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Search for "hydrogenation" in Full Text gives 473 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Synthesis of odorants in flow and their applications in perfumery

  • Merlin Kleoff,
  • Paul Kiler and
  • Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

Graphical Abstract
  • . For compound 6, both individual steps were combined for a two-step aldol condensation/hydrogenation flow sequence providing raspberry ketone methyl ether (6) on a gram scale in 75% overall yield. Interestingly, also alternative flow protocols for the synthesis of 4-aryl-3-buten-2-ones 3 and 4 were
  • of hydrogen with a pressure of 1 bar, a good selectivity for the hydrogenation of the external alkene is achieved providing enone 27. The reaction mixture containing enone 27 is then mixed with tosylhydrazone and passed through a column with sulfonic acidic resin Amberlyst-15 to catalyze the
  • -nonadien-1-al are nearly ubiquitous in modern perfumery for both women and men, even appearing in dark or woody fragrances such as Hugo Boss: Soul. In 2012, Barbaro and co-workers developed a synthesis for alkene 32 by selective hydrogenation of the corresponding alkyne (Scheme 7) [37]. Instead of using a
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Published 27 Jun 2022

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

  • Conrad Kuhwald,
  • Sibel Türkhan and
  • Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

Graphical Abstract
  • hydrogenation. 2.3 Dry and steam methane reforming The commencement of the energy transformation is associated with the search for alternative and more environmentally friendly energy sources [27]. The dry reforming of methane is a particularly interesting process in this context (Scheme 2, reaction 1). A
  • pressure, much higher temperatures around 950 °C are actually required. At these high temperatures, the selectivity of the process is a challenge. Possible side reactions such as hydrogenation of CO and CO2, decomposition of CH4, and the Boudouard reaction lead to the formation of elemental carbon [31
  • performance is characterized by the specific absorption rate (SAR) of the material. The tested materials showed high SAR values when brought into an electromagnetic field of 50 mT at a frequency of 54 kHz. Under these conditions the particles were able to catalyze the hydrogenation of CO. The presence of
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Published 20 Jun 2022

New synthesis of a late-stage tetracyclic key intermediate of lumateperone

  • Mátyás Milen,
  • Bálint Nyulasi,
  • Tamás Nagy,
  • Gyula Simig and
  • Balázs Volk

Beilstein J. Org. Chem. 2022, 18, 653–659, doi:10.3762/bjoc.18.66

Graphical Abstract
  • carbonyl (21b→22b) preceded the reduction of the C–C double bond of 22b. Both the hydrolytic desethoxycarbonylation of (±)-9a as well as the removal of the benzyloxycarbonyl group of (±)-9b by catalytic hydrogenation afforded (±)-10 which was N-alkylated with 4-chloro-1-(4-fluorophenyl)butan-1-one (11) to
  • . Reduction of the quaternary ammonium salt 28 with sodium borohydride gave tetrahydroquinoxaline 29. Its reaction with trifluoroacetic anhydride (TFAA) to give 30 and removal of the benzyl group by catalytic hydrogenation afforded N-trifluoroacetyl-1,2,3,4-tetrahydroquinoxaline (31). Compound 31 was then
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Published 10 Jun 2022

BINOL as a chiral element in mechanically interlocked molecules

  • Matthias Krajnc and
  • Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

Graphical Abstract
  • ) [59]. The catenane catalyst allows for the asymmetric transfer hydrogenation of 2-substituted quinolines by Hantzsch esters in a highly stereoselective fashion [60]. It was found that the catenated catalyst gives superior stereoselectivities in comparison to the macrocyclic and the acyclic reference
  • desymmetrization reaction of meso-1,2-diols with rotaxane (R)-42. Synthesis of Niemeyer´s axially chiral [2]catenane (S,S)-47. Results for the enantioselective transfer hydrogenation of 2-phenylquinoline with catalysts (S,S)-47, (S)-48, and (S)-49. Synthesis of Niemeyer´s chiral [2]rotaxanes (S)-56/57. Results for
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Published 06 May 2022

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

  • Sayan Pramanik and
  • Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

Graphical Abstract
  • generation of new cascade reactions to construct carbo- and heterocyclic moieties [27][28], we aimed to synthesize dispirocyclopentanebisoxindoles in one pot operation using a new protocol. Chemical hydrogenation of double bonded compounds like α,β-unsaturated ketones, approaching to saturated ketones, is an
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Published 27 Apr 2022

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

  • Martin Vrbický,
  • Karel Macek,
  • Jaroslav Pochobradský,
  • Jan Svoboda,
  • Miloš Sedlák and
  • Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

