- Palladium-catalysed room-temperature Suzuki–Miyaura coupling in water extract of pomegranate ash, a bio-derived sustainable and renewable medium
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An agro waste-derived, ‘water extract of pomegranate ash’ (WEPA), has been utilized for the first time as a renewable medium for Pd(OAc)2-catalysed Suzuki–Miyaura cross-coupling at room temperature. This method offers a simple and sustainable synthesis of biaryls from aryl halides and arylboronic acids under ligand- and external base-free aerobic and ambient conditions. This method has been found effective for both activated and unactivated aryl halides in the production of biaryls with moderate to nearly quantitative yields. The protocol shows high chemoselectivity over identical/similar reactive sites in aryl halides (i.e. selectivity over identical halogens or different halogens of aryl halides). This method exhibits high regioselectivity, i.e. the selective reactivity of a halogen over other identical halogens at different positions on the aromatic nucleus. Therefore, we disclose here a clean, benign, substantial chemo- and regioselective and highly economic alternative method for the palladium-assisted synthesis of biaryls using an agro waste-derived medium.
- Appa, Rama Moorhy,Prasad, S. Siva,Lakshmidevi, Jangam,Naidu, Bandameeda Ramesh,Narasimhulu, Manchala,Venkateswarlu, Katta
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- Highly active and reusable hydrotalcite-supported Pd(0) catalyst for Suzuki coupling reactions of aryl bromides and chlorides
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A palladium(0) nanocluster supported on hydrotalcite has been prepared and tested for the Suzuki coupling reaction. The prepared catalyst showed very efficient catalytic activity for cross coupling of iodo- and bromoarenes under very mild reaction conditions, affording >90% yield. Under the optimized reaction conditions, chloroarenenes also showed very good reactivity. Transmission electron microscopic imaging data showed the formation of very small Pd(0)-nanoclusters (d = 2.2 ± 0.5 nm) well dispersed on the support, which enhanced the activity and stability of the catalyst for the Suzuki cross-coupling reaction. This catalytic system offers an easy method of preparation with good activity and reusability up to five cycles.
- Karanjit, Sangita,Kashihara, Masaya,Nakayama, Atsushi,Shrestha, Lok Kumar,Ariga, Katsuhiko,Namba, Kosuke
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supporting information
p. 948 - 954
(2018/01/27)
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- DIARYLUREAS AS CB1 ALLOSTERIC MODULATORS
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The present invention provides novel diarylurea derivatives (compounds of formula (I)) and their uses. The compounds of the present invention are demonstrated to be allosteric modulators of the CB1 receptor, and therefore useful for the treatment of diseases and conditions mediated by CB1.
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Paragraph 69; 72; 94
(2018/12/02)
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- An Active Palladium Colloidal Catalyst for the Selective Oxidative Heterocoupling of (Hetero)Aryl Boronic Acids
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A highly selective oxidative heterocoupling protocol for (hetero)aryl boronic acids with an active palladium colloidal catalyst was developed. The judicious choice of electronically different aryl boronic acids made possible such couplings under mild conditions, with air as oxidant, while embracing a wide substrate scope. This successful approach further allowed the development of a unique one-pot sequential oxidative heterocoupling/Suzuki–Miyaura cross-coupling tandem process for accessing substituted terphenyls.
- Sable, Vaibhav,Maindan, Karan,Bhilare, Shatrughn,Chrysochos, Nicolas,Schulzke, Carola,Kapdi, Anant R.
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supporting information
p. 2489 - 2498
(2018/09/10)
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- Novel Diarylurea Based Allosteric Modulators of the Cannabinoid CB1 Receptor: Evaluation of Importance of 6-Pyrrolidinylpyridinyl Substitution
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Allosteric modulators of the cannabinoid CB1 receptor have recently been reported as an alternative approach to modulate the CB1 receptor for therapeutic benefits. In this study, we report the design and synthesis of a series of diarylureas derived from PSNCBAM-1 (2). Similar to 2, these diarylureas dose-dependently inhibited CP55,940-induced intracellular calcium mobilization and [35S]GTP-γ-S binding while enhancing [3H]CP55,940 binding to the CB1 receptor. Structure-activity relationship studies revealed that the pyridinyl ring of 2 could be replaced by other aromatic rings and the pyrrolidinyl ring is not required for CB1 allosteric modulation. 34 (RTICBM-74) had similar potencies as 2 in all in vitro assays but showed significantly improved metabolic stability to rat liver microsomes. More importantly, 34 was more effective than 2 in attenuating the reinstatement of extinguished cocaine-seeking behavior in rats, demonstrating the potential of this diarylurea series as promising candidates for the development of relapse treatment of cocaine addiction.
- Nguyen, Thuy,German, Nadezhda,Decker, Ann M.,Langston, Tiffany L.,Gamage, Thomas F.,Farquhar, Charlotte E.,Li, Jun-Xu,Wiley, Jenny L.,Thomas, Brian F.,Zhang, Yanan
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p. 7410 - 7424
(2017/09/22)
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- Benzotriazol-1-ylmethanol: An excellent bidentate ligand for the copper/palladium-catalyzed C-N and C-C coupling reaction
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An efficient benzotriazole based N,O bidentate ligands for the Cu-catalyzed N-arylation of π-excessive nitrogen heterocycles is described. This ligand accomplishes C-N coupling of Nheterocycles and C-C coupling of boronic acids with a variety of hindered, functionalized aryl/heteroaryl halides under mild reaction conditions in good to excellent yields. Using his ligand C-N and C-C (Suzuki) couplings with bromoarenes could be conducted with less catalyst loading. A wide array of deactivated and hindered aryl halides react cleanly to afford the functionalized biaryl derivatives in high yields. ARKAT-USA, Inc.
