Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• ]quinoxalinoporphyrins in good yields via a sequential reaction of copper(II) 2,3-diamino-5,10,15,20-tetraarylporphyrins, 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes, and dimedone in the presence of a catalytic amount of trichloroacetic acid in chloroform at 65 °C. Further, the newly prepared copper(II

• ; multicomponent synthesis; one-pot reaction; trichloroacetic acid; Introduction π-Conjugated porphyrin macrocycles are known for their applications in numerous areas ranging from oxygen transport, photosynthesis, catalysis and medicine [1][2][3]. In the past several years, diverse organic scaffolds have been

• present study discloses an easy and first synthetic approach to build highly π-conjugated copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins through a trichloroacetic acid-catalyzed one-pot four-component reaction of 2,3-diamino-5,10,15,20-tetraarylporphyrins, 2-hydroxynaphthalene-1,4-dione, aromatic

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• , TFA, and trichloroacetic acid) and even weak acids (e.g., HF, Et3N·3HF, and AcOH) react with iodonium ylides to give formal X–H insertions [127][128][129][130]. In 2022, Murphy et al. disclosed a computational and experimental investigation into the reaction scope and the mechanism by which such X–H

Trichloroacetic acid fueled practical amine purifications

• Aleena Thomas,
• Baptiste Gasch,
• Enzo Olivieri and
• Adrien Quintard

Beilstein J. Org. Chem. 2022, 18, 225–231, doi:10.3762/bjoc.18.26

• . Inspired by recent work on out of equilibrium molecular machinery, using trichloroacetic acid (TCA), we disclose a purification technique considerably decreasing the number of operations and the waste generation required for such purifications. At first, TCA triggers the precipitation of the amines through

• formation of protonated amines which evolve spontaneously over time back again to the neutral amine upon release of CO2 from the initial acid. Among the potential acids available for such processes, trichloroacetic acid (TCA) has been used to fuel different supramolecular switches [6][7][8][9][10]. This

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• attached cells were incubated with various concentrations of the test compounds and the cells were cultured for 48 h. Then, the culture medium was removed from each well and the cells were fixed with 10% cold trichloroacetic acid at 4 °C for 1 h. After the supernatant was discarded and the plates were

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• , 71.48, 67.39, 63.02, 62.97, 61.82, 56.20, 37.85, 37.78, 36.76, 36.36, 29.33, 25.14, 19.69, 14.17; 31P NMR (121 MHz, DMSO-d6, δ) 25.54, 4.74, −2.89. Cit-Dod-NBD DMT-Cit-Dod-NBD (787 mg, 0.96 mmol) was dissolved in a trichloroacetic acid solution (3% in DCM/MeOH 1:1, v/v) at rt. The reaction mixture was

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• -ketoenamides KE due to the competing in situ cyclization to the corresponding pyridin-4-ols (PY, Table 1, entries 12 and 24). The related reactions with trichloroacetic acid provided the β-ketoenamides in slightly better yields with lower amounts of the corresponding pyridin-4-ols (Table 1, entries 3, 14, and

Rapid transformation of sulfinate salts into sulfonates promoted by a hypervalent iodine(III) reagent

• Elsa Deruer,
• Vincent Hamel,
• Samuel Blais and
• Sylvain Canesi

Beilstein J. Org. Chem. 2018, 14, 1203–1207, doi:10.3762/bjoc.14.101

• be used to open and functionalize simple heterocycles such as THF through a ring-opening approach [37]. In the presence of trichloroacetic acid and DIB, the corresponding compound 12 was obtained in 40% yield. One advantage is that this method begins with the inexpensive compound THF and produces a

Sequential Ugi reaction/base-induced ring closing/IAAC protocol toward triazolobenzodiazepine-fused diketopiperazines and hydantoins

• Robby Vroemans,
• Fante Bamba,
• Jonas Winters,
• Joice Thomas,
• Jeroen Jacobs,
• Luc Van Meervelt,
• Jubi John and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 626–633, doi:10.3762/bjoc.14.49

• the synthesis of hydantoin-fused triazolobenzodiazepines starting from the Ugi reaction of o-azidobenzaldehyde (1a), propargylamine (2a), trichloroacetic acid (9) and benzyl isocyanide (4a, Scheme 5). The Ugi adduct was subjected to base-induced ring closing with NaOEt in EtOH which furnished the

• 7a. ‘One-pot’ synthesis of diketopiperazine-fused triazolobenzodiazepines 7a and 7b. Synthesis of hydantoin-fused triazolobenzodiazepine 10. Reaction conditions: 1. 2-azidobenzaldehyde 1 (1.85 mmol), propargylamine (2a, 1.85 mmol), trichloroacetic acid (9, 1.85 mmol), benzyl isocyanide 4 (1.85 mmol

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• -derived primary amine catalysts (cat. 15 and 16) and achieved the asymmetric aldol reaction of 1,1-dimethoxyacetone with isatins (Scheme 30) [46]. The reactions were carried out at room temperature using 10% catalyst loading and trichloroacetic acid (TCA) as the additive, affording the corresponding 3

