Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• 10.3762/bjoc.21.203 Abstract Various 5-arylidene derivatives were prepared via a Knoevenagel condensation-type reaction of aromatic/heteroaromatic aldehydes with rhodanine or thiazolidine-2,4-dione (TZD) catalyzed by EDA/AcOH under microwave heating. This convenient methodology is broad in scope (49

• condensation-type reaction between aromatic aldehydes with rhodanine or thiazolidine-2,4-dione [39]. Various protocols have been reported employing diverse catalyst systems and reaction conditions. Common catalysts include inorganic bases such as sodium acetate (NaOAc) [40], urea/thiourea [41], NaOH [42

• condensation-type reaction using ethylenediamine (EDA) as catalyst in AcOH under microwave (μw) heating. This convenient methodology is broad in scope, provides the condensation products in high yields (up to 99%), with a reasonable catalyst loading (10 mol %) in only 30 minutes. This approach also enabled the

Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• cation were consistent with earlier reports [2][26], though the configurations of the intermediates were clearly delineated. The authors proposed that dicarbonyl compound 50 serves as the key intermediate diverging to all Illicium sesquiterpenes, with a retro-Dieckmann condensation and aldol reaction

• protected prior to the RCM step. Oxidative cleavage of the cyclopentene followed by Pinnick oxidation of the resulting aldehyde to the carboxylic acid and esterification yielded ketoester 56. Dieckmann condensation of 56, esterification of the resulting enolate with 57, and subsequent one-pot partial

• introduced a tertiary alcohol at the C4 position, yielding retro-Dieckmann precursor 61. Subsequent retro-Dieckmann condensation under basic conditions, deprotection of the PMP group, and selective ketalization of the C11 carbonyl group afforded compound 62. The C1 methyl group was installed via enol

Rapid access to the core of malayamycin A by intramolecular dipolar cycloaddition

• Yilin Liu,
• Yuchen Yang,
• Chen Yang,
• Sha-Hua Huang,
• Jian Jin and
• Ran Hong

Beilstein J. Org. Chem. 2025, 21, 2542–2547, doi:10.3762/bjoc.21.196

• smoothly to deliver the aldehyde which was immediately subjected to the condensation reaction with benzylhydroxylamine. The corresponding nitrone 10 then underwent an intramolecular cycloaddition. Adduct 11 was isolated as the major product in 42% yield for 2 steps. Comprehensive NMR analysis revealed the

• from the use of crotyl bromide as a mixture of geometric isomers. After installation of the crotyl group, hydrolysis of the acetonide group and oxidative cleavage of diol 16, oxime 17 was prepared through the condensation of the aldehyde with hydroxylamine in overall 59% yield. Upon oxidation with

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• contraction of six-membered cycles in the synthesis of functionalized cyclopentane/enones, which are biologically active compounds. The main synthetic methods of ring contraction (ozonolysis–aldol condensation, ozonolysis–Dieckmann reaction, Baeyer–Villiger cleavage–Dieckmann reaction) and rearrangements

• cyclohexane/ene ring contraction. The structure of the review includes examples of simple transformations (ozonolysis–aldol condensation, ozonolysis–Dieckmann reaction, and Baeyer–Villiger cleavage–Dieckmann reaction) and rearrangements (photochemical, benzil, semi-pinacol, Wolff, Meinwald, Wagner–Meerwein

• aldol condensation of the resulting dialdehyde. This strategy is widely used at the key stage in the formation of a cyclopentane ring in the synthesis of various building blocks, including echinopine A (3) [10][11][12] (Scheme 1). The ozonolysis–cyclization sequence was used by Alvarez-Manzaneda et al

Comparative analysis of complanadine A total syntheses

• Reem Al-Ahmad and
• Mingji Dai

Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178

• underwent ketone release and amine-ketone condensation to form iminium ion 27. Under the same acidic conditions, enamide 26 underwent hydrolysis and tautomerization to form enol 28. Conjugate addition of enol 28 to iminium ion 27 gave 29 for the subsequent intramolecular Mannich cyclization to deliver 30

• , which continued with an amide-ketone condensation to finally produce 31 in this highly efficient one-step biomimetic cascade sequence. The secondary amine of 31 was selectively protected as a Boc carbamate and the dihydropyridone moiety was oxidized to a pyridone with Pb(OAc)4. Pyridone 32 was prepared

• hemiaminal opening and amine–ketone condensation, iminium ion 65 was produced for the next pyrrole nucleophilic addition to form a strategically important C–C bond and afford 66, which was protected as Boc carbamate in the same pot to give 67 in 96% yield from 64. In this tandem sequence, the nucleophilicity

Halogenated butyrolactones from the biomass-derived synthon levoglucosenone

• Johannes Puschnig,
• Martyn Jevric and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175

