Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• significant difference in the values of β-angles, which results in some differences in the densities [10]. The solubility of crystalline indigo is poor even in polar solvents such as aniline, nitrobenzene, phenol, phthalic anhydride, DMSO, and DMF upon heating. The reason for the low solubility and high

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• substituted anthraquinones 166 aiming at further preparation of 9,10-diphenyltanthracenes 167 (Scheme 37) [71]. First, they reacted arenes 163 with phthalic anhydride (164) in the presence of aluminum chloride and hydrochloric acid, to obtain benzoylbenzoic acid derivatives 165. Then, the H3PO4-promoted

• substituted anthraquinone derivatives 191 from phthalic anhydride (164) and several arenes 190 by using a combined system of AlCl3 and MeSO3H (Scheme 44) [80]. Arenes 190 containing electron-donating groups yielded the anthraquinone derivatives 191a–c in very good yields (80–93%). On the other hand, reactions

Synthesis of 6,13-difluoropentacene

• Matthias W. Tripp and
• Ulrich Koert

Beilstein J. Org. Chem. 2020, 16, 2136–2140, doi:10.3762/bjoc.16.181

• Matthias W. Tripp Ulrich Koert Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35034 Marburg, Germany 10.3762/bjoc.16.181 Abstract 6,13-Difluoropentacene was synthesized from 1,4-difluorobenzene. Friedel–Crafts annulation of the latter with phthalic anhydride and

• subsequent reduction of the anthraquinone gave 1,4-difluoroanthracene. After ortho-lithiation and reaction with phthalic anhydride a carboxylic acid was obtained whose Friedel–Crafts acylation and subsequent reductive removal of the oxygen-functionalities resulted in the formation of the target compound. The

• acid precursor could be prepared by reaction of the anthracenyllithium 7 with phthalic anhydride (8). Intermediate 7 could be accessed by ortho-lithiation of anthracene 9. The synthesis of 9 by two consecutive Friedel–Crafts acylation reactions and reduction of the resulting anthraquinone could start

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• pyrrolidine byproduct. Using the Stork–Zhao conditions [23], the Nicolaou group performed an α-methyliodomethylenation of 24 to give 33 with a good stereoselectivity (Z:E ≈ 95:5, Scheme 4) [24][25]. After the hydrolysis of the dimethylaminal and the reaction of the resultant amine with phthalic anhydride, a

[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

• involves condensation of phthalic anhydride with unprotected amino acid. The synthetic procedures and characterization of compounds are reported in Supporting Information File 1. Irradiation of 1 was conducted first in CH3CN in the presence of AN, with or without addition of H2O (Table 1). Phthalimide 1

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• ) and phthalic anhydride (2) producing 1-(o-carboxybenzoyl)pyrene (3) was selected for the optimization of reaction conditions since all reagents and catalyst are solids (Scheme 1, Table 1) [25]. In solution, this reaction is facile and the product could be obtained in quantitative yield (Table 1, entry

• 15). The results on optimization of reaction conditions in the ball mill indicate that FC acylation could be effectively carried out mechanochemically. The best mechanochemical reaction conditions (Table 1, entry 4): 2 h, equimolar amount of phthalic anhydride and 2.5 equivalents of AlCl3, afforded

• were less reactive in comparison to phthalic anhydride. Benzoic anhydride was used as a substitute for benzoyl chloride and the reaction proceeded in better yield. The observed disparity in reactivity might be associated with the difference in the physical state of the reagents. Furthermore, succinic

A chemically contiguous hapten approach for a heroin–fentanyl vaccine

• Yoshihiro Natori,
• Candy S. Hwang,
• Lucy Lin,
• Lauren C. Smith,
• Bin Zhou and
• Kim D. Janda

Beilstein J. Org. Chem. 2019, 15, 1020–1031, doi:10.3762/bjoc.15.100

• % fentanyl in heroin week 8 R2 = 0.3715. General outline of HF-1, HF-2, HF-3, HF-7 synthesis from fentanyl intermediate 5 and heroin intermediates 1, 16, and 36. Synthesis of fentanyl intermediate 5. Reaction conditions: a) phthalic anhydride, AcOH, reflux, 81%; b) t-BuOH, EDC, Et3N, DMAP, CH2Cl2, 0 °C to rt

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• benzene ring as a linker and their activities in copolymerization reactions. The dinuclear cobalt complexes showed a higher catalytic activity for the copolymerization of propylene oxide with phthalic anhydride than the corresponding mononuclear cobalt–salen complex and achieved one of the highest

• compared to the corresponding mononuclear cobalt–salen complexes [40]. During the course of our study, the dinuclear cobalt–salen complex (R,R,S,S)-1 was found to exhibit a high catalytic activity for the alternating copolymerization of propylene oxide (PO) with phthalic anhydride (PA, Figure 1). The

• )-8 and (R,R,R,R)-8 were then treated with cobalt(II) nitrate and the following oxidation under air afforded the corresponding dinuclear cobalt–salen complexes (R,R,S,S)-2 and (R,R,R,R)-2, respectively. Copolymerization of propylene oxide with phthalic anhydride The catalysts’ performances were

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• application, glycosyl donor precursors were reacted with phthalic anhydride to afford the corresponding esters. The activation with thionyl chloride was used for tethering the donors to the glycosyl acceptor counterpart and the regioselectivity was controlled using tin-mediated coupling under microwave

The facile construction of the phthalazin-1(2H)-one scaffold via copper-mediated C–H(sp²)/C–H(sp) coupling under mild conditions

• Wei Zhu,
• Bao Wang,
• Shengbin Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2015, 11, 1624–1631, doi:10.3762/bjoc.11.177