Graphical Abstract
  • 26 were chosen. The reduction of the nitro groups in 24 and 26 via the hydrogenation procedure proceeded smoothly with almost quantitative yields; the amine intermediates were immediately used in the next step. Hence, the N-acylation reactions were performed by the action of the corresponding
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Published 14 Apr 2022

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

Graphical Abstract
  • deposition of gold on metallic fluorides allowed the one-pot hydroacetylation of menadione (10) to diacetylated menadiol 72, while the deposition of gold on silica allowed only the hydrogenation of 10 to 14 (Scheme 22B). The authors also observed that catalysis by hydroxylated fluorides led to a higher
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Published 11 Apr 2022

Site-selective reactions mediated by molecular containers

  • Rui Wang and
  • Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

Graphical Abstract
  • hydrogenation reaction mediated by a supramolecular catalyst was reported by Raymond, Bergman and Toste in 2019 (Figure 7) [64]. In this example, the supramolecular catalyst was prepared in situ by mixing a rhodium complex with the Ga4L612− cage host G, which had a relatively larger size with pyrene-walled
  • achieved with just the rhodium catalyst, by which in contrast, the fully hydrogenated product was obtained. Other series of intermolecular comparative experiments also showed the selectivity of the hydrogenation for the sterically accessible alkene over other sites and even in the presence of inherently
  • more reactive alkynes and allylic alcohols. Both the microenvironment of the supramolecular catalyst and the steric profile of the substrate were responsible for the site-selectivity of hydrogenation. This beautiful work of a supramolecular-mediated catalytic site-selective reaction exhibited the
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Published 14 Mar 2022

Synthesis and late stage modifications of Cyl derivatives

  • Phil Servatius and
  • Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

Graphical Abstract
  • as impurity, which could not be separated from the product. Subsequent hydrogenation proceeded readily and afforded the saturated cyclopeptide 13. However, the impurity could also not be removed on this stage. Apparently, the Cyl derivatives with a short side chain are not good candidates for further
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Published 04 Feb 2022

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

  • Irina Kuznetcova,
  • Felix Bacher,
  • Daniel Vegh,
  • Hsiang-Yu Chuang and
  • Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

Graphical Abstract
  • led exclusively to the desired isomer 5 with the nitrophenyl group in position 3, most likely due to the steric effect. Then, the nitro group in 5 was reduced by hydrogenation under 4 bar using Pd/C as catalyst to yield the desired amine 6 in 78% yield. Subsequently, the desired chloroacetyl
  • previous observations [38]. Reduction of the nitro group by palladium-catalyzed hydrogenation in dry methanol gave 2a in 92% yield. Interestingly compound 2a undergoes ring-closure reaction spontaneously at room temperature to give trace amounts of 3a (59 mg, 2%) after column chromatography, when a 3.1 g
  • [2,3-d][1]benzazepin-6(5H)-one (3a). This procedure delivered analytically pure 3a in 80% yield as also confirmed by SC-XRD (Figure 3). The final step to structure C required removal of the benzyl group. Debenzylation of amines is commonly performed by palladium-catalyzed hydrogenation [40]. However
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Published 26 Jan 2022

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

  • Thaipparambil Aneeja,
  • Cheriya Mukkolakkal Abdulla Afsina,
  • Padinjare Veetil Saranya and
  • Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

Graphical Abstract
  • 2008, Bhanage et al. developed a novel methodology for the synthesis of alkyl iodides/nitriles using ruthenium tris(2,2,6,6-tetramethyl-3,5-heptanedionate) (Ru(TMHD)3) as the catalyst (Scheme 24) [47]. This catalyst was found highly efficient in the hydrogenation, iodination, and cyanation reaction of
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Published 04 Jan 2022

The enzyme mechanism of patchoulol synthase

  • Houchao Xu,
  • Bernd Goldfuss,
  • Gregor Schnakenburg and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

Graphical Abstract
  • proceeded with full retainment of the labelling in both cases (Scheme 1B). Subsequent chemical degradation through acid catalysed conversion into 5, oxidative cleavage to the diketone 13, BF3∙OEt2 mediated ring closure by aldol reaction and catalytic hydrogenation gave 14. For both experiments a full
  • experiment with [12,13-14C,1-3H]FPP was expected for the aldol reaction of 13, but is more difficult to understand in the experiment with [12,13-14C,6-3H]FPP. In this case the loss of 3H was explained by an exchange against 1H during catalytic hydrogenation [9]. One year later, Akhila et al. proposed an
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Published 03 Jan 2022

