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

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• -methacryloyloxyethylsuccinoyl chloride in neat CF3CO2H could directly furnish an acrylic hydroxyproline monomer equipped with a linker segment [47]. This was later exploited by others (detailed later). The stability of hydroxyproline in the strongly acidic medium was found to be reassuring, substantiating the 1972 work by

Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

• Erdal Ertas,
• İlknur Demirtas and
• Turan Ozturk

Beilstein J. Org. Chem. 2015, 11, 403–415, doi:10.3762/bjoc.11.46

• iodides 40 using potassium iodide. Treatment of 40 with the dianionic salt 5 in dry acetone at room temperature produced 41 [55], which was transformed into the corresponding oxo form 42 by applying the same reaction conditions used to obtain 26a. Coupling of 26a with 42 was performed in neat triethyl

• ; (ii) LiAlH4, dry ether, rt, 24 h; (iii) tosyl chloride, dry pyridine, 0 °C, 4 h; (iv) KI, dry acetone, N2, reflux, overnight; (v) dry THF, 75 °C, N2, 48 h; (vi) P4S10, toluene, reflux, 3 h; (vii) Hg(OAc)2, AcOH/CHCl3, rt, 2 h; (viii) neat (EtO)3P, N2, 3 h; (ix) sample in THF at 0 oC , add 20% HCl

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• –h was prepared including alkyl, aryl, and silyl ethers. Most of the compounds were prepared by solvolysis of cholesteryl p-tosylate in an appropriate alcohol (neat or mixed with dioxane) in the presence of potassium acetate as a buffer. TBDMS ether 6h was obtained by silylation of i-cholesterol 6a

Enantioselective synthesis of polyhydroxyindolizidinone and quinolizidinone derivatives from a common precursor

• Nemai Saha and
• Shital K. Chattopadhyay

Beilstein J. Org. Chem. 2014, 10, 3104–3110, doi:10.3762/bjoc.10.327

• -piperidine derivative 7 (Scheme 1) in very good yield. The 4-OH group in compound 7 was then protected as its TBDMS ether (8) wherein the use of TBS triflate was essential as the more conventional TBSCl was found to be ineffective. Treatment of the free amino group in 8 with neat acrylic acid provided the

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• ether (Et2O) were investigated as the reaction media. Additionally, both lipase catalysts were also screened in neat vinyl acetate (Table 1). The courses of all the enzymatic reactions were monitored by gas chromatography (GC), arrested deliberately after 7 days, and only then their final evolution were

Modification of physical properties of poly(L-lactic acid) by addition of methyl-β-cyclodextrin

• Toshiyuki Suzuki,
• Ayaka Ei,
• Yoshihisa Takada,
• Hiroki Uehara,
• Takeshi Yamanobe and
• Keiko Takahashi

Beilstein J. Org. Chem. 2014, 10, 2997–3006, doi:10.3762/bjoc.10.318

• temperature. The neat PLLA film was prepared with same way. The obtained films were dried in vacuo. Casted films with MeCD/PLLA ratios of 1:1 (50 wt % PLLA), 1:2 (67 wt % PLLA), and 1:5 (83 wt % PLLA) were prepared. The samples were abbreviated as PL-MCD and the wt % values of PLLA were written after the

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

• Diego Cortizo-Lacalle,
• Calvyn T. Howells,
• Upendra K. Pandey,
• Joseph Cameron,
• Neil J. Findlay,
• Anto Regis Inigo,
• Tell Tuttle,
• Peter J. Skabara and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283

• investigate aggregation we prepared films of neat 9 and 10 for PLQY measurements. At an excitation of 550 nm we acquired a PLQY of 1.5% for 9 and 0.8% for 10. The spectra from the integrating sphere are shown in Figures S5 and S6 (Supporting Information File 1). This difference in PLQY is a firm indication of

• carrier efficiency (IPCE) setup consisting of a NPL calibrated photodiode, Keithley 6517A picoammeter and a TMc300 monochromator. For microscopy and photophysical studies, films were prepared from chlorobenzene on fused silica substrates. Neat films were prepared from a 10 mg mL−1 solution and composite

Design and synthesis of novel bis-annulated caged polycycles via ring-closing metathesis: pushpakenediol

