- Preparation method of hydroxyphenylboronic acid
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The invention discloses a preparation method of hydroxyphenylboronic acid, which belongs to the technical field of boric acid synthesis in medical intermediates. The method comprises the following steps: starting from bromophenol, carrying out BOC, trimethylsilyl or benzyl protection, forming a Grignard reagent, reacting with borate, or carrying out one-pot reaction with borate and n-butyllithium,and hydrolyzing to obtain hydroxyphenylboronic acid. According to the invention, cheap and easily available protecting groups are adopted, so that the protecting groups are easy to remove during boronation reaction hydrolysis, industrial amplification is easy to realize, batch production is carried out on the scale of dozens of kilograms, and the process stability is good.
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- Method for preparing boric acid derivative (by machine translation)
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The invention provides a preparation method of p-hydroxyphenylboronic acid. The method is characterized by comprising the following -0.1 mpa steps: at 0 - 10 °C vacuum conditions and temperature, heating the alkoxyl phenylboronic acid and acid first chloride compound in organic solvent, then heating the aqueous layer minutes every interval until 10 °C 15 the temperature is raised to, and then 30 - 100 °C carrying out 1 - 2h constant temperature reaction to obtain the intermediate pH. The aqueous layer 9-11 is further recrystallized by organic solvent 3-4 to obtain intermediate compound and second alkali adjusting system pH. 3rd. The p-hydroxyphenylboronic acid is obtained. The method has the advantages that the reaction temperature is relatively mild, the reaction time can be obviously shortened, the consumption of the catalyst is reduced, and the method has higher yield and purity. (by machine translation)
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Paragraph 0038-0039; 0046-047
(2020/12/29)
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- Transition-Metal-Free Borylation of Aryl Bromide Using a Simple Diboron Source
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In this study, we developed a simple transition-metal-free borylation reaction of aryl bromides. Bis-boronic acid (BBA), was used, and the borylation reaction was performed using a simple procedure at a mild temperature. Under mild conditions, aryl bromides were converted to arylboronic acids directly without any deprotection steps and purified by conversion to trifluoroborate salts. The functional group tolerance was considerably high. The mechanism study suggested that this borylation reaction proceeds via a radical pathway.
- Han, Min Su,Lim, Taeho,Ryoo, Jeong Yup
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p. 10966 - 10972
(2020/09/23)
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- Enantioselective Conjugate Addition of Aryl Halides and Triflates to Electron-Deficient Olefins via Nickel- And Rhodium-Catalyzed Sequential Relay Reactions
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Asymmetric conjugate addition of aryl halides or aryl triflates to electron-deficient olefins was realized by sequential Miyaura borylation and Hayashi-Miyaura conjugate addition in one pot. A nickel-catalyzed borylation of aryl halides or triflates and a rhodium-chiral diene complex catalyzed enantioselective conjugate addition was executed as a pair of relay reactions as a more efficient and greener protocol.
- Fan, Chenrui,Wu, Qixu,Zhu, Chengfeng,Wu, Xiang,Li, Yougui,Luo, Yunfei,He, Jian-Bo
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supporting information
p. 8888 - 8892
(2019/10/14)
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- Bedford-type palladacycle-catalyzed miyaura borylation of aryl halides with tetrahydroxydiboron in water
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A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is developed. The developed methodology requires low catalyst loading of Bedford-type palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 °C in short time of 6 h in water. In addition, our studies show that for Miyaura borylation using BBA in aqueous condition, maintaining a neutral reaction pH is very important for reproducibility and higher yields of corresponding borylated products. Moreover, our protocol is applicable for a broad range of aryl halides, corresponding borylated products are obtained in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional group tolerance.
- Zernickel, Anna,Du, Weiyuan,Ghorpade, Seema A.,Sawant, Dinesh N.,Makki, Arwa A.,Sekar, Nagaiyan,Eppinger, J?rg
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p. 1842 - 1851
(2018/02/23)
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- An efficient method for the hydrolysis of potassium organotrifluoroborates promoted by montmorillonite K10
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An efficient and non-expensive method for conversion of diverse potassium organotrifluoroborates to their corresponding boronic acids promoted by montmorillonite K10 using water as the reaction solvent is described. Further interconversion of potassium organotrifluoroborates to their corresponding boronic esters, via boronic acid intermediates was also successfully accomplished. The products were obtained in good yields, being the rate of hydrolysis influenced by the type of substituent present in the boronic acid.
