108-27-0Relevant articles and documents
Synthesis of γ-Lactams by Mild, o-Benzoquinone-Induced Oxidation of Pyrrolidines Containing Oxidation-Sensitive Functional Groups
Rong, Hao-Jie,Cheng, Yong-Feng,Liu, Fan-Fan,Ren, Shu-Jian,Qu, Jin
, p. 532 - 540 (2017)
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.
Raney-Ni catalyzed conversion of levulinic acid to 5-methyl-2-pyrrolidone using ammonium formate as the H and N source
Amarasekara, Ananda S.,Lawrence, Yen Maroney
, p. 1832 - 1835 (2018)
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.
Synthetic Utility of N-Benzoyloxyamides as an Alternative Precursor of Acylnitrenoids for γ-Lactam Formation
Huh, Soohee,Hong, Seung Youn,Chang, Sukbok
, p. 2808 - 2812 (2019)
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.
Tropylium-promoted Ritter reactions
Doan, Son H.,Hussein, Mohanad A.,Nguyen, Thanh Vinh
supporting information, p. 8901 - 8904 (2021/09/10)
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.
Ammonia borane enabled upgrading of biomass derivatives at room temperature
Meier, Sebastian,Riisager, Anders,Yang, Song,Zhao, Wenfeng
supporting information, p. 5972 - 5977 (2020/11/03)
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
Continuous flow synthesis of amines from the cascade reactions of nitriles and carbonyl-containing compounds promoted by Pt-modified titania catalysts
Altu?, Cevher,Mu?oz-Batista, Mario J.,Rodríguez-Padrón, Daily,Balu, Alina M.,Romero, Antonio A.,Luque, Rafael
, p. 300 - 306 (2019/01/28)
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.
