 11, 2254–2260, doi:10.3762/bjoc.11.245

• precursors were dissolved in the neat substrate (5 mL) and stirred for 30 min to ensure halide abstraction prior to EDA addition. The experiments have been carried out using a flask connected to a pressure gauge that provides the variation in the increase of the internal pressure (see Experimental). Figure 1

Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

• Hynek Balcar,
• Naděžda Žilková,
• Martin Kubů,
• Michal Mazur,
• Zdeněk Bastl and
• Jiří Čejka

Beilstein J. Org. Chem. 2015, 11, 2087–2096, doi:10.3762/bjoc.11.225

• composition of the neat compounds calculated from the integrated intensities of photoelectron spectra and their nominal stoichiometry was observed. For HGIIN+Cl−/SBA-15 the atomic ratio Cl/Ru = 3 indicates both cationic and anionic parts of the parent complex were present in the hybrid catalysts, as shown

• . Textural parameters of MCM-22, MCM-56, MCM-36, and corresponding hybrid catalysts. Atomic concentration ratios of N, F, Cl, and P to Ru determined from XP spectra for neat HGIIN+X (X = Cl−, PF6−) and hybrid catalysts HGIIN+Cl−/MCM-22, HGIIN+Cl−/SBA-15, and HGIIN+PF6−/MCM-22. (For HGIIN+PF6−/MCM-22 catalyst

Stereochemistry of ring-opening/cross metathesis reactions of exo- and endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitriles with allyl alcohol and allyl acetate

• Piotr Wałejko,
• Michał Dąbrowski,
• Lech Szczepaniak,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 1893–1901, doi:10.3762/bjoc.11.204

• are discussed. Surprisingly good yields of the ROCM products were obtained under neat conditions. Keywords: Grubbs’ catalysts; metathesis; ROCM; ROMP; Z-selectivity; Introduction Substituted tetrahydrofurans are a common motif found in many biologically active natural products [1][2], e.g

• and their E/Z stereochemistry was studied. Our results seem to be in some contradiction to the commonly accepted opinion that ROCM reactions should be carried out in high dilution to avoid polymerization. It was found that ROCM reactions proceed quite efficiently even under neat conditions

• and 12) gave substantially higher yields of ROCM products. Our results seem to be in contradiction to those reported by Blechert [15] and Arjona [20]. Satisfactory results were obtained even when the reactions were carried out under neat conditions (Table 1, entries 5, 6, 9, and 12). Furthermore, the

Preparation of conjugated dienoates with Bestmann ylide: Towards the synthesis of zampanolide and dactylolide using a facile linchpin approach

• Jingjing Wang,
• Samuel Z. Y. Ting and
• Joanne E. Harvey

Beilstein J. Org. Chem. 2015, 11, 1815–1822, doi:10.3762/bjoc.11.197

• (neat) cm−1: 2958 (m), 2929 (m), 1706 (s), 1625 (s), 1449 (m), 1236 (s), 1172 (s), 997 (m), 689 (m); HRMS (ESI) m/z: [M + H]+ calcd for C17H21O2, 257.1536 found, 257.1529, (Δ = 2.7 ppm). (1′R,2′S,5′R,2E,4E,6E)-2′-Isopropyl-5′-methylcyclohex-1′-yl deca-2,4,6-trienoate (11f). Rf = 0.14 (40:1 pet

• , 3H), 0.87 (partially obs. m, 1H), 0.76 (d, J = 7.1 Hz, 3H); 13C NMR (125 MHz, CDCl3) δ 166.8, 144.6, 141.0, 140.2, 130.0, 127.8, 120.5, 73.9, 47.2, 41.0, 35.0, 34.3, 31.4, 26.3, 23.6, 22.2, 22.0, 20.7, 16.4, 13.7; IR (neat) cm−1: 2955 (s), 2930 (s), 2869 (s), 1694 (s), 1615 (s), 1456 (m), 1342 (m

• , 7.1 Hz, 1H), 2.63 (dd, J = 16.9, 5.9 Hz, 1H), 0.14 (s, 9H); 13C NMR (125 MHz, CDCl3) δ 166.2, 159.2, 145.2, 140.7, 136.0, 130.1, 129.3, 129.1, 128.8, 127.2, 126.2, 121.0, 113.8, 101.9, 87.1, 73.0, 70.7, 69.4, 55.2, 22.3, 0.00; IR (neat) cm−1: 3028 (w), 2957 (m), 2901 (m), 2178 (m), 1709 (s), 1625 (s