- Silva, Renato L.,Santos, Cosme S.,Santos, Jonh A. M.,Oliveira, Roberta A.,Menezes, Paulo H.,Freitas, Juliano C. R.
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p. 1777 - 1785
(2018/09/04)
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- Containing diphenylacetylene cyclopentadienyl iron salt such two-photon absorbing material and its preparation method
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The invention relates to three cyclopentadienyl iron salt two-photon absorption materials having a diphenylacetylene group and a preparation method thereof; a diphenylacetylene structure and a cationic cyclopentadienyl iron receptor are jointly composed of a D-(pi)-A type two-photon absorption functional group, and thus the three synthesized novel cyclopentadienyl iron salts have a strong two-photon absorption ability at 532 nm, and has great application value in the two-photon photoetching field when used as the two-photon absorption type cationic photo-initiator.
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- A process for preparing between neighbour para-substituted hydroxy, thio boric acid
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A method of preparing phenylboronic acid ortho- meta- and para-substituted with hydroxy and mercapto is disclosed. The method includes adding a compound of a formula I into an organic solvent, adding 1.2-2.0 eq of acetyl chloride, lowering the temperature of the solution to a temperature between -10 DEG C and 0 DEG C, adding 0.1-0.3 eq of anhydrous aluminium chloride, heating to 20-120 DEG C, stirring for 2-10 h to obtain a compound of a formula II, adding an alkali to adjust pH to be 11-12 after TLC detection proves that the reaction is finished, layering, removing the organic layer, adding hydrochloric acid into the water layer to adjust pH to be 2-3, extracting with ethyl acetate, subjecting the organic layer to rotary drying, and beating the obtained crude product with a mixture of acetone or dichloromethane and n-heptane to obtain a solid product of a formula III, wherein R in the formula I is methyl or tert-butyl, and M in the formula I, M in the formula II and M in the formula III are oxygen simultaneously or sulfur simultaneously. The product produced by the method is high in purity and high in yield.
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Paragraph 0022; 0023; 0024
(2017/08/25)
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- Development of a Concise Multikilogram Synthesis of LPA-1 Antagonist BMS-986020 via a Tandem Borylation-Suzuki Procedure
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The process development for the synthesis of BMS-986020 (1) via a palladium catalyzed tandem borylation/Suzuki reaction is described. Evaluation of conditions culminated in an efficient borylation procedure using tetrahydroxydiboron followed by a tandem Suzuki reaction employing the same commercially available palladium catalyst for both steps. This methodology addressed shortcomings of early synthetic routes and was ultimately used for the multikilogram scale synthesis of the active pharmaceutical ingredient 1. Further evaluation of the borylation reaction showed useful reactivity with a range of substituted aryl bromides and iodides as coupling partners. These findings represent a practical, efficient, mild, and scalable method for borylation.
- Smith, Michael J.,Lawler, Michael J.,Kopp, Nathaniel,McLeod, Douglas D.,Davulcu, Akin H.,Lin, Dong,Katipally, Kishta,Sfouggatakis, Chris
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p. 1859 - 1863
(2017/11/24)
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- Modification of an Enzyme Biocatalyst for the Efficient and Selective Oxidative Demethylation of para-Substituted Benzene Derivatives
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The bacterial CYP199A4 enzyme is able to oxidise a narrow range of aromatic acids, which includes 4-methoxybenzoic acid, efficiently. A serine 244 to aspartate variant was identified with enhanced activity for a wide range of para-methoxy-substituted benzenes. Substrates in which the acidic benzoic acid moiety is replaced with a phenol and the amide, aldehyde and bromide analogues were all oxidised with high activity by the S244D mutant (product formation rate >600 nmol nmolCYP ?1 min?1) with turnover numbers of up to 20 000. If the carboxylate moiety was modified to a nitro, ketone, boronic acid, hydroxymethyl or nitrile group, these substrates were also oxidised at a significantly higher activity by S244D than the wild-type enzyme. 3,4-Dimethoxybenzaldehyde was demethylated selectively and oxidatively to 3-methoxy-4-hydroxybenzaldehyde by the S244D mutant 84-fold more rapidly than with the wild-type enzyme. CYP199A4 would have applications in the catalytic regioselective oxidative demethylation of suitably substituted benzene substrates under mild conditions and in the presence of more oxidatively sensitive functional groups, such as an aldehyde.
