Lewis acid-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence to access phosphoric esters

• Jin Yang,
• Dang-Wei Qian and
• Shang-Dong Yang

Beilstein J. Org. Chem. 2022, 18, 1188–1194, doi:10.3762/bjoc.18.123

• catalyst through a similar transformation under solvent-free conditions [44]. Recently, Zhang’s group disclosed a cesium carbonate-catalyzed Pudovik reaction–phospha-Brook rearrangement sequence and extended the phosphorus source from phosphate to phosphonate [45]. Despite of these important advancements

A versatile way for the synthesis of monomethylamines by reduction of N-substituted carbonylimidazoles with the NaBH₄/I₂ system

• Lin Chen,
• Xuan Zhou,
• Zhiyong Chen,
• Changxu Wang,
• Shunjie Wang and
• Hanbing Teng

Beilstein J. Org. Chem. 2022, 18, 1032–1039, doi:10.3762/bjoc.18.104

• chemicals, agrochemicals, pharmaceuticals and dyes [1][2][3][4]. Traditional methods for the preparation of N-methylamines involve the direct methylation of amines by using methyl halides [5][6][7], dimethyl sulfate [8], diazomethane [9], methyl triflate [10][11] or dimethyl carbonate [12][13][14][15] as

Molecular diversity of the base-promoted reaction of phenacylmalononitriles with dialkyl but-2-ynedioates

• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 991–998, doi:10.3762/bjoc.18.99

• ). Results and Discussion Initially, the reaction conditions were briefly optimized by using p-methylphenacylmalononitrile (1a) and diethyl but-2-ynedioate (2a) as standard according to the previous reported work [31]. In the presence of potassium carbonate and tetrabutylammonium chloride (TBAC), the

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• )dithieno[3,2-b:2’,3’-d]thiophene (26): a) Br2, CHCl3, rt, overnight, reflux, 4 h, 94% [33]; b) n-BuLi, −78 °C, 30 min, 1-formylpiperidine, anhydrous THF, −78 °C, then rt, overnight [15], 88%; c) ethyl thioglycolate, anhydrous potassium carbonate, anhydrous N,N-dimethylformamide, rt, 3 d, 83% [15]; d) 1 M

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• solution of sodium hydrogen carbonate, and extracted with ethyl acetate (3 × 50 mL). The organic phase was washed with water (50 mL), brine (30 mL), dried over magnesium sulfate, and concentrated to dryness. A chromatography over silica gel (cyclohexane/ethyl acetate 55:45) at 60 °C gave first compound 4

Synthesis and HDAC inhibitory activity of pyrimidine-based hydroxamic acids

• Virginija Jakubkiene,
• Gabrielius Ernis Valiulis,
• Markus Schweipert,
• Asta Zubriene,
• Daumantas Matulis,
• Franz-Josef Meyer-Almes and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 837–844, doi:10.3762/bjoc.18.84

• alkylation reaction of compound 19 with methyl 6-bromohexanoate and select the conditions favoring the formation of the O-isomer, a weak base, potassium carbonate, and a bipolar aprotic solvent, dimethylformamide, were used. The reaction was carried out at room temperature for 120 hours and a significant

A trustworthy mechanochemical route to isocyanides

• Francesco Basoccu,
• Federico Cuccu,
• Federico Casti,
• Rita Mocci,
• Claudia Fattuoni and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 732–737, doi:10.3762/bjoc.18.73

• organic bases like potassium tert-butoxide and imidazole proved to be as effective as triethylamine. Much to our surprise, we observed that the association between only 1 equivalent of triethylamine and 6 equivalents of sodium carbonate brought a good conversion rate of 1f in 2f at a frequency of 36 Hz

• after 1h (70%, GC–MS analysis). Reducing the amount of sodium carbonate did not provide any advantage. Interestingly, using anhydrous sodium carbonate instead of its hydrated form improved reaction yields, likely due to the hydrolysis of tosyl chloride. With these data in hand, we then opted for

• many troublesome downsides characterise them, any possible alternative synthetic route has been unfairly put aside. Nonetheless, we demonstrated the feasibility of their synthesis through a greener procedure employing cheap reagents such as sodium carbonate [46] and waste materials deriving from

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

• inductive heating (Scheme 3) [35]. The cycle can be divided into two individual processes: First, the carbonation step, in which the CaO absorbs the CO2 to form the calcium carbonate at 650–680 °C, and second, the subsequent calcination step, in which the CaO-based sorbent is sintered at temperatures of 850

