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Search for "carbon dioxide" in Full Text gives 127 result(s) in Beilstein Journal of Organic Chemistry.
An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles
Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265
- combined with the liberation of large amounts of gases such as nitric oxides and carbon dioxide which must be scrubbed from the system (Scheme 2). Interestingly, despite these considerations this method of synthesis is currently still run by the speciality chemicals company Lonza but now as a continuous
The chemistry of amine radical cations produced by visible light photoredox catalysis
Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234
- to reductively quench the photoexcited state while they are oxidized to amine radical cations. This single-electron transfer process was investigated intensively in the late 1970s and early 1980s because amines were used as a sacrificial electron donor in water splitting [31][32] and carbon dioxide
Integrating reaction and analysis: investigation of higher-order reactions by cryogenic trapping
Beilstein J. Org. Chem. 2013, 9, 1837–1842, doi:10.3762/bjoc.9.214
- ][26], an oxidizing agent [27] or by physical decomposition by radiation [28] or heating [29][30][31] of a precursor system. Here, we used benzenediazonium-2-carboxylate as a benzyne precursor, which thermally decomposes by elimination of nitrogen and carbon dioxide. Results and Discussion Initially
Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process
Beilstein J. Org. Chem. 2013, 9, 1718–1723, doi:10.3762/bjoc.9.197
- product 3, Fe(II) and carbon dioxide. The Fe(III) catalyst is then reformed via DTBP oxidation [71]. Conclusion In conclusion, an efficient procedure for the Fe(acac)3-catalyzed direct alkenylation of sp3 C–H bonds of cycloalkanes with DTBP as an oxidant has been reported. This method provides a useful
Thermochemistry and photochemistry of spiroketals derived from indan-2-one: Stepwise processes versus coarctate fragmentations
Beilstein J. Org. Chem. 2013, 9, 1668–1676, doi:10.3762/bjoc.9.191
- we investigate the fragmentation reactions of cyclic ketals. Three ketals with different ring sizes derived from indan-2-one were decomposed by photolysis and pyrolysis. Particularly clean is the photolysis of the indan-2-one ketal 1, which gives o-quinodimethane, carbon dioxide and ethylene. The
- spectroscopy. Unfortunately no product could be unambiguously identified. The FVP of 2 yielded the product spectrum shown in Figure 5. Again, both carbon monoxide and carbon dioxide were formed along with the organic products. Carbon monoxide was formed in large excess over carbon dioxide (CO/CO2 = 13.5:1
- spiroketal linkage. The relative ratio of carbon dioxide and carbon monoxide being formed (CO2/CO = 1:27) indicates that a coarctate fragmentation of 1 can play a minor role only, if any. The composition of the product mixture is best rationalized by a series of stepwise processes, which starts with either a
Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors
Beilstein J. Org. Chem. 2013, 9, 1156–1163, doi:10.3762/bjoc.9.129
- residence time in the porous PdO reactor at 40 °C. Evolution of carbon dioxide (CO2) was observed during the reaction, although hydrogen (H2) was not found in the gas phase. Dehydrogenation of formic acid did not occur to any practical degree in the absence of p-nitrophenol. Consequently, the nitro group
- have studied flow reactions, including the decomposition of hydrogen peroxide, oxidation of organic dyes, carbon–carbon coupling, and conversion of formic acid to hydrogen (H2) and carbon dioxide (CO2), using catalytic tubular reactors [10][11][12][13]. p-Aminophenol is an important intermediate
Camera-enabled techniques for organic synthesis
Beilstein J. Org. Chem. 2013, 9, 1051–1072, doi:10.3762/bjoc.9.118
- with various solid-phase Brønsted acid catalysts in supercritical carbon dioxide (Figure 7), Poliakoff and co-workers studied the effect of varying the concentration of the organic reagent in the liquid CO2 solvent [46]. The high pressures required (100–400 bar) stipulated the use of a sealed reaction
Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria
Beilstein J. Org. Chem. 2013, 9, 942–950, doi:10.3762/bjoc.9.108
- ][15] followed by its conversion into its CoA-thioester by DmdB and oxidation by the FAD-dependent dehydrogenase DmdC. The addition of water to 3-(methylthio)acryloyl-CoA by the enoyl-CoA hydratase DmdD results in a hemithioacetal, which collapses under release of acetaldehyde, carbon dioxide and MeSH
Direct alkenylation of indolin-2-ones by 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles: a novel approach
Beilstein J. Org. Chem. 2013, 9, 809–817, doi:10.3762/bjoc.9.92
- carbon dioxide to deliver product 8 without undergoing further cyclization to yield either 6 or 7, possibly due to the lower dielectric constant of THF (7.42) compared to methanol (32.7) (Scheme 3). As is evident from Scheme 3, there are three possible tautomeric forms for 8, viz. 8x, 8y, 8z for the
