2019-72-9Relevant academic research and scientific papers
Synthesis of 1,3,2-oxazaphospholidin-4-ones
Totschnig, Klaus,Ellmerer-Mueller, Ernst P.,Peringer, Paul
, p. 173 - 177 (1996)
The subject of this paper is the preparation of 1,3,2-oxazaphospholidin-4-ones by reaction of phenyldichlorophosphine with the N-methyl amides of α-hydroxy isobutyric acid and the two chiral carboxylic acids (S) lactic acid and (R,S) mandelic acid, which leads to diastereomeric products. Reaction control by means of 31P n.m.r. demonstrates two surprising findings: the preferred generation of the thermodynamically less stable cis-isomer and an epimerization of the phosphorus chirality centre at room temperature.
155. N-Methyl-C-(trichlortitanio)formimidoylchlorid. Ein effizientes Reagenz zur Homologisierung von Aldehyden und Ketonen zu α-Hydroxy-carbonsaeureamiden
Schiess, Martin,Seebach, Dieter
, p. 1618 - 1623 (1983)
The known title compound 6 formed by addition of titanium tetrachloride to methyl isocyanide in methylene chloride adds to the carbonyl group of aldehydes and ketones.The adducts 7 are hydrolized to N-methyl-α-hydroxycarboxamides 8 which are (from ketones) or are not branched (from aldehydes) in the α-position.The yields in this new modification of the Passerini reaction are near 90percent, also with readily enolized ketones such as acetone and acetophenone.In contrast to the previously used organotitanium reagents of the type RTiX3, the preparation of the reagent 6 does not require any Li-, Mg- or Zn-derivative as a precursor.
Method for synthesizing chiral alpha-hydroxy amide by catalyzing prochiral alpha-keto-amide
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Paragraph 0097; 0098; 0099, (2017/12/28)
The invention provides a novel method for preparing chiral alpha-hydroxy amide through asymmetric hydrogenation of pro-chiral alpha-keto-amide using a novel tridentate nitrogen phosphine ligand to prepare a series of chiral alpha-hydroxy amide compounds.
Selective α-Oxyamination and Hydroxylation of Aliphatic Amides
Li, Xinwei,Lin, Fengguirong,Huang, Kaimeng,Wei, Jialiang,Li, Xinyao,Wang, Xiaoyang,Geng, Xiaoyu,Jiao, Ning
, p. 12307 - 12311 (2017/09/11)
Compared to the α-functionalization of aldehydes, ketones, even esters, the direct α-modification of amides is still a challenge because of the low acidity of α-CH groups. The α-functionalization of N?H (primary and secondary) amides, containing both an unactived α-C?H bond and a competitively active N?H bond, remains elusive. Shown herein is the general and efficient oxidative α-oxyamination and hydroxylation of aliphatic amides including secondary N?H amides. This transition-metal-free chemistry with high chemoselectivity provides an efficient approach to α-hydroxy amides. This oxidative protocol significantly enables the selective functionalization of inert α-C?H bonds with the complete preservation of active N?H bond.
The 2 - hydroxy malonic cyanogen synthesis method of α - hydroxy amide
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Paragraph 0014; 0015; 0016, (2016/10/10)
The invention relates to synthesis of alpha-oxyamide through reaction of 2-hydroxy propylene cyanide as well as corresponding aldehyde or ketone and amine, which mainly solves the problems that the preparation of common alpha-oxyamide has a plurality of reaction steps, the reaction operation is complicated, the reaction cost is high, the post treatment is a trouble, and the like. According to the method, 2-hydroxy propylene cyanide as well as corresponding aldehyde or ketone and amine are directly mixed, methanol or acetonitrile is taken as the solvent, and the product can be obtained by stirring for 10-120 minutes. The method for synthesizing alpha-oxyamide is safe and efficient.
Ru-catalyzed highly enantioselective hydrogenation of α-keto Weinreb amides
Zhao, Meng Meng,Li, Wan Fang,Ma, Xin,Fan, Wei Zheng,Tao, Xiao Ming,Li, Xiao Ming,Xie, Xiao Min,Zhang, Zhao Guo
, p. 342 - 348 (2013/07/26)
Asymmetric hydrogenation of α-keto Weinreb amides has been realized with [Ru((S)-Sunphos)(benzene)Cl]Cl as the catalyst and CeCl3· 7H2O as the additive. A series of enantiopure α-hydroxy Weinreb amides (up to 97% ee) have been obtained. Catalytic amount of CeCl 3·7H2O is essential for the high reactivity and enantioselectivity and the ratio of CeCl3·7H2O to [Ru((S)-Sunphos)(benzene)Cl]Cl plays an important role in the hydrogenation reaction.
β-Lactam-Forming Photochemical Reactions of N-Trimethylsilylmethyl- and N-Tributylstannylmethyl-Substituted α-Ketoamides
Wang, Runtang,Chen, Chuanfeng,Duesler, Eileen,Mariano, Patrick S.,Yoon, Ung Chan
, p. 1215 - 1220 (2007/10/03)
Two mechanisms have been proposed for the β-lactam-forming photochemical reactions of α-ketoamides. One, suggested by Aoyama, involves excited-state H-atom abstraction while the other, put forth by Whitten, follows a sequential SET-proton-transfer route. The photochemical properties of N-trimethylsilylmethyl- and N-tributylstannylmethyl-substituted α-ketoamides were explored in order to gain information about the mechanism of this process and to develop a regioselective method for β-lactam formation. The results of this effort show that (1) photoreactions of N-trimethyl-silylmethyl-substituted α-ketoamides proceed by competitive H-atom abstraction and sequential SET-desilylation pathways and (2) a sequential SET-destannylation pathway is preferentially followed in photochemical reactions of the tributylstannylmethyl-substituted α-ketoamides.
Base catalysed rearrangement of N-alkyl-O-acyl hydroxamic acids: Synthesis of 2-acyloxyamides
Clark, Andrew J.,Al-Faiyz, Yassair S.S.,Broadhurst, Michael J.,Patel, Divya,Peacock, Joanne L.
, p. 1117 - 1127 (2007/10/03)
Activated N-alkyl-O-acyl hydroxamic acid derivatives 21a-t undergo thermal and base catalysed rearrangement to give 2-acyloxyamides 22a-t in good to excellent yields (50-100%). A range of inorganic and organic bases were screened for their efficiency in mediating the rearrangement 21 to 22, however, simple organic bases such as Et3N were found to be the most efficient. Both aromatic and aliphatic derived O-acyl groups were tolerated in the reaction. The electronic nature of the O-acyl group was found to effect the rate of the rearrangement with electron withdrawing groups (211 and 21o) increasing the observed rate and electron donating groups (21m and 21n) decreasing the observed rate. Cross-over experiments with 21a and 21h indicated a mechanism involving the intermediacy of free acyloxy anions. The requirement of a readily enolisable proton adjacent to the carbonyl group of the amide was found to be neccessary for the rearrangement as 21r and 21t both failed to rearrange under the reaction conditions investigated.
Base-Promoted Reaction of O-Sulfonylated Hydroxamic Acids with Nucleophiles. A New Mehtod for the Synthesis of α-Substituted Amides
Hoffman, Ribert V.,Nayyar, Naresh K.,Chen, Wenting
, p. 5700 - 5707 (2007/10/02)
Treatment of a series of hydroxamic acids 2 with mesyl chloride in the presence of 2 equiv of triethylamine at 0 deg C gives 2-chloroamides 3 in good yields.Use of a single equivalent of triethylamine gives the N-(mesyloxy)amides 1, which are versatile sy