- Chao, Rebecca R.,Lau, Ian C.-K.,De Voss, James J.,Bell, Stephen G.
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p. 3626 - 3635
(2016/12/14)
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- Scalable, Metal- and Additive-Free, Photoinduced Borylation of Haloarenes and Quaternary Arylammonium Salts
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We report herein a simple, metal- and additive-free, photoinduced borylation of haloarenes, including electron-rich fluoroarenes, as well as arylammonium salts directly to boronic acids. This borylation method has a broad scope and functional group tolerance. We show that it can be further extended to boronic esters and carried out on gram scale as well as under flow conditions.
- Mfuh, Adelphe M.,Doyle, John D.,Chhetri, Bhuwan,Arman, Hadi D.,Larionov, Oleg V.
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supporting information
p. 2985 - 2988
(2016/03/19)
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- Synthesis and optical properties of novel D-π-A-π-D type cationic cyclopentadienyliron complexes of arenes
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Diphenylethynyl chromophores were successfully introduced into the arene ligands of cationic cyclopentadienyliron complexes through nucleophilic substitution and Suzuki coupling reactions. Three novel cationic cyclopentadienyliron complexes with symmetrical di(4-methoxy-phenylethynyl) chromophores (CFSs) were obtained and completely characterized by IR, 1H NMR, 13C NMR, and MS. The linear and nonlinear optical properties of the obtained molecules were tuned using phenylethynyl linkages. The UV-Vis absorption spectra showed that increasing the conjugation by substituting phenylacetylene spacer resulted in a red shift in the absorption bands and a stronger absorption in CFSs than in the previously reported (η6-cumene)(η5-cyclopentadienyl)iron hexafluorophosphate (I-261). These cross-conjugated D-π-A-π-D type compounds also showed larger third-order nonlinear susceptibility than I-261.
- Zhao,Li,Shi,Zhang,Wang
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p. 54749 - 54756
(2015/06/30)
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- Porphyrin-Metalation-Mediated Tuning of Photoredox Catalytic Properties in Metal-Organic Frameworks
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Photoredox catalytic activation of organic molecules via single-electron transfer processes has proven to be a mild and efficient synthetic methodology. However, the heavy reliance on expensive ruthenium and iridium complexes limits their applications for scale-up synthesis. To this end, photoactive metal-organic frameworks (MOFs) exhibit unique advantages as novel heterogeneous photocatalytic systems, yet their utilization toward organic transformations has been limited. Here we describe the preparation and synthetic applications of four isostructural porphyrinic MOFs, namely, UNLPF-10a, -10b, -11, and -12, which are composed of free base, InIII-, SnIVCl2-, and SnIV-porphyrin building blocks, respectively. We demonstrate that the metalation with high valent metal cations (InIII and SnIV) significantly modifies the electronic structure of porphyrin macrocycle and provides a highly oxidative photoexcited state that can undergo efficient reductive quenching processes to facilitate organic reactions. In particular, UNLPF-12 exhibits both outstanding photostability and efficient photocatalytic activities toward a range of important organic transformations including aerobic hydroxylation of arylboronic acids, amine coupling, and the Mannich reaction.
