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

• -hydroxypyrazoles 143 and not tautomeric 3-pyrazolones. Alternative access to alkynones can be achieved by nucleophilic addition of lithiated alkynes to N-substituted phthalimides 145, followed by ring opening to give, upon the addition of water, the corresponding 3-hydroxyindolines. These intermediates are in

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• radicals by activation of C–O bonds using visible-light photoredox catalysis offers a mild and environmentally benign approach to useful chemical transformations. Alcohols, carboxylic acids, anhydrides, xanthates, oxalates, N-phthalimides, and thiocarbonates are some examples of alkyl and acyl precursors

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• notable advantages in terms of both step- and atom-economy. Taking inspiration from the groundbreaking work of Shang and Fu [6], Li and colleagues demonstrated an innovative approach for the photocatalytic [3 + 2] and [4 + 2] annulation of enynals 32 and γ,σ-unsaturated N-(acyloxy)phthalimides 33 (Scheme

• and γ,σ-unsaturated N-(acyloxy)phthalimides. Proposed mechanism for the decarboxylative [3 + 2]/[4 + 2] annulation. Decarboxylative cascade annulation of alkenes/1,6-enynes with N-hydroxyphthalimide esters. Decarboxylative radical cascade cyclization of N-arylacrylamides. NaI/PPh3-driven

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• article, we focus on the application of these alternative sulfenylating reagents in organic transformations. Keywords: electrophile; N-(sulfenyl)succinimides/phthalimides; organic transformations; organosulfur; sulfenylation; Introduction Sulfur-containing compounds are of high importance in organic

• bonds of unactivated aryls or aromatic sulfenylation by electrophilic aromatic substitution (SEAr) has also recently received attention [38]. In recent years, N-(aryl/alkylsulfenyl)succinimides and N-(arylsulfenyl)phthalimides have been widely employed as new alternative sulfenylating reagents in the

• the best of our knowledge there are no review articles focusing on the application of N-(sulfenyl)succinimides/phthalimides in sulfenylation reactions. In this context, we describe various sulfenylation reactions, such as electrophilic aromatic substitution, ring-opening, dehydrogenative cross

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• disclosed a visible light-mediated radical tandem cyclization of N-arylacrylamides with N-(acyloxy)phthalimides to access 3,3-dialkylated oxindoles in the presence of [Ru(bpy)3Cl2]·6H2O [46]. However, these seminal methods remain limited by the need of noble-metal-based photocatalysts, excess additives and

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

• Naoki Kise and
• Toshihiko Sakurai

Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

• -dihydronaphthalene-1,4-diones (Scheme 1) [5]. In addition, we disclosed that the electroreduction of phthalimides with α,β-unsaturated carbonyl compounds under the same conditions and subsequent treatment with trifluoroacetic acid (TFA) produced 3- and 2-substituted 4-aminonaphthalen-1-ols (Scheme 2) [6]. In this

• ). Electroreductive coupling of phthalimides with α,β-unsaturated carbonyl compounds and subsequent treatment with TFA (previous work). Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds and subsequent treatment with 1 M HCl (this work). Electroreductive coupling of 1a with 2a and

Direct C–H amination reactions of arenes with N-hydroxyphthalimides catalyzed by cuprous bromide

• Dongming Zhang,
• Bin Lv,
• Pan Gao,
• Xiaodong Jia and
• Yu Yuan

Beilstein J. Org. Chem. 2022, 18, 647–652, doi:10.3762/bjoc.18.65

• decades. With the combination of C–H activation, many aminations of aryl compounds have been established [6][7][8][9][10][11][12][13][14][15][16]. However, it is necessary to introduce the directing group into the arene in most successful cases. As a good amino source, phthalimides have been widely

• gel (ethyl acetate/petroleum ether 1:10) to afford the desired products 3a–u. Amination of arenes with phthalimides. Substrate scope of the copper-catalyzed C–H imidation of arenes. Reaction conditions: 1 (2.0 mL as substrate and solvent), 2a (0.10 mmol), CuBr (0.04 mmol) and P(OEt)3 (0.6 mmol) were

