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Search for "dehydrogenation" in Full Text gives 88 result(s) in Beilstein Journal of Organic Chemistry.
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
- was reduced via hydrogen transfer from formic acid to p-nitrophenol and not by hydrogen generated by dehydrogenation of formic acid. Keywords: catalytic tubular reactor; flow chemistry; formic acid; hydrogenation; p-aminophenol; p-nitrophenol; Introduction The flow reaction process enables
- of 92.1% at 30 °C (Figure 5), which corresponds to a 1.7 times excess of the reducing agent to the p-nitrophenol. Further increases of concentration did not improve the reaction outcomes (Figure 5). Transfer hydrogen from formic acid to p-nitrophenol Dehydrogenation of formic acid and its subsequent
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
- ) alkoxycarbene. The complex could be generated stoichiometrically when norbornene was utilized as a hydrogen acceptor. The reaction was shown to be general for several methyl ethers and tetrahydrofuran, but other ethers were prone to 1,2-dehydrogenation or decarbonylation [88][89] The use of methyl amines as
An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines
Beilstein J. Org. Chem. 2012, 8, 829–840, doi:10.3762/bjoc.8.93
- cyclohexanone, catalyzed by PPA, followed by dehydrogenation over Pd–C has also been reported for the preparation of the unsubstituted α-carboline [48], but no other successful applications of this strategy have appeared in the literature. A more common strategy to α-carbolines closes the pyridine ring onto an
Synthesis of 2,6-disubstituted tetrahydroazulene derivatives
Beilstein J. Org. Chem. 2012, 8, 693–698, doi:10.3762/bjoc.8.77
- , which was transformed into the 2,6-disubstituted tetrahydroazulene 7 as a viscous oil. It is important to note that tetrahydroazulenes, in contrast to perhydroazulenes, are not very resistant towards dehydrogenation (oxidation) and, when kept at room temperature for a few days, form the corresponding
- with Schlieren-like textures were present but were never recovered or reproduced. In the case of compound 10, the same behavior was observed. As we mentioned earlier, tetrahydroazulenes, in contrast to perhydroazulenes, are not very resistant against dehydrogenation (oxidation), and when kept at room
Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester
Beilstein J. Org. Chem. 2012, 8, 606–612, doi:10.3762/bjoc.8.67
- nitrile oxides involves the dehydration of primary nitro compounds [21]. Aryl nitrile oxides are more commonly prepared by chlorination of aldoximes followed by dehydrohalogenation of the resulting hydroximoyl chlorides, or by direct oxidative dehydrogenation of the aldoximes (Scheme 2) [17]. While the
- halogenation–dehydrohalogenation process is most common, several methods involving direct oxidative dehydrogenation of aldoximes have been reported, including the use of lead tetraacetate [22][23], mercury(II) acetate [24], hypervalent iodine [25][26], and manganese(IV) oxide [27]. We were interested in
Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10
Beilstein J. Org. Chem. 2012, 8, 579–596, doi:10.3762/bjoc.8.65
- , III will directly form 34. On the other hand, reduction of III would furnish IV, and subsequent elimination of water would lead to V, the immediate precursor of 11-methyldodec-2Z-enoic acid. However, V may also be formed upon dehydrogenation of 11-methyldodecanoyl-SCoA (VI), which, in turn, may be
Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca
Beilstein J. Org. Chem. 2011, 7, 1697–1712, doi:10.3762/bjoc.7.200
- counterparts 50 and 51 by dehydrogenation. A two-carbon elongation of 50 and 51 by means of the fatty acid biosynthetic pathway can generate 55 and 56, while their reduction to the respective alcohols provides 47 and 48. Acetoin (44) was also found as a major compound, together with its derivatives 3
Manganese dioxide mediated one-pot synthesis of methyl 9H-pyrido[3,4-b]indole-1-carboxylate: Concise synthesis of alangiobussinine
Beilstein J. Org. Chem. 2011, 7, 1407–1411, doi:10.3762/bjoc.7.164
- means of either a Pictet–Spengler or a Bischler–Napieralski cyclization followed by an oxidative dehydrogenation process [13][14][15]. Inspired by nature’s example, we wished to design a synthetic route to the β-carboline scaffold, which was biomimetic and could be carried out in a single operation. One
- tetrahydrocarboline 5. In the presence of manganese dioxide intermediate 5 is not isolated, but instead, undergoes a series of dehydrogenation reactions in order to furnish our desired, fully aromatic β-carboline 6 (Scheme 1). This approach to the synthesis of β-carbolines is particularly elegant as the manganese
Synthesis of novel 5-alkyl/aryl/heteroaryl substituted diethyl 3,4-dihydro-2H-pyrrole-4,4-dicarboxylates by aziridine ring expansion of 2-[(aziridin-1-yl)-1-alkyl/aryl/heteroaryl-methylene]malonic acid diethyl esters
Beilstein J. Org. Chem. 2011, 7, 831–838, doi:10.3762/bjoc.7.95
- quantitative yields, either by reduction with sodium borohydride, or by catalytic hydrogenation using platinum on carbon [33][34]. The pyrrolines can be aromatized either by a two step procedure (i) NBS bromination and (ii) dehydrohalogenation in basic medium [35][36][37], or by dehydrogenation with Pd/C [38
Molecular rearrangements of superelectrophiles
Beilstein J. Org. Chem. 2011, 7, 346–363, doi:10.3762/bjoc.7.45
- dehydrogenation. For example, 2-decalone (51) (primarily trans) was reacted with HF-SbF5-CCl4 at 0 °C to give products 52 and 53 in 25% and 12% yields, respectively (Scheme 12). The proposed mechanism involves protonation and hydride abstraction to give superelectrophile 54. It is notable that the carbocation
An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives
Beilstein J. Org. Chem. 2009, 5, No. 66, doi:10.3762/bjoc.5.66
- condensation reactions, such as the condensation of oxazolo[3,2-b]pyridazinium perchlorates with malononitrile, ethyl cyanoacetate and ethyl malonate in the presence of sodium ethoxide [15]; the condensation of 1,4,7-triketones with hydrazine followed by dehydrogenation [16]; the condensation of cyanoacetic
A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions
Beilstein J. Org. Chem. 2009, 5, No. 31, doi:10.3762/bjoc.5.31
- stable enol 4, which is converted by dehydrogenation into the benzanthrone derivative 7. Under acidic conditions 4 isomerises to the spiro compound 11 and the bicyclo[4.3.1]decane derivative 12. Furthermore, the formation of 7 and the hydrogenated compound 13 is observed. A mechanism for the formation of
- monitored by 1H NMR spectroscopy (Figure 1) in CDCl3. This conversion is much slower when the CDCl3 is filtered through an alumina plug before use. The reaction constitutes a formal dehydrogenation of 4 (Scheme 2). As shown in Scheme 2, we propose that the formation of 4 and 7 starts as a 1,4-addition
Ru-catalyzed dehydrogenative coupling of carboxylic acids and silanes - a new method for the preparation of silyl ester
Beilstein J. Org. Chem. 2008, 4, No. 27, doi:10.3762/bjoc.4.27
- heating for 24 h at 100 °C (Table 3, Runs 4–8). In the presence of 4 mol% of ethyl bromide, the dehydrogenation was slightly slower compared with EtI, and a small amount of Et3SiH was still found. Without EtI, the dehydrocoupling was sluggish and 81% of Et3SiH were detected even being heated for 24 h at
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