scholarly journals Hypervalent iodine(III)-mediated decarboxylative acetoxylation at tertiary and benzylic carbon centers

2018 ◽  
Vol 14 ◽  
pp. 1046-1050 ◽  
Author(s):  
Kensuke Kiyokawa ◽  
Daichi Okumatsu ◽  
Satoshi Minakata
Keyword(s):  
Carboxylic Acids ◽  
Mixed Solvent ◽  
Hypervalent Iodine ◽  
Reaction Conditions ◽  
Carbon Centers ◽  
Benzylic Carbon

The decarboxylative acetoxylation of carboxylic acids using a combination of PhI(OAc)2 and I2 in a CH2Cl2/AcOH mixed solvent is reported. The reaction was successfully applied to two types of carboxylic acids containing an α-quaternary and a benzylic carbon center under mild reaction conditions. The resulting acetates were readily converted into the corresponding alcohols by hydrolysis.

Synthetic Routes to Oxazolines

2019 ◽  
Vol 16 (6) ◽  
pp. 507-526
Author(s):  
Ensar Mulahmetovic ◽  
Gráinne C. Hargaden
Keyword(s):  
Zinc Oxide ◽  
Carboxylic Acids ◽  
Lewis Acids ◽  
Building Blocks ◽  
Hypervalent Iodine ◽  
Acid Catalysts ◽  
Triflic Acid ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Synthetic Routes

In this mini-review, the main synthetic routes used in the preparation of oxazolines is presented. The review is systematically carried out and the syntheses are presented in terms of precursors utilised (nitriles, aldehydes and carboxylic acids). Additionally, the reported synthesis of all chiral and achiral oxazolines involve either the use of amino alcohols as essential building blocks or some form of intramolecular cyclisation reactions. A comparison of the effectiveness of various reaction initiators such as Lewis acids, bases, oxidants and metals as well as their respective reaction conditions is also described. Lewis acid catalysts such as zinc chloride, zinc oxide and indium (III) chloride as well as triflic acid and ruthenium complexes are presented as effective catalysts in the formation of oxazolines from nitrile precursors. Oxidising agents such as N-bromosuccinimide, hypervalent iodine reagents and reducing agents such as butyllithium have been used in the formation oxazolines from aldehydes. While carboxylic acids have been used effectively as good precursors to oxazolines when using reagents such as cyanuric chloride as well as transition metal containing catalysts such as copper, ruthenium and titanium. In some cases, catalyst free reaction conditions have also been reported offering substituted oxazolines through microwave and ultrasonic irradiation as well as under standard reflux conditions.

Carbon-Based Leaving Group in Substitution Reactions: Functionalization of sp3-Hybridized Quaternary and Tertiary Benzylic Carbon Centers

2012 ◽  
Vol 14 (13) ◽  
pp. 3474-3477 ◽  
Author(s):  
Stuart J. Mahoney ◽  
Tiantong Lou ◽  
Ganna Bondarenko ◽  
Eric Fillion
Keyword(s):  
Substitution Reactions ◽  
Carbon Centers ◽  
Benzylic Carbon ◽  
Leaving Group ◽  
Carbon Based

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

2018 ◽  
Vol 14 ◽  
pp. 1203-1207 ◽  
Author(s):  
Elsa Deruer ◽  
Vincent Hamel ◽  
Samuel Blais ◽  
Sylvain Canesi
Keyword(s):  
Ring Opening ◽  
Hypervalent Iodine ◽  
Cyclic Ethers ◽  
Reaction Conditions ◽  
Alternative Method ◽  
Aromatic Systems ◽  
Mediated Oxidation ◽  
Rapid Transformation

An alternative method for forming sulfonates through hypervalent iodine(III) reagent-mediated oxidation of sodium sulfinates has been developed. This transformation involves trapping reactive sulfonium species using alcohols. With additional optimization of the reaction conditions, the method appears extendable to other nucleophiles such as electron-rich aromatic systems or cyclic ethers through a ring opening pathway.

scholarly journals NaIO4/Br- as a mild system for the oxidation of 1-methyl-anthra-9,10-quinones

2015 ◽  
Author(s):  
Marcin Cybulski ◽  
Adam Formela ◽  
Katarzyna Sidoryk ◽  
Olga Michalak ◽  
Anna Rosa ◽  
...  
Keyword(s):  
High Pressure ◽  
Carboxylic Acids ◽  
Scale Up ◽  
Lithium Bromide ◽  
Cost Effective ◽  
Building Blocks ◽  
Multidrug Resistant ◽  
Resistant Cell ◽  
Direct Oxidation ◽  
Reaction Conditions