• morpholine via an aza-Michael addition and condensation (Scheme 3). It was envisaged that the β-amino group could act as a stable functional group resulting in Baylis–Hillman-like reactivity. An extensive survey of reaction conditions using Selectfluor and N-fluorobenzenesulfonimide (NFSI) as the sources of

Synthesis of triazolo- and tetrazolo-fused 1,4-benzodiazepines via one-pot Ugi–azide and Cu-free click reactions

• Xiaoming Ma,
• Zijie Gao,
• Jiawei Niu,
• Wentao Shao,
• Shenghu Yan,
• Sai Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 2202–2210, doi:10.3762/bjoc.21.167

• , the Ugi–azide adducts could undergo lactamization and lead to the formation of highly condensed 1,4-benzodiazepines 8 fused with triazole, tetrazole, and piperazinone rings. This is a new example of combining MCR and post-condensation modification as a one-pot synthesis to access novel heterocyclic

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• the direct condensation and co-polymerization of both monomers promoted by a bicatalytic system including stannous chloride (SnCl2·2H2O) and methane sulfonic acid (MSA). PLGA films were prepared by the solvent casting technique, for which the presence of glycolic acid was found to increase their

• -proline as a catalyst (Scheme 25) [100]. The C–C-bond formation between biomass-based feedstock by aldol condensation reactions of furfural with 1-hydroxyacetone has been reported by Subrahmanyam and co-workers (Scheme 26) [101]. C4 biobased carbonyl platforms Acetoin Acetoin is a very important C4

• protonated forms (Scheme 40). HFO can be hydrolyzed to succinic acid, however, it is a slow process in aqueous solution. In NaOH solution at pH 9–10, a complete conversion of HFO to succinic acid is rapidly achieved (Scheme 41) [126]. Substitution and condensation reactions of HFO (crude from furfural

The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products

• Dong-Xing Tan and
• Fu-She Han

Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164

• steps, respectively. As shown in Scheme 6 [58], the Cu-catalyzed 1,4-conjugated addition of 71 [59] with vinylMgBr followed by intramolecular Claisen condensation furnished bicyclic diketone 72 on a gram scale. Notably, for such a bicyclic substrate, it is quite challenging to achieve desymmetric

• -mediated condensation with 112 accomplished the total synthesis of (−)-platensilin (23). Based on the aforementioned successful work, the authors focused on the synthesis of (−)-platencin (24) and (−)-platensimycin (25) (Scheme 11) [82]. Accordingly, Wittig reaction of 108 followed by 1,4-elimination and

Multicomponent reactions IV

• Thomas J. J. Müller and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2082–2084, doi:10.3762/bjoc.21.163

• a strong emphasis on heterocycle synthesis. Beyond traditional condensation-based approaches, mechanistically innovative crossovers – linking metal catalysis with radical chemistry and, more recently, with photo(redox) catalysis – are opening entirely new avenues for MCR development. Finally, seven

Bioinspired total syntheses of natural products: a personal adventure

• Zhengyi Qin,
• Yuting Yang,
• Nuran Yan,
• Xinyu Liang,
• Zhiyu Zhang,
• Yaxuan Duan,
• Huilin Li and
• Xuegong She

Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160

• aldehyde followed by base-promoted aldol condensation reaction successfully provided tabertinggine. This approach achieved the first total synthesis of tabertinggine in only ten steps and capable of supplying enough material for the following skeletal diversifications. With sufficient tabertinggine in hand

Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid

• Yana I. Sakhno,
• Oleksander V. Buravov,
• Kostyantyn Yu. Yurkov,
• Anastasia Yu. Andryushchenko,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158

• depending on the conditions, can either be limited to a Biginelli condensation with the formation of hydroxytetrahydropyrimidines or proceed with further post-cyclization to form oxygen-bridged triazolobenzoxadiazocine derivatives. Furthermore, a multicomponent synthesis of oxygen-bridged pyrimidine systems

Photochemical reduction of acylimidazolium salts

• Michael Jakob,
• Nick Bechler,
• Hassan Abdelwahab,
• Fabian Weber,
• Janos Wasternack,
• Leonardo Kleebauer,
• Jan P. Götze and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153

• transformations of carbonyl substrates with umpolung processes of aldehydes such as the benzoin condensation and Stetter reaction being particularly well studied [4][5][6][7][8][9][10][11]. In these processes, addition of the NHC to the aldehyde followed by proton transfer generates the enamine-like Breslow

Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization

• Miao Xiao,
• Liuyang Pu,
• Qiaoli Shang,
• Lei Zhu and
• Jun Huang

Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152

• was initially investigated (Scheme 3). Chan’s diene (16) was subjected to condensation with freshly distilled aldehyde 17 in THF at room temperature, using a catalytic system comprising Ti(OiPr)4/(S)-BINOL complex (2.0 mol %). Subsequent deprotection with pyridinium p-toluenesulfonate (PPTS) at 0 °C

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• synthetic organic chemistry and pharmaceutical applications due to their diverse biological activities. In this study, we synthesized three novel glycidyl esters of phosphorus acids 1–3 via the condensation of chlorophosphine oxides or phosphorus oxychloride with glycidol in the presence of a base

• encountered in the literature. In this paper, we report the synthesis, biological activity, and electrochemical evaluation of glycidyl esters of phosphorus acids. Results and Discussion Synthesis of glycidyl esters of phosphorus acids 1–3 Glycidyl esters of phosphorus acids 1–3 were obtained by condensation

• electrochemical behavior. The compounds were efficiently obtained via the condensation of chlorophosphine oxides and phosphorus oxychloride with glycidol, affording high-purity products in moderate to good yields. Cytotoxicity studies revealed that all three compounds possess antiproliferative activity against

Preparation of spirocyclic oxindoles by cyclisation of an oxime to a nitrone and dipolar cycloaddition

• Beth L. Ritchie,
• Alexandra Longcake and
• Iain Coldham

Beilstein J. Org. Chem. 2025, 21, 1890–1896, doi:10.3762/bjoc.21.146

• condensation, cyclisation, and cycloaddition as an efficient strategy for the rapid formation of complex spirocyclic products that could have value for the formation of novel, bioactive oxindoles. Keywords: cascade; cycloaddition; oxindole; spirocycle; stereochemistry; Introduction The Alstonia alkaloids are

Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• various saddle-shaped eight-membered azaheterocycles, conformationally rigid seven-membered cyclic compounds can also exhibit inherent chirality. In 2017, Antilla et al. developed the CPA-catalyzed asymmetric condensation of 4-substituted cyclohexanones with O-arylhydroxylamines, which yielded axially

• chiral cyclohexylidene oxime ethers with high enantioselectivity [56]. In 2024, through the utilization of this method, Liu and co-workers disclosed the enantioselective synthesis of inherently chiral 7-membered tribenzocycloheptene oximes 76 through CPA 18-catalyzed asymmetric condensation between 7

• with poor diastereoselectivity while maintaining high enantioselectivity for both diastereomers (see 76d–g). Furthermore, the authors have investigated the asymmetric condensation using other seven-membered cyclic ketones (see 77a) as well as the coupling with alkylhydroxylamine (see 77b

Systematic pore lipophilization to enhance the efficiency of an amine-based MOF catalyst in the solvent-free Knoevenagel reaction

• Pricilla Matseketsa,
• Margret Kumbirayi Ruwimbo Pagare and
• Tendai Gadzikwa

Beilstein J. Org. Chem. 2025, 21, 1854–1863, doi:10.3762/bjoc.21.144

• functionalized MOFs to the Knoevenagel condensation reaction. A well-defined MOF material composed of both amine- and hydroxy-bearing linkers was reacted with a series of aliphatic isocyanates (isopropyl, tert-butyl, n-hexyl, and tetradecyl) and, incongruously, was found to preferentially react at the hydroxy

• preventing its interference with the Lewis acidic catalyst surface sites, but we wondered, if similar reaction acceleration of a condensation reaction could be achieved by the lipophilization of the internal surfaces of an amine-based MOF catalyst. The majority of studies of lipophilic MOFs applied to

• by increasing the binding affinity for the lipophilic reactants and by decreasing the energy required to desolvate acid/base amino acid catalysts [34][35]. Lipophilicity has also been found to be beneficial in condensation reactions as the removed water molecules are repelled by the hydrophobic

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• -triazoles 28 can be obtained by click chemistry (Scheme 6B) via one-pot deprotection of 26 and Cu(I)-catalysed reaction with an azide [43][44]. Heteroarylimines 31a,b can be easily obtained by condensation of a (hetero)aromatic aldehyde 30a,b with a (hetero)aromatic amine 29a,b [36][37][38] (Scheme 7). The

• acylhydrazones are accessible with comparatively low synthetic effort, especially compared to diarylethenes and fulgides. The synthesis of arylhydrazones is usually performed through condensation between a carbonyl 112 and a hydrazine 111 (Scheme 35A) [109]. Alternatively, one can perform an azo-coupling between

• a diazonium salt 113 and a nucleophile 114 (Scheme 35B) [113] or a Grignard/aryllithium reagent 115 and a diazo compound 116 (Scheme 35C) [108]. Acylhydrazones 110 can be synthesised by reaction of hydrazine with 118 and subsequent acid-catalysed condensation of 119 with carbonyl 120 (Scheme 36

