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1.
Rohit B. Kamble Kishor D. Mane Bapurao D. Rupanawar Pranjal Korekar A. Sudalai Gurunath Suryavanshi 《RSC advances》2020,10(2):724
A new heterogeneous catalytic system (Ti-superoxide/saccharin/TBHP) has been developed that efficiently catalyzes oxidative amidation of aldehydes to produce various primary amides. The protocol employs saccharin as amine source and was found to tolerate a wide range of substrates with different functional groups. Moderate to excellent yields, catalyst reusability and operational simplicity are the main highlights. A possible mechanism and the role of the catalyst in oxidative amidation have also been discussed.Heterogeneous catalytic system using Ti-superoxide and saccharin with TBHP has been developed which catalyzes oxidative amidation of aldehyde to produce primary amides. It tolerates a wide range of substrates with different functional groups. 相似文献
2.
Soheil Zamani Anbardan Javad Mokhtari Ahmad Yari Abolfazl Hassani Bozcheloei 《RSC advances》2021,11(34):20788
Oxidative dehydrogenative homo-coupling of amines to imines and cross-coupling of amines with alcohols to amides was achieved with high to moderate yields at room temperature in THF using Cu-MOF as an efficient and recyclable heterogeneous catalyst under mild conditions. Different primary benzyl amines and alcohols could be utilized for the synthesis of a wide variety of amides and imines. The Cu-MOF catalyst could be recycled and reused four times without loss of catalytic activity.Oxidative dehydrogenative homo or cross-coupling of amines with alcohols to imines and amides was achieved with high to moderate yields at room temperature using Cu-MOF as an efficient and recyclable heterogeneous catalyst. 相似文献
3.
Zhi-Xin Zhang Bo-Han Zhu Pei-Xi Xie Jia-Qi Tang Xin-Ling Li Chunyin Zhu Ying-Wu Yin Long-Wu Ye 《RSC advances》2018,8(33):18308
A novel and efficient scandium-catalyzed oxidative reaction between ynamides and alcohols for the facile synthesis of various α-alkoxyl amides is reported in this paper. The reaction avoids the need for the use of α-diazo carbonyls which are unstable and may cause some safety concerns. Instead, by using alkynes as the starting materials, this protocol features readily available substrates, compatibility with a broad range of functional groups, simple procedure, mild reaction conditions, and high chemoselectivity.A novel scandium-catalyzed oxidative reaction between ynamides and alcohols has been developed, allowing the concise and efficient synthesis of various substituted α-alkoxyl amides. 相似文献
4.
Haoteng Zheng Qinjie Xiao Feiying Mao Anming Wang Mu Li Qiuyan Wang Pengfei Zhang Xiaolin Pei 《RSC advances》2022,12(28):17873
Nitriles are broadly applied to synthesize pharmaceuticals, agrochemicals, and materials because of their versatile transformation. Although various methods have been developed for introducing a nitrile group into organic molecules, most of them entail the use of highly toxic chemicals, transition metals, or harsh conditions. In this work, we reported a greener chemo-enzymatic cascade to synthesize alky and aryl nitriles from readily accessible aldehydes, that were further transformed into corresponding amides via an artificial enzyme cascade. A biphasic reaction system was designed to bridge chemical synthesis and enzymatic catalysis through simple phase separation. The biphasic system mainly perfectly avoided the inactivation of hydroxylamine on aldoxime dehydratase from Pseudomonas putida (OxdF1) and nitrile hydratase from Aurantimonas manganoxydans ATCC BAA-1229 (NHase1229). For the synthesis of various nitriles, moderate isolation yields of approximately 60% were obtained by the chemo-enzymatic cascade. Interestingly, two seemingly conflicting reactions of dehydration and hydration were sequentially proceeded to synthesize amides by the synergistic catalysis of OxdF1 and NHase1229 in E. coli cells. An isolation yield of approximately 62% was achieved for benzamide at the one-liter scale. In addition, the shuttle transport of substrates and products between two phases is convenient for the product separation and n-hexane recycling. Thus, the chemo-enzymatic cascade shows a potential application in the cyanide-free and large-scale synthesis of nitriles and amides.A chemo-enzymatic cascade was developed for the cyanide-free synthesis of nitriles from aldehydes and further one-pot transformation into amides. 相似文献
5.
