- Synthesis of γ-Lactams by Mild, o-Benzoquinone-Induced Oxidation of Pyrrolidines Containing Oxidation-Sensitive Functional Groups
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The late-stage oxidation of substituted pyrrolidines offers good flexibility for the construction of γ-lactam libraries, and especially in recent years the methods for functionalization of pyrrolidine have been available. We reported a new strategy for oxidation of pyrrolidines to γ-lactams: reaction of pyrrolidine with an o-benzoquinone gives an N,O-acetal by direct oxidation of the α-C-H bond of the pyrrolidine ring, and then the N,O-acetal is further oxidized by the o-benzoquinone to the γ-lactam. Because the first oxidation occurs selectively at the α-C-H of the pyrrolidine ring, oxidation-sensitive functional groups (allyl-, vinyl-, hydroxyl-, and amino groups) on pyrrolidine ring are unaffected. The synthetic utility of this novel method was demonstrated by the facile syntheses of (S)-vigabatrin and two analogues.
- Rong, Hao-Jie,Cheng, Yong-Feng,Liu, Fan-Fan,Ren, Shu-Jian,Qu, Jin
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Read Online
- Hydrogen-independent reductive transformation of carbohydrate biomass into γ-valerolactone and pyrrolidone derivatives with supported gold catalysts
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A golden opportunity: A highly robust catalyst system consisting of gold nanoparticles supported on acid-tolerant ZrO2 promoted the conversion of biomass-derived levulinic acid (1) and formic acid (2) into γ-valerolactone without the use of an external H2 supply (see scheme, red). The Au/ZrO2 catalyst was also used for the direct one-pot synthesis of highly valuable pyrrolidone derivatives from 1, 2, and primary amines (see scheme, blue).
- Du, Xian-Long,He, Lin,Zhao, She,Liu, Yong-Mei,Cao, Yong,He, He-Yong,Fan, Kang-Nian
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Read Online
- Raney-Ni catalyzed conversion of levulinic acid to 5-methyl-2-pyrrolidone using ammonium formate as the H and N source
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Renewable biomass based levulinic acid was converted to 5-methyl-2-pyrrolidone in 94% yield by a Raney-Ni catalyzed process using ammonium formate in aqueous medium and heating at 180 °C for 3 h. The Raney-Ni could be reused for four catalytic cycles with about 10% loss in catalytic activity. In a similar reaction levulinic acid could be converted 1-substituted-5-methyl-2-pyrrolidones in 90–95% yield by using a mixture of formic acid and the corresponding primary amine.
- Amarasekara, Ananda S.,Lawrence, Yen Maroney
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Read Online
- Preparation of γ- and δ-lactams by ring closure of β,γ-unsaturated amides using trifluoromethanesulfonic acid
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γ-Lactams and δ-lactams can be prepared by the reaction of β,γ-unsaturated amides with trifluoromethanesulfonic acid.
- Marson, Charles M.,Fallah, Asad
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Read Online
- Synthetic Utility of N-Benzoyloxyamides as an Alternative Precursor of Acylnitrenoids for γ-Lactam Formation
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Described herein is the development of a new entry of acylnitrenoid precursors for γ-lactam synthesis via an intramolecular C-H amidation reaction. Upon Ir catalysis, N-benzoyloxyamides serve as efficient substrates to afford 5-membered amides. Mechanistic studies revealed that the generation of a putative Ir-carbonylnitrenoid via N-O bond cleavage is facilitated by the chelation of countercations. This protocol offers a convenient and step-economic route to γ-lactams starting from the corresponding carboxylic acids.
- Huh, Soohee,Hong, Seung Youn,Chang, Sukbok
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Read Online
- Tropylium-promoted Ritter reactions
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The Ritter reaction used to be one of the most powerful synthetic tools to functionalize alcohols and nitriles, providing valuableN-alkyl amide products. However, this reaction has not been frequently used in modern organic synthesis due to its employment of strongly acidic and harsh reaction conditions, which often lead to complicated side reactions. Herein, we report the development of a new method using salts of the tropylium ion to promote the Ritter reaction. This method works well on a range of alcohol and nitrile substrates, giving the corresponding products in good to excellent yields. This reaction protocol is amenable to microwave and continuous flow reactors, offering an attractive opportunity for further applications in organic synthesis.