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• as Mn(0) and MnO2, that had been employed in the previous work by the same authors to ensure catalytic turnover [110]. Substrates containing functional groups, like esters, phthalimides, silyl enol ethers, boronates, ketones, tertiary alcohols, epoxides, and cyclobutanes, were compatible with the

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin

• Margareta Sohora,
• Leo Mandić and
• Nikola Basarić

Beilstein J. Org. Chem. 2020, 16, 1296–1304, doi:10.3762/bjoc.16.110

• systems for the control of photoreactivity. Keywords: [3 + 2] cycloadditions; β-cyclodextrin; inclusion complexes; photochemistry; phthalimides; Introduction Cycloadditions are highly useful reactions in organic synthesis providing complex cyclic structures from easily available precursors [1][2]. Among

• complex molecules and natural products [11] since the pioneering work of Kanaoka et al. [12]. Photochemical reactions of phthalimides include H-abstractions, cycloadditions and photoinduced electron transfer (PET)[13]. We became interested in the application of photochemical H-abstraction reactions

• initiated by phthalimides in organic synthesis [14][15]. Furthermore, H-abstractions were investigated in inclusion complexes, in the cavity of β-cyclodextrins (β-CD) [16]. We found out that H-abstraction reactions were about ten times more efficient in the β-CD complexes than in the isotropic solution, and

Synthesis and anion binding properties of phthalimide-containing corona[6]arenes

• Meng-Di Gu,
• Yao Lu and
• Mei-Xiang Wang

Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193

• noncovalent interactions between anions and the tetrazine rings. Keywords: anion–π interactions; coronarenes; host–guest complexation; N-functionalized phthalimides; O6-corona[3]arene[3]tetrazines; Introduction Synthetic macrocycles [1][2] are always attractive and important because they are unique

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

• also been prepared in situ and used for a three-component transition-metal-free synthesis of phthalimides 79 induced by fluoride (Scheme 23) [102]. The reaction makes use of 2-(trimethylsilyl)aryl triflates 77, isocyanides 42 and CO2 (78), and takes place in acetonitrile as solvent and without the need

• reaction of trimethylsilylaryltriflates 77, isocyanides 42 and CO2 (78). Plausible mechanism for the three-component synthesis of phthalimides 79. Copper-catalysed three-component reaction of 2-formylbenzonitriles 85, arenes 86 and diaryliodonium salts 87. Copper-catalysed three-component reaction of 2

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• phthalimides 16 and 23 [29]. These intermediary compounds 16 and 23 also allowed an N-methylation of the azaindole moiety with sodium hydride (NaH) and methyl iodide (MeI) to yield 17 and 24. By ethanolic hydrazinolysis and microwave irradiation the phthalimides (16, 17, 23, and 24) were deprotected yielding

Imide arylation with aryl(TMP)iodonium tosylates

• Souradeep Basu,
• Alexander H. Sandtorv and
• David R. Stuart

Beilstein J. Org. Chem. 2018, 14, 1034–1038, doi:10.3762/bjoc.14.90

• Souradeep Basu Alexander H. Sandtorv David R. Stuart Department of Chemistry, Portland State University, Portland OR 97201, United States 10.3762/bjoc.14.90 Abstract Herein, we describe the synthesis of N-aryl phthalimides by metal-free coupling of potassium phthalimide with unsymmetrical aryl

• (TMP)iodonium tosylate salts. The aryl transfer from the iodonium moiety occurs under electronic control with the electron-rich trimethoxyphenyl group acting as a competent dummy ligand. The yields of N-aryl phthalimides are moderate to high and the coupling reaction is compatible with electron

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

• three-step process. The protocol utilized the photodecarboxylative addition of readily available carboxylates to N-(bromoalkyl)phthalimides as a versatile and efficient key step. The initially obtained hydroxyphthalimidines were readily converted to the desired N-diaminoalkylated 3-arylmethylene-2,3

