- Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand
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The mechanism of an L-proline-catalyzed pyridazine formation from acetone and aryl-substituted tetrazines via a Diels–Alder reaction with inverse electron demand has been studied with NMR and with electrospray ionization mass spectrometry. A catalytic cyc
- Schnell, Anne,Alexander Willms,Nozinovic,Engeser, Marianne
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- Trihaloisocyanuric acids in ethanol: an eco-friendly system for the regioselective halogenation of imidazo-heteroarenes
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Herein, we describe an efficient, rapid and benign protocol for the direct C(sp2)-H bond halogenation (Cl, Br, I) of 2-arylimidazo[1,2-a]pyridines using trihaloisocyanuric acids in ethanol. Furthermore, this sustainable protocol was successfull
- Neto, José S. S.,Balaguez, Renata A.,Franco, Marcelo S.,de Sá Machado, Victor C.,Saba, Sumbal,Rafique, Jamal,Galetto, Fábio Z.,Braga, Antonio L.
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supporting information
p. 3410 - 3415
(2020/07/30)
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- Reaction of trihaloisocyanuric acids with alkynes: An efficient methodology for the preparation of β-haloenol acetates
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The reaction between trihaloisocyanuric acids and alkynes in the presence of acetic acid provides an efficient methodology for preparation of β-haloenol acetates in yields ranging from 34 to 94%, depending on the halogen and alkynes used. This methodology provides an alternative to typical procedures, which usually employ metal catalysis and are limited to terminal alkynes.
- Crespo, Livia T.C.,Nogueira, Geisa P.,De Mattos, Marcio C.S.,Esteves, Pierre M.
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p. 205 - 214
(2018/02/07)
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- A new synthetic method of 1β- and 2β-hydroxyprovitamin D3, the precursor of the 1β- and 2β-hydroxyvitamin D3
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A new method was described for the synthesis of 1β- and 2β-hydroxyprovitamins D3, the photoprecusors of 1β- and 2β-hydroxyvitamin D3. The key step of stereoselective introduction of C-1 and C-2 hydroxy groups was performed with a very mild method for the hydroxybromination of the D-A cyclo adduct with tribromoisocyanuric acid(TBCA)/water. The newly developed method requires no toxic or expensive reagents and 1β(2β)-hydroxyprovitamin D3 was obtained with excellent yield and stereoselectivity.
- Sun, Bin,Jin, Can,Su, Wei-Ke
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p. 193 - 203
(2016/07/06)
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- Appel reaction of carboxylic acids with tribromoisocyanuric acid/triphenylphosphine: A mild and acid-free preparation of esters and amides
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A facile and efficient method for esterification and amidation of carboxylic acids under neutral conditions has been developed. Esters and amides can be prepared by reacting a carboxylic acid (1 mmol) with tribromoisocyanuric acid (0.37 mmol) and triphenylphosphine (1 mmol) in dichloromethane at room temperature, followed by addition of an alcohol or an amine, respectively.
- Da Cunha Sindra, Haryadylla,De Mattos, Marcio C.S.
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p. 1129 - 1136
(2016/07/06)
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- Tribromoisocyanuric acid (TBCA) as a mild and metal free catalyst for the acetylation and formylation of hydroxyl groups under solvent free conditions
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A convenient approach for acetylation and formylation of various types of alcohols and phenols with acetic anhydride and formic acid in the presence of Tribromoisocyanuric acid (TBCA) as catalyst is reported. The reactions were carried out under solvent-free condition and in good to high yields at room temperature. This present method is featured with relatively mild reaction conditions, simple operation, broad substrate scope, clean work-up, short reaction times, good to high yields, excellent selectivity and also avoids tedious purifications and the use of toxic reagents.
- Hekmatian, Zahra,Khazaei, Ardeshir
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p. 1565 - 1570
(2016/01/26)
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- Tribromoisocyanuric acid as a green reagent for benzylic bromination of alkylarenes
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The reaction of diverse alkylarenes with tribromoisocyanuric acid (0.34 mol equiv) in reflux EtOAc in the absence of any catalysts or light irradiation produced the corresponding benzyl bromides in 53-88% yield.
- De Almeida, Leonardo S.,Esteves, Pierre M.,De Mattos, Marcio C.S.
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p. 6843 - 6845
(2015/11/27)
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- Expeditious synthesis of the marine natural products prepolycitrin a and polycitrins a and b through heck arylations
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New, efficient protocols for the syntheses of the marine natural products prepolycitrin A as well as polycitrins A and B were developed by employing the Heck-Matsuda arylation of maleic anhydride or dimethyl fumarate with aryldiazonium tetrafluoroborates. Both symmetrical and unsymmetrical 3,4-diarylmaleic anhydrides were easily and effectively prepared. Efficient bromination reactions that employed tribromoisocyanuric acid provided access to the polycitrin family of compounds. Under microwave irradiation in the presence of tyramine, the corresponding maleimides were obtained in high yields from the brominated 3,4-diarylmaleic anhydrides. This methodology provided for the concise synthesis of prepolycitrin A and the total syntheses of the marine alkaloids polycitrins A and B in overall yields of 37 and 47 % from maleic anhydride and dimethyl fumarate, respectively. The efficient and concise syntheses of the marine natural products prepolycitrin A as well as polycitrins A and B were accomplished by using a Heck-Matsuda arylation of maleic anhydride with aryldiazonium tetrafluoroborates. Polycitrins A and B were synthesized in overall yields of 37 and 47 %, respectively. Copyright
- Canto, Karen,Da Silva Ribeiro, Rodrigo,Biajoli, Andre F. P.,Correia, Carlos Roque D.
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p. 8004 - 8013
(2014/01/06)
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- A peptide bromoiodinane approach for asymmetric bromolactonization
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A series of 37 peptides containing an iodo-aryl amide active site were generated by means of both solid phase and conventional synthesis. These peptides were screened for asymmetric induction in the bromolactonization of 4-phenyl-4-pentenoic acid based on the generation of chiral bromoiodinane bromenium sources. The study culminated in the discovery of a tri-peptide iodo-aryl amide that effected the desired bromolactonization in quantitative conversion with 24% ee. The experiments disclosed herein provided valuable insight that ultimately facilitated the development of more synthetically useful enantioselective halocyclization methodology.
- Whitehead, Daniel C.,Fhaner, Matthew,Borhan, Babak
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supporting information; experimental part
p. 2288 - 2291
(2011/05/16)
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- Tribromoisocyanuric acid/NaNO2: A new reagent for mononitration of phenols under mild and heterogeneous conditions
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Nitrophenols can be obtained via direct nitration of phenols with tribromoisocyanuric acid, NaNO2 and wet SiO2 at room temperature in good to high yields.
- Niknam, Khodabakhsh,Zolfigol, Mohammad Ali,Madrakian, Elaheh,Ghaemi, Ezat
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p. 109 - 112
(2008/09/17)
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- Tribromoisocyanuric acid: A new reagent for regioselective cobromination of alkenes
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A simple one-step method for the preparation of tribromoisocyanuric acid in good yield (87%) has been developed. The reaction of tribromoisocyanuric acid with alkenes in presence of nucleophilic solvents (MeOH, i-PrOH, AcOH and a mixture of H2O-acetone, 1:5) led to the corresponding β-bromoethers, β-bromoacetates and bromohydrins, in high regioselectivity and good yields (73-98%). Georg Thieme Verlag Stuttgart.
- De Almeida, Leonardo S.,Esteves, Pierre M.,De Mattos, Marcio C. S.
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p. 1515 - 1518
(2007/10/03)
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