Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• -supported sulfuric acid (MNPs-SO3H) [22]. As shown in Table 1, entries 2–4, all methods give the desired amidoalkylnaphthols in 77–97% yields. Zolfigol et al. successfully applied 1-methylimidazolium tricyanomethanide {[HMIM]C(CN)3} as the first nanostructured molten salt [23]. As depicted in Table 1, entry

• ], silica-supported perchloric acid (HClO4-SiO2) [34][35][36] and sulfuric acid [35], chlorosulfonic acid [38], sodium hydrogen sulfate (NaHSO4·H2O) [39], ferric(III) hydrogen sulfate [Fe(HSO4)3; 40], strontium(II) triflate, Sr(OTf)2; [41], copper-exchanged heteropoly acids, Cu1·5PMo12O40 (CuPMo) and Cu1

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• Pd0.20/C/T electrodes in the absence of sulfuric acid. Figure 9 depicts the fractional conversions and product yields as a function of the coulombic charge passed for both electrodes in the absence and presence of 0.1 M H2SO4 for comparative purposes. Even though no changes were observed in terms of

• v/v) and 0.1 M H2SO4, or (ii) 0.5 M benzophenone in ethanol 96% /water (90:10 v/v) in the absence of the sulfuric acid electrolyte in order to explore the influence of the medium acidity upon the electrochemical hydrogenation. A peristaltic pump Ismatel Reglo DIG MS/CA 2–8 provided a catholyte flow

Synthesis and stability of strongly acidic benzamide derivatives

• Frederik Diness,
• Niels J. Bjerrum and
• Mikael Begtrup

Beilstein J. Org. Chem. 2018, 14, 523–530, doi:10.3762/bjoc.14.38

• of the corresponding imidoyl chlorides 10 with PCl5 in POCl3, followed by the additional reaction with trifluoromethanesulfonamide (1) and protonation by sulfuric acid (Scheme 1) [10]. In recent years, we have reported high yielding catalyst-free N-arylation by SNAr reaction of mono- or

Aminomethylation/hydrogenolysis as an alternative to direct methylation of metalated isoquinolines – a novel total synthesis of the alkaloid 7-hydroxy-6-methoxy-1-methylisoquinoline

• Benedikt C. Melzer,
• Jan G. Felber and
• Franz Bracher

Beilstein J. Org. Chem. 2018, 14, 130–134, doi:10.3762/bjoc.14.8

• hydrogenolysis experiments with 5, which were aimed at simultaneous O-debenzylation at the 7-position and conversion of the N,N-dimethylaminomethyl group at C1 into a methyl group. Hydrogenation in presence of palladium as catalyst at 1 bar in the presence or absence of small amounts of sulfuric acid gave the

Acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with alcohols

• Katrina Tait,
• Alysia Horvath,
• Nicolas Blanchard and
• William Tam

Beilstein J. Org. Chem. 2017, 13, 2888–2894, doi:10.3762/bjoc.13.281

• ). The effect of inorganic protic acids was then investigated (Table 1, entries 4–6), producing moderate yields of the ring-opened product. The use of fluoroboric acid (Table 1, entry 4) and sulfuric acid (Table 1, entry 5) produced ring-opened product 26 in 45% and 48% yield, respectively, while using

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• . Sulfuric acid-catalyzed dehydrations of the benzylated hydroxyphthalimidines 3a–q in dichloromethane at room temperature resulted in the corresponding olefins 7a–q in good to excellent yields of 66–95% (Scheme 5 and Table 3). The simple reaction protocol enabled parallel operations in a Radleys Carousel 6

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• -Sulfinyl propargylamine 7k was prepared, following approach II under varying conditions (Table 2). Fluoral hydrate was dehydrated with concentrated sulfuric acid to give trifluoroacetaldehyde by distillation [93]. The reaction of trifluoroacetaldehyde with tert-butyl sulfinamide (S)-1 in the presence of

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• with acetone-free 2. A stream of gas was generated by dropping water on calcium carbide (CaC2) and passed through two washing bottles with concentrated sulfuric acid to remove polar impurities (Figure 2). Oxygen was carefully excluded from the reaction system to prevent oxidation of 1 to inactive the

An efficient synthesis of a C₁₂-higher sugar aminoalditol

• Łukasz Szyszka,
• Anna Osuch-Kwiatkowska,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