- Jha, Rajeev R.,Singh, Jaspal,Tiwari, Rakesh K.,Verma, Akhilesh K.
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p. 228 - 248
(2013/02/23)
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- Benzotriazole: An efficient, inexpensive and phosphine-free ligand for the palladium-catalyzed Suzuki-Miyaura reaction
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Benzotriazole has been disclosed as an efficient and inexpensive ligand for the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction of arylhalides with arylboronic acids. This preparative convenient system afforded the corresponding coupling products, biaryls and terphenyls in good to excellent yields.
- Jha, Rajeev Ranjan,Chaudhary, Ritu,Chandra, Ramesh,Verma, Akhilesh Kumar
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experimental part
p. 1187 - 1194
(2012/04/04)
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- Decarboxylative cross-coupling of aryl tosylates with aromatic carboxylate salts
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(Figure Presented) A bimetallic copper/palladium catalyst system is disclosed that enables the use of tosylates as carbon electrophiles in decarboxylative coupling reactions. A variety of aromatic carboxylate salts, regardless of their substitution pattern, have been coupled with these inexpensive and readily available electrophiles to give the corresponding biaryl compounds in good yields (see scheme).
- Goossen, Luksa J.,Rodriguez, Nuria,Lange, Paul P.,Linder, Christophe
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supporting information; experimental part
p. 1111 - 1114
(2010/04/29)
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- Biaryl and aryl ketone synthesis via Pd-catalyzed decarboxylase coupling of carboxylate salts with aryl triflates
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A bimetallic catalyst system has been developed that for the first time allows the decarboxylative crosscoupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non-coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic crosscoupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho-substituted or otherwise activated derivatives to a broad range of ortho-, meta-, and para-substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of CuI/1,10- phenanthroline (10-15 mol %) and PdI2/phosphine (23 mol%) in NMP for 1-24 h, the other involving CuI/l,10-phenanthroline (615mol%) and PdBr2/Tol-BINAP (2 mol % ) in NMP using microwave heating for 5-10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non-activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylase crosscouplings are discussed.
- Goossen, Lukas J.,Linder, Christophe,Rodriguez, Nuria,Lange, Paul P.
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supporting information; experimental part
p. 9336 - 9349
(2010/04/03)
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- Phosphine-free palladium(II)-catalyzed arylation of naphthalene and benzene with aryl iodides
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(Chemical Equation Presented) A phosphine-free arylation of naphthalene and benzene with aryl iodides to give biaryls in moderate to good yields is carried out in the presence of catalytic Pd(OAc)2 and stoichiometric CF 3CO2 Ag in TFE or/and TFA.
- Qin, Chunxia,Lu, Wenjun
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supporting information; experimental part
p. 7424 - 7427
(2009/05/07)
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- Decarboxylative biaryl synthesis from aromatic carboxylates and aryl triflates
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A new catalyst system, generated in situ from Cu2O, 1,10-phenanthroline, PdI2, and Tol-BINAP, for the first time allows the decarboxylative coupling of carboxylic acids with aryl triflates. In contrast to previous decarboxylative couplings that remained limited to certain activated carboxylates, e.g., ortho-substituted benzoates, this halide-free protocol is generally applicable to aromatic carboxylic acid salts regardless of their substitution pattern. Copyright
- Goossen, Lukas J.,Rodriguez, Nuria,Linder, Christophe
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supporting information; experimental part
p. 15248 - 15249
(2009/03/11)
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- Microwave-assisted Suzuki coupling reactions with an encapsulated palladium catalyst for batch and continuous-flow transformations
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This article describes the design, optimisation and development of a Suzuki cross-coupling protocol mediated by an efficient palladium-en-capsulated catalyst (Pd EnCat) under microwave irradiation. The methodology has been used in both batch mode for classical library preparation and in continuous-flow applications furnishing multigram quantities of material. Described is a method that uses direct focused microwave heating whilst applying an external cooling source. This enables a lower than normal bulk temperature to be maintained throughout the reaction period leading to significant improvements in the overall yield and purity of the reaction products. Additional aspects of this novel heating protocol are discussed in relation to the prolonged lifetime and enhanced reactivity of the immobilised catalyst system.
- Baxendale, Ian R.,Griffiths-Jones, Charlotte M.,Ley, Steven V.,Tranmer, Geoffrey K.
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p. 4407 - 4416
(2008/02/07)
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- Synthesis of Retinoids with Aryltetrahydroanthracene Structure
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We describe the synthesis of analogues of the retinoid Temarotene (Ro 15-0778) (1a), which shows due to its lack of a polar end group no signs of hypervitaminosis A.A variety of substituted tetrahydroanthracenes 6, 8, 11, 13 is prepared starting from 2-methoxynaphthalene (5b) using palladium-catalyzed coupling techniques. - Key Words: Retinoids / Arotinoids / Coupling reactions, palladium-catalyzed / Temarotene analogues
- Hanefeld, Wolfgang,Jung, Manfred
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