- Johnson, Jacob A.,Luo, Jian,Zhang, Xu,Chen, Yu-Sheng,Morton, Martha D.,Echeverría, Elena,Torres, Fernand E.,Zhang, Jian
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p. 5283 - 5291
(2015/09/15)
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- Photocatalytic hydroxylation of arylboronic acids using continuous flow reactors
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The photocatalytic oxidation of mono- and di-substituted arylboronic acids to phenols has been investigated using a continuous flow photoreactor fitted with white LEDs. An EtOH-H2O solvent system accelerated conversion at 2 MPa; whereas reactions at atmospheric pressure allowed for moderately efficient desymmetrisation.
- Penders, In?¤s G. T. M.,Amara, Zacharias,Horvath, Raphael,Rossen, Kai,Poliakoff, Martyn,George, Michael W.
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p. 6501 - 6504
(2015/02/19)
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- Sequential one-pot access to molecular diversity through aniline aqueous borylation
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On the basis of our recently reported aniline aqueous borylation, molecular diversity was achieved in a one-pot process by combining other reactions such as esterification, Suzuki-Miyaura coupling, hydrogenolysis, or Petasis borono-Mannich.
- Erb, William,Albini, Mathieu,Rouden, Jacques,Blanchet, Jrme
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p. 10568 - 10580
(2015/01/08)
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- Susceptibility to hydrolysis of phenylboronic pinacol esters at physiological pH
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Boronic acids and their esters are highly considered compounds for the design of new drugs and drug delivery devices, particularly as boron-carriers suitable for neutron capture therapy. However, these compounds are only marginally stable in water. Hydrol
- Achilli, Cesare,Ciana, Annarita,Fagnoni, Maurizio,Balduini, Cesare,Minetti, Giampaolo
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p. 137 - 139
(2013/08/25)
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- Nickel-catalyzed borylation of halides and pseudohalides with tetrahydroxydiboron [B2(OH)4]
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Arylboronic acids are gaining increased importance as reagents and target structures in a variety of useful applications. Recently, the palladium-catalyzed synthesis of arylboronic acids employing the atom-economical tetrahydroxydiboron (BBA) reagent has been reported. The high cost associated with palladium, combined with several limitations of both palladium- and copper-catalyzed processes, prompted us to develop an alternative method. Thus, the nickel-catalyzed borylation of aryl and heteroaryl halides and pseudohalides using tetrahydroxydiboron (BBA) has been formulated. The reaction proved to be widely functional group tolerant and applicable to a number of heterocyclic systems. To the best of our knowledge, the examples presented here represent the only effective Ni-catalyzed Miyaura borylations conducted at room temperature.
- Molander, Gary A.,Cavalcanti, Livia N.,Garcia-Garcia, Carolina
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p. 6427 - 6439
(2013/07/26)
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- Scope of the palladium-catalyzed aryl borylation utilizing bis-boronic acid
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The Suzuki-Miyaura reaction has become one of the more useful tools for synthetic organic chemists. Until recently, there did not exist a direct way to make the most important component in the coupling reaction, namely the boronic acid. Current methods to make boronic acids often employ harsh or wasteful reagents to prepare boronic acid derivatives and require additional steps to afford the desired boronic acid. The scope of the previously reported palladium-catalyzed, direct boronic acid synthesis is unveiled, which includes a wide array of synthetically useful aryl electrophiles. It makes use of the newly available second generation Buchwald XPhos preformed palladium catalyst and bis-boronic acid. For ease of isolation and to preserve the often sensitive C-B bond, all boronic acids were readily converted to their more stable trifluoroborate counterparts.
- Molander, Gary A.,Trice, Sarah L. J.,Kennedy, Steven M.,Dreher, Spencer D.,Tudge, Matthew T.
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supporting information; experimental part
p. 11667 - 11673
(2012/09/05)
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- Base free aryl coupling of diazonium compounds and boronic esters: Self-activation allowing an overall highly practical process
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Boronic esters have long been considered as poor partners in cross-coupling reactions with arene diazoniums. Here is reported an unprecedented application of self-activated boronic esters in a base-free cross-coupling reaction with diazonium salts under mild and user friendly conditions.
- Bonin, Helene,Delbrayelle, Dominique,Demonchaux, Patrice,Gras, Emmanuel
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supporting information; experimental part
p. 2677 - 2679
(2010/07/08)
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