- Studies on the synthesis, pungency and anti-biofouling performance of capsaicin analogues
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Ten capsaicin analogues were synthesized and their pungency degrees were determined through Scoville Organoleptic Test. The relationship between the structure and pungency degree of these capsaicin analogues was discussed. Then four of these capsaicin analogues with higher pungency degree were picked out and added to anti-biofouling paints as repellents to study their anti-biofouling performance by shallow sea buoyant raft hung-plate experimentation. The results showed that capsaicin and dihydrocapsaicin exhibited equally good anti-biofouling performance while nordihydrocapsaicin and N-vanillylnonanamide had poor anti-biofouling performance. Experimental results also showed that the paints with only 0.1% capsaicin or dihydrocapsaicin as repellent without any other biocides had also exhibited good anti-biofouling performance, which provided a new idea for developing novel, more environment-friendly and Cu 2O-free antifouling paints.
- Peng, Bixian,Wang, Junlian,Peng, Zhenghong,Zhou, Shengze,Wang, Fengqi,Ji, Yongliang,Ye, Zhangji,Zhou, Xiangfeng,Lin, Tong,Zhang, Xiaobin
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Read Online
- Self-regulated catalysis for the selective synthesis of primary amines from carbonyl compounds
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Most current processes for the general synthesis of primary amines by reductive amination are performed with enormously excessive amounts of hazardous ammonia. It remains unclear how catalysts should be designed to regulate amination reaction dynamics at a low ammonia-to-substrate ratio for the quantitative synthesis of primary amines from the corresponding carbonyl compounds. Herein we show a facile control of the reaction selectivity in the layered boron nitride supported ruthenium catalyzed reductive amination reaction. Specifically, locating ruthenium to the edge surface of layered boron nitride leads to an increased hydrogenation activity owing to the enhanced interfacial electronic effects between ruthenium and the edge surface of boron nitride. This enables self-accelerated reductive amination reactions which quantitatively synthesize structurally diverse primary amines by reductive amination of carbonyl compounds with twofold ammonia. This journal is
- Fan, Xiaomeng,Gao, Jin,Gao, Mingxia,Jia, Xiuquan,Ma, Jiping,Xu, Jie
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supporting information
p. 7115 - 7121
(2021/09/28)
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- Method for preparing primary amine by catalytically reducing nitrile compounds through nano-porous palladium catalyst
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The invention belongs to the technical field of heterogeneous catalysis, and provides a method for preparing primary amine by catalytically reducing nitrile compounds with a nano-porous palladium catalyst. According to the invention, aromatic and aliphatic nitrile compounds are adopted as raw materials, nano-porous palladium is adopted as a catalyst, ammonia borane is adopted as a hydrogen source, no additional additive is added, and selective hydrogenation is performed to prepare the corresponding primary amine. The method provided by the invention has the beneficial effects of mild reaction conditions, no additive, environmental protection, no need of hydrogen, simple operation, stable hydrogen source, safety, harmlessness, high conversion rate, high selectivity and good catalyst stability, and makes industrialization possible.
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Paragraph 0077-0080
(2021/05/29)
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- Cobalt-Catalyzed Hydrogenative Transformation of Nitriles
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Here, we report the transformation of nitrile compounds in a hydrogen atmosphere. Catalyzed by a cobalt/tetraphosphine complex, hydrogenative coupling of unprotected indoles with nitriles proceeds smoothly in a basic medium, yielding C3 alkylated indoles. In addition, the direct hydrogenation of nitriles under the same conditions yielded primary amines. Isotope labeling experiments, along with a series of control experiments, revealed a reaction pathway that involves nucleophilic addition of indoles and 1,4-reduction of a conjugate imine intermediate. Different from reductive alkylation of indoles under an acidic condition, E1cB elimination is believed to occur in this base-promoted hydrogenative coupling reaction.