• ; arylmethylenedihydroisoindolinones; photochemistry; photodecarboxylation; phthalimide; Introduction Phthalimides and their related 3-alkyl- and 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones play an important role in medicinal chemistry due to their biological activities for a wide range of therapeutic applications [1][2][3][4

• ][15][16][17][18][19][20][21][22]. The photodecarboxylative addition of phenylacetates to phthalimides represents a mild alternative entrance to these target molecules [23][24][25][26][27][28][29][30][31]. The reaction utilizes phenylacetate salts as readily available alkylation agents [32][33

Mechanochemical N-alkylation of imides

• Anamarija Briš,
• Mateja Đud and
• Davor Margetić

Beilstein J. Org. Chem. 2017, 13, 1745–1752, doi:10.3762/bjoc.13.169

• . Reactions under solvent-free conditions in a ball mill gave good yields and could be put in place of the classical solution conditions. The method is general and can be applied to various imides and alkyl halides. Phthalimides prepared under ball milling conditions were used in a mechanochemical Gabriel

• equimolar amount of ethyl bromide resulted in the dominant formation of the mono-alkylated 1-ethyl product 38. The N-alkylated phthalimides 23 and 24, which were prepared in the previous section were employed in solvent-free Gabriel synthesis of primary amines (Scheme 4). In these milling reactions, the

Nitration of 5,11-dihydroindolo[3,2-b]carbazoles and synthetic applications of their nitro-substituted derivatives

• Roman A. Irgashev,
• Nikita A. Kazin,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2017, 13, 1396–1406, doi:10.3762/bjoc.13.136

• phthalimides (PhthN-ICZ) 6 and 7 (Scheme 3, Table 3), which have been isolated in 53–89% yields, based on the starting nitro compounds 2 and 3. Synthesis of 6,12-dinitro and 6-nitro-substituted indolo[3,2-b]carbazoles and their further reactions In the frames of this research study we have elucidated the

• 6,12-dinitro-ICZ 9a with N- and S-nucleophiles. Nitration of ICZ 1a under different reaction conditions. Scope and yields of nitro-substituted ICZs 2 and 3. Scope and yields of phthalimides 6 and 7. Scope and yields of alkyl(aryl)thio-substituted ICZs 15 and 16. Supporting Information Supporting

Direct and indirect single electron transfer (SET)-photochemical approaches for the preparation of novel phthalimide and naphthalimide-based lariat-type crown ethers

• Dae Won Cho,
• Patrick S. Mariano and
• Ung Chan Yoon

Beilstein J. Org. Chem. 2014, 10, 514–527, doi:10.3762/bjoc.10.47

• which nitrogen-linked side chains containing polyethoxy-tethered phthalimides and naphthalimides, possessing terminal α-trialkylsilyl groups, are synthesized utilizing concise routes and UV-irradiation to form macrocyclic ring systems. In contrast, the indirect route developed for the synthesis of

• lariat-type crown ethers employs sequences in which SET-promoted macrocyclization reactions of α-trialkylsilyl-terminated, polyethoxy-tethered phthalimides and naphthalimides are followed by a side chain introduction through substitution reactions at the amidol centers in the macrocyclic ethers. The

• ][26][27][28][29][30][31][32][33][34]. In intensive early investigations, Kanaoka [35][36][37][38][39][40] and Colye [41][42][43][44] demonstrated the participation of phthalimides in several different kinds of interesting SET-promoted photochemical reactions. Since phthalimides have high excited state

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

• Maurizio Fagnoni,
• Stefano Protti,
• Davide Ravelli and
• Angelo Albini

Beilstein J. Org. Chem. 2013, 9, 800–808, doi:10.3762/bjoc.9.91

• [40]; see Figure 3b). As for DCA, only a tiny amount of the radical anion [35] was generated (data not shown). A purple color and conspicuous bands developed in the case of phthalimides DCP and DCP-Me, with sharp peaks at 577–578 and 535–536 nm and a broad band at ca. 400 nm (see Figure 3c and Figure

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• acetone-sensitised photodecarboxylation chemistry initially developed by Griesbeck [58] under batch conditions was suggested as being ideally suited to microflow conditions [59][60]. The chemistry involves the decarboxylative addition of potassium carboxylates to phthalimides, thus offering an alternative