Md Ayub Ali Ashutosh Nath Md Midul Islam Sharmin Binte Shaheed Ifat Nur Dibbo 《RSC advances》2022,12(18):11255
Amides are the most extensively used substances in both synthetic organic and bioorganic chemistry. Unfortunately, the traditional synthesis of amides suffers from some important drawbacks, including low atom efficiency, high catalyst loading, separation of products from the reaction mixture and production of byproducts. Al2O3 is an amphoteric catalyst that activates the carbonyl carbon of the secondary amide group and helps the C–N cleavage of the reactant amide group by attacking the N–H hydrogen. By using the concepts of amphoteric properties of Al2O3, amides were synthesized from secondary amides and amines in the presence of triethylamine solvent. Several aliphatic and aromatic amines were used for the transamidation of N-methylbenzamide in the presence of the Al2O3 catalyst. Moreover, using the Gaussian09 software at the DFT level, HUMO, LUMO and the intrinsic reaction coordinates (IRCs) have also been calculated to find out the transition state of the reaction and energy. In this study, five successful compounds were synthesized by the transamidation of secondary amides with amines using a reusable Al2O3 catalyst. The catalyst was reused several times with no significant loss in its catalytic activity. The products were purified by recrystallization and column chromatography techniques. This catalytic method is effective for the simultaneous activation of the carbonyl group and N–H bond by using the Al2O3 catalyst.Amides are the most extensively used substances in both synthetic organic and bioorganic chemistry. 相似文献
6.
We have identified a novel one-pot method for the synthesis of β-amino alcohols, which is based on C–H bond hydroxylation at the benzylic α-carbon atom with a subsequent nitrile or amide functional group reduction. This cascade process uses molecular oxygen as an oxidant and sodium bis(2-methoxyethoxy)aluminum hydride as a reductant. The substrate scope was examined on 30 entries and, although the respective products were provided in moderate yields only, the above simple protocol may serve as a direct and powerful entry to the sterically congested 1,2-amino alcohols that are difficult to prepare by other routes. The plausible mechanistic rationale for the observed results is given and the reaction was applied to a synthesis of a potentially bioactive target.A one-pot method for β-amino alcohol synthesis based on α-hydroxylation and subsequent amide or nitrile functional group reduction has been identified and examined. 相似文献
7.
A one-step method to synthesize small size cup-like hollow ZSM-5 single crystals is reported in this paper. Characterization methods show that the product has a typical ZSM-5 structure and most crystals are uniform, mono dispersed crystal shells with distinct hollow structure. The average size of a single crystal is about 350 nm. Every cup-like hollow ZSM-5 crystal can act as a microreactor in the reaction, and the ZSM-5 based catalyst POM-MOF-ZSM-5 (polyoxometalates (POM), metal–organic frameworks (MOF)) shows excellent oxidative desulfurization performance of DBT (dibenzothiophene).One-pot synthesis of small size cup-like hollow ZSM-5 single crystals and their oxidative desulfurization performance. 相似文献
8.
Histaminium tetrachlorozincate nanoparticles are prepared, characterized and applied as an effective and recoverable photocatalyst in the one-pot, green and multi-component synthesis of various chromenes by the reaction of dimedone and/or 1,3-cyclohexanedione, arylaldehyde and 4-hydroxycoumarin in high yields under solventless conditions at ambient temperature. This new catalyst is characterized by FT-IR, XRD, EDX, NMR, SEM and TEM techniques. The incorporation of histaminium ions into the framework of ZnCl42− significantly affected the photocatalytic activity of tetrachlorozincate such that good reusability and recyclability are attained. Moreover, reactive species such as ˙O2− and hydroxyl radicals have proved to be active species in the presented photocatalytic reaction. In addition, the hot filtration test confirms enough stability of the photocatalyst and no significant leaching and destruction of the framework in the course of the reaction. The major advantages of the presented methodology include easy work-up, cost effectiveness, nontoxic nature, broad substrate scope, 100% atom economy, ease of separation, and environment friendly reaction conditions. Finally, the catalyst could be reused many times without significant loss of activity.(His.)ZnCl4 nanocatalyst is realized for the preparation of chromenes with a green LED. ˙O2−, OH˙ and h+ are reactive species for this reaction. Complementary tests assured good stability and reusability of the nanophotocatalyst. 相似文献
9.
10.