- Doan, Son H.,Hussein, Mohanad A.,Nguyen, Thanh Vinh
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supporting information
p. 8901 - 8904
(2021/09/10)
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- Highly Robust Iron Catalyst System for Intramolecular C(sp3)?H Amidation Leading to γ-Lactams
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Disclosed here is the use of an iron catalyst system for an intramolecular C?H amidation toward γ-lactam synthesis from dioxazolone precursors. (Phthalocyanine)FeIIICl was found to catalyze this cyclization with extremely high turnover numbers of up to 47 000 under mild and aerobic conditions. On the basis of experimental and computational mechanistic studies, the reaction is suggested to proceed by a stepwise radical pathway involving fast hydrogen atom abstraction followed by radical rebound. A plausible origin for the high turnover numbers along with air-compatibility is also rationalized.
- Kweon, Jeonguk,Chang, Sukbok
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supporting information
p. 2909 - 2914
(2020/12/11)
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- Efficient palladium catalysis for the upgrading of itaconic and levulinic acid to 2-pyrrolidones followed by their vinylation into value-added monomers
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The production of monomers from bio-based platform chemicals shows great potential to reduce the chemical industry's demand for fossil resources. We herein present a two-step approach, which yields N-vinyl-2-pyrrolidone monomers from bio-based carboxylic acids, such as itaconic and levulinic acid. A highly active, heterogeneous palladium catalyst facilitating the reductive amidation of itaconic acid (TOF = 950 molPyr·molPd-surface-1 h-1) as well as the reductive amination of levulinic acid (TOF = 4000 molPyr·molPd-surface-1 h-1) was designed. Especially the reductive amidation of itaconic acid to 3- and 4-methyl-2-pyrrolidone was found to be structure sensitive. A clear trend between Pd particle size and catalyst activity could be shown by the synthesis of Pd/C catalysts with varying Pd particle sizes. The vinylation of the synthesized methyl-2-pyrrolidones with acetylene was tested using common industrial conditions (10-18 bar acetylene, 150 °C, KOH catalyst, no solvent). Similar to the industrial vinylation of 2-pyrrolidone, good yields of up to 80% N-vinyl-methyl-2-pyrrolidone were received. Therefore, and due to the excellent maximum yield of methyl-2-pyrrolidones in reductive amidation (95 mol%), the envisioned process can be a promising drop-in technology, directly replacing fossil resources in the production of an established monomer class. This journal is
- Haus, Moritz O.,Hofmann, Jan P.,Konrad, Marc,Louven, Yannik,Palkovits, Regina
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p. 4532 - 4540
(2020/11/02)
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- Ammonia borane enabled upgrading of biomass derivatives at room temperature
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Simplifying biomass conversion to valuable products with high efficiency is pivotal for the sustainable development of society. Herein, an efficient catalyst-free system using ammonia borane (AB) as the hydrogen donor is described, which enables controllable reaction selectivity towards four value-added products in excellent yield (82-100%) under very mild conditions. In particular, the system is uniquely efficient to produce γ-valerolactone (GVL) at room temperature. Combined in situ NMR and computational studies elucidate the hydrogen transfer mechanism of AB in methanol, the novel pathway of GVL formation from levulinate in water, and a competitive mechanism between reduction and reductive amination in the same system. Moreover, carbohydrates are converted directly into GVL in good yield, using a one-pot, two-step strategy. Products of a rather broad scope are prepared within a short reaction time of 30 min by using this catalyst-free strategy in methanol at room temperature. This journal is
- Meier, Sebastian,Riisager, Anders,Yang, Song,Zhao, Wenfeng
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p. 5972 - 5977
(2020/11/03)
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- A Facile Direct Route to N-(Un)substituted Lactams by Cycloamination of Oxocarboxylic Acids without External Hydrogen
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Lactams are privileged in bioactive natural products and pharmaceutical agents and widely featured in functional materials. This study presents a novel versatile approach to the direct synthesis of lactams from oxocarboxylic acids without catalyst or external hydrogen. The method involves the in situ release of formic acid from formamides induced by water to facilitate efficient cycloamination. Water also suppresses the formation of byproducts. This unconventional pathway is elucidated by a combination of model experiments and density functional theory calculations, whereby cyclic imines (5-methyl-3,4-dihydro-2-pyrrolone and its tautomeric structures) are found to be favorable intermediates toward lactam formation, in contrast to the conventional approach encompassing cascade reductive amination and cyclization. This sustainable and simple protocol is broadly applicable for the efficient production of various N-unsubstituted and N-substituted lactams.