First total synthesis of hoshinoamide A

  • Haipin Zhou,
  • Zihan Rui,
  • Yiming Yang,
  • Shengtao Xu,
  • Yutian Shao and
  • Long Liu

Beilstein J. Org. Chem. 2021, 17, 2924–2931, doi:10.3762/bjoc.17.201

Graphical Abstract
  • , ensuring the smooth progress of the total synthesis of hoshinoamide A. With the tripeptide 7 in hand, we went on to construct the peptide scaffold (Scheme 3). When tripeptide 7 was subjected to Pd-catalyzed hydrogenation conditions [16], the benzyl group was selectively cleaved to generate 8. Treatment of
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Published 15 Dec 2021

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

  • Lukáš Ďurina,
  • Anna Ďurinová,
  • František Trejtnar,
  • Ľuboš Janotka,
  • Lucia Messingerová,
  • Jana Doháňošová,
  • Ján Moncol and
  • Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

Graphical Abstract
  • hydrogenolysis conditions led only to the formation of several undesired byproducts. To our satisfaction when compound 12 was subjected to catalytic hydrogenation using Pd(OH)2/C in methanol [39], 2 was formed in 71% yield. Finally, (±)-codonopsinol B (1) was directly obtained from 12 in the yield of 58% (over
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Published 24 Nov 2021

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

  • Yi Liu,
  • Puying Luo,
  • Yang Fu,
  • Tianxin Hao,
  • Xuan Liu,
  • Qiuping Ding and
  • Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

Graphical Abstract
  • the hydrogenation of dihydropyridinones 32 and a following desulfonylation and aromatization to give pyridine derivatives 33 in moderate to good yield. Synthesis of pyrroles via tandem annulation of 1,3-enynes Recently, great achievements have been made in electrophilic iodocyclization of alkynes for
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Published 22 Sep 2021

Synthesis of 5-arylacetylenyl-1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions

  • Andrey I. Puzanov,
  • Dmitry S. Ryabukhin,
  • Anna S. Zalivatskaya,
  • Dmitriy N. Zakusilo,
  • Darya S. Mikson,
  • Irina A. Boyarskaya and
  • Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2021, 17, 2417–2424, doi:10.3762/bjoc.17.158

Graphical Abstract
  • , as a hydride ion source, was conducted to achieve the ionic hydrogenation of intermediate cationic species. However, no products of ionic hydrogenation were obtained, only the product of the hydrophenylation of the acetylene bond 5a was quantitatively isolated (compare with data shown in Scheme 5
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Published 15 Sep 2021

Strategies for the synthesis of brevipolides

  • Yudhi D. Kurniawan and
  • A'liyatur Rosyidah

Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157

Graphical Abstract
  • -carbon precursor for the synthesis. The forward synthesis transformed 2-acetylfuran (20) to its corresponding alcohol 21 through an asymmetric transfer hydrogenation catalyzed by a ruthenium complex (0.5 mol %) in 98% yield with 95% ee (Scheme 2). The azeotropic mixture of HCO2H/Et3N 5:2 was employed as
  • ) asymmetric dihydroxylation and epoxidation; 3) asymmetric hydrogenation; 4) Horner–Wadsworth–Emmons olefination; and 5) cyclopropanation, which are summarized in Table 4, including the overall yields and the number of steps required. This work is expected to provide useful information for researchers to
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Published 14 Sep 2021

Recent advances in the syntheses of anthracene derivatives

  • Giovanni S. Baviera and
  • Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

Graphical Abstract
  • brominated naphthalene 153 with PhLi yielded compound 154, which collapsed to naphthotriyne 155 at elevated temperatures. Sequential addition of furan generated the trisadduct 156. Then, dibenz[a,c]anthracene 158 was obtained in good yield (86%) in two steps by hydrogenation of 156 and further dehydration of
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Published 10 Aug 2021

Sustainable manganese catalysis for late-stage C–H functionalization of bioactive structural motifs

  • Jongwoo Son

Beilstein J. Org. Chem. 2021, 17, 1733–1751, doi:10.3762/bjoc.17.122

Graphical Abstract
  • multipeptides of varying ring size were successfully obtained with excellent functional group tolerance. In addition, selective N-methylation of the 2-pyridine directing group and successive hydrogenation processes provided an efficient traceless removal of the directing group, affording free-NH tryptophan
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Published 26 Jul 2021

