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Search for "polymerization" in Full Text gives 356 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Amine–borane complex-initiated SF5Cl radical addition on alkenes and alkynes
Beilstein J. Org. Chem. 2020, 16, 3069–3077, doi:10.3762/bjoc.16.256
- recently, it has been shown that some of these common amine–borane complexes can also be used as radical initiators for atom transfer radical addition of alkyl halides to alkenes [48]. They were also used in the free-radical polymerization of alkene-containing monomers such as methyl methacrylate or
Selected peptide-based fluorescent probes for biological applications
Beilstein J. Org. Chem. 2020, 16, 2971–2982, doi:10.3762/bjoc.16.247
- polymerization reaction between polydiacetylene. PDA liposomes turn colorless to red upon formation of cross-linked liposomes. The fluorescence of the naphthimide is completely quenched due to the energy transfer from the fluorophore to the cross-linked polymer. However, addition of LPS restores the fluorescence
Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans
Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226
- reactions of unsaturated compounds, e.g., alkene and enyne cross metathesis (CM [1] and EYCM [2][3][4]), alkene and enyne ring-closing metathesis (RCM and RCEYM) [5][6], ring-opening metathetic polymerization (ROMP) [7], etc., the CM and RCM are the most popular in organic synthesis [8]. Furthermore, the
- be too unstable and prone to polymerization. On the other hand, the reactivity of oxaenediyne 3 was too sluggish. Hence, 4-(allyloxy)hepta-1,6-diyne (2a) and its derivatives became the framework of choice. The key starting compound for the synthesis of oxaenediyne 2a and its derivatives was hepta-1,6
Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners
Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186
- 27 in a single step. They also pointed out that when ethylene gas was used as an alkene source for the ring-opening step, diluted reaction conditions were necessary to dissolve the ethylene in dichloromethane to avoid polymerization. Therefore, after several experimentations, they noticed that liquid
Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes
Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173
- sequence. On the other hand, the successful thermal iminium-ion induced SE(Ar) reactions shown in Scheme 2 were not applicable to the iminium-substituted norbornadiene 2, which suffered undefined polymerization on moderate heating in various solvents. In contrast to so far unknown 9‑amino-9
Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio
Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154
- )-configured 3-hydroxy fatty acids [13], and 3-hydroxybutyric acid in 3 and 4 and 3-hydroxyhexanoic acid in 2 are the most common two building blocks for PHAs [14]. However, degrees of polymerization as low as for 1–4 and the dehydrative modifications are unprecedented, besides for 5 [9]. Because PHAs are by
Synthesis, docking study and biological evaluation of ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones as potential inhibitors of the mycobacterial galactan synthesis targeting the galactofuranosyltransferase GlfT2
Beilstein J. Org. Chem. 2020, 16, 1853–1862, doi:10.3762/bjoc.16.152
- decaprenyl-P-P-GlcNAc-Rha, (glycolipid 2, GL2), which serves as a lipid carrier for arabinogalactan polymerization [7][8]. The latter enzyme, GlfT2, extends the product of GlfT1-catalyzed reaction, decaprenyl-P-P-GlcNAc-Rha-Galf2 (glycolipid 4, GL4), producing the lipid-linked galactan polymer [8]. Both
- -up of lipid-linked galactan precursors. The crude enzymes used in the assay allow for in situ synthesis of the acceptor for galactan polymerization, decaprenyl-P-P-GlcNAc-Rha (GL2), from endogenous decaprenyl phosphate and sugar nucleotides UDP-GlcNAc and TDP-Rha supplied in the reaction mixture
One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: theoretical evidence for an asynchronous concerted pathway
Beilstein J. Org. Chem. 2020, 16, 1805–1819, doi:10.3762/bjoc.16.148
- polymerization of the compounds containing cyclic carbonates such as methyl 4,6-O-benzylidene-2,3-O-carbonyl-α-ᴅ-glucopyranoside (MBCG) (5) [19][20] and glycerol carbonate (6) [21] were also reported (Scheme 1). Therefore, numerous synthetic approaches have been developed to date for the preparation of
Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers
Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127
- catalyst, if necessary. The solvents of choice were usually organic polar aprotic liquids, for example, N,N-dimethylformamide or dimethyl sulfoxide (DMSO). An alternative synthetic route relied on interfacial polymerization, where two immiscible solutions, one consisting of CDs dissolved in an alkaline
Oxime radicals: generation, properties and application in organic synthesis
Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107
- used in the development of organic magnetic materials [1], organic batteries [2][3][4], in the preparation of polymers by living polymerization [5][6], in the studies of biomolecules and living systems by EPR [7] and NMR [8] techniques. Stable N-oxyl radicals occupy a central place in organic chemistry
Activated carbon as catalyst support: precursors, preparation, modification and characterization
Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104
