Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• ). Firstly, we chose NaOH to optimize the reaction conditions. Apparently, in the absence of a solubilizer, no reaction occurred due to poor solubility of 1a in boiling water (Table 1, entry 6). Macrogol 400 (PEG-400) is emerging as an environmentally friendly nonionic solubilizer due to its unique merits

• , such as nontoxicity, inexpensiveness, nonflammability, low volatility and good water solubility, which are consistent with the concept of green chemistry [74][75]. Therefore, we tested the reaction in the presence of PEG-400 (Table 1, entries 7–9). It was found that the reaction uniquely produced 3a in

• 48% yield when using 3.0 equiv of PEG-400 as solubilizer (Table 1, entry 8), and further increasing the PEG-400 loading could not remarkably improve the yield of 3a (Table 1, entry 9). With this in mind, we selected 3.0 equiv of PEG-400 as solubilizer in our study. Next, we examined the influence of

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• -pot process can be conducted in various solvents such as in PEG 400 [79], ionic liquids like 1-butyl-3-methylimidazolium hydroxide ((Bim)OH) [80], the nanoionic liquid 1-methylimidazolium trinitrocarbide ([[HMIM]C(NO2)3]) [81], N-methylpyridinium tosylate (NMPYT) [82], or glucose-based strong eutectic

Dissecting Mechanochemistry III

• Lars Borchardt and
• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

• for the halogenation of organic substrates. For example, Banerjee and co-workers reported the mono-, di-, and trihalogenation of aromatics by controlling the stoichiometry of the N-halosuccinimide (NXS) and PEG-400 as the grinding auxiliary in a mechanical grinder (Scheme 1a) [3]. N-Halosuccinimides

• José G. Hernández Bochum, Medellín, October 2022 ORCID® iDs Lars Borchardt - https://orcid.org/0000-0002-8778-7816 José G. Hernández - https://orcid.org/0000-0001-9064-4456 a) Mechanochemical PEG-400-assisted halogenation of phenols and anilines using NXS. b) Halogenation of azobenzenes with NXS

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

• Dharmendra Das,
• Akhil A. Bhosle,
• Amrita Chatterjee and
• Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

• catalyst-free halogenation of phenols and anilines via liquid-assisted grinding using PEG-400 as the grinding auxiliary. A series of mono-, di-, and tri-halogenated phenols and anilines was synthesized in good to excellent yields within 10–15 min in a chemoselective manner by controlling the stoichiometry

• of N-halosuccinimides (NXS, X = Br, I, and Cl). It was observed that PEG-400 plays a key role in controlling the reactivity of the substrates and to afford better regioselectivity. Almost exclusive para-selectivity was observed for the aromatic substrates with free o- and p-positions for mono- and

• reaction time, and mild reaction conditions are a few noticeable merits of this environmentally sustainable mechanochemical protocol. Keywords: automated grinding; chemoselectivity; mechanochemistry; N-bromosuccinimide; PEG-400; regioselectivity; stoichiometry-controlled halogenation; Introduction Aryl

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• (33) is replaced by bromoisobenzofuranone 61, also leading to isoindoloquinazoline derivatives 57 (Scheme 18) [99]. After optimization of the reaction conditions, a 4:1 combination of water and PEG-400 was chosen as the best solvent and an array of nineteen isoindoloquinazolinones 57 with yields

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• -diazopyrazole derivative 158 with 4-substituted benzylidene-3-methyl-1H-pyrazol-5(4H)-one 159 in PEG-400. The reaction resulted in the synthesis of 6,7-dihydropyrazolo[1,5-a]pyrimidine derivatives 160 (Scheme 45). Selected compounds were studied for their interaction with calf thymus DNA using various

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• , and could be easily recovered and reused. Aryl iodides, activated aryl bromides and chlorides, and heteroaryl bromides were smoothly converted to phenols. In 2011, the Chen group developed a PEG-400-mediated protocol for the synthesis of phenols using CuI as the catalyst and KOH as the base (Scheme 14

• ) [36]. In this reaction system, non-toxic and cheap PEG-400 played a dual role as both ligand and solvent. The effective catalytic system could convert aryl iodide to phenols in high yields within 5 hours at 100 °C. The conversion of aryl bromides bearing either an electron-donating group or an

• of aryl halides using DMEDA as ligand. Hydroxylation of aryl halides using PAO as ligand. Hydroxylation of aryl halides using D-glucose as ligand. Hydroxylation of aryl halides using INDION-770 as ligand. PEG-400 mediated hydroxylation of aryl halides. Hydroxylation of aryl halides using glycolic

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• multicomponent CuAAC reaction proceeded well in PEG-400 among various solvents, mainly due to the hydrophilic and hydrophobic character of the PEG-400. As shown in Scheme 12, the CuAAC gave the desired bistriazoles 31 in good to excellent yield when electron-withdrawing groups were present in the benzyl bromides

A novel and facile synthesis of 3-(2-benzofuroyl)- and 3,6-bis(2-benzofuroyl)carbazole derivatives

• Wentao Gao,
• Meiru Zheng and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 1533–1540, doi:10.3762/bjoc.7.180

• described. The synthesis mainly relies on the ultrasound-assisted Rap–Stoermer reaction of 3-chloroacetyl- (1) or 3,6-dichloroacetyl-9-ethyl-9H-carbazole (4) with various salicylaldehydes 2a–k as well as 2-hydroxy-1-naphthaldehyde (2l) in CH3CN with the presence of PEG-400 as catalyst. The procedure offers

• easy access to benzofuroylcarbazoles in short reaction times and the products are obtained in moderate to good yields. Keywords: 2-benzofuroyl; carbazole; PEG-400; Rap–Stoermer reaction; salicylaldehydes; ultrasound-assisted; Introduction Carbazole, and especially heterocycle-containing carbazole

• impressive, our attempts to follow the route to synthesize 3a were also frustrated by the very complex mixture of the resulting products, from which we could not separate any desired products in appreciable yields. After many trials, we found that when the Rap–Stoermer reaction was carried out with PEG-400