Fe(II)/Et₃N-Relay-catalyzed domino reaction of isoxazoles with imidazolium salts in the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates, its ylide and betaine derivatives

• Ekaterina E. Galenko,
• Olesya A. Tomashenko,
• Alexander F. Khlebnikov,
• Mikhail S. Novikov and
• Taras L. Panikorovskii

Beilstein J. Org. Chem. 2015, 11, 1732–1740, doi:10.3762/bjoc.11.189

• 110 °C for 24 h. Then reaction mixture was evaporated to dryness and water (5 mL) was added. The suspension was filtered, the solid was washed with water (2 × 5 mL) and thoroughly dried to obtain lithium salt 14b in quantitive yield. To convert the lithium salt 14b into 6b trichloroacetic acid (35 mg

Efficient deprotection of F-BODIPY derivatives: removal of BF₂ using Brønsted acids

• Mingfeng Yu,
• Joseph K.-H. Wong,
• Cyril Tang,
• Peter Turner,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 37–41, doi:10.3762/bjoc.11.6

• . used 11B NMR to monitor the stability of BODIPYs in the presence of di- or trichloroacetic acid, reporting ‘partial decomposition’ of an F-BODIPY derivative without characterizing the breakdown product(s) [33]. While Liras et al. reported the synthesis of a single aminodipyrrin product from the

Regio- and stereoselective synthesis of new diaminocyclopentanols

• Evgeni A. Larin,
• Valeri S. Kochubei and
• Yuri M. Atroshchenko

Beilstein J. Org. Chem. 2014, 10, 2513–2520, doi:10.3762/bjoc.10.262

• recently been synthesized via the ammonium-directed olefinic oxidation of cyclic allylic amines. It has been reported that functionalization of a range of allylic 3-(N,N-dibenzylamino)cycloalkenes with m-CPBA in the presence of trichloroacetic acid gave exclusively corresponding syn-epoxides [22]. Examples

Primary-tertiary diamine-catalyzed Michael addition of ketones to isatylidenemalononitrile derivatives

• Akshay Kumar and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2014, 10, 929–935, doi:10.3762/bjoc.10.91

• spirooxindoles. Results and Discussion Initially, the Michael addition of acetone (2a) to isatylidenemalononitrile (3a) catalyzed by chiral diamine 1a (10 mol %) with trichloroacetic acid (10 mol %) as an additive under mild conditions at room temperature was investigated (Scheme 1). The Michael adduct 4a was

Flow synthesis of phenylserine using threonine aldolase immobilized on Eupergit support

• Jagdish D. Tibhe,
• Hui Fu,
• Timothy Noël,
• Qi Wang,
• Jan Meuldijk and
• Volker Hessel

Beilstein J. Org. Chem. 2013, 9, 2168–2179, doi:10.3762/bjoc.9.254

• mL of sample was collected and the reaction was terminated by adding a 30% trichloroacetic acid solution. Then, all samples were extracted with 2 mL of internal standard solution (1,3-dimethoxybenzene in ethyl acetate). The enantiomeric excess (ee) and the diasteriomeric excess (de) of phenylserine

• pumped at different flow rates (25 μL/min, 12.5 μL/min, 6 μL/min). The samples were collected at the outlet and immediately hydrolyzed by adding a 30% solution of trichloroacetic acid. For each reaction three samples were collected. Then a sample was taken from the syringe after 12 hours and conversion

Tandem catalysis of ring-closing metathesis/atom transfer radical reactions with homobimetallic ruthenium–arene complexes

• Yannick Borguet,
• Xavier Sauvage,
• Guillermo Zaragoza,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2010, 6, 1167–1173, doi:10.3762/bjoc.6.133

• cyclopentadiene and trichloroacetic acid was already observed by Quayle et al. under similar conditions [13][14]. These authors successfully trapped the diene via a Diels–Alder reaction with maleic anhydride. They also reported that a heterobimetallic catalytic system derived from the Grubbs second-generation

• complex [RuCl2(=CHPh)(SIMes)(PCy3)], CuCl, and dHbipy (SIMes is 1,3-dimesitylimidazolin-2-ylidene, dHbipy is 4,4'-di-n-heptyl-2,2'-bipyridine) was able to promote the ATRA of trichloroacetic acid onto cyclopentadiene followed by a lactonization into 3,3-dichloro-3,3a,4,6a-tetrahydro-2H-cyclopenta[b]furan

Enantioselective synthesis of tricyclic amino acid derivatives based on a rigid 4-azatricyclo[5.2.1.0^2,6]decane skeleton

• Matthias Breuning,
• Tobias Häuser,
• Christian Mehler,
• Christian Däschlein,
• Carsten Strohmann,
• Andreas Oechsner and
• Holger Braunschweig

Beilstein J. Org. Chem. 2009, 5, No. 81, doi:10.3762/bjoc.5.81

• MeOCH=PPh3 (Scheme 4). The selective hydrolysis of the enol ether moiety in 18 in the presence of the N-Boc-protective group was achieved by using trichloroacetic acid. The desired endo-configured aldehyde 15 was thus available in only two steps in good 64% overall yield from 9. After oxidation of 15 to