Influence of bulky yet flexible N-heterocyclic carbene ligands in gold catalysis

• Alba Collado,
• Scott R. Patrick,
• Danila Gasperini,
• Sebastien Meiries and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 1809–1814, doi:10.3762/bjoc.11.196

• catalytic activity of complexes 7–9 in the synthesis of homoallylic ketones via hydroalkoxylation/Claisen rearrangement [61][62]. [Au(NHC)(NTf2)] complexes have proven to be efficient catalysts for this transformation, promoting the reaction under neat conditions and low catalyst loadings [61]. The

A facile synthetic route to benzimidazolium salts bearing bulky aromatic N-substituents

• Gabriele Grieco,
• Olivier Blacque and
• Heinz Berke

Beilstein J. Org. Chem. 2015, 11, 1656–1666, doi:10.3762/bjoc.11.182

• -benzenediamines 5, 6, 7 and 8. i) Pd(dba)2, P(t-Bu)3, t-BuONa, toluene, 92 °C. ii) Pd(dba)2, P(t-Bu)3, t-BuONa, toluene, 115 °C. iii) SNAr reaction: 2-chloropyridine, neat, 185 °C, microwave. Previous synthesis of the benzannulated NHCs 3-Cl and 4-BF4. Ring closure. i) (EtO)3CH, HCl (conc.), HCOOH, 80 °C [44]. ii

Design and synthesis of hybrid cyclophanes containing thiophene and indole units via Grignard reaction, Fischer indolization and ring-closing metathesis as key steps

• Sambasivarao Kotha,
• Ajay Kumar Chinnam and
• Mukesh E. Shirbhate

Beilstein J. Org. Chem. 2015, 11, 1514–1519, doi:10.3762/bjoc.11.165

• products were purified by column chromatography to obtain the diol 6 (or 6a). Compound 6: Semi solid, 104 mg (52%), by using the general procedure 100 mg (0.71 mmol) of thiophene-2,5-carbaldehyde 4 was reacted with 4-pentenylmagnesium bromide. IR (neat): 3943, 3677, 3601, 3050, 2923, 1261, 739 cm−1; 1H NMR

• (Q-Tof) m/z: [M + Na]+ calcd for C16H24NaO2S, 303.1389; found, 303.1394. Compound 6a: Semi solid, 107 mg (48%), by using the general procedure 100 mg (0.71 mmol) of thiophene-2,5-carbaldehyde 4 was reacted with 5-hexenylmagnesium bromide. IR (neat): 743, 1270, 2933, 3042, 3589, 3694, 3942 cm−1; 1H

• (73%), by using the general procedure 100 mg (0.35 mmol) of thiophene derivative 6 was oxidized with MnO2 to deliver 3. IR (neat): 738, 1267, 1687, 2934, 3055, 3357, 3690, 3945 cm−1; 1H NMR (400 MHz, CDCl3) δ 1.84 (q, J = 7.28 Hz, 4H), 2.15 (q, J = 7.05 Hz, 4H), 2.93 (t, J = 4.12 Hz, 4H), 4.99–5.07 (m

Synthesis of a tricyclic lactam via Beckmann rearrangement and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha,
• Ongolu Ravikumar and
• Jadab Majhi

Beilstein J. Org. Chem. 2015, 11, 1503–1508, doi:10.3762/bjoc.11.163

• mixture of amide isomers 9a and 9b (1.06 g, 48%). The amide mixture was crystalized in different solvents and finally isomer 9a was isolated from ethanol. White solid 9a; mp = 150–155 °C; yield 15%: Rf = 0.30 (EtOAc/pentane 1:1 v/v); IR (neat): 3195 (m), 3067 (w), 2938 (s), 2868 (m), 1674 (s), 1627 (m

• chromatography by eluting appropriate mixture of ethyl acetate/petroleum ether to afford compounds 11a (2.29 g, 23%) and 11b (4.61 g, 47%) as colourless solids. 11a: Rf = 0.29 (EtOAc/pentane 2:8 v/v); IR (neat): 3325 (m), 3013 (m), 2400 (w), 1725 (w), 1337 (w), 1216 (m), 927 (m), 759 (s) cm−1; 1H NMR (500 MHz

• (125 Hz, CDCl3) δ 165.1, 149.1, 133.3, 133.1, 126.4, 51.0, 50.5, 46.1, 45.9, 44.1 ppm; HRMS (Q-Tof) m/z: [M + Na]+ calcd for C10H11NNaO, 184.0733; found, 184.0734. 11b: mp = 89–91 °C; Rf = 0.30 (EtOAc/petroleum ether 2:8 v/v); IR (neat): 3322 (m), 3020 (m), 2396 (w), 2125 (w), 1705 (m), 1217 (m), 926

Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

• Karolina Żukowska,
• Eva Pump,
• Aleksandra E. Pazio,
• Krzysztof Woźniak,
• Luigi Cavallo and
• Christian Slugovc

Beilstein J. Org. Chem. 2015, 11, 1458–1468, doi:10.3762/bjoc.11.158

• initiation efficacy is above all determined by the position of the trans–cis equilibrium which can be quickly reached at 110 °C [29][55]. In the second step, the initiators were tested in neat monomer using simultaneous thermal analysis (STA) for monitoring the polymerizations. As the monomer, either endo

Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• . A low activation barrier found for the CO2 insertion into the zinc–alkoxide bond may be related to the use of a relatively high energy unsaturated 16-electron complex. In the reaction mixture of neat cyclohexene oxide, the complex will readily coordinate additional cyclohexene oxide as solvent

One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea

• Mohammad Abbasi and
• Reza Khalifeh

Beilstein J. Org. Chem. 2015, 11, 1265–1273, doi:10.3762/bjoc.11.141

• NMR (250 MHz, CDCl3) δ 7.95–7.91 (m, 2H), 7.58–7.52 (m, 1H), 7.45–7.39 (m, 2H), 3.24 (t, J = 6.7 Hz, 2H), 2.86 (t, J = 6.7 Hz, 2H), 2.16 (s, 3H); 13C NMR (62.5 MHz, CDCl3) δ 206.5, 191.9, 136.8, 133.5, 128.6, 127.2, 43.4, 29.9, 22.7; IR (neat) ν (cm−1): 1717 (C=O ketone), 1655 (C=O thioester); anal

• –1.54 (m, 2H), 1.43–1.31 (m, 2H), 0.90 (t, J = 7.3 Hz, 3H); 13C NMR (62.5 MHz, CDCl3) δ 191.5, 171.8, 136.8, 133.5, 128.6, 127.2, 64.7, 34.5, 30.6, 24.1, 19.1, 13.7; IR (neat) ν (cm−1): 1732 (C=O ester), 1666 (C=O thioester); anal. calcd for (C14H18O3S): C, 63.13; H, 6.81; S, 12.04; found: C, 63.19; H

• , 22.7, 14.1; IR (neat) ν (cm−1): 1666 (C=O thioester); anal. calcd for (C17H26OS): C, 73.33; H, 9.41; S, 11.52; found: C, 73.31; H, 9.48; S, 11.46. S-Prop-2-yn-1-yl benzothioate (19) 1H NMR (250 MHz, CDCl3) δ 7.88–7.84 (m, 2H), 7.53–7.46 (m, 1H), 7.40–7.33 (m, 2H), 3.75 (d, J = 2.7 Hz, 2H), 2.15 (t, J

Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Ongolu Ravikumar

Beilstein J. Org. Chem. 2015, 11, 1259–1264, doi:10.3762/bjoc.11.140

• , 47.6, 46.7, 45.9, 42.7, 41.2, 41.1, 40.9, 37.0, 32.3 ppm; HRMS (Q–ToF) m/z: [M + Na]+ calcd for C25H32NaO2, 359.1982; found, 359.1988; IR (neat) νmax: 3050, 2954, 1691, 1610, 1266 cm−1. 6b; 1H NMR (500 MHz, CD3OD) δ 6.23 (dd, J = 5.6, 3.0 Hz, 1H), 6.17 (dd, J = 5.7, 2.8 Hz, 1H), 6.15–6.08 (m, 1H), 5.95

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• external cooling using dry ice/acetone. Pleasingly, a simple flow setup in which the two streams of neat reagents were mixed in a PTFE T-piece maintained at 25 °C was found effective in order to prepare the desired adduct 68 in high yield and quality showcasing the benefits of superior heat dissipation

• results with the devised simulations. More recently, scientists at Novartis (Switzerland) extended this study by developing a semi-continuous flow approach for the synthesis of the oral antidiabetic vildagliptine (77) using in situ generated Vilsmeier reagent (Scheme 13) [74]. Neat streams of DMF and

• delivers the desired 1,4-triazole regioisomer without the need for a metal catalyst that requires stringent purification afterwards. Due to the reduced reactivity of 100 the crucial cycloaddition step was conducted neat at elevated temperature (210 °C) yielding pure 102 within short residence times (5–30