One of the anthraquinone classes comprises compounds with a carbonyl group. These natural or synthetic anthraquinones find their application as building blocks in the synthesis of the compounds with a biological activity. Recently, 4-substituted anthra-9,10-quinone-1-carboxylic acids (2) have been used as key intermediates in the synthesis of patented compounds (3) with anticancer activity against multidrug resistant cell lines. Although 2,7-dihydro-3H-dibenz[de,h]cinnolin-3,7-diones (3) were successfully synthetized in a small laboratory scale, several problems were observed during the preparation of their acid intermediates (2) in a multi-gram scale. The known methods for the preparation of 2 are based on the oxidation of the methyl group in anthra-9,10-quinones (1). The most common are: the oxidation with the diluted nitric acid under high pressure in a sealed tube at the temperature of 195-220 oC, the oxidation in nitrobenzene by passing chlorine gas through the reaction mixture at the temperature of 160-170 oC or in a presence of the fuming sulphuric acid. The mentioned methods require aggressive reagents and specific reaction conditions including high pressure and temperature. Thus, there was a need to find a new efficient, cost-effective and reproducible synthetic method of preparation of 2. While searching literature it was found that the direct oxidation of alkylarenes mediated by the sodium periodate/lithium bromide combination produces benzyl acetates throughout benzyl bromides in the acetic acid, or benzylic acids in the diluted inorganic acid. Based on these results we examined a variety of reaction conditions with or without the bromine source and the oxidizing anion. As a result, a novel procedure for the preparation of highly pure 4-substituted anthra-9,10-quinone-1-carboxylic acids (HPLC > 99.5%) using oxidizing anion/ brominating reagent system was developed. It enabled 2 isolation by the simple filtration of the reaction mixture and was applied in the scale-up of 2,7-dihydro-3H-dibenz[de,h]cinnolin-3,7-dione derivatives.

Efficient synthesis of pyrido[2,3-d]pyrimidine-7-carboxylic acids catalyzed by a TiO2/SiO2 nanocomposite in aqueous media at room temperature

2018 ◽  
Vol 73 (9) ◽  
pp. 641-645 ◽  
Author(s):  
Sepehr Sadegh-Samiei ◽  
Shahrzad Abdolmohammadi
Keyword(s):  
Heterogeneous Catalyst ◽  
Carboxylic Acids ◽  
Room Temperature ◽  
Aqueous Media ◽  
Reaction Times ◽  
Molar Ratio ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
Moderate Reaction ◽  
Recyclable Heterogeneous Catalyst

AbstractA novel and efficient synthesis of eight 5-aryl-1,3-dimethyl-2,4-dioxo-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidine-7-carboxylic acids using a TiO2/SiO2 nanocomposite with a molar ratio of 1:1 as a recyclable heterogeneous catalyst is described. The desired products, five of which are new, are formed in short reaction times (2–3 h) with high to excellent yields (94%–98%) under very moderate reaction conditions (room temperature, aqueous media).

Trichloroisocyanuric Acid Mediated High-Yielding Synthesis of N-Acylbenzotriazoles under Mild Reaction Conditions

Synthesis ◽  
2019 ◽  
Vol 51 (10) ◽  
pp. 2183-2190 ◽  
Author(s):  
Mala Singh ◽  
Anoop Singh ◽  
Nidhi Mishra ◽  
Anand Agrahari ◽  
Vinod Tiwari
Keyword(s):  
Carboxylic Acids ◽  
Reaction Path ◽  
Reaction Conditions ◽  
Salient Features ◽  
Trichloroisocyanuric Acid

N-Acylbenzotriazoles are achieved in good yields from the corresponding carboxylic acids by using only 0.35 equivalent of trichloroisocyanuric acid and 1.2 equivalents of PPh3. The salient features of the developed reaction path include an economic, facile, base-free, and equally useful method in milligram to gram scale.

scholarly journals Manganese-mediated reductive functionalization of activated aliphatic acids and primary amines

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhan Li ◽  
Ke-Feng Wang ◽  
Xin Zhao ◽  
Huihui Ti ◽  
Xu-Ge Liu ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Late Stage ◽  
Materials Science ◽  
Reaction Pathway ◽  
Chemical Conversion ◽  
Primary Amines ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Aliphatic Acids ◽  
Redox Active

Abstract Alkyl carboxylic acids as well as primary amines are ubiquitous in all facets of biological science, pharmaceutical science, chemical science and materials science. By chemical conversion to redox-active esters (RAE) and Katritzky’s N-alkylpyridinium salts, respectively, alkyl carboxylic acids and primary amines serve as ideal starting materials to forge new connections. In this work, a Mn-mediated reductive decarboxylative/deaminative functionalization of activated aliphatic acids and primary amines is disclosed. A series of C-X (X = S, Se, Te, H, P) and C-C bonds are efficiently constructed under simple and mild reaction conditions. The protocol is applicable to the late-stage modification of some structurally complex natural products or drugs. Preliminary mechanistic studies suggest the involvement of radicals in the reaction pathway.

ChemInform Abstract: Influence of the Reaction Conditions in the N-Alkylation of Acridone-2-carboxylic Acids.

ChemInform ◽  
2010 ◽  
Vol 32 (45) ◽  
pp. no-no
Author(s):  
Lisbet Xuarez Marill ◽  
Rolando F. Pellon Comdom ◽  
Miriam Mesa Hernandez
Keyword(s):  
Carboxylic Acids ◽  
Reaction Conditions
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