Mei Wu Sheng Huang Huiqing Hou Jie Lin Mei Lin Sunying Zhou Zhiqiang Zheng Weiming Sun Fang Ke 《RSC advances》2022,12(23):14724
The development of green protocols for photocatalysis where water acts as a nucleophile, induced by a weak organic base, is difficult to achieve in organic chemistry. Herein, an efficient light-mediated strategy for the synthesis of amides in which a weak organic base acts as a reductant to induce the formation of OH– from water under metal-free conditions is reported. A mechanistic study reveals that the generation of an N,N-diisopropylethylamine (DIPEA) radical via single electron transfer (SET), with the assistance of photocatalyst, that increases the nucleophilicity of the water molecules with respect to the cyanides is essential. Moreover, the removal rate of nitrile in wastewater can be as high as 83%, indicating that this strategy has excellent potential for nitrile degradation.Under weak organic base condition DIPEA as a reductant to increase the nucleophilicity of H2O an excellent potential system for nitrile degradation.The synthesis of amides is a subject of continuous interest and great importance because of their important applications in detergents, agrochemicals, polymers and pharmaceuticals.1 Traditional methods for their synthesis require the transformation of an acid into the corresponding acyl chloride, facilitated by the use of the Schotten–Baumann reaction.2 Although these methods produce amides in good yields, stoichiometric amounts of an activating reagent are required, making these poorly atom economic processes. Various strategies for carboxamide synthesis, such as oxidative alcohol–amine and aldehyde–amine coupling reactions, amine dehydrogenation or oxidation reactions, and C–N coupling reactions, have been developed in recent years.3 Despite this, one of the most straightforward and atom-economical ways to synthesize amides remains the hydration of organonitriles.4 Conventional strategies mostly use strong inorganic bases to generate strongly nucleophilic hydroxide ions, require tough conditions, and are sensitive, especially when using bioactive molecules,5 to the substrate. Moreover, water molecules are usually used as nucleophiles in the hydration of nitriles. Thus, compared to the use of strong basic conditions, the direct nucleophilic addition of water to the cyano group is kinetically slow due to the high energy of the carbon–nitrogen triple bond.6 To circumvent these problems, transition metal (TM) catalytic procedures, where the metal center of the catalyst acts as a Lewis acid to activate the nitrile and the ligand acts as a Lewis base-activated nucleophile, have been developed in recent years.7 But these protocols are associated with certain debilitating disadvantages that include the presence of toxic transition metal cations within the molecular structure of the reagents and difficulties in preventing over-hydrolysis to the corresponding carboxylic acids.Recently, there have been some reports that reductants have been used to change the morphology of water to increase its nucleophilicity.8 Organoamine bases, such as N,N-diisopropylethylamine (DIPEA), have acted in the role of both base and nitrogen radical intermediate and are considered to be reductants.9 However, DIPEA does not lose electrons easily and therefore has a low reductive activity, which means the nitrogen center has to cross a higher energetic barrier. Recently, it was shown that DIPEA could reductively quench many excited photocatalysts by single electron transfer (SET) to generate nitrogen-centered radicals.10 For example, Xu and coworkers11 proposed a new approach using DIPEA to construct difluoroalkylated diarylmethane compounds via visible light photocatalytic radical–radical cross-coupling reactions, in which DIPEA can carry out electron transfer due to the induction of the photocatalyst. It indicates that photooxidation–reduction and organic amine reduction are, when exposed to sufficient light intensity, co-catalytic processes and can generate nitrogen-centered radicals so that the downstream reaction process can continue.12 Herein, an efficient light-mediated strategy for the synthesis of amides in which a weak organic base acts as a reductant to induce the formation of OH– from water under metal-free conditions is reported.Initially, the reaction of the benzonitrile (1a) was selected for the screening of the reaction conditions (Fig. 1, ,22 and and33.Optimization of the reaction conditionsa
Open in a separate windowaStandard conditions: 1a (0.5 mmol), DIPEA (2.0 equiv.), eosin Y (0.1 equiv.), blue light, 12 W, H2O 3 mL, 24 h, rt.bIsolated yield.c10 mmol 1a, 15 equiv. DIPEA and 0.1 equiv. eosin Y, blue light 12 W, H2O 25 mL 36 h.Open in a separate windowFig. 1General methods for the hydration of organonitriles.Open in a separate windowFig. 2Pharmaceuticals and biomolecules containing a primary amide functional group.Open in a separate windowFig. 3Variation of removal rate of nitrile at different reaction times.With the optimized conditions in hand, the substrate scope was investigated (
Entry | Variations from the standard conditions | Yieldb (%) |
---|---|---|
1 | None | 89 |
2 | Eosin B instead of eosin Y | 41 |
3 | Rose bengal instead of eosin Y | 73 |
4 | Rhodamine B instead of eosin Y | Trace |
5 | Erythrosin B instead of eosin Y | 78 |
6 | TEA instead of DIPEA | 64 |
7 | DABCO instead of DIPEA | 13 |
8 | DMSO/H2O (1/2) instead of H2O 3 mL | 54 |
9 | DMF/H2O (1/2) instead of H2O 3 mL | 27 |
10 | 12 h instead of 24 h | 47 |
11 | 28 h instead of 24 h | 90 |
12 | Blue light 5 W instead of blue light 12 W | 63 |
13 | White light instead of blue light | 43 |
14 | DIPEA 1.0 equiv. instead of 2.0 equiv. | 59 |
15c | Gram-scale experiment | 72 |