Dendrimer Folding in Aqueous Media: An Example of Solvent-Mediated Chirality Switching (original) (raw)
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Supplementary Information Chem. Commun. 2012 D'Errico et al
All the reagents were obtained from commercial sources (Sigma-Aldrich) and were used without further purification. 1 H and 13 C-NMR spectra were acquired on a Varian Mercury Plus 400 MHz and on a Varian Unit Inova 700 MHz in CD 3 OD or CDCl 3 . Chemical shifts are reported in parts per million (δ) relative to the residual solvent signals: CD 2 HOD 3.31 and CHCl 3 7.27 for 1 H-NMR; CD 2 HOD 49.0 and CHCl 3 77.0 for 13 C-NMR. 1 H-NMR chemical shifts were assigned by 2D NMR experiments. The abbreviations s, bs, d, dd and m stand for singlet, broad singlet, doublet, doublet of doublets and multiplet, respectively. HPLC analyses and purifications were carried out on a Jasco UP-2075 Plus pump equipped with a Jasco UV-2075 Plus UV detector using a 4.60 x 150 mm LUNA (Phenomenex) silica column (particle size 5 µm) eluted with a linear gradient of MeOH in AcOEt (from 0 to 5% in 15 min, flow 1.0 mL min -1 , system A), with a linear gradient of AcOEt in n-hexane (from 0 to 100% in 30 min, flow 1.0 mL min -1 , system B) or using a 4.8 x 150 mm C-18 reverse-phase column (particle size 5 µm) eluted with a linear gradient of MeOH in H 2 O (from 0 to 100% in 30 min, flow 1.3 mL min -1 , system C). UV spectra were recorded on a Jasco V-530 UV spectrophotometer. High Resolution MS spectra were recorded on a Bruker APEX II FT-ICR mass spectrometer using electrospray ionization (ESI) technique in positive mode. Elemental analyses were performed on a Thermo Finnigan Flash EA 1112 CHN analyser. IR spectra were recorded on a Jasco FT-IR 430 spectrophotometer. Optical rotations were determined on a Jasco polarimeter using a 1 dm cell at 25 °C; concentrations are in g/100 mL. Preparative PLC chromatography was performed using F254 silica gel plates (0.5 mm thick, Merck). Analytical TLC analyses were performed using F254 silica gel plates (0.2 mm thick, Merck). TLC spots were detected under UV light (254 nm). For MTS assays the UV absorbance at 490 nm was read using a Beckman Anthos 96 well Microplate Reader.
N-Methyloxazolinium salts: diastereomer ratios by proton NMR
J Org Chem, 1985
Preparation of a+ Aspartyl-L-phenylalanine Methyl Ester Hydrochloride 9. L-Phenylalanine (7.4 g, 0.045 mol) was stirred in 90 mL of water. The pH of this solution was adjusted to 10.2 (0-2 'C) with 50% NaOH. Then a solution of pure NCA 7 (8.3 g, 0.048 mol) in 8 mL of THF was added in 15 min with vigorous stirring. The pH was maintained at 10.0-10.2 by the addition of 7 N NaOH solution. The reaction mixture was then stirred at 0-2 'C for 2 h (pH 10.0-10.2). One equivalent of 37% hydrochloric acid (9.7 g) was added at the end of the hold period. Liquid chromatography indicated an 80-82 % yield of aspartyl ester 8 based on L-phenylalanine. This clear solution was extracted twice with 50-mL portions of ethyl acetate. To the aqueous solution, 4.2 g of 37% HC1 (0.043 mol) was added. The solution was concentrated in vacuo to a total weight of 31.1 g. Another 8.4 g (0.085 mol) of 37% HC1 was added, and the reaction slurry was held at 40 'C for 6 h to convert 8 to a-L-aspartyl-Lphenylalanine hydrochloride 10. Solid (NaC1) was collected and washed with 2.6 g (0.026 mol) of 37% HCl and 7.5 g of methanol. Seed crystals were added to the combined filtrate and washings. The resulting solution was stirred at ambient temperature for 68 h. The thick slurry was cooled to 0-2 "C, and the solid was collected by filtration and washed with 7 mL of cold water. The dry weight of 9 was 9 g (55% yield' based on L-phenylalanine). This material was then neutralized with sodium hydroxide to give aspartame 1," [(YI2OD 30.3" (c 1.0, HOAc), authentic sample, [(YI2OD 30.1' (c 1.0, HOAc).
Journal of Organic Chemistry, 1989
t) ppm. (lE,3E)-l-Phenyl-4-(phenylthi0)-1,3,5-hexatriene (7k) was prepared on a 0.50-mmol scale from tram-cinnamaldehyde in 83% yield. The triene was found to be unstable and polymerized on standing at room temperature and was not fully characterized: Rf0.25 (1% ether/petroleum ether); 'H NMR (CDCl,, 300 MHz) 6 7. 18-7.46 (m, 11 H), 6.99 (dd, J = 16.5, 10.5 Hz, 1 H), 6.58-6.98 (m, 2 H), 7.75 (d, J = 16.5 Hz, 1 H), 5.33 (dt, J = 10.5, 1.5 Hz, 1 H) ppm; 13C NMR (CDCl,, 75 MHz) 6 136.87 (s), 136.48 (d), 135.50 (s), 135.16 (d), 132.72 (s), 130.53 (d), 129.70 (d), 128.90 (d), 128.65 (d), 128.09 (d), 126.67 (d), 126.34 (d), 123.30 (d), 118.99 (t) ppm.