Fe-catalyzed efficient synthesis of 2,4- and 4-substituted quinolines via C(sp²)–C(sp²) bond scission of styrenes

• Prafull A. Jagtap,
• Manish M. Petkar,
• Vaishnavi R. Sawant and
• Bhalchandra M. Bhanage

Beilstein J. Org. Chem. 2025, 21, 1799–1807, doi:10.3762/bjoc.21.142

• during GC–MS analysis) and formaldehyde (2a′′) via C–C bond scission of styrene in the presence of FeIII/O2, possibly through a 1,2-addition of O2 to styrene [49][58][59][60]. This in-situ generated aldehyde species then undergoes condensation with the amine 1a, leading to the formation of the

Synthesis of chiral cyclohexane-linked bisimidazolines

• Changmeng Xi,
• Qingshan Sun and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1786–1790, doi:10.3762/bjoc.21.140

• , condensation of N-sulfonylated 1,2-diphenylethane-1,2-diamines and cyclohexane-1,2-dicarboxylic acid, and the final cyclization with the in situ generated Hendrickson reagent. Keywords: bisimidazoline; cyclohexane; cyclohexane-1,2-dicarboxylic acid; 1,2-diphenylethane-1,2-diamine; Introduction Chiral

• cyclohexane-linked bisimidazolines were prepared from enantiopure (1S,2S)-cyclohexane-1,2-dicarboxylic acid and (1R,2R)- and (1S,2S)-1,2-diphenylethane-1,2-diamines via the monosulfonylation of 1,2-diphenylethane-1,2-diamines, condensation of N-sulfonylated 1,2-diphenylethane-1,2-diamines with (1S,2S

Research progress on calixarene/pillararene-based controlled drug release systems

• Liu-Huan Yi,
• Jian Qin,
• Si-Ran Lu,
• Liu-Pan Yang,
• Li-Li Wang and
• Huan Yao

Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139

• a hot topic [75]. PAs can be prepared via the Friedel–Crafts condensation, which involves combining 1,4-dimethoxybenzene with paraformaldehyde in the presence of a Lewis acid. The central axis of these aromatic hydrocarbon molecules possesses n fold rotational symmetry [76]. PAs possess highly

Convenient alternative synthesis of the Malassezia-derived virulence factor malassezione and related compounds

• Karu Ramesh and
• Stephen L. Bearne

Beilstein J. Org. Chem. 2025, 21, 1730–1736, doi:10.3762/bjoc.21.135

• DCC-induced condensation of phenylacetic acid reported by Bhandari and Ray [22] and others [23][24][25][26][27]. Initially, we converted indole-3-acetic acid to its methyl ester, followed by protection of the indole nitrogen with a Boc group and subsequent hydrolysis of the methyl ester to regenerate

Approaches to stereoselective 1,1'-glycosylation

• Daniele Zucchetta and
• Alla Zamyatina

Beilstein J. Org. Chem. 2025, 21, 1700–1718, doi:10.3762/bjoc.21.133

• were readily prepared by self-condensation of the corresponding acetylated methyl 1,2-orthoacetates using BF3·OEt2 as a promoter [55]. While the 1,2-orthoester functionality in the glycosyl donor 17 directed the 1,2-trans selectivity towards the formation of an α-mannosidic linkage, the anomeric β

• due to the strong electron-withdrawing effect of the picolinium substituent, effectively preventing anomerization or self-condensation. Good stereoselectivity and yields were achieved in the glycosylation reactions of 4-O-picoloyl-protected TMS-α-glycoside acceptors with stereodirecting thioglycoside

• derivatives 130 and 131, respectively [63]. A separate case of obtaining symmetric 1,1-disaccharides of the manno- and talo-series 133 and 135, respectively, via self-condensation of the corresponding 3,4,6-tri-O-benzylated 2-iodolactols 132 and 134, has also been reported (Scheme 11) [115]. In specific cases

Catalytic asymmetric reactions of isocyanides for constructing non-central chirality

• Jia-Yu Liao

Beilstein J. Org. Chem. 2025, 21, 1648–1660, doi:10.3762/bjoc.21.129

• condensation between 27 and the aldehyde afforded INT-A, which was activated by the CPA catalyst through hydrogen bonding interaction. The nucleophilic addition of isocyanide to Int-A produced INT-B bearing a stereogenic center. Subsequently, INT-B underwent intramolecular cyclization to generate axially

• functionality in 63 allowed for versatile derivatizations, such as reduction, reductive amination, condensation, and olefination, which further expanded the structural diversity of the resulting products. Summary and Outlook The past few years have witnessed exciting progress in developing catalytic asymmetric