- Zhang, Shaoke,Duan, Ya-Nan,Qian, Yu,Tang, Wenyue,Zhang, Runtong,Wen, Jialin,Zhang, Xumu
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p. 13761 - 13767
(2021/11/17)
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- Ultra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines
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We report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kalevaru, Narayana V.,Kamer, Paul C. J.,Senthamarai, Thirusangumurugan,Zbo?il, Radek
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p. 2973 - 2981
(2020/03/27)
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- Nitrile Synthesis by Aerobic Oxidation of Primary Amines and in situ Generated Imines from Aldehydes and Ammonium Salt with Grubbs Catalyst
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Herein, a Grubbs-catalyzed route for the synthesis of nitriles via the aerobic oxidation of primary amines is reported. This reaction accommodates a variety of substrates, including simple primary amines, sterically hindered β,β-disubstituted amines, allylamine, benzylamines, and α-amino esters. Reaction compatibility with various functionalities is also noted, particularly with alkenes, alkynes, halogens, esters, silyl ethers, and free hydroxyl groups. The nitriles were also synthesized via the oxidation of imines generated from aldehydes and NH4OAc in situ. (Figure presented.).
- Utsumi, Tatsuki,Noda, Kenta,Kawauchi, Daichi,Ueda, Hirofumi,Tokuyama, Hidetoshi
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p. 3583 - 3588
(2020/08/05)
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- Method for preparing primary amines through hydrogen transfer selective nitrile reduction
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The invention discloses a method for preparing primary amines through hydrogen transfer selective nitrile reduction. The method includes the step of adding low-price copper, iron and other metal saltsor low-price easy-to-obtain iodine elementary substances as additives with a nitrile compound as the raw material and oxazole borane as the hydrogen transfer agent under the mild conditions, therebypromoting the hydrogen transfer reaction and selectively synthesizing a series of corresponding primary amines under different conditions respectively. The high yield and high selectivity are achievedin the reaction. The oxazole borane is obtained through reaction of alkamine and a tetrahydrofuran complex of borane. In addition, the method is mild in reaction condition, easy to operate, free of high-pressure devices, environmentally friendly and high in raw material general applicability, the agents required for the reaction are all low in price and easy to obtain, the reduction product is only primary amines, and selectivity and repeatability are high. Thus, an effective scheme is provided for the industrial production of other high-additional-value compounds of similar structures in future.
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Paragraph 0052-0056
(2019/05/02)
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- Mild palladium-catalysed highly efficient hydrogenation of CN, C-NO2, and CO bonds using H2 of 1 atm in H2O
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Here we present the first example of a mild and high-efficiency protocol enabling a process in water using 1 atm of H2 for the efficient and selective hydrogenation of nitriles, nitro compounds, ketones, and aldehydes to yield primary amines and alcohols with satisfactory yields of up to >99%. Several palladium-based nanoparticle catalysts were prepared from K2PdCl4 and ligands, and one of them was found to be the best and most suitable for the hydrogenation of CN, C-NO2, and CO bonds. In addition, the catalyst Pd-NPs can be easily recycled and reused without losing their activity and selectivity. A plausible mechanism for the hydrogenation of a CN bond was also proposed, representing the first example that possesses great potential for sustainable industrial purposes.
- Liu, Yaxu,He, Shaopo,Quan, Ziyi,Cai, Huizhuo,Zhao, Yang,Wang, Bo
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supporting information
p. 830 - 838
(2019/02/27)
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- A ppm level Rh-based composite as an ecofriendly catalyst for transfer hydrogenation of nitriles: Triple guarantee of selectivity for primary amines
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Hydrogenation of nitriles to afford amines under mild conditions is a challenging task with an inexpensive heterogeneous catalyst, and it is even more difficult to obtain primary amines selectively because of the accompanying self-coupling side reactions. An efficient catalytic system was designed as Fe3O4@nSiO2-NH2-RhCu@mSiO2 to prepare primary amines through the transfer hydrogenation of nitrile compounds with economical HCOOH as the hydrogen donor. The loading of rhodium in the catalyst could be at the ppm level, and the TOF reaches 6803 h-1 for Rh. This catalytic system has a wide substrate range including some nitriles that could not proceed in the previous literature. The experimental results demonstrate that the excellent selectivity for primary amines is guaranteed by three tactics, which are the strong active site, the inhibition of side products by the hydrogen source and the special pore structure of the catalyst. In addition, the catalyst could be reused ten times without activity loss through convenient magnetic recovery.
