Coupling of C-nitro-NH-azoles with arylboronic acids. A route to N-aryl-C-nitroazoles

• Marta K. Kurpet,
• Aleksandra Dąbrowska,
• Małgorzata M. Jarosz,
• Katarzyna Kajewska-Kania,
• Nikodem Kuźnik and
• Jerzy W. Suwiński

Beilstein J. Org. Chem. 2013, 9, 1517–1525, doi:10.3762/bjoc.9.173

• higher yields of the product. It turned out that the ratio of reagents has an important influence on the chemical yield of 3-nitro-1-phenyl-1H-pyrazole. A ratio of arylboronic acid to 3-nitro-1H-pyrazole to the base of 2.6:1.6:1.6 seems to be optimal. This gave the highest (up to 82%) yield of the

Synthesis and structure of trans-bis(1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) dichloride and diacetate. Suzuki–Miyaura coupling of polybromoarenes with high catalytic turnover efficiencies

• Jeelani Basha Shaik,
• Venkatachalam Ramkumar,
• Babu Varghese and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2013, 9, 698–704, doi:10.3762/bjoc.9.79

• mol % of complex 1 as catalyst and 4 mol % of PPh3 irrespective of the number of bromines present in the polybromoarenes (Scheme 2, Table 1). Typically for polybromoarenes 1.0 to 1.2 equivalents of arylboronic acid and 2 equivalents of NaOH per bromine were used. For example, in the case of 1,4

Synthesis of oleophilic electron-rich phenylhydrazines

• Aleksandra Jankowiak and
• Piotr Kaszyński

Beilstein J. Org. Chem. 2012, 8, 275–282, doi:10.3762/bjoc.8.29

• arylboronic acid V to AD [18][19][20]. The latter method is especially suited for arylhydrazides substituted with sensitive functional groups. Protected electron-rich arylhydrazines, hydrazides II, containing the 2,2,2-trichloroethyl group (R = CH2CCl3) are conveniently prepared by direct electrophilic

• lithiation of aryl bromides 5 with t-BuLi to avoid the formation of n-BuBr with n-BuLi and N-butylation of hydrazide 2. Hydrazide 2a was also obtained by the Cu2+-catalyzed addition [18] of arylboronic acid 6a [28] to DTBAD. The yields of both syntheses of 2a were comparable. The trichloroethyl hydrazide 3a

Scaling up of continuous-flow, microwave-assisted, organic reactions by varying the size of Pd-functionalized catalytic monoliths

• Ping He,
• Stephen J. Haswell,
• Paul D. I. Fletcher,
• Stephen M. Kelly and
• Andrew Mansfield

Beilstein J. Org. Chem. 2011, 7, 1150–1157, doi:10.3762/bjoc.7.133

• monolith catalyst. A reactant solution containing an aryl halide (0.1 M), arylboronic acid (0.12 M), K2CO3 (0.3 M) in DMF/H2O (3:1) solvent was pumped through the reactor with an HPLC pump, and a backpressure valve (45–75 psi) was used to minimize the formation of gas bubbles (see Supporting Information

• added to the individual samples as an internal standard. Samples were treated with 1 M aqueous NaOH to remove unreacted arylboronic acid and extracted with DCM. The remaining organic material was then washed three times with distilled water, collected and dried over MgSO4. Individual samples were

Au(I)/Au(III)-catalyzed Sonogashira-type reactions of functionalized terminal alkynes with arylboronic acids under mild conditions

• Deyun Qian and
• Junliang Zhang

Beilstein J. Org. Chem. 2011, 7, 808–812, doi:10.3762/bjoc.7.92

• mild conditions has been developed. Keywords: arylboronic acid; gold-catalysis; Sonogashira cross-coupling; Introduction The Sonogashira reaction has become the most important and widely used method for the synthesis of arylalkynes and conjugated enynes, which are precursors for natural products

Air-stable, recyclable, and time-efficient diphenylphosphinite cellulose-supported palladium nanoparticles as a catalyst for Suzuki–Miyaura reactions