- . Poly(propiolate) salts are formed by polymerization of the starting materials after heating. The different cations of the propiolates cause changes in the thermal behavior of the starting materials since different temperatures are required for the decomposition or different amounts of gases are
- structures in the carbon source [6]. Diamadopoulos and co-workers observed also the production of smaller surface areas by H3PO4 activation of bagasse and rice husk due to a reaction of the activating reagent with the carbon precursor. Thereby, phosphate esters or polymerization byproducts are formed, which
- conform to the LaMer model and starts with a polymerization step of the carbohydrate monomers and followed by a carbonization step when the nucleation is caused by the supersaturation of the solution. The resulting nuclei grow uniformly until the final size is obtained depending on the growth parameters
Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis
Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103
Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore
Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98
- applications as internal donors in Ziegler–Natta catalysts for polymerization [14] or as building blocks in polymer chemistry [15]. A very closely related group of cyclobutanes are the 1,3-diaminotruxillic ester derivatives (Figure 1b). This type of bis-amino esters also shows remarkable pharmacological
Aldehydes as powerful initiators for photochemical transformations
Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76
- ) aldehydes have as photoinitiators. The photophysical properties and photoreactivity of benzaldehyde are initially provided, followed by applications of aldehydes as initiators for polymerization reactions. Finally, the applications to date regarding aldehydes as photoinitiators in organic synthesis are
- are useful photocatalysts, the corresponding aldehydes are not so widely utilized to promote chemical reactions. In this review, our goal was to summarize the photophysical properties of aromatic aldehydes, highlight the use of aldehydes as photoinitiators in polymerization reactions, and provide all
- carbonyl compounds, including aliphatic or aromatic ketones and aldehydes, have been employed as photoinitiators in polymerization reactions. The first studies reported in the literature where carbonyl compounds were used as initiators inspired researchers to study the use of aldehydes as well. In 1978
A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions
Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52
- 10 cycles. A mixture of GO, 1-vinylimidazole (98), and cross-linker 99 in ethanol was sonicated for 20 min [85]. Afterwards, the mixture was deoxygenated in an Ar atmosphere for 20 min. In the next step, polymerization was generated by adding AIBN (3 wt %). This was then heated at 70 °C for 24 h
KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones
Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44
- proceeded well with heterocycle-containing chlorides such as 2-chloro-5-(chloromethyl)thiophene (4e), leading to 2-aminoethyl acetate product 3k in 66% yield which has potential as bifunctional monomer for polymerization. Furthermore, oxazole derivative 2,4,4-trimethyl-4,5-dihydrooxazole (2b) was also
Synthesis of 4-amino-5-fluoropyrimidines and 5-amino-4-fluoropyrazoles from a β-fluoroenolate salt
Beilstein J. Org. Chem. 2020, 16, 445–450, doi:10.3762/bjoc.16.41
- ) and electron-withdrawing groups (compound 10l) were formed in nearly quantitative yields (95–99%). Only the 4-hydroxyphenyl derivative 10j was obtained in a moderate yield (69%) presumably due to competing polymerization of the enolate. The 4-chloro and 4-bromo derivatives (10m and 10n) were also
- 2). In the first reactions, only traces of the desired compound 13a were observed. Changing the temperature did not increase the yield. Acidic conditions were tested next but phenylhydrazine hydrochloride and acetic acid again gave only traces of 13a and polymerization of the enolate took place. To
- investigate the use of non-nucleophilic bases, but with DBU, polymerization of the fluoroenolate took place. When using aqueous sodium hydroxide as the base, a 19% yield could be achieved. Switching the solvent to water led to an improvement of the yield to 36% (Table 2). In water, but without using a base
Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0
Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40
- in lower molecular weight products caused by cleavage of the methine chain and conjugate acid, see Equation 7 [5][63]. The latter can initiate ring opening polymerization of aziridines [5] and oxiranes [63]. We also prefer to use the term conjugate acid instead of proton. The use of the latter widely
- = −0.64 V [5][84]) or the triazine 89 (Ered = −0.77 V [5]) carrying no charge as acceptor (Scheme 5). Thus, the positive charge of the iodonium cation is likely not the reason because 89 exhibits no charge. Both possess similar reduction potentials but the efficiency to initiate radical polymerization was
- as an issue. Particularly 48 showed remarkable polymerization efficiency in combination with 88 [5][63]. Photoinduced electron transfer typically followed an exothermal reaction route resulting in the formation of the cation radical of the sensitizer and the iodyl radical (Ar2-I•) formed by reduction
Room-temperature Pd/Ag direct arylation enabled by a radical pathway
Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36
- -conjugated materials, avoiding the prefunctionalization required for traditional cross-coupling methods. A major effort in organic electronic materials development is improving the environmental and economic impact of production; direct arylation polymerization (DArP) is an effective method to achieve these
- goals. Room-temperature polymerization would further improve the cost and energy efficiencies required to prepare these materials. Reported herein is new mechanistic work studying the underlying mechanism of room temperature direct arylation between iodobenzene and indole. Results indicate that room
- bond (M = SnR3, B(OH)2, etc.) and a C–X (X = I, Br, OTs) coupling partner. In contrast, direct arylation couples C–H and C–X bonds directly without the need to prepare the C–M substrate. As a polymerization method, direct arylation polymerization (DArP) is of great interest due to its potential to
Formal preparation of regioregular and alternating thiophene–thiophene copolymers bearing different substituents
Beilstein J. Org. Chem. 2020, 16, 317–324, doi:10.3762/bjoc.16.31
- a monomer. Nickel-catalyzed polymerization of bithiophene with substituents at the 3-position, including alkyl-, fluoroalkyl-, or oligosiloxane-containing groups, afforded the corresponding copolymers in good to excellent yield. The solubility test in organic solvents was performed to reveal that
- head-to-tail (HT) orientation with respect to the substituent at the 3-position are extensively studied to date since they generally show superior performances as materials [1][2][3][4][5][6]. Cross-coupling polymerization catalyzed by a transition metal complex has been recognized as an effective tool
- by polymerization catalyzed by a nickel complex, leading to the regioregular HT polythiophene (Scheme 1) [8][9]. An additional feature of the deprotonative protocol for polythiophene is the possibility to use chlorothiophene 3, in which the use of a nickel N-heterocyclic carbene (NHC) complex was
Functionalization of the imidazo[1,2-a]pyridine ring in α-phosphonoacrylates and α-phosphonopropionates via microwave-assisted Mizoroki–Heck reaction
Beilstein J. Org. Chem. 2020, 16, 15–21, doi:10.3762/bjoc.16.3
- result being consistent with analogous reactions reported in the literature [22][23]. In the reaction with acrylic acid and acrylamide, substrate 1a was recovered, probably due to the propensity of these acrylic substrates to polymerization. In case of ethyl crotonate and methyl metacrylate, only traces
A green, economical synthesis of β-ketonitriles and trifunctionalized building blocks from esters and lactones
Beilstein J. Org. Chem. 2019, 15, 2930–2935, doi:10.3762/bjoc.15.287
- alkoxide anions. This reduces the occurrence of undesirable side-reactions, e.g., intermolecular aldol reaction, lactone/ketonitrile product dimerization and ring-opening polymerization. The application of this method to produce the analogous hemiketal 6 from γ-butyrolactone was not as efficient. Although
- the occurrence of side-reactions and side-products, e.g., aldol reactions and polymerization, and results in a higher yield of the desired product compared to that obtained from γ-butyrolactone. With compounds 5 and 6 in hand, simple and mild reduction protocols at rt satisfyingly afforded the desired
Carbazole-functionalized hyper-cross-linked polymers for CO2 uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole
Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279
- a high surface area and a high total pore volume. The BET specific surface areas of P3 was up to 769 m2 g−1 with narrow pore size distribution and the CO2 adsorption capacity of P11 was up to 52.4 cm3 g−1 (273 K/1.00 bar). Keywords: 9-phenylcarbazole; CO2 uptake; Friedel–Crafts polymerization
- carbon. Based on the above peaks in the solid state NMR, the Friedel–Crafts polymerization product was confirmed. TGA analysis The thermal stability of HCPs was investigated by TGA tests (Figure 3 and Supporting Information File 1, Figure S3). A slight weight loss at 100 °C was observed for P2, P4, P5
- polymerization process; to explore the effect of the reaction temperature on the porosity, we have synthesized P6 and P7 by increasing the reaction temperature T1 from rt (P3) to 40 and 50 °C. When comparing the sorption isotherms of the HCPs (Supporting Information File 1, Figure S4), it was envisioned that
1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds
Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253
- ]. Conclusion We have observed that the reaction of N-triflyl-N-phenylpropiolamides with triphenylphosphane results in undefined polymerization and formation of N-phenyltriflamide. In the presence of several active methylene compounds, however, a clean three-component reaction leads to a novel type of
Experimental and computational electrochemistry of quinazolinespirohexadienone molecular switches – differential electrochromic vs photochromic behavior
Beilstein J. Org. Chem. 2019, 15, 2473–2485, doi:10.3762/bjoc.15.240
- substrates [11][12][13][14][15], or vinylcarbazole or alkoxystyrene derivatives for radical cation cylcloaddition and polymerization reactions [16][17][18][19][20]). We thus proposed the replacement of the naphthalene in 1a with a more electron-deficient quinoline ring. Due to the saturated spirocyclic
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