- Liu, Lei,Li, Jifan,Ai, Yongjian,Liu, Yuhong,Xiong, Jialiang,Wang, Hongdong,Qiao, Yijun,Liu, Wenrui,Tan, Shanchao,Feng, Shaofei,Wang, Kunpeng,Sun, Hongbin,Liang, Qionglin
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p. 1390 - 1395
(2019/03/26)
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- Highly efficient nitrobenzene and alkyl/aryl azide reduction in stainless steel jars without catalyst addition
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The mechanochemical and selective reduction of aryl nitro and aryl/alkyl azide derivatives, with either formate salts or hydrazine, to the corresponding, synthetically useful amines occurs in excellent yields in a planetary ball mill without the addition of a catalyst. This newly developed and solvent-free protocol is efficient, fast and does not require the addition of a metal hydrogenation catalyst as the stainless steel jar itself fulfils that role. The method has been applied to a broad range of compounds and excellent yields have been obtained. The formylation of alkyl amines has been successfully performed, by means of mechanochemical activation, in the presence of ammonium formate alone.
- Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Moran, Maria Jesus,Cravotto, Giancarlo,Cintas, Pedro
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supporting information
p. 18881 - 18888
(2018/11/26)
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- N-Alkylation of Aqueous Ammonia with Alcohols Leading to Primary Amines Catalyzed by Water-Soluble N-Heterocyclic Carbene Complexes of Iridium
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A new catalytic system for the N-monoalkylation of aqueous ammonia with a variety of alcohols was developed. Water-soluble dicationic complexes of iridium bearing N-heterocyclic carbene and diammine ligands exhibited high catalytic activity for this type of reaction on the basis of hydrogen-transfer processes without generating harmful or wasteful byproducts. Various primary amines were efficiently synthesized by using safe, inexpensive, and easily handled aqueous ammonia as a nitrogen source. For example, the reaction of 1-(4-methylphenyl)ethanol with aqueous ammonia in the presence of a water-soluble N-heterocyclic carbene complex of iridium at 150 °C for 40 h gave 1-(4-methylphenyl)ethylamine in 83 % yield.
- Fujita, Ken-Ichi,Furukawa, Shohichi,Morishima, Namino,Shimizu, Mineyuki,Yamaguchi, Ryohei
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p. 1993 - 1997
(2018/03/13)
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- Cobalt complex, preparation method thereof, and application thereof in selective catalysis of transfer hydrogenation reaction of cyano group
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The invention discloses a cobalt complex, a preparation method thereof, and an application thereof in the selective catalysis of a transfer hydrogenation reaction of a cyano group. The structural formula of the cobalt complex is represented by formula I. The cobalt complex is prepared through a reaction of a cobalt salt and an NNP ligand or a PNP ligand under the protection of an inert atmosphere;and the chemical formula of the cobalt salt is CoX12, wherein X1 represents halogen, a sulfate radical, a perchlorate radical, a hexafluorophosphate radical, a hexafluoroantimonate radical, a tetrafluoroborate radical, a trifluoromethanesulfonate radical or a tetra(pentafluorophenyl)borate radical. The cobalt complex can be used in the selective catalysis of the transfer hydrogenation reaction ofthe cyano group to obtain a primary amine compound, a secondary amine compound and a tertiary amine compound, the primary amine compound, the secondary amine compound and the tertiary amine compoundare important intermediates in a series of subsequent functionalizing reactions, and the cobalt complex has a very high catalysis activity, and has great research values and a great application prospect.