• ; Anal. calcd for C76H79N3O11: C, 75.41; H, 6.58; N, 3.47; found: C, 75.41; H, 6.47; N, 3.34. Acetolysis of glycoside 4; synthesis of 5 Azide 4 (0.36 g, 0.3 mmol) was dissolved in ethyl acetate (2.3 mL) to which acetic anhydride (4.6 mL) and sulfuric acid (0.72 mL of the solution: conc. H2SO4 (0.05 mL

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• chemistry is a reaction that can be catalyzed without any metal-containing catalysts and it is selected as an appropriate approach, spontaneously. Phenolic resins can be produced commercially using bases (ammonia and sodium hydroxide) or acids (hydrochloric acid and sulfuric acid) as catalysts via

Enzymatic separation of epimeric 4-C-hydroxymethylated furanosugars: Synthesis of bicyclic nucleosides

• Neha Rana,
• Manish Kumar,
• Vinod Khatri,
• Jyotirmoy Maity and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2017, 13, 2078–2086, doi:10.3762/bjoc.13.205

• ) in 98% yield. The glycosyl donor 7a,b was prepared from acetolysis of compound 6 with acetic acid/acetic anhydride/sulfuric acid (100:10:0.1) in 93% yield. The Vorbrüggen coupling [17] of 7a,b with uracil in the presence of N,O-bis(trimethylsilyl)acetamide (BSA) and trimethylsilyltrifluoromethane

• procedure for the acetolysis of compounds 6 and 11: synthesis of tetraacetate compounds 7a,b and 12a,b. Similar as described in [18] acetic anhydride (6.2 mL, 65.43 mmol) and concentrated sulfuric acid (0.03 mL, 0.65 mmol) was added to a stirred solution of compound 6 (3 g, 6.5 mmol) in acetic acid (37.4 mL

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• aromatic systems with strong electron-donating substituents (e.g., alkoxy-, polyalkoxy- and aminoarenes), or some activated heterocyclic systems such as indole [3][8][10][24][25]. The α-imidoalkylation reaction using N-(1-hydroxyalkyl)imides (almost entirely N-hydroxymethylphthalimide) in sulfuric acid

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• lab to create 3D images. Ionizing radiation reactions in the Fricke dosimeter. Sulfuric acid/urea promoted synthesis of LMG. Synthesized DTBs and their LMG (1) relative radiation dose sensitivity. Acknowledgements J. A. is grateful to the numerous students who have worked on this project and to Dr

First total synthesis of kipukasin A

• Chuang Li,
• Haixin Ding,
• Zhizhong Ruan,
• Yirong Zhou and
• Qiang Xiao

Beilstein J. Org. Chem. 2017, 13, 855–862, doi:10.3762/bjoc.13.86

• plates with detection by UV (254 nm) or charting with 10% sulfuric acid in ethanol. Column chromatography was performed on silica gel (200–300 mesh, Qing-Dao Chemical Company, China). NMR spectra were recorded on a Bruker AV400 spectrometer, and chemical shifts (δ) are reported in ppm. 1H NMR and 13C NMR

• acid (10 mL) and Ac2O (1.94 g, 19.0 mmol) was added concentrated sulfuric acid (0.2 mL) dropwise over 10 min. After addition, the reaction mixture was stirred at room temperature for 2 h. TLC detection showed the reaction was finished. The compound was diluted with CH2Cl2 (80 mL) and washed with water

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• -tuning the reaction conditions, combined with the use of additives, can lead to modifications in the emissive properties of the nanoparticles [20]. The team was able to show that the use of sulfuric acid with a carbohydrate, although the exact carbohydrate used is not disclosed in the article, generally

N-Propargylamines: versatile building blocks in the construction of thiazole cores

• S. Arshadi,
• E. Vessally,
• L. Edjlali,
• R. Hosseinzadeh-Khanmiri and
• E. Ghorbani-Kalhor

Beilstein J. Org. Chem. 2017, 13, 625–638, doi:10.3762/bjoc.13.61

• yields. It was also observed that products 2 rapidly formed by reaction of 1 with carbon disulfide in the presence of sodium hydroxide as the base in water at 20 °C. Further, the authors showed that treatment of methylene compound 2 with cold concentrated sulfuric acid gave the corresponding isomeric

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• first synthesis of 1-indanone from carboxylic acid has been described by Price and Lewis in 1939 [12]. They cyclized hydrocinnamic acid (1) to the unsubstituted 1-indanone (2), in 27% yield using 20% sulfuric acid at 140 °C (Scheme 1). Another reaction leading to the formation of the unsubstituted 1

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

• Maximilian Maier,
• Magnus S. Schmidt,
• Markus Ringwald and
• Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

