Highly enantioselective α-sulfenylation of 5H-oxazol-4-ones to N-(sulfanyl)succinimides

An unprecedented asymmetric α-sulfenylation of 5H-oxazol-4-ones to N-(sulfanyl)succinimides has been established, to access various α-sulfenylated adducts with good to excellent enantioselectivities (86–95% ee) by utilizing a cinchona alkaloid-derived squaramide as catalyst. The conditions of this α-sulfenylation protocol simultaneously satisfy N-(arylthio)succinimides, N-(benzylthio)succinimides, and N-(alkylthio)succinimides by tuning the substituted groups of 5H-oxazol-4-ones on the 2-position as well as additives.     

Die Massenspektren substituierter Succinimide

The mass spectra of succinimide, four monosubstituted and ten disubstituted saturated succinimides and six unsaturated ( = ethylidene substituted) succinimides are recorded and interpreted. Fragmentation schemes are derived which permit the identification of unknown substituted succinimides obtained by degradation of natural pyrrole pigments.     

Synthesis,X-Ray Crystallography,and Reactions of N-Acyl and N-Carbamoyl Succinimides

A collection of N-acyl and N-carbamoyl succinimides were prepared by acylation of succinimide with acyl chlorides or by ethylene dichloride (EDC) coupling of carboxylic acids. The x-ray crystal structures of N-benzoyl and N-p-nitrobenzoyl succinimides were determined. The N-acyl succinimides were effective in acylating primary amines, a secondary amine, and an aromatic amine.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

环状酰亚胺不对称还原烷基化的一些结果

苹果酰亚胺的不对称还原烷基化是合成γ-内酰胺的有效方法,为扩大该法的应用范围,本文研究了多种环状酰亚胺的还原烷基化反应。探讨了影响还原烷基化反应的因素并提出相关的解释。总结出3-取代和3,4-二取代琥珀酰亚胺可成功地进行还原烷基化的规律,并提出了相应的解释。     

A regioselective reduction of gem-disubstituted succinimides

The NaBH₄ reduction of mono- and disubstituted succinimides in the presence of hydrochloric acid leading to ω-carbinol-lactams shows a remarkable regio- and/or stereo-selectivity. The reduction takes place at the most substituted CO in the succinimides. Possible explanations are reviewed. The preparative value of the method is amply illustrated.     

DABCO/AgOAc cooperatively catalyzed α-sulfenylation of isocyanoacetates with N-(sulfanyl)succinimides

The first organo/metal cooperatively catalyzed α-sulfenylation of isocyanoacetates with N-(sulfanyl)succinimides has been developed. The reaction condition was suitable to α-aryl and alkyl-substituted isocyanoactates as well as N-(arylthio)succinimides, affording the corresponding products with high yields (90–96%). Preliminary asymmetric organocatalysis has also been evaluated.     

Spiro cyclisations of N-acyliminium ions involving an aromatic π-nucleophile

Spiro 2-pyrrolidin-5-ones were obtained from N-substituted succinimides by a two-step procedure, involving 5- or 6-endo-trig cyclisation of N-acyliminium ion intermediates with a tethered aromatic π-nucleophile.     

Simple and efficient synthesis of N-alkyl and N-aryl succinimides in hot water

A new, simple synthesis of succinimides is described. The reactions were carried out under the ultimate green conditions excluding both catalyst and organic solvent by applying simple stirring at 100?°C. A wide variety of N-susbstituted succinimides have been prepared in high yields by using succinic acid and primary amines in hot water. Yield of N-alkyl substituted succinimides were found to be higher than those of N-aryl substituted succinimides.     

Cyclization of a cysteine conjugate of N-(3,5-Dichlorophenyl)succinimide

N-(3,5-Dichlorophenyl)-2-cysteinylsuccinimide methyl ester hydrochloride ( 5 ) was prepared from N-(3,5-dichlorophenyl)maleimide ( 3 ) and cysteinyl methyl ester hydrochloride. Attempted neutralization of the cysteine conjugate salt with triethylamine resulted in spontaneous cyclization of 5 to form the more stable 2-(N-3,5-dichlorophenylcarbamoylmethyl)-5-carbomethoxy-1,4-thiazine- 3