- Li, Hu,Wu, Hongguo,Zhang, Heng,Su, Yaqiong,Yang, Song,Hensen, Emiel J. M.
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p. 3778 - 3784
(2019/08/07)
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- Synthesis method of 5-methyl-2-pyrrolidone
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The invention discloses a preparation method of 5-methyl-2-pyrrolidone. A biomass derivative levulinic acid is used as an initial raw material; ammonium formate is used as a hydrogen source and a nitrogen source; a supported bimetallic catalyst is used as a hydrogenation catalyst; and the 5-methyl-2-pyrrolidone is synthesized in water by adopting a one-pot method. The supporting metal of the supported bimetallic catalyst is bimetallic composed of two precious metals, bimetallic composed of one precious metal and one non-precious metal A or non-precious metal B, or bimetallic composed of one non-precious metal A and one non-precious metal B. According to the method, the conversion rate of the levulinic acid can reach 100%, and the yield of the 5-methyl-2-pyrrolidone can reach 94% or above.The method provided by the invention has the advantages of environment-friendly process, simple operation, recyclable catalyst, high reaction selectivity, high product yield, and obvious industrial production advantages.
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Paragraph 0033-0050
(2020/01/08)
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- Ambient Reductive Amination of Levulinic Acid to Pyrrolidones over Pt Nanocatalysts on Porous TiO2 Nanosheets
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Construction of N-substituted pyrrolidones from biomass-derived levulinic acid (LA) via reductive amination is a highly attractive route for biomass valorization. However, realizing this transformation using H2 as the hydrogen source under mild conditions is still very challenging. Herein, we designed porous TiO2 nanosheets-supported Pt nanoparticles (Pt/P-TiO2) as the heterogeneous catalyst. The prepared Pt/P-TiO2 was highly efficient for reductive amination of LA to produce various N-substituted pyrrolidones (34 examples) at ambient temperature and H2 pressure. Meanwhile, Pt/P-TiO2 showed good applicability for reductive amination of levulinic esters, 4-acetylbutyric acid, 2-acetylbenzoic acid, and 2-carboxybenzaldehyde. Systematic studies indicated that the strong acidity of P-TiO2 and the lower electron density of the Pt sites as well as the porous structure resulted in the excellent activity of Pt/P-TiO2.
- Xie, Chao,Song, Jinliang,Wu, Haoran,Hu, Yue,Liu, Huizhen,Zhang, Zhanrong,Zhang, Pei,Chen, Bingfeng,Han, Buxing
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p. 4002 - 4009
(2019/03/07)
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- Method for synthesizing lactam derivative without catalyst
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The invention discloses a simple synthesis method for a lactam derivative. The method comprises the step that with formamide as an amine source and a hydrogen donor (hydrolyzed to produce formic acid)and keto acid as raw materials, the lactam derivative is easily synthesized through a cycloamination reaction without a solvent or a catalyst. Compared with previous reports, the time required for the reaction is greatly shortened, the selectivity is remarkably improved, the conversion rate of the keto acid derivative is 99%, and the yield of the lactam derivative can reach 70-94%.