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

  • Thiago S. Silva and
  • Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

Graphical Abstract
  • products instead of reductive ones. Their formation also leads to the generation of Pd(0) species that require the presence of an external oxidant to regenerate the active Pd(II) complex, as well as an additional hydrogenation step, if the hydrofunctionalized product is desired [18]. This particularity
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Published 07 Jul 2021

Total synthesis of ent-pavettamine

  • Memory Zimuwandeyi,
  • Manuel A. Fernandes,
  • Amanda L. Rousseau and
  • Moira L. Bode

Beilstein J. Org. Chem. 2021, 17, 1440–1446, doi:10.3762/bjoc.17.99

Graphical Abstract
  • on these results, it was evident that the selective removal of the trityl group in the presence of the benzyl group is substrate specific. Eventually, hydrogenation under neutral conditions at atmospheric pressure for 24 h allowed for the selective removal of the benzyl group, affording amine 20 in a
  • tosylate under basic conditions affording 24 in a yield of 83%. The displacement of the tosyl group with an azide whilst heating the reaction at 80 °C allowed for the isolation of azide 25 in a good yield of 75%. Heating at higher temperatures resulted in product decomposition. Hydrogenation of the azide
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Published 10 Jun 2021

Double-headed nucleosides: Synthesis and applications

  • Vineet Verma,
  • Jyotirmoy Maity,
  • Vipin K. Maikhuri,
  • Ritika Sharma,
  • Himal K. Ganguly and
  • Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

Graphical Abstract
  • protection of 16 followed by introduction of an azide group in the C-2′ position of the molecule to afford nucleoside 22. The treatment of azide 22 with pyrrolidine in acetonitrile followed by hydrogenation afforded aminonucleoside 23, which was used as a key intermediate for the synthesis of the double
  • . Global deprotection of 32 using palladium-catalyzed hydrogenation conditions resulted in the formation of the targeted double-headed nucleoside 33 (Scheme 8) [33]. The double-headed nucleoside 33 was dimethoxytritylated, phosphitylated, and incorporated into duplex and its ability to recognize
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Published 08 Jun 2021

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

  • Guido Gambacorta,
  • James S. Sharley and
  • Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Graphical Abstract
  • also proved the possibility to perform an in situ hydrogenation of 86 by mixing the resin with a Pd catalyst (50% Amberlyst® 15/2% Pd on silica/alumina). The desired material was indeed obtained with high yields (up to 80%) and selectivity (up to 95%) [124]. In 2013, a continuous-flow multistep
  • authors screened several other 3D printed reactors evaluating materials (PTFE, PLA or Nylon), volumes (1 or 10 mL), and channel shape (circular, square, or rectangular). The process was then merged with a hydrogenation step using the H-Cube® apparatus (Pd/C, 30 °C, 15 bar) for the continuous preparation
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Published 18 May 2021

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

  • Joseane A. Mendes,
  • Paulo R. R. Costa,
  • Miguel Yus,
  • Francisco Foubelo and
  • Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

Graphical Abstract
  • been also an advanced intermediate in the synthesis of alkaloids. For instance, hydrogenation of 117 yielded (+)-coniine (118), the major alkaloid extracted from poison hemlock and responsible for its toxicity, as its hydrochloride, and N-Boc protected derivative of 117 submitted to Wacker oxidation
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Published 12 May 2021

β-Lactamase inhibition profile of new amidine-substituted diazabicyclooctanes

  • Zafar Iqbal,
  • Lijuan Zhai,
  • Yuanyu Gao,
  • Dong Tang,
  • Xueqin Ma,
  • Jinbo Ji,
  • Jian Sun,
  • Jingwen Ji,
  • Yuanbai Liu,
  • Rui Jiang,
  • Yangxiu Mu,
  • Lili He,
  • Haikang Yang and
  • Zhixiang Yang

Beilstein J. Org. Chem. 2021, 17, 711–718, doi:10.3762/bjoc.17.60

Graphical Abstract
  • of S:R isomers = 6:1). The synthesis of intermediate 2 started from the hydrogenation of 7 by following a previously described method using N,N-dimethylformamide (DMF)/CH2Cl2 [23] as solvent led to a low yield in our hands. Therefore, we planned to switch the solvent from DMF to EtOAc whereupon the
  • -dimethylaminopyridine (DMAP) as the base. Then, the palladium-catalyzed hydrogenation of compounds B1–21 in THF or EtOAc led to the hydroxy derivatives C1–21. It has been observed that a catalytic amount of triethylamine (TEA) in EtOAc enhances the rate of the hydrogenolysis of benzyl ethers. Compounds C1–21 were then
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Published 12 Mar 2021
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