• Sambasivarao Kotha and
• Mirtunjay Kumar Dipak

Beilstein J. Org. Chem. 2014, 10, 2664–2670, doi:10.3762/bjoc.10.280

• mmol) in a dropwise manner. After completion of the reaction (TLC monitoring, 11 h), the solvent was evaporated under reduced pressure, and the residue was purified by silica-gel column chromatography (3% ethyl acetate/petroleum ether) to give 19 (1.13 g, 71.5%) as a thick yellow liquid. IR (Neat) νmax

Total synthesis of the proposed structure of astakolactin

• Takayuki Tonoi,
• Keisuke Mameda,
• Moe Fujishiro,
• Yutaka Yoshinaga and
• Isamu Shiina

Beilstein J. Org. Chem. 2014, 10, 2421–2427, doi:10.3762/bjoc.10.252

• . After evaporation of the solvent, the crude product was purified by thin-layer chromatography on silica gel (hexane/ethyl acetate 2:1) to afford 1 (9 mg, 71%). IR (neat): 3455, 2931, 1735 cm−1; 1H NMR (CDCl3) δ 7.33 (s, 1H, 5’’-H), 7.21 (s, 1H, 2’’-H), 6.27 (s, 1H, 4’’-H), 5.33 (t, J = 7.5 Hz, 1H, 1’-H

Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

• Christopher Albler,
• Ralph Hollaus,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2014, 10, 2230–2234, doi:10.3762/bjoc.10.231

• maintain our procedure as simple as possible. Hence, compounds 6a–c were acetylated under standard conditions, subsequently reduced with DTT/DIPA and N-acetylated to yield compounds 7a–c which could be easily purified. Final treatment with sodium methoxide in dry methanol then furnished the neat title

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• in presence and in absence of a copper catalyst. Interestingly, the byproduct 13 was formed in 83% conversion (GC–MS) without adding a catalyst to the reaction under neat conditions. Pathways to intermediate 8 for routes E and F The third potential substrates for formation of target structure 1 are

Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

• Meriem Smadhi,
• Sophie de Bentzmann,
• Anne Imberty,
• Marc Gingras,
• Raoudha Abderrahim and
• Peter G. Goekjian

Beilstein J. Org. Chem. 2014, 10, 1981–1990, doi:10.3762/bjoc.10.206

• = 0.42. [α]D +14.5 (c 1, H2O); IR (neat) υ = 3287.6 cm−1 (OH) 1474.3 (triazole); 1H NMR (400 MHz, DMSO-d6) δ 8.20 ppm (s, 3H, H-d), 5.45 (d, J = 9.2 Hz, 3H, H-1), 5.22 (d, J = 6.0 Hz, 3H, OH-2), 5.01 (d, J = 5.7 Hz, 3H, OH-3), 4.69 (t, 3H, OH-6), 4.64 (d, J = 5.4 Hz, 3H, OH-4), 4.52 (s, 6H, H-b), 4.01

Relay cross metathesis reactions of vinylphosphonates

• Raj K. Malla,
• Jeremy N. Ridenour and
• Christopher D. Spilling

Beilstein J. Org. Chem. 2014, 10, 1933–1941, doi:10.3762/bjoc.10.201

• ethylimidazole would reacted with dimethyl methylphosphonate to give ethylimidazolium methylphosphonate in quantitative yield [32]. We were pleased to observe [31P NMR] that dimethyl vinylphosphonate 12b reacted with neat methylimidazole at 100 °C to give the imidazolium salt 37 (Scheme 13). Treatment of the

Synthesis of a bifunctional cytidine derivative and its conjugation to RNA for in vitro selection of a cytidine deaminase ribozyme

• Nico Rublack and
• Sabine Müller

Beilstein J. Org. Chem. 2014, 10, 1906–1913, doi:10.3762/bjoc.10.198

• stirring 16 in a 1:1 mixture of concentrated aqueous ammonia and methylamine. Subsequent treatment of 17 with triethylamine trihydrofluoride (TEA·3HF) at 55 °C for 2 h delivered compound 18, which was reacted with neat TFA. Each deprotection step was monitored by MALDI mass spectrometry. The

Macrocyclic bis(ureas) as ligands for anion complexation

• Claudia Kretschmer,
• Gertrud Dittmann and
• Johannes Beck

Beilstein J. Org. Chem. 2014, 10, 1834–1839, doi:10.3762/bjoc.10.193

• 578.2 clearly indicate the masses of the neat macrocycle 2 and the complex [NO3·2]. Signals originating from higher masses at 640.13 (2 with two molecules nitrate) or 1094.31 (two molecules of 2 with one molecule nitrate) could not be detected. So the 1:1 binding mode seems the most plausible ratio