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Paragraph 0018; 0019; 0020; 0021
(2019/07/10)
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- Continuous flow synthesis of amines from the cascade reactions of nitriles and carbonyl-containing compounds promoted by Pt-modified titania catalysts
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The effective design of an active and stable catalytic system was performed by a simple modification of a commercial titania with a low platinum loading. The prepared material was fully characterized by XRD, XPS, N2 adsorption-desorption measurements, ICP-MS, TEM and SEM analyses. Such techniques corroborated the successful incorporation of Pt onto the titania surface, without affecting its original structure, morphology and chemical nature. The obtained TiO2-Pt catalyst was effectively applied in several continuous flow reactions between nitriles and carbonyl containing compounds for amine preparation. Remarkably, conversion of levulinic acid, a biomass derived molecule, was achieved with outstanding conversion (87%) and selectivity (80%) to 1-ethyl-5-methylpyrrolidin-2-one. The catalytic system demonstrated a high stability through 120 min of reaction. Moreover, the effect of the nitrile was investigated by performing the reaction with benzonitrile and ethylcyanoacetate. The TiO2-Pt catalyst was also tested in the conversion of benzaldehyde, displaying remarkable results. The influence of substitution in the aromatic ring was investigated using p-nitro-benzaldehyde and p-chloro-benzaldehyde.
- Altu?, Cevher,Mu?oz-Batista, Mario J.,Rodríguez-Padrón, Daily,Balu, Alina M.,Romero, Antonio A.,Luque, Rafael
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p. 300 - 306
(2019/01/28)
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- Synthesis method of 5-methyl-2-pyrrolidone or derivatives thereof
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The invention discloses a synthesis method of 5-methyl-2-pyrrolidone or derivatives thereof, the synthesis method comprises the following steps: fully mixing levulinic acid (ester) with urea or amideand formic acid, and adding the mixture and a catalyst into a high-pressure reaction kettle for reaction to obtain the target product 5-methyl-2-pyrrolidone or derivatives thereof. After the reactionis completed, the catalyst is filtered and recovered, cleaned and dried before reuse. The method can realize efficient conversion of the levulinic acid (ester) in a solvent-free system, the low-cost and environment-friendly urea or amide is taken as a N source, and the biomass formic acid is taken as a H source, so that the synthesis method has good economy.
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Paragraph 0030-0035; 0038-0046
(2019/10/15)
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- NHC-based coordination polymers as solid molecular catalysts for reductive amination of biomass levulinic acid
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A class of robust solid molecular NHC-based catalysts were readily fabricated via self-assembly from a p-phenylene-bridged bis-benzimidazolium salt with selected metal precursors. Among them, the NHC-Ru polymer demonstrated high catalytic activity and excellent stability as a solid molecular catalyst for the solvent-free reductive amination of biomass levulinic acid with inexpensive ammonium formate, furnishing a challenging unprotected 5-methyl-2-pyrrolidone quantitatively at a 0.15 mol% catalyst loading. The solid catalyst was readily recovered and reused for 37 runs without obvious loss of activity. Remarkably, a TON value up to 6.7 × 104 was achieved in a molar-scale reaction with a catalyst loading at 0.001 mol%. Inspired by the results of a preliminary mechanistic study, notably, one-pot tandem reductive reactions of LA with aldehydes or ketones were successfully developed, affording a variety of structurally intriguing and functional N-substituted 5-methyl-2-pyrrolidones in high chemo-selectivity with good to excellent yields.
- Sun, Zheming,Chen, Jiangbo,Tu, Tao
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supporting information
p. 789 - 794
(2017/08/18)
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- CARBAZOLE-CONTAINING AMIDES, CARBAMATES, AND UREAS AS CRYPTOCHROME MODULATORS
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The subject matter herein is directed to carbazole-containing amide, carbamate, and urea derivatives and pharmaceutically acceptable salts or hydrates thereof of structural formula I wherein the variable R1, R2, R3, R4, R5, R6, R7, A, D, E, G, J, L, M, Q, a, and b are accordingly described. Also provided are pharmaceutical compositions containing the compounds of formula I to treat a Cry-mediated disease or disorder, such as diabetes, complications associated with diabetes, Cushing's syndrome, NASH, NAFLD, asthma, and COPD.