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Paragraph 0157-0159; 0161
(2018/05/07)
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- Highly Stable COF-Supported Co/Co(OH)2 Nanoparticles Heterogeneous Catalyst for Reduction of Nitrile/Nitro Compounds under Mild Conditions
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Ordered nanoporosity in covalent organic framework (COF) offers excellent opportunity for property development. Loading nanoparticles (nPs) onto them is one approach to introducing tailor-made properties into a COF. Here, a COF–Co/Co(OH)2 composite containing about 16 wt% of 2 nPs is prepared on a N-rich COF support that catalyzes the release of theoretical equivalence of H2 from readily available, safe, and cheap NaBH4. Furthermore, the released H2 is utilized for the hydrogenation of nitrile and nitro compounds to amines under ambient conditions in a facile one-pot reaction. The COF “by choice” is built from “methoxy” functionalized dialdehydes which is crucial in enabling the complete retention of the COF structure under the conditions of the catalysis, where the regular Schiff bonds would have hydrolyzed. The N-rich binding pockets in the COF ensure strong nP–COF interactions, which provides stability and enables catalyst recycling. Modeling studies reveal the crucial role played by the COF in exposing the active facets and thereby in controlling the activation of the reducing agent. Additionally, via density functional theory, we provide a rational explanation for how these COFs can stabilize nanoparticles which grow beyond the limiting pore size of the COF and yet result in a truly stable heterogeneous catalyst – a ubiquitous observation. The study underscores the versatility of COF as a heterogeneous support for developing cheap and highly active nonnoble metal catalysts.
- Mullangi, Dinesh,Chakraborty, Debanjan,Pradeep, Anu,Koshti, Vijay,Vinod, Chathakudath P.,Panja, Soumendranath,Nair, Sunil,Vaidhyanathan, Ramanathan
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- Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts
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The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Alshammari, Ahmad S.,Pohl, Marga-Martina,Beller, Matthias,Jagadeesh, Rajenahally V.
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p. 8553 - 8560
(2018/11/30)
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- Design and synthesis of neolamellarin a derivatives targeting heat shock protein 90
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In this study, we designed and synthesized a novel family of neolamellarin A derivatives that showed high inhibitory activity toward heat shock protein 90 (Hsp90), a kinase associated with cell proliferation. The 3,4-bis(catechol)pyrrole scaffold and the benzyl group with methoxy modification at N position of pyrrole are essential to the Hsp90 inhibitory activity and cytotoxicity of these compounds. Western blot analysis demonstrated that these compounds induced dramatic depletion of the examined client proteins of Hsp90, and accelerated cancer cell apoptosis. Docking simulations suggested that the binding mode of 9p was similar to that of the VER49009, a potent inhibitor of Hsp90. Further molecular dynamics simulation indicated that the hydrophobic interactions as well as the hydrogen bonds contributed to the high affinity of 9p to Hsp90.
- Jiang, Long,Yin, Ruijuan,Wang, Xueting,Dai, Jiajia,Li, Jing,Jiang, Tao,Yu, Rilei
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- Versatile Dynamic Covalent Assemblies for Probing π-Stacking and Chirality Induction from Homotopic Faces
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Herein we report for the first time the use of dynamic covalent reactions (DCRs) for building a π-stacking model system and further quantifying its substituent effects (SEs), which remain a topic of debate despite the rich history of stacking. A general DCR between 10-methylacridinium ion and primary amines was discovered, in which π-stacking played a stabilizing role. Facile quantification of SEs with in situ competing π-stacking systems was next achieved in the form of amine exchange exhibiting structural diversity by simply varying components. The linear correlation with σm in Hammett plots indicates the dominance of purely electrostatic SEs, and the additivity of SEs is in line with the direct interaction model. With α-chiral amines π-stacking within the adduct enabled chirality transfer from homotopic faces. The strategy of dynamic covalent assembly should be appealing to future research of probing weak interactions and manipulating chirality.
- Ye, Hebo,Hai, Yu,Ren, Yulong,You, Lei
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supporting information
p. 3804 - 3809
(2017/03/27)
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- Cobalt-Catalyzed and Lewis Acid-Assisted Nitrile Hydrogenation to Primary Amines: A Combined Effort
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The selective hydrogenation of nitriles to primary amines using a bench-stable cobalt precatalyst under 4 atm of H2 is reported herein. The catalyst precursor was reduced in situ using NaHBEt3, and the resulting Lewis acid formed, BEt3, was found to be integral to the observed catalysis. Mechanistic insights gleaned from para-hydrogen induced polarization (PHIP) transfer NMR studies revealed that the pairwise hydrogenation of nitriles proceeded through a Co(I/III) redox process.
- Tokmic, Kenan,Jackson, Bailey J.,Salazar, Andrea,Woods, Toby J.,Fout, Alison R.