Cholyl 1,3,4-oxadiazole hybrid compounds: design, synthesis and antimicrobial assessment

• Anas J. Rasras,
• Mohamed El-Naggar,
• Nesreen A. Safwat and
• Raed A. Al-Qawasmeh

Beilstein J. Org. Chem. 2022, 18, 631–638, doi:10.3762/bjoc.18.63

• ]. Having oxadiazole-2-thiol 2 at hands, the reactive thiol was subjected to the reaction with propargyl bromide and sodium carbonate as a base to afford the thiopropargylated derivative 3 in 82% yield after 24 h (Scheme 2) [33]. Compound 3 was the starting point for a Mannich reaction to generate a library

Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• carbonate. In the light of the above, it was unclear, in which direction would proceed the reaction of bromopropargylic alcohols and phenols. In the present paper, we report on the results of these studies. Results and Discussion Initially, bromopropargylic alcohol 1a and phenol (2a) were chosen as the

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

• irradiation, generating the reduced adduct in 79% yield (Scheme 20). Depending on the type of solvent used, the yield may vary due to oxidation of the alcohol 14 back to 10 because of its low stability in solution. The pegylation strategy involved monomethoxypoly(ethyleneglycol)succinimide carbonate (mPEG-SC

High-speed C–H chlorination of ethylene carbonate using a new photoflow setup

• Takayoshi Kasakado,
• Takahide Fukuyama,
• Tomohiro Nakagawa,
• Shinji Taguchi and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2022, 18, 152–158, doi:10.3762/bjoc.18.16

• Research & Development Group, Nankai Chemical Co. Ltd., 1-1-38 Kozaika, Wakayama 641-0007, Japan Department of Applied Chemistry, National Yang Ming Chiao Tung University (NYCU), Hsinchu 30010, Taiwan 10.3762/bjoc.18.16 Abstract We report the high-speed C–H chlorination of ethylene carbonate, which gives

• chloroethylene carbonate, a precursor to vinylene carbonate. A novel photoflow setup designed for a gas–liquid biphasic reaction turned out to be useful for the direct use of chlorine gas. The setup employed sloped channels so as to make the liquid phase thinner, ensuring a high surface-to-volume ratio. When

• ethylene carbonate was introduced to the reactor, the residence time was measured to be 15 or 30 s, depending on the slope of the reactor set at 15 or 5°, respectively. Such short time of exposition sufficed the photo C–H chlorination. The partial irradiation of the flow channels also sufficed for the C–H

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• -bromobenzonitrile (2) under different amounts of DABCO. Two inorganic bases were tested: potassium carbonate (K2CO3) and sodium hydrogen carbonate (NaHCO3). Reactions in the absence of inorganic bases were also performed (Table 1). An excited iridium photocatalyst (Ir[dF(CF3)ppy]2(dtbbpy)PF6) was used for the one

Synthesis of new pyrazolo[1,2,3]triazines by cyclative cleavage of pyrazolyltriazenes

• Nicolai Wippert,
• Martin Nieger,
• Claudine Herlan,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2021, 17, 2773–2780, doi:10.3762/bjoc.17.187

• . Diisopropylamine and an aqueous solution of potassium carbonate were added to the in-situ generated diazonium salt according to literature-known protocols [40]. The resulting 3-(3,3-diisopropyltriaz-1-en-1-yl)-1H-pyrazole-4-carbonitrile (15) was used as starting material for the attempts to add different side

• chains to the pyrazole moiety. The addition of several aliphatic bromides or iodides 14 in combination with potassium or cesium carbonate in DMSO gave a mixture of the regioisomeric compounds 12 and 13 due to the addition of the alkyl substituents to one of both pyrazole-nitrogen atoms. As shown in Table

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• should lead to an N-methyl group and to reductive cleavage of the carbonate-protected phenol(s); route B is based on treatment with an alkyllithium compound [26], which should remove all ethoxycarbonyl groups and provide N-nor analogues of the products obtained in route A (Figure 3). The required

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• with bis(trichloromethyl)carbonate (BTC) afforded the crude product 3b, which was sufficiently pure for use in the next reaction step without further purification (Scheme 1). The next steps of the catalyst synthesis were the attachment of tert-butanesulfinamide 4 to iso(thio)cyanates 3a and 3b with

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

• Pratibha Sharma,
• Raakhi Gupta and
• Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

• ) in the presence of cesium carbonate and an N-benzylquininium salt as catalyst (cat. 48) (solid–liquid phase-transfer conditions) to give the corresponding adducts in 40–90% yields with excellent ee of up to 99% (Table 10) [44]. A different type of asymmetric aza-Michael addition was developed by Wang