• been used from the MCAT company stock and were used without further purification. Measurements. TLC was carried out on Silica Gel 60 F254 (Merck, layer thickness 0.2 mm) with detection by UV light (254 nm) and/or by charring with 15% sulfuric acid in ethanol. Flash column chromatography (FC) was

A novel method for heterocyclic amide–thioamide transformations

• Walid Fathalla,
• Ibrahim A. I. Ali and
• Pavel Pazdera

Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20

• heating isatine with malonic acid followed by esterification of the produced quinoline carboxylic acid with methanol in the presence of sulfuric acid at 80 °C for 6 h. 4-Arylphthalazin-1(2H)-ones A7 and A8 [24][25] were prepared by Friedel–Crafts acylation reaction of N-aminophthalimide with either

Synthesis and evaluation of anti-oxidant and cytotoxic activities of novel 10-undecenoic acid methyl ester based lipoconjugates of phenolic acids

• Naganna Narra,
• Shiva Shanker Kaki,
• Rachapudi Badari Narayana Prasad,
• Sunil Misra,
• Koude Dhevendar,
• Venkateshwarlu Kontham and
• Padmaja V. Korlipara

Beilstein J. Org. Chem. 2017, 13, 26–32, doi:10.3762/bjoc.13.4

• with sulfuric acid in methanol to obtain methyl undecenoate (1) in quantitative yield. Next, ester 1 was treated with 1,1′-azobis(cyclohexanecarbonitrile) (ABCN) and 2-mercaptoethylamine hydrochloride in dioxane/ethanol 70:30 (v:v) to obtain methyl 11-(2-aminoethylthio)undecanoate (2) in 89% yield. The

• acid (10 g, 54.34 mmol), was added to methanol (17.6 mL) and sulfuric acid (0.1 mL, 2 wt % 10-undecenoic acid) and stirred at refluxing temperature of methanol for 6 h. After completion of the reaction as shown by TLC (hexane/ethyl acetate 80:20, v/v), excess methanol was removed under reduced pressure

Facile synthesis of indolo[3,2-a]carbazoles via Pd-catalyzed twofold oxidative cyclization

• Chao Yang,
• Kai Lin,
• Lan Huang,
• Wei-dong Pan and
• Sheng Liu

Beilstein J. Org. Chem. 2016, 12, 2490–2494, doi:10.3762/bjoc.12.243

• dibromobenzoic acid with sulfuric acid in methanol) with an excess of anilines in the presence of cesium carbonate and catalytic quantities of Pd(OAc)2 and BINAP were processed smoothly. The desired methyl 2,4-dianilinobenzoates (2a–e) were obtained in good to excellent yield. In a parallel synthesis, using the

Isosorbide and dimethyl carbonate: a green match

• Fabio Aricò and
• Pietro Tundo

Beilstein J. Org. Chem. 2016, 12, 2256–2266, doi:10.3762/bjoc.12.218

• Fleche and co-workers reported the first synthesis of isosorbide from D-sorbitol using sulfuric acid as catalyst [61][62]. The reaction was performed at 400 K in a batch reactor. This process results in good yields (ca 70%), but it also poses some issues such as difficult separation of isosorbide from

• the reaction mixture and the use of a large amount of sulfuric acid. As a result current research on new synthetic approaches for the cyclic sugar isosorbide has been focussed on less toxic and easy to recover heterogeneous acidic catalysts. In particular, mixed oxides [49], phosphated or sulfated

Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

• Raimondo Maggi,
• N. Raveendran Shiju,
• Veronica Santacroce,
• Giovanni Maestri,
• Franca Bigi and
• Gadi Rothenberg

Beilstein J. Org. Chem. 2016, 12, 2173–2180, doi:10.3762/bjoc.12.207

• toluene (120 mL) and the resulting supported propylmercaptane has been oxidized to propanesulfonic acid by treatment with 30% aq H2O2 (100 mL; 1 mol) for 24 h under stirring at rt, adding a few drops of concentrated sulfuric acid after 12 h. Acidity has been measured via the titration method [35] (0.51

Solvent-free synthesis of novel para-menthane-3,8-diol ester derivatives from citronellal using a polymer-supported scandium triflate catalyst

• Lubabalo Mafu,
• Ben Zeelie and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 2046–2054, doi:10.3762/bjoc.12.193

• citronellal para-Menthane-3,8-diol (3) was synthesised according to our earlier developed procedure, which has not been reported in open literature. The synthesis procedure involves the acid-catalysed cyclisation of 1 in aqueous sulfuric acid (Scheme 2) at 100 °C. After which the oil simply separates from the