1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions
Beilstein J. Org. Chem. 2013, 9, 647–654, doi:10.3762/bjoc.9.73
- carbon dioxide transfer in the formation of ketoacetates [46][47] and carboxylation of epoxides [48]. Some of us have recently reported a green application of BMIM-2-CO2, highlighting its efficiency for the conversion of raw glycerol to glycerol carbonate by transesterification [49]. More recently, this
- previous study reported by Tommasi et al. [47], we suggest that the liberated carbon dioxide reacts with the alcohol initiator ROH, leading to the formation of a ROC(O)O− anion (monobenzylcarbonate if benzyl alcohol is used as initiator, Scheme 3). The expelled proton reacts with the carbene species and
S-Fluorenylmethyl protection of the cysteine side chain upon Nα-Fmoc deprotection
Beilstein J. Org. Chem. 2012, 8, 2149–2155, doi:10.3762/bjoc.8.242
- reaction of the E1cb type, in which Nα is deprotected with the release of carbon dioxide and formation of dibenzofulvene (Scheme 3). Then, presumably, the cysteine thiol is deprotonated by morpholine. Since the nucleophilicity of the so formed thiolate is higher than that of morpholine or the generated
Cyclodextrin-based nanosponges as drug carriers
Beilstein J. Org. Chem. 2012, 8, 2091–2099, doi:10.3762/bjoc.8.235
- nanosponges have shown an ability to store large amounts of carbon dioxide, 1-methylcyclopropene and oxygen [8]. Three different cyclodextrin nanosponges were synthesised cross-linking α-, β- or γ-cyclodextrin with carbonyldiimidazole as oxygen-encapsulating formulations [50]. The nanosponges were able to
Flow photochemistry: Old light through new windows
Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229
The chemistry of bisallenes
Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225
- 1.2) [74][75][76] can probably also be exploited to introduce other substituents than TMS. Thus the quenching of the corresponding carbanions with, e.g., carbon dioxide to produce carboxylic acid derivatives of conjugated bisallenes could be tried [83][138][144]. 2. Acyclic nonconjugated bisallenes
Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization
Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177
- were observed when carbon dioxide, carbonyl sulfide, and isocyanates were utilized, cleanly generating the Ir(I) carbonyl as a byproduct (Scheme 11) [71]. The nucleophilicity of the iridium center was demonstrated through a series of experiments. First, it was noted that the carbene complex does not
- ]. Single-crystal X-ray structure of a silver(I) triflate adduct of (PNP)Ir═C(H)Ot-Bu with most H atoms and phosphine substituents (except ipso carbon atoms) omitted for clarity. Heterolytic cleavage of H2 by a phosphine/borane FLP by H2 polarization in the P–B cavity [5][11]. Insertion of carbon dioxide
Photoreactions of cyclic sulfite esters: Evidence for diradical intermediates
Beilstein J. Org. Chem. 2012, 8, 1208–1212, doi:10.3762/bjoc.8.134
- in the photochemistry of vicinal diaryloxiranes based on the photochemical formation of methyl ethers in methanol solution [8]. Mechanistically, stereoselective oxygen scrambling was found in the photoextrusion of carbon dioxide from benzyl benzoate esters [9]. Furthermore, photodecarboxylation
Chiral multifunctional thiourea-phosphine catalyzed asymmetric [3 + 2] annulation of Morita–Baylis–Hillman carbonates with maleimides
Beilstein J. Org. Chem. 2012, 8, 1098–1104, doi:10.3762/bjoc.8.121
- : phosphines attack the middle carbon atom of allenes to produce the 1,3-dipolar synthon (Scheme 1, reaction 1), and phosphines add to the β-position of MBH carbonate to remove carbon dioxide and tert-butanol, affording the 1,3-dipolar synthon (Scheme 1, reaction 2). Concerning the asymmetric [3 + 2
Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents
Beilstein J. Org. Chem. 2011, 7, 1261–1277, doi:10.3762/bjoc.7.147
- has been shown to be of radical nature, and it affords the cross-coupling products in very short reaction times, often less than 5 min. 4 MgCl2-Enhanced reactivity of functionalized organozincs towards their addition to aldehydes, ketones and carbon dioxide The addition reactions of organometallic
- reagents to ketones, aldehydes and carbon dioxide are essential transformations in organic synthesis as they provide a convenient access to various types of alcohols or carboxylic acids. Usually, organozinc reagents only react with these types of electrophiles in the presence of catalytic amounts of
- transition metal salts and in a very limited scope. Recently, we showed that the cheap and non-toxic main group Lewis acid MgCl2 allows smooth addition reactions of different aromatic, heteroaromatic, alkyl and benzylic zinc reagents to various carbonyl derivatives and carbon dioxide without the use of polar
A practical microreactor for electrochemistry in flow
Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127
- 1,2-diphenylethane (7a) were obtained with the device depicted in Figure 1; the reactions are shown in Scheme 3. The Kolbe reaction did not seem to be a very suitable reaction for a flow reactor due to the large amount of carbon dioxide and hydrogen that is formed at the anode during the
- decarboxylation reaction. This was partially overcome by neutralising the solution with triethylamine as base, hence carbon dioxide gas was not liberated during the reaction [18]. The reactions were carried out in acetonitrile instead of methanol to reduce the amount of side-products that could be formed due to
Kinetic evaluation of the solvolysis of isobutyl chloro- and chlorothioformate esters
Beilstein J. Org. Chem. 2011, 7, 543–552, doi:10.3762/bjoc.7.62
- included a unimolecular fragmentation–ionization process with loss of carbon dioxide [5][6][11][12]. For 5, in nine of the more nucleophilic solvents the l/m ratio of 3.38 (Table 3) was a typical value for an addition–elimination (association–dissociation) mechanism [12]. We have proposed that neopentyl
Olefin metathesis in nano-sized systems
Beilstein J. Org. Chem. 2011, 7, 94–103, doi:10.3762/bjoc.7.13
- as possible and that polluting classic organic solvents be replaced by “greener” solvents such as water or super-critical carbon dioxide. Therefore during the last decade, we have attempted to make progress in this field with dendrimers using nano-organometallic chemistry [10]. There are several ways
Intramolecular hydroxycarbene C–H-insertion: The curious case of (o-methoxyphenyl)hydroxycarbene
Beilstein J. Org. Chem. 2010, 6, 1061–1069, doi:10.3762/bjoc.6.121
- regarding the nature of the fascinating [1,2]H-tunneling mechanism in phenylhydroxycarbenes (with parent 3, Scheme 1), we sought to study the behavior of derivatives of 3 in Ar matrices at temperatures as low as 11 K. We attempted to generate novel o-methoxy-substituted carbene 5 by extrusion of carbon
- dioxide from (o-methoxyphenyl)glyoxylic acid (6) by HVFP and subsequent condensation and isolation of the pyrolysis products in an excess of Ar (Scheme 3). However, neither 5 nor its tunneling product, o-anisaldehyde (7), could be detected: Comparison with an authentic spectrum of matrix-isolated 7 showed
Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate
Beilstein J. Org. Chem. 2010, 6, 1043–1055, doi:10.3762/bjoc.6.119
- synthesis of hydrogen peroxide [71], and by the combination of these processes into a one-pot synthesis of propylene oxide from propene, hydrogen and oxygen [72][73]. In addition, it has been shown that in the presence of an appropriate catalyst, the reaction between epoxides and carbon dioxide can be
- achieved at atmospheric pressure and room temperature [74][75][76][77], or in a gas-phase continuous flow reactor [78], thus facilitating the use of waste carbon dioxide in this process [79]. In this paper we give full details of the use of catalyst 2 in propylene carbonate, and describe kinetic studies
Insights into the mechanical properties of a silicone oil gel with a ‘latent’ gelator, 1-octadecylamine, and CO2 as an ‘activator’
Beilstein J. Org. Chem. 2010, 6, 984–991, doi:10.3762/bjoc.6.111
- , DE 19711, USA 10.3762/bjoc.6.111 Abstract A detailed study of the rheological properties of silicone oil gels, made from a low-molecular-mass organic gelator, a combination of 1-octadecylamine (a latent gelator) and carbon dioxide (an ‘activating’ molecule), is reported. Information gleaned from the
- triatomic gas [8][9], especially carbon dioxide [10][11], is added). Although the structures of SAFINs and rheological properties of their gels made with ‘normal’ LMOGs have been extensively investigated [2][12], the mechanical properties of gels made from latent LMOGs have not received much attention
- LMOG, 1-octadecylamine (ODA), and a triatomic molecular ‘activator’, carbon dioxide, with silicone oil, tetramethyltetraphenyltrisiloxane, as the liquid component [10][11]. This liquid has been selected because its very low vapor pressure avoids a potential complication, i.e., evaporation of a portion
Functionalized copolyimide membranes for the separation of gaseous and liquid mixtures
Beilstein J. Org. Chem. 2010, 6, 789–800, doi:10.3762/bjoc.6.86
- market currently has a steady growth of approximately 10–15% each year [3]. Membrane based separations of gaseous mixtures have been well established for natural gas treatments (removal of carbon dioxide), for hydrogen removal (e.g. in cracking processes) for oxygen enrichment from air (medical devices
- new, economic and reliable membrane materials. In the following section, three examples of new applications, namely, the separation of gaseous olefin/paraffin mixtures, aromatic/aliphatic separation and the removal of carbon dioxide from natural gas a with high CO2 content, are discussed in detail
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