• Qingwei Du and
• Yiqun Li

Beilstein J. Org. Chem. 2011, 7, 378–385, doi:10.3762/bjoc.7.48

• –Pd0). General procedure for the Suzuki–Miyaura cross-coupling reaction In a typical experiment, the Cell–OPPh2–Pd0 catalyst (0.005 mmol of Pd) was added to a mixture of aryl halide (1.0 mmol), arylboronic acid (1.2 mmol), and K2CO3 (2.0 mmol) in 95% ethanol (5 cm3), and the reaction mixture was

Studies on Pd/NiFe₂O₄ catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

• Sanjay R. Borhade and
• Suresh B. Waghmode

Beilstein J. Org. Chem. 2011, 7, 310–319, doi:10.3762/bjoc.7.41

• reaction conditions. The results thus obtained are summarized in Table 5. The reactions were performed by using 1.0 mol % of Pd at 90 °C and 3.5 equiv of arylboronic acid in 1:1 DMF/H2O solvent for 2 h. The reaction between various di- and trihalo aryls with phenyl- and 3-(hydroxymethyl)phenylboronic acids

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

• Carolin Fischer and
• Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

• biologically active molecules A key intermediate (88) for the potent matrix metalloproteases (MMPs) inhibitor AG3433 (89) was synthesized by coupling an electron-deficient pyrrole (86) with an arylboronic acid (87) in excellent yield (93%, Scheme 21). Screening numerous boronic acids it was found that only

• , was achieved by reacting 9-N-purines 91 with an excess of arylboronic acid 92 in the presence of copper(II) acetate, molecular sieves and phenanthroline (Scheme 22). Bakkestuen and Gundersen showed that electron-donating and electron-withdrawing substituents on the arylboronic acid were tolerated

• functional groups in the arylboronic acid (101, 104). Thus, a single reaction step from commercial precursors allowed the synthesis of new enterovirus inhibitors with activity in the low µM range [75]. A very recent example of 7-N-arylation of purines is the synthesis of highly substituted xanthine

Suzuki–Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported N-heterocyclic carbene–palladium complex catalyst

• Guangming Nan,
• Fang Ren and
• Meiming Luo

Beilstein J. Org. Chem. 2010, 6, No. 70, doi:10.3762/bjoc.6.70

• -aryltriazene (0.5 mmol), arylboronic acid (1 mmol) were mixed in dioxane (5 mL). The mixture was stirred and BF3·OEt2 (65 μL, 0.50 mmol) added dropwise at room temperature under an argon atmosphere. When the reaction was complete, the catalyst was filtered, washed with ether (5 mL × 3), and then dried under

Regioselective alkynylation followed by Suzuki coupling of 2,4-dichloroquinoline: Synthesis of 2-alkynyl- 4-arylquinolines

• Ellanki A. Reddy,
• Aminul Islam,
• K. Mukkanti,
• Venkanna Bandameedi,
• Dipal R. Bhowmik and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 32, doi:10.3762/bjoc.5.32

• heated to 80 °C. To this mixture was added a solution of PCy3 (0.05 mmol) and CsCO3 (3.5 mmol) dissolved in water (3.0 mL) and arylboronic acid (1.5 mmol) dissolved in dioxane (3.0 mL) at the same temperature. The mixture was stirred at 80 °C according to the time indicated in Table 2. After completion

N-Arylation of amines, amides, imides and sulfonamides with arylboroxines catalyzed by simple copper salt/EtOH system

• Zhang-Guo Zheng,
• Jun Wen,
• Na Wang,
• Bo Wu and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2008, 4, No. 40, doi:10.3762/bjoc.4.40

• recently in the mechanism of the cross-coupling reaction based on boronic acid. The group of Chan has reported the dynamic behavior of boronic acid in the copper salt catalytic system. The results implied that the active arylating agent such as arylboronic acid in the cross-coupling reaction is indeed its