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• site in accordance with well-established precedents [38][39]; and after ten minutes it could be recovered after neutralization with aqueous sodium hydrogen carbonate (Table 1, entries 6, 10). No apparent reaction occurred with dilute hydrochloric acid in ethanol (Table 1, entry 14) unless the solution

• ). When a solution of 15a in dichloromethane was treated with Amberlyst 15, an ion exchange resin with a strongly acidic sulfonic acid [40], it was rapidly adsorbed and presumably protonated, but it could be displaced from the resin upon treatment with aqueous sodium hydrogen carbonate (Table 1, entries

Direct C(sp³)–H allylation of 2-alkylpyridines with Morita–Baylis–Hillman carbonates via a tandem nucleophilic substitution/aza-Cope rearrangement

• Siyu Wang,
• Lianyou Zheng,
• Shutao Wang,
• Shulin Ning,
• Zhuoqi Zhang and
• Jinbao Xiang

Beilstein J. Org. Chem. 2021, 17, 2505–2510, doi:10.3762/bjoc.17.167

• our studies on a direct benzylic allylic reaction of 2-alkylpyridines with MBH carbonates as allylic precursors under base- and catalyst-free conditions. As depicted in Scheme 2, we envisioned that the MBH carbonate 2 can undergo the SN2’ reaction with the nucleophilic 2-picoline 1a, giving the

• intramolecular SN2’ type reaction (path a) or an aza-Cope rearrangement under thermal conditions to generate product 3. Results and Discussion To evaluate our idea for the allylic alkylation reaction of MBH carbonates to 2-alkylpyridines, 2-picoline (1a) and MBH carbonate 2a were selected as the model substrates

• well tolerated, providing the desired products in moderate to good yields (3c–g, yield 69–78%). Compared with electron-withdrawing groups, the presence of electron-donating groups led to a slightly sluggish reaction and a low reaction yield was observed for 4-MeO substituted carbonate (3b, yield 47

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

• desired epoxide 30 after one hour in 85% yield (dr 10:1). This species was next converted to the terminal carbonate derivative 31 to transform the epoxy functionality to a vicinal diol through a two-step manipulation involving protection of the terminal alcohol as Boc derivative followed by BF3·Et2O

• -promoted intramolecular oxacyclization. After TBS protection, intermediate 32 was collected in 86% yield from epoxide 30. Basic methanolysis of the cyclic carbonate followed by treatment with NaH and N-tosylimidazole then afforded terminal epoxide 34 in 97% yield. Unfortunately, attempts to open the

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• non-conductive polymers like water-soluble poly(2-ethyl-2-oxazoline) (PEtOx) [35], polypropylene (PP) [36][37] photo-cross-linkable and biodegradable poly(ʟ-lactide-co-ε-caprolactone-co-acryloyl carbonate) [38], or thermoplastic elastomers [39] have successfully been processed via MEW [40

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

Asymmetric organocatalyzed synthesis of coumarin derivatives

• Natália M. Moreira,
• Lorena S. R. Martelli and
• Arlene G. Corrêa

Beilstein J. Org. Chem. 2021, 17, 1952–1980, doi:10.3762/bjoc.17.128

• stereoselective one-pot procedure for the synthesis of five-membered annulated coumarins 28 was described by the group of Enders [40]. Using dual catalysis, with a cinchona primary amine derivative 22 and silver carbonate, a series of functionalized coumarin derivatives 28 were obtained in good yields (up to 91

Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution

• Ryan M. Alam and
• John J. Keating

Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127

• effect of varying these reaction parameters, using n-pentyl bromide as the prototypical N-alkylating reagent (Table 1). Early investigations revealed that the combination of cesium carbonate (Cs2CO3) in dimethylformamide (DMF) at room temperature (≈ 20 °C) afforded a mixture of N-1 and N-2 regioisomers

• , respectively). Substituting potassium carbonate (K2CO3) for Cs2CO3 did not show any improvement in the regioisomeric distribution of 10 and 11 (ratio N-1 (10)/N-2 (11) = 1.4:1) (Table 1, entry 4). Similarly, the use of sodium carbonate under identical conditions gave a notably lower combined yield of 10 and 11

• , using THF as the reaction solvent with potassium or sodium carbonate bases failed to give the N-alkylated products 10 or 11 (Table 1, entries 7 and 8, respectively). Further variation of the reaction solvent revealed no significant improvement in N-1 regioselectivity, when using acetonitrile (MeCN