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Paragraph 0366
(2015/10/28)
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- Oxidant-free conversion of cyclic amines to lactams and H2 using water as the oxygen atom source
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Direct conversion of cyclic amines to lactams utilizing water as the only reagent is catalyzed by pincer complex 2. In contrast to previously known methods of amine-to-amide conversion, this reaction occurs in the absence of oxidants and is accompanied by liberation of H2, with water serving as a source of oxygen atom. Formation of a cyclic hemiaminal intermediate plays a key role in enabling such reactivity. This represents an unprecedented, conceptually new type of amide formation reaction directly from amines and water under oxidant-free conditions.
- Khusnutdinova, Julia R.,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 2998 - 3001
(2014/03/21)
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- Ruthenium-catalyzed conversion of levulinic acid to pyrrolidines by reductive amination
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Combo deal: An aqueous solution of levulinic acid (LA) and formic acid (FA) derived from biomass-based carbohydrates can be converted efficiently to pyrrolidines via a ruthenium catalyst without need for an energy-intensive separation of LA or an external H2 source. The ruthenium catalyst combines two processes: decomposition of FA to H2 and reductive amination of LA with an amine. Copyright
- Huang, Yao-Bing,Dai, Jian-Jun,Deng, Xiao-Jian,Qu, Yan-Chao,Guo, Qing-Xiang,Fu, Yao
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experimental part
p. 1578 - 1581
(2012/03/22)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- First examples of intramolecular addition of primary amidyl radicals to olefins
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The first examples of intramolecular addition of primary amidyl radicals to olefins are described. Amidyl radicals were generated from N-(phenylthio)amides in refluxing benzene using a catalytic amount of 2,2′- azobis(isobutyronitrile) (5 mol%) and tributyltin hydride (sim;2.2 equiv.). The resulting yields of cyclic products ranged from 63% to 85%.
- Gaudreault, Philippe,Drouin, Christian,Lessard, Jean
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p. 543 - 545
(2007/10/03)
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- Production of 5-methyl-N-(methyl aryl)-2-pyrrolidone, 5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid esters with cyano compounds
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This invention relates to a process for producing 5-methyl-N-(methyl aryl)-2-pyrrolidone, 5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid esters with aryl or alkyl cyano compounds utilizing a metal catalyst, which is optionally supported.
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- Production of 5-mehyl-N-aryl-2-pyrrolidone and 5-methyl-N-alkyl-2-pyrrolidone by reductive of levulinic acid esters with aryl and alkyl amines
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This invention relates to a process for producing 5-methyl-N-aryl-2-pyrrolidone, 5-methyl-N-alkyl-2-pyrrolidone, and 5-methyl-N-cycloalkyl-2-pyrrolidone by reductive amination of levulinic acid esters with aryl or alkyl amines utilizing a metal catalyst, which is optionally supported.
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- Production of 5-methyl-1-hydrocarbyl-2-pyrrolidone by reductive amination of levulinic acid
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This invention relates to a process for producing 5-methyl-1-R-2-pyrrolidone or 5-methyl-2-pyrrolidone, wherein R is a hydrocarbyl or substituted hydrocarbyl, by reductive amination of levulinic acid utilizing a metal catalyst, which may be optionally supported.
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- Evaluation of pyrrolidin-2-imines and 1,3-thiazolidin-2-imines as inhibitors of nitric oxide synthase
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Syntheses and evaluation of pyrrolidin-2-imines and 1,3-thiazolidin-2- imines as inhibitors of nitric oxide synthase (NOS) are discussed. An extensive SAR was established for pyrrolidin-2-imines class of compounds. The amidines came out as the most potent inhibitors in addition to displaying selectivity.
