Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• -dithiocyanatopyrimidine (NDTP) as the coupling reagent for cinnamic acid amidation with swift reaction time (Scheme 4) [22]. The reaction of cinnamic acid (7) with NDTP resulted in the active acyl thioester 11 followed by a reaction with an amine to give the corresponding amide 10. The byproduct of the coupling reagent

• could be recycled by adding POCl3 and KSCN, thus promoting the reagent’s sustainability by reducing waste. Carboxyl group activation can also be achieved by using triazine-based reagents. For example, Saberi and Salimiyan (2019) applied 2,4,6-trichloro-1,3,5-triazine (TCT) to perform amidation of

• applications in organic reactions. Similarly, Kunishima and co-workers (2021) utilized (N,N’-dialkyl)triazinedione-4-(dimethylamino)pyridine (ATD-DMAP) for the amidation of cinnamic acid (7) to generate the corresponding amide 10 in excellent yield (Scheme 5B) [37]. Mechanistically, the carboxyl group attacks

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

• Seeun Lim,
• Teresa Kim and
• Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

• 98% yield. Ortho-bromoaryl-substituted nitrile 3m also underwent tandem amidation and copper-catalyzed cyclization, efficiently producing lactam 9 in a 98% yield. Scheme 7 illustrates a plausible reaction mechanism based on previous studies [34]. The process begins with the formation of NHC–copper

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• 10.3762/bjoc.21.50 Abstract The electrochemical synthesis of 2-aminoprolines based on anodic decarboxylation–intramolecular amidation of readily available N-acetylamino malonic acid monoesters is reported. The decarboxylative amidation under Hofer–Moest reaction conditions proceeds in an undivided cell

• [7][8] (Figure 2, reactions 1 and 2, respectively). Results and Discussion N-Acetylamino malonic acid monoester 9a possessing a tosyl-protected tethered amine was selected as a model substrate for the development of the intramolecular amidation under Hofer–Moest conditions. The acid 9a was prepared

• in three steps (62% overall yield) from commercially available diethyl acetamidomalonate by an alkylation/hydrolysis/Boc-cleavage sequence (Scheme 1). The development of decarboxylative amidation commenced by examining the published conditions for anodic decarboxylation/etherification [4

Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• coupled to either one of the two unit A precursors 18 and 19 by Yamaguchi esterification. CDA fragments 20 and 21 were connected to unit B derivatives 11 and 13 through amidation which provided seco-cryptophycins 22 and 23 in yields of 49% and 38%, respectively. Starting from seco-cryptophycin 22

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• widely used as N-acylamide sources in amidation processes of challenging substrates, typically employing precious transition metals. However, these catalytic systems often present several challenges associated with cost, toxicity, stability, and recyclability. Among the 3d transition metals, copper

• advancements in the synthetic transformations of dioxazolones, with particular examples of copper salts. Keywords: amidation; copper salts; dioxazolones; electrophilic nitrogen; N-acyl nitrene; Introduction Dioxazolones, first synthesized and reported by Beck and co-workers [1], have been employed as

• electrophiles in various nucleophilic transformations due to their susceptibility to rapid decomposition into the corresponding isocyanates (Scheme 1a) [2][3]. They have attracted increasing interest as electrophilic amide sources in amidation using transition-metal catalysts such as ruthenium, rhodium, and

Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D

• Sasha Hayes,
• Yaoying Lu,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266

• /CH2Cl2 at room temperature (17% yield). Subjecting the methoxylated benzaldehyde intermediate 9 to a Doebner–Knoevenagel condensation with malonic acid and pyridine afforded the brominated cinnamic acid analogue 10 in 54% yield [19]. Amidation chemistry using carbonyldiimidazole (CDI) [18] and the

Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams

• Valentina Giraldi,
• Giandomenico Magagnano,
• Daria Giacomini,
• Pier Giorgio Cozzi and
• Andrea Gualandi

Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210

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

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• heteroaromatic halides. The reaction sequence utilizes a photochemically enhanced Negishi cross-coupling as a key step, followed by oximation and reduction. The prepared amino esters were validated for on-DNA reactivity via a reverse amidation–hydrolysis–reverse amidation protocol. Keywords: amino acids; DEL

• first attached to carboxylic acid functionalized DNA headpiece 7a (first reverse amidation). Next, the ester was hydrolyzed to obtain acid 9, and finally, a second reverse amidation with aniline afforded 10. Both the reverse amidation and the ester hydrolysis were performed following literature

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• high yields of the target compounds. When stored individually or in solution at room temperature, the acids 4 gradually decompose and undergo decarboxylation and other accompanying processes. The example of acid 4a demonstrates the possibility of easy amidation to form new β-lactam derivatives 3s and