• interest is the addition of carboxylates 46 to phthalimides 45 shown in Scheme 16. This reaction has also been compared for microflow and batch reactors for a number of substrates [61][62], and again, although residence times are lower under microflow conditions, productivity is higher for the batch

• completion [61]. In an extension of the above reactions, it was shown that α-thioalkyl-substituted carboxylates 50 could be added to phthalimides 45 in a microflow reactor (Scheme 16). Although the flow reaction proved successful, the final ratio of the desired product 51 to the unwanted reductive dimer 52

Microphotochemistry: 4,4'-Dimethoxybenzophenone mediated photodecarboxylation reactions involving phthalimides

• Oksana Shvydkiv,
• Kieran Nolan and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2011, 7, 1055–1063, doi:10.3762/bjoc.7.121

• intra- and intermolecular photodecarboxylation reactions involving phthalimides have been examined under microflow conditions. Conversion rates, isolated yields and chemoselectivities were compared to analogous reactions in a batch photoreactor. In all cases investigated, the microreactions gave

• [20][21][22][23] and specialized micro-photoreactors for laboratory- to technical-scale synthesis have been developed [24][25][26]. We have recently reported on acetone-sensitized photodecarboxylation (PDC) reactions of phthalimides in a commercially available microreactor [27]. The photochemistry of

• phthalimides and its analogues has been intensively studied over the last decades [28][29][30][31][32]. Among the various transformations developed, photodecarboxylation reactions have emerged as efficient and powerful alkylation procedures with high quantum yields of up to 60% [33][34]. Selected

Photoinduced electron-transfer chemistry of the bielectrophoric N-phthaloyl derivatives of the amino acids tyrosine, histidine and tryptophan

• Axel G. Griesbeck,
• Jörg Neudörfl and
• Alan de Kiff

Beilstein J. Org. Chem. 2011, 7, 518–524, doi:10.3762/bjoc.7.60

• Norrish cleavage. The tryptophan derivative 10 is photochemically inert and shows preferential decarboxylation only when induced by intermolecular PET. Keywords: amino acids; decarboxylation; electron transfer; photochemistry; phthalimides; Introduction Phthalimides are versatile electron acceptors in

• photoinduced electron-transfer (PET) reactions. N-Alkylated phthalimides typically absorb in the 295 nm region with extinction coefficients around 103. The quantum yields for intersystem crossing ФISC significantly change with the substitution on the imide nitrogen, e.g., ФISC = 0.5 for N-isobutylphthalimide

• +, electronically excited phthalimides are potent electron acceptors [2]. The rich photochemistry of this chromophore has recently been reviewed [3][4]. Intramolecular hydrogen abstraction is an archetype process for electronically excited carbonyl groups (Norrish type II reaction). The 1,4-biradicals formed by γ

Photoinduced homolytic C–H activation in N-(4-homoadamantyl)phthalimide

• Nikola Cindro,
• Margareta Horvat,
• Kata Mlinarić-Majerski,
• Axel G. Griesbeck and
• Nikola Basarić

Beilstein J. Org. Chem. 2011, 7, 270–277, doi:10.3762/bjoc.7.36

• for the abstraction. Keywords: homoadamantanes; photoinduced H-abstraction; phthalimides; Introduction Since the pioneering work of Ciamican and Paterno [1][2], the photochemistry of ketones has been intensively studied [3][4][5][6]. One important chemical pathway for the deactivation of ketones

• products [34]. Furthermore, suitably substituted phthalimides deactivate from the excited state by intramolecular H-abstractions to yield cyclization products, often benzazepinone derivatives [35][36][37]. Therefore, photoinduced homolytic C–H activation by phthalimide derivatives can, in principle, be

• protic solvent, undergoes H-abstraction to give products with ten times higher quantum yields than in an aprotic solvent. Such a finding is in accordance with previous reports for phthalimides and is probably due to a switching of the relative order of the singlet and the triplet excited states of the