- Shankaran,Donnelly, Karla L.,Shah, Shrenik K.,Guthikonda, Ravindra N.,MacCoss, Malcolm,Humes, John L.,Pacholok, Stephen G.,Grant, Stephan K.,Kelly,Wong
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p. 4539 - 4544
(2007/10/03)
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- Stereoselective alkylation of N-Boc-2-pyrrolidinones and N-Boc-2- piperidinones. Synthesis and characterization of disubstituted lactams
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Alkylation of enolates of monosubstituted N-Boc lactams 4-6 afforded trans-disubstituted lactams as the major isomer. In the pyrrolidinone series, 1,3-induction seems to be ruled by steric interactions and the diastereoselection is low for the alkylation of enolates with small substituents at C-5 (e.g., Me) and methyl iodide. The trans selectivity improves with bulkier substituents at C-2 and/or bulkier electrophiles. The formation of 3,6-trans-disubstituted piperidinones benefits from the axial orientation of the substituent at C-2 due to the A strain with the N-Boc group and excellent trans preference is observed even in the alkylation of the lithium enolate of N-Boc-6-methyl piperidinone with methyl iodide.
- Maldaner, Adriano O.,Pilli, Ronaldo A.
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p. 13321 - 13332
(2007/10/03)
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- SUBSTITUTION OF 3H-FURAN-2-ONES IN AMINATION AND HYDROAMINATION REACTIONS
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The amination and hydroamination of 5-alkyl-3H-furan-2-ones and their 3-benzylidene- and 3-formyl-derivatives were studied.The characteristics of the reactions, the requirements for the nature of the nucleophilic reagents, and the reaction conditions leading to the destruction of the furan ring and recyclization to pyrrolidinone and pyrrolinone structures are indicated.
- Morozova, N. A.,Sedavkina, V. A.,Egorova, A. Yu.
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p. 308 - 311
(2007/10/02)
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- Enzymatic formation of lactams in organic solvents
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Porcine pancreatic lipase in organic solvents catalyses the intramolecular cyclisation of aminoesters and the formation of macrocyclic bislactams from diesters and diamines.
- Gutman, Arie L.,Meyer, Elazar,Yue, Xu,Abell, Chris
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p. 3943 - 3946
(2007/10/02)
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin or hair for inducing, maintaining or increasing hair growth comprises: (i) a first chemical inhibitor chosen from proteoglycanase inhibitors, glycosaminoglycanase inhibitors, glycosaminoglycan chain cellular uptake inhibitors or mixtures thereof; and (ii) a cosmetically acceptable vehicle for the chemical inhibitor; provided that when the first chemical inhibitor is a weak inhibitor, such that a 1 mM aqueous solution of the inhibitor reduces proteoglycanase activity, glycosaminoglycanase activity or cellular uptake of glycosaminoglycan chains, by from 5 to 50%, in accordance with at least one of the assay tests as herein described, then there is also present in the composition a second chemical inhibitor and/or an activity enhancer. When minoxidil is the sole chemical inhibitor, then the activity enhancer is a penetration enhancer chosen from a limited number of materials, including certain esters and cationic polymers. The total amount of chemical inhibitor present in the composition is sufficient to increase hair growth in the rat, when said composition is applied topically thereto, by at least 10% more than that obtainable using a control composition from which the said inhibitors have been omitted.
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- Cobalt-Catalyzed Photochemical Carbonylation of Allylic Amines
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Allylic amines are carbonylated at room temperature in the presence of cobalt catalysts under UV irradiation.With allylamine, 2-pyrrolidone, N,N'-diallylurea, and N-allyl-3-butenamide were obtained.The photochemical cleavage of C-N bond of amines coordinated to cobalt metals was suggested.
- Mori, Sadayuki,Matsuyoshi, Hiroaki,Kudo, Kiyoshi,Sugita, Nobuyuki
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p. 1397 - 1400
(2007/10/02)
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- STEREOSELECTIVE FORMAL SYNTHESIS OF (+/-)-MONOMORINE I FROM 6-METHYL-2-PIPERIDINONE
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The stereoselective formal synthesis of (+/-)-monomorine I from 6-methyl-2-piperidinone was achieved.A general method for the synthesis of ω-alkylated lactams is also described.