• acids and their subsequent amidation has been demonstrated. Synthetic routes to 2-oxoazetidine-3-carboxylic acid derivatives. Scope of diazotetramic acids 1 thermolysis in the presence of various nucleophiles. PMP = p-methoxyphenyl, PCP = p-chlorophenyl, PMB = p-methoxybenzyl, PFB = p-fluorobenzyl

• ; reaction scale – 0.25 mmol; ascaled-up (1.5 mmol) yield. Negative results with several N-, O-, and C-nucleophiles and with diazo reagent 1m. Preparation of acids 4 by hydrogenolysis of benzyl esters and examples of acid 4a amidation. Supporting Information Deposition Number CCDC 2323689 (for 3t) contains

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• ][98]. Therefore, in the present study, we report for the first time a milder, greener strategy to prepare a series of epoxyisoindolinones from aminofuranes and maleic anhydride via cascade amidation and stereocontrolled IMDAF reaction in bio-based solvents as an alternative reaction medium. Results

• ] cycloaddition between maleic anhydride and secondary amine occurs first, followed by the corresponding amidation (Figure 3, path II) [110]. Although IMDAF reactions involving furan systems bearing amide functionality are generally reversible [134], the formation of the addition products in high yields in this

Oxidative hydrolysis of aliphatic bromoalkenes: scope study and reactivity insights

• Amol P. Jadhav and
• Claude Y. Legault

Beilstein J. Org. Chem. 2024, 20, 1286–1291, doi:10.3762/bjoc.20.111

• the regioisomeric mixture of Ritter-type amidation side products 3. Conclusion In summary we have developed a hypervalent iodine-catalyzed synthetic method for the oxidative hydrolysis of diverse dialkyl bromoalkenes. The current approach can tolerate both symmetrical as well as unsymmetrical dialkyl

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• ], and sulfonic acids [31]. On the other hand, nitrogen-based nucleophiles amenable to this reaction manifold have thus far been limited to nitriles in the context of Ritter-type iodo(III)amidation [29]. In light of the significance of vinylated azoles, our attention was attracted to the feasibility of

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• carboxylation, C(sp2)–H alkenylation and allylation, C(sp2)–H arylation, C(sp2)–H amidation, and C(sp2)–H thiolation. Preceding the section of applications, a brief description of the structure of NHCs, nature of NHC–metal bond, and methods of preparation of NHC–Cu complexes is provided. Keywords: conjugate

• conversion occurred using either Pd–NHC or Cu–NHC alone. 2.9 C(sp2)–H amidation Chang and co-workers [96] reported an NHC–Cu-catalyzed direct amidation of C–H bonds by using N-chlorocarbamates or N-chloro-N-sodiocarbamates as amino source. In this mechanism, a copper–aryl intermediate reacts with the

• amidating reagent leading to the isolation of copper–arylcarbamato species and the desired product. The developed amidation protocol works highly efficiently and selectively over a broad range of substrates including polyfluorobenzenes, azoles, and quinoline N-oxides (Scheme 74). 2.10 C(sp2)–H thiolation

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• conditions. In 2020, the Polyzos group also demonstrated the carbonylative amidation of aryl halides in continuous flow with the in situ-generated [Ir2]0 (Figure 19A) [79]. This multi-photon tandem photocatalysis protocol provides an elegant alternative to established classical procedures for condensing

• carboxylic acids with amines that typically generate stochiometric amounts of harmful byproducts released [80][81], while simultaneously operating under milder reaction conditions than those applied in transition metal-catalyzed carbonylative amidation protocols [82][83]. Following the same distinct, yet

• . Notably, carbonylative amidation of a borylated aryl bromide to 26d proceeded well, where a Pd-catalyzed carbonylative amidation reaction would be plagued by undesired Suzuki coupling. Several secondary cyclic and acyclic amines, as well as primary amines were successfully employed as amine coupling

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• ) [77][78]. The allyl moiety in 144 allows for facile further functionalization. Amidation of the dihydrodibenzo[b,f]azepine (2a) derivatives with acyl halides 145 allowed for the introduction of variable length amide linkers by Kastrinsky et al. [3] (Scheme 33B). An industrial synthesis of opipramol (5

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

• Shubham Sharma,
• Dharmender Singh,
• Sunit Kumar,
• Vaishali,
• Rahul Jamra,
• Naveen Banyal,
• Deepika,
• Chandi C. Malakar and
• Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

• , metal-free and easy to perform reaction conditions. Moreover, the pyrazole C-3/5-linked amide conjugates were also synthesized via an oxidative amination of pyrazole carbaldehydes and 2-aminopyridines using hydrogen peroxide as an oxidant. Keywords: C–S/O bond formation; metal-free; oxidative amidation