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supporting information
p. 13554 - 13561
(2017/10/05)
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- Stereoelectronic effects in the reaction of aromatic substrates catalysed by: Halomonas elongata transaminase and its mutants
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A transaminase from Halomonas elongata and four mutants generated by an in silico-based design were recombinantly produced in E. coli, purified and applied to the amination of mono-substituted aromatic carbonyl-derivatives. While benzaldehyde derivatives were excellent substrates, only NO2-acetophenones were transformed into the (S)-amine with a high enantioselectivity. The different behaviour of wild-type and mutated transaminases was assessed by in silico substrate binding mode studies.
- Contente, Martina Letizia,Planchestainer, Matteo,Molinari, Francesco,Paradisi, Francesca
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p. 9306 - 9311
(2016/10/13)
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- Preparation method of benzylamine compound
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The invention discloses a preparation method of a benzylamine compound. The method adopting an aryl methane compound as a raw material comprises the following steps: carrying out an NBS bromination reaction to synthesize a bromobenzyl compound, carrying out an N-hydrocarbylation reaction to synthesize a 1-benzylpyrrolidyl-2,5-dione compound, and carrying out a hydrolyzing reaction to obtain the benzylamine compound. The preparation method of the benzylamine compound has the advantages of wide source of the raw material, no need of separation of intermediates generated in above reactions, realization of an all-in-a-pot technology, simple operation, mild reaction conditions, high reaction yield, few three wastes, and convenience for industrial production.
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Paragraph 0041-0043
(2017/01/23)
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- Mild and Selective Cobalt-Catalyzed Chemodivergent Transfer Hydrogenation of Nitriles
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Herein, we describe a selective cobalt-catalyzed chemodivergent transfer hydrogenation of nitriles to synthesize primary, secondary, and tertiary amines. The solvent effect plays a key role for the selectivity control. The general applicability of this procedure was highlighted by the synthesis of more than 70 amine products bearing various functional groups in high chemoselectivity. Moreover, this mild system achieved >2000 TONs (turnover numbers) for the transfer hydrogenation of nitriles.
- Shao, Zhihui,Fu, Shaomin,Wei, Mufeng,Zhou, Shaolin,Liu, Qiang
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supporting information
p. 14653 - 14657
(2016/11/23)
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- Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines
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Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.
- Blondiaux, Enguerrand,Cantat, Thibault
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p. 9349 - 9352
(2014/08/05)
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- Synthetic communications reviews: Synthesis of primary amines by one-pot reductive amination of aldehydes
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We report here a novel, one-pot, two-step reductive amination of aldehydes for the atom-economical synthesis of primary amines. The amination step has been carried out with hydroxylammonium chloride and does not require the use of a base. In the subsequent reduction step, a metal zinc/hydrochloride acid system has been used. This method is applicable to both aliphatic and aromatic aldehydes. The operational simplicity, the short reaction times, and the mild reaction conditions add to the value of this method as a practical alternative to the reductive amination of aldehydes. Copyright
- Ayedi, Mohamed Ali,Le Bigot, Yves,Ammar, Houcine,Abid, Souhir,Gharbi, Rachid El,Delmas, Michel
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p. 2127 - 2133
(2013/07/25)
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- Stability of benzylic-type isothiocyanates in hydrodistillation-mimicking conditions
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Pentadiplandra brazzeana Baillon (Pentadiplandraceae) is known to contain benzyl-, 3-methoxybenzyl-, 4-methoxybenzyl-, 3,4-dimethoxybenzyl-, and indole-type glucosinolates, and the essential oil obtained from its roots is mainly constituted of benzyl isothiocyanate and benzyl cyanide. In a previous study by the authors, it was surmised that partial hydrolytic degradation of 4-methoxybenzyl isothiocyanate, one major expected compound, occurred during the hydrodistillation process of essential oil preparation. To probe this hypothesis, a selection of diversely substituted benzylic-type isothiocyanates was submitted to standard hydrodistillation-mimicking conditions. After extraction with dichloromethane, the reaction mixtures were analyzed using GC-MS. The aqueous phases resulting from liquid-liquid extraction were analyzed by HPLC and GC-MS. 2-Methoxybenzyl, 4-methoxybenzyl, 3,4-dimethoxybenzyl, and 3,4,5-trimethoxybenzyl isothiocyanates underwent conversion into 2-methoxybenzyl, 4-methoxybenzyl, 3,4-dimethoxybenzyl, and 3,4,5- trimethoxybenzyl alcohols, respectively, whereas benzyl, 3-methoxybenzyl, and 4-chlorobenzyl isothiocyanates were converted into the corresponding benzylamines.