- Nagasaka, Tatsuo,Kato, Hiroki,Hayashi, Hideki,Shioda, Masako,Hikasa, Hiromi,Hamaguchi, Fumiko
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p. 561 - 566
(2007/10/02)
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- APPLICATIONS OF THE THERMAL ENE REACTION OF ALDEHYDE t-BUTYL- AND PHENYL- HYDRAZONES
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The Thermal Ene reaction of aldehyde t-butyl- and phenyl- hydrazones with enophiles gave C-trapped azo-adducts which can be diverted into synthetically useful γ-keto-esters, γ-keto-nitriles, γ-alkyl-2-pyrrolidones, and γ-amino-esters.
- Baldwin, Jack E.,Adlington, Robert M.,Jain, Ashok U.,Kolhe, Jayant N.,Perry, Matthew W. D.
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p. 4247 - 4252
(2007/10/02)
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- Michael Additions of Hydrazones for Carbon-Carbon Bond Formation
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The lithium salts of t-butyl- and trityl-hydrazones react with methyl crotonate to form C-trapped azo-esters and similar products were observed from a thermal ene-reaction of aldehyde t-butylhydrazones with methyl acrylate or acrylonitrile, and aldehyde phenylhydrazones with methyl acrylate; these products can be diverted into synthetically useful γ-keto-esters, γ-keto-nitriles, saturated esters, γ-alkyl-2-pyrrrolidones, and γ-amino-esters.
- Baldwin, Jack E.,Adlington, Robert M.,Bottaro, Jeffrey C.,Jain, Ashok U.,Kolhe, Jayant N.,et al.
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p. 1095 - 1096
(2007/10/02)
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- A GENERAL PROCEDURE FOR MILD AND RAPID REDUCTION OF ALIPHATIC AND AROMATIC NITRO COMPOUNDS USING AMMONIUM FORMATE AS A CATALYTIC HYDROGEN TRANSFER AGENT
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Various aliphatic and aromatic nitro compounds were selectively and rapidly reduced to their corresponding amino derivatives in very good yield using anhydrous ammonium formate as a catalytic hydrogen transfer agent.
- Ram, Siya,Ehrenkaufer, Richard E.
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p. 3415 - 3418
(2007/10/02)
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- The photochemical addition of N-haloamides to olefins: the influence of various factors on the competition between 1,2-addition and hydrogen abstraction
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In the photodecomposition of N-haloamides (ZCONRX) in the presence of olefins, the 1,2-addition chain competes with the hydrogen abstraction chain(s) leading to the parent amide (the quantum yields for these processes are greater than unity).The following factors were shown to have an influence on this competition as measured by the yield of 1,2-addition and the yield of parent amide in methylene chloride solutions: (i) the N-halogen (higher yields of addition with X=Cl than with X=Br); (ii) the electronegativity of Z (increase of the yield of addition as the electronegativity of Z increases); (iii) the temperature (higher yields of addition at lower temperatures, and at -70 degC, better yields of addition (>90percent, R=H) for X=Br than for X=Cl); and (iv) the size of R (dramatic decrease of the yield of 1,2-addition in going from R=H to R=CH3).Surprisingly, the presence of a scavenger for HX had no influence on the yield of 1,2-addition.Both the size and electronegativity of Z had an effect on the stereochemistry of 1,2-addition to cyclohexene.High yields of addition to a variety of olefins were obtained with N-chloroamides such as ClCH2CONHCl, C2H5OCONHCl, CF3CONHCl.Their addition to enol ethers at -70 degC led to the synthesis of α-amido acetals or ketals (aldehydes or ketones) and to an α-amido glycoside in good yields.
- Lessard, Jean,Mondon, Martine,Touchard, Daniel
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p. 431 - 450
(2007/10/02)
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- FACILE SYNTHESIS OF γ-, δ-, AND ε-LACTAMS BY CYCLODEHYDRATION OF ο-AMINO ACIDS ON ALUMINA OR SILICA GEL
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It has been found that γ-, δ-, and ε-amino acids cyclodehydrate easily to their corresponding lactams by the action of alumina or silica gel in boiling toluene.
- Blade-Font, Artur
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p. 2443 - 2446
(2007/10/02)
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