J. Serb. Chem. Soc. 82 (3) 241–251 (2017).pdf
Journal of the Serbian Chemical Society , 2017
A series of novel bis(1,2,3-triazoles) derivatives 7a–m were synthesized by the 1,3-dipolar cycloaddition (click-reaction) of 1-methyl-3,5-bis(2-(prop-2-yn-1-yloxy)phenyl)-4,5-dihydro-1H-pyrazole (5) with various aralkyl azides 6a–m in the presence of sodium ascorbate and copper sulphate with good yields. The required precursor 5 was synthesized by reacting (E)-1,3-bis(2-hydroxyphenyl)prop-2-en-1-one (3) with methylhydrazine hydrate via 2,2′-(1-methyl-4,5-dihydro-1H-pyrazole-3,5-diyl)diphenol 4, followed by reaction with propargyl bromide. The homogeneity of all the newly synthesized compounds was checked by TLC. The IR, NMR, mass spectral data and elemental analysis were in accord with the assigned structure. The title compounds were evaluated for their antibacterial activity against various bacterial strains, i.e., Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis; compounds 7f–7h and 7j were found to be moderately active against the bacteria, when compared with that of the standard drug. Furthermore, the same library of compounds was evaluated for their antioxidant activity using the nitric oxide radical scavenging activity. The results of the study showed that compounds 7e–7h and 7k–7m showed good radical scavenging activity.
Reactive trityl derivatives: stabilised carbocation mass-tags for life sciences applications
Organic & Biomolecular Chemistry, 2008
Instrumentation. 500 MHz 1 H and 125.7 MHz 13 C NMR spectra were recorded on a Bruker DRX-500 spectrometer and referenced to CDCl 3 (7.25 ppm) and DMSO-d 6 (2.50 ppm). 1 H-13 C gradient-selected HMQC and HMBC spectra were obtained by using 2048 (t 2 )×256 (t 1 ) complex point data sets, zero filled to 2048 (F 2 )×1024 (F 1 ) points. The spectral widths were 13 ppm and 200 ppm for 1 H and 13 C dimensions, respectively. HMBC spectra were measured with 50 ms delay for evolution of long-range couplings. (MA)LDI-TOF mass spectra were obtained using a Voyager Elite Biospectrometry Research Station (PerSeptive Biosystems, Vestec Mass Spectrometry Products) in a positive ion mode. EI-TOF HRMS and ESI-TOF HRMS spectra in positive ion mode were obtained using Micromass LCT reflection TOF mass spectrometer. Analytical thin-layer chromatography was performed on the Kieselgel 60 F 254 precoated aluminium plates (Merck), spots were visualised under UV light (254 nm). Column chromatography was performed on silica gel (Merck Kieselgel 60 0.040-0.063 mm). Reagents and solvents. Reagents obtained from commercial suppliers were used as received. 4-Hydroxy-4′-methoxybenzophenone (3), [1] Pd(PPh 3 ) 4 , tert-butyl 6-bromohexanoate, were prepared as described. Solvents were mainly HPLC grade and used without further purification unless otherwise noted. DCM was always used freshly distilled over CaH 2 . THF was distilled over powdered LiAlH 4 or over sodium benzophenone ketyl and stored over 4Å molecular sieves under nitrogen. DMF was freshly distilled under reduced pressure. OH O O O O O Cl(CH 2 ) 3 CO 2 Bu t MeONa / HMPA 75%
Published by ChemTec Publishing, 2001
The writer of the book is George Wypych This is book which is helpful for organic chemistry student. The book was an edition in 2001, thus, some information may be not correct in comparison to new edition. However, almost data in this book will be a good reference for students in their education and work.
J. Org. Chem., 2017, 82 (18), pp 9751–
A series of scarce fulleropyrrolines were synthesized via DMAP-mediated one-step reaction of [60]fullerene with commercially inexpensive aromatic aldehydes and arylmethanamines in the absence or presence of manganese(III) acetate. In the case of aminodiphenylmethane, novel 2,5,5-trisubstituted fulleropyrrolines could be easily obtained without the addition of manganese(III) acetate. As for arylmethanamines without α-substitutions, the addition of manganese(III) acetate was required to suppress the formation of fulleropyrrolidines, in order to generate the desired 2,5disubstituted fulleropyrrolines. Two tautomers were produced as expected when different aryl groups (Ar 1 ≠ Ar 2 ) from aromatic aldehydes and arylmethanamines were employed in the synthesis. A plausible reaction mechanism for the formation of fulleropyrrolines is proposed. a All reactions were performed in ODCB (6 mL) under air conditions at 180°C unless otherwise indicated, molar ratio refers to C 60 /1/2a/DMAP = 1:5:5:2. b Isolated yield, those in parentheses were based on consumed C 60 . a Unless otherwise indicated, all reactions were performed in ODCB (6 mL) under air conditions. b Molar ratio refers to C 60 /1a/2a/metal oxidant/ base. c Isolated yield; those in parentheses were based on consumed C 60 . d The reaction was conducted under nitrogen conditions. e 0.5 g of C 60 dissolved in 84 mL of ODCB was used to prepare 5a on a larger scale.