- De Nicola, Gina R.,Montaut, Sabine,Rollin, Patrick,Nyegue, Maximilienne,Menut, Chantal,Iori, Renato,Tatibou?t, Arnaud
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p. 137 - 142
(2013/03/28)
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- Rapid and convenient microwave-assisted synthesis of primary amines via reductive N-alkylation of methyl carbamate with aldehydes
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Microwave-assisted reductive alkylation of methyl carbamate with a range of aldehydes provides, after basic work-up, an experimentally simple, one-pot method for rapid functional group interconversion of structurally diverse aldehydes into primary amines. The method has several advantages over more traditional methods of carrying out this transformation and is particularly amenable to high-throughput synthesis.
- Lehmann, Fredrik,Scobie, Martin
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p. 1679 - 1681
(2008/12/22)
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- 2-aminobenzoxazole derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminobenzoxazole derivative compounds of the following formula: wherein R1 to R4 and Z have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminobenzoxazole derivative compounds.
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- 4-unsubstituted dihydroisoquinolinone derivatives and combinatorial libraries thereof
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The present invention relates to novel dihydroisoquinolinone (DHQ) derivative compounds of the following formula: wherein R1to R7, X, Y, Z, b, c and d have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing DHQ derivative compounds.
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- Application of hydrazinium monoformate as new hydrogen donor with Raney nickel: A facile reduction of nitro and nitrile moieties
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The nitro groups in aliphatic and aromatic nitrocompounds also containing reducible substituents such as ethene, acid, phenol, halogen, ester etc., are rapidly reduced at room temperature to corresponding amines by employing hydrazinium monoformate, a new hydrogen donor, in the presence of Raney nickel. It was observed that the nitrile function also undergoes reduction to methylamine (-CH2-NH2). Hydrazinium monoformate is a more effective donor than hydrazine or formic acid and reduction of nitro and nitrile groups occurs without hydrogenolysis in the presence of low cost Raney nickel, compared to expensive metals like palladium, platinum or ruthenium. The reduction is reasonably fast, clean and high yielding.
- Gowda, Shankare,Gowda, D.Channe
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p. 2211 - 2213
(2007/10/03)
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- Deprotection of N-tert-butoxycarbonyl (Boc) groups in the presence of tert-butyl esters
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Deprotection of Boc groups in the presence of tert-butyl esters was achieved by using concentrated H2SO4 (1.5-3.0 equiv.) in tBuOAc or MeSO3H (1.5-3.0 equiv.) in tBuOAc:CH2Cl2 (4:1 v/v). The yields ranged from 70 to 100% for a variety of amino acid and dipeptide substrates. (C) 2000 Elsevier Science Ltd.
- Lin,Lanza T.,De Laszlo,Truong,Kamenecka,Hagmann
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p. 7013 - 7016
(2007/10/03)
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- Al-NiCl(2°)6H2O-THF: A new, mild and neutral system for selective reduction of organic functional groups
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A mild and neutral reducing system consisting of Al-NiCl(2°)6H2O-THF has been developed and reacted with a series of organic compounds containing different functional groups in order to evaluate its synthetic utility. It was observed that this system very efficiently reduces the α-enones to the saturated ketones, aromatic aldehydes and ketones to the corresponding alcohols, nitriles and nitroarenes to amines, acid anhydrides and acid chlorides to aldehydes, disulphides to thiols and epoxides to the corresponding alcohols. On the other hand isolated double bonds, carboxylic acids, esters, lactones, primary, benzyl and allyl halides, aliphatic aldehydes and ketones and aliphatic nitro compounds were found to remain inert to this system. Furthermore, the reducing properties of Al-NiCl(2°)6H2O in several other organic solvents were also studied.
- Sarmah,Barua
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p. 8587 - 8600
(2007/10/02)
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