• oxidative amidation reaction of pyrazole-3-carbaldehyde 1 and 2-aminopyridine (F) in the presence of TBHP in DMSO as a solvent at 130 °C (entry 1, Table 2). However, the reaction required longer time (20 h) for the completion, and afforded a product in 29% yield only. It was realized that the isolated

• yield was observed (entries 2–5, Table 2). The oxidant TBHP (10 equiv) failed to deliver the anticipated product in good yield (36%, entry 6, Table 2). Similar results were obtained with H2O2 (25.0 equiv) under neat reaction conditions (entry 7, Table 2). Next, we performed the oxidative amidation

Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A

• Takumi Matsumoto,
• Takefumi Kuranaga,
• Yuto Taniguchi,
• Weicheng Wang and
• Hideaki Kakeya

Beilstein J. Org. Chem. 2022, 18, 1560–1566, doi:10.3762/bjoc.18.166

• 29. Then, five rounds of DIC/Oxyma-mediated amidation [22] and Nα-deprotection with piperidine led to resin-bound peptide 5. Treatment of 5 with TFA/CH2Cl2 1:99 released 30 into the solution without unmasking the acid-labile protecting groups of the side chains. Subsequently, peptide 30 was cyclized

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• mesoxalic ester amide 102 in a Friedel–Crafts reaction followed by a spontaneous lactamization to give (rac)-cladoniamide G (103). The mesoxalic ester amide 102 was synthesized from malonyl chloride 104 through amidation and Regitz diazotransfer, yielding diazo compound 105. Subsequent oxidation and

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

• Daniele Rocco,
• Ana A. Folgueiras-Amador,
• Richard C. D. Brown and
• Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

• atom is reversed (umpolung) from electrophilic to nucleophilic (Scheme 3). This approach can be exploited in many organic reactions, such as: the benzoin condensation [16][17], esterification and amidation of benzaldehydes and cinnamaldehydes [18][19], synthesis of γ-butyrolactones [20], synthesis of

• electrochemistry, NHC instability (and anodic electroactivity) prevented its cathodic generation and subsequent use as catalyst or reagent. Instead, the NHC was generated by chemical deprotonation using a strong base (DBU) and then applied in anodic esterification [30][31][32], and amidation of aromatic aldehydes

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• (Scheme 5) [25]. The metal-free intramolecular oxidative C–H bond amidation of methyl and ethyl 2,6-dimethylphenylphosphonamidates 24, 26, and 28 is an interesting strategy for the synthesis of 1-methoxy/ethoxy-7-methyl-2-hydrobenzo[c][1,2]azaphosphol-3-one 1-oxide derivatives 25, 27, and 29 in

DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• the presence of DDQ, the intramolecular C(sp2)–H amidation of N-(2-(arylideneamino)phenyl)-p-toluenesulfonamides leads to 1,2-disubstituted benzimidazoles and the one-pot coupling of 2-aminobenzamides with aryl/alkyl aldehydes resulted in substituted quinazolin-4(3H)-one derivatives in high yields

• . Keywords: ball mill; 1H-benzo[d]imidazole; C(sp2)–H amidation; DDQ; mechanochemistry; quinazolin-4(3H)-one; Introduction The reawakening approaches to use solvent-free and environmentally benign conditions in organic synthesis have facilitated new opportunities [1][2][3][4]. The research area of

• mechanochemical C–N coupling reactions using DDQ. The newly formed C–N bonds are shown as red lines for clarity. a) The intramolecular C(sp2)-H amidation leading to 1,2-disubstituted benzimidazoles. b) One-pot coupling to synthesize substituted quinazolin-4(3H)-ones. Scope of the mechanochemical synthesis of

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• solution, the mechanochemical reactions were accomplished in the absence of solvents, in short reaction times, and in yields comparable to or higher than their solvent-based counterparts. Keywords: amidation; ball mill; fluorination; in situ monitoring; mechanochemistry; NFSI; Raman monitoring

• -milling conditions. NFSI is a colorless crystalline powder (mp 114–116 °C), bench-stable, and an easy-to-handle reagent, which, due to its commercial availability, has been extensively used as a fluorinating agent in solution [7][8][9]. Additionally, NFSI has also been explored as an oxidant, amidation

• functionalizations [22][23]. In particular, efficient fluorination protocols are long sought after in several areas of science, including medicinal chemistry [24]. Next to fluorination, in this work, we also have investigated NFSI as a source for mechanochemical sulfonylation of imidazoles and amidation reactions

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

• batch of 1a was reduced. It is likely that 2a can be cyclized by base catalysis, or by using common peptide coupling reagents (e.g., EDCI, HATU) upon saponification of the ester group. However, we opted for a trimethylaluminum-mediated amidation reaction [4][39] to give rise to 8-benzyl-7-hydroindolo