Properties of PTFE tape as a semipermeable membrane in fluorous reactions

• Brendon A. Parsons,
• Olivia Lin Smith,
• Myeong Chae and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2015, 11, 980–993, doi:10.3762/bjoc.11.110

• was followed by numerous improved and modified designs including a quadraphasic/tetraphasic PV reaction [10], a photochemical PV reaction [11][12], a stacked phase-vanishing reaction [13], a PV reaction on neat substrates [11][14][15][16] and, most recently, a Grignard reaction [17]. Jana and Verkade

• delivery tube is then inserted into a vessel which contains substrate, either neat or dissolved in a solvent. The reagent diffuses across the PTFE tape barrier into the outer vessel (Figure 1). The reaction generally takes place in the vessel, although in some instances due to the diffusion of the

• still vary between individual trials. A possible solution to this problem is to place bromine, or the reagent in general, dissolved in a suitable amount of solvent, into the delivery tube rather than using a neat reagent. The solvent uptake process can be controlled to an extent by varying the depth to

Chiroptical properties of 1,3-diphenylallene-anchored tetrathiafulvalene and its polymer synthesis

• Masashi Hasegawa,
• Junta Endo,
• Seiya Iwata,
• Toshiaki Shimasaki and
• Yasuhiro Mazaki

Beilstein J. Org. Chem. 2015, 11, 972–979, doi:10.3762/bjoc.11.109

• 203.0, 135.6, 131.7, 128.0, 120.7, 117.1, 28.8, 22.7, 22.4; IR (neat): 2961, 2926, 2870, 1919, 1489, 1464, 1074, 1009, 825 cm−1; HRMS (APCI-orbitrap) calcd for C21H22Br2 (M+) 432.0088; found, 432.0089. Synthesis of 9: To a solution of 1,3-bis(4-bromophenyl)allene derivative 8 (1.0 g, 2.3 mmol) in Et2O

• (neat): 2961, 2926, 2869, 1918, 1483, 1463, 1383, 1216 cm−1; HRMS (APCI-orbitrap) calcd for C21H22I2 (M+) 527.98108; found, 527.98108. Synthesis of 3: To a solution of 4,5-bis(methylthio)TTF (640 mg, 2.2 mmol) [20] in THF (30 mL) was added dropwise nC4H9Li (1.3 mL, 2.2 mmol) at –78 °C under Ar

Carboxylated dithiafulvenes and tetrathiafulvalene vinylogues: synthesis, electronic properties, and complexation with zinc ions

• Yunfei Wang and
• Yuming Zhao

Beilstein J. Org. Chem. 2015, 11, 957–965, doi:10.3762/bjoc.11.107

• 8.01 (d, J = 8.4 Hz, 2H), 7.25 (d, J = 8.3 Hz, 2H), 6.51 (s, 1H), 3.91 (s, 3H), 2.44 (d, J = 2.8 Hz, 6H) ppm; 13C NMR (75 MHz, CDCl3) δ 166.8, 140.5, 136.2, 129.9, 127.9, 126.7, 126.3, 124.5, 113.3, 52.0, 19.0, 18.9 ppm; FTIR (neat): 2914, 1704, 1599, 1567, 1545, 1492, 1422, 1265, 1175, 1096, 851, 798

• 7.97 (d, J = 8.7 Hz, 4H), 7.46 (d, J = 8.7Hz, 4H), 3.89 (s, 6H), 2.44 (s, 6H), 2.38 (s, 6H) ppm; 13C NMR (75 MHz, CDCl3) δ 166.6, 141.1, 140.3, 130.1, 129.1, 127.9, 126.1, 125.5, 122.9, 52.0, 18.9, 18.8 ppm; FTIR (neat): 2942, 2918, 1709, 1600, 1519, 1473, 1430, 1273, 1182, 1107, 766, 713, 465 cm−1

• = 8.5 Hz, 4H), 7.48 (d, J = 8.4 Hz, 4H), 2.48 (s, 6H), 2.40 (s, 6H) ppm; 13C NMR (75 MHz, DMSO-d6) δ 166.7, 140.0, 139.1, 130.0, 128.8, 126.8, 125.9, 125.1, 122.7, 18.2, 18.2 ppm; FTIR (neat): 2916-2536 (br), 1672, 1596, 1515, 1467, 1416, 1280, 1186, 789, 541, 469 cm−1; APPI–HRMS (m/z, negative mode) [M