• on the use of prefunctionalized benzoic acid, such as phthalic anhydride or 2-formylbenzoic acid, as starting materials and suffer from low yields, poor regioselectivity and scope limitations [11][12]. Therefore, there is still a need for synthetic chemists to develop efficient and expedient routes

Radical-mediated dehydrative preparation of cyclic imides using (NH₄)₂S₂O₈–DMSO: application to the synthesis of vernakalant

• Dnyaneshwar N. Garad,
• Subhash D. Tanpure and
• Santosh B. Mhaske

Beilstein J. Org. Chem. 2015, 11, 1008–1016, doi:10.3762/bjoc.11.113

• important monomers for the synthesis of polymers used in high temperature applications [61][62][63]. Methyl maleic anhydride and p-bromoaniline smoothly provided the corresponding maleimide (Table 3, entry 5). The reaction of p-toluidine and phthalic anhydride was very facile and the corresponding

Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

• Jong Yeob Jeon,
• Seong Chan Eo,
• Jobi Kodiyan Varghese and
• Bun Yeoul Lee

Beilstein J. Org. Chem. 2014, 10, 1787–1795, doi:10.3762/bjoc.10.187

• /epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA) copolymerizations and PO/CO2/PA terpolymerizations. In the PO/PA copolymerizations, full conversion of PA was achieved within 5 h, and strictly alternating copolymers of poly(1,2-propylene phthalate)s were

• -transition temperature (48 °C) than the CO2/PO alternating copolymer (40 °C). Keywords: carbon dioxide; CO2 chemistry; cobalt complex; phthalic anhydride; propylene oxide; terpolymerization; Introduction Carbon dioxide (CO2) can be utilized to prepare aliphatic polycarbonates through coupling reactions

• from the resin for use in our daily life. In this work, we demonstrate the complete incorporation of the third monomer of phthalic anhydride (PA) in CO2/PO copolymerizations using catalyst 1. Results and Discussion PO/PA copolymerizations Alternating copolymerizations of epoxides and cyclic anhydrides

Aza-Diels–Alder reaction between N-aryl-1-oxo-1H-isoindolium ions and tert-enamides: Steric effects on reaction outcome

• Amitabh Jha,
• Ting-Yi Chou,
• Zainab ALJaroudi,
• Bobby D. Ellis and
• T. Stanley Cameron

Beilstein J. Org. Chem. 2014, 10, 848–857, doi:10.3762/bjoc.10.81

• analogous to the final step of imino [4 + 2] Diels–Alder reactions between N-acyliminium ions and electron-rich dienophiles are reported [13][14][15]. We synthesized eight N-aryl-3-hydroxyisoindolinones from substituted anilines and phthalic anhydride following the reported procedure [13]. Previously

• -arylphthalimides were synthesized by reacting phthalic anhydride with appropriate anilines following a literature procedure [46]. Borohydride reduction [13] of these N-arylphthalimides afforded seventeen N-aryl-3-hydroxyisoindolinones. General procedure for the synthesis of 5-(2-oxopyrrolidin-1-yl)-6,6a

Synthesis and characterization of a novel carboxyl group containing (co)polyimide with sulfur in the polymer backbone

• Miroslav Mrsevic,
• David Düsselberg and
• Claudia Staudt

Beilstein J. Org. Chem. 2012, 8, 776–786, doi:10.3762/bjoc.8.88

• fluorinated sulfur- and carboxylic acid groups consisting of 4,4′-(hexafluoroisopropylidene)di(phthalic anhydride) (6FDA), 3,5-diaminobenzoic acid (DABA), 4,4′-diaminodiphenylsulfide (4,4′-SDA) and 3,3′-diaminodiphenylsulfone (3,3′-DDS) were synthesized in a two-step polycondensation reaction. The synthesized

• monomers, such as 6FDA (4,4′-(hexafluoroisopropylidene)di(phthalic anhydride)) are known to exhibit excellent solubilities in common organic solvents [19]. Because of the aforementioned properties of sulfur-containing polyimides and fluorinated polyimides, a (co)polyimide with a high refractive index and

Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine

• Marc Enßle,
• Stefan Buck,
• Roland Werz and
• Gerhard Maas

Beilstein J. Org. Chem. 2012, 8, 433–440, doi:10.3762/bjoc.8.49

• trap HCl) with the acid chloride of 6a. Although the yield was modest (28%), it was still better and gave fewer byproducts than the β-ketoester route. The phthaloylation of 5a–c was achieved with phthalic anhydride in the presence of a catalytic amount of triethylamine to lower the reaction temperature

• . Proposed relative configurations of the diastereomeric cyclic sulfonium ylides 12aA and 12aB. 1H NMR shifts δH (ppm) and NOE relationships are shown (E = CO2Et). Synthesis of cyclic sulfonium ylides 2; n = 0–3. Non-carbenoid formation of sulfonium ylide 4. Conditions: (a) phthalic anhydride, NEt3 (10 mol

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

• three amino acids are described in this publication. Results Synthesis of phthalimide substrates The C-unprotected N-phthaloyl amino acids 8–10 were available from tyrosine, histidine, and tryptophan (Figure 1). The phthalimide derivatives were prepared either by thermal reaction of phthalic anhydride

• substrate 10 this process can only be initiated by intermolecular electron transfer suggesting efficient back electron transfer in the photoexcited substrate. Experimental Synthesis of N-phthaloyl tyrosine (8) [18]. A well ground mixture of 2.00 g (13 mmol) of L-tyrosine and 2.45 g (13 mmol) of phthalic

• anhydride were added to a 10 mL flask with a magnetic stirring bar. The flask was heated in an oil bath, stirred at 150–160 °C for 20 min and then the mixture was allowed to cool to room temperature. Recrystallization of the crude solid material from ethanol gave 3.67 g of N-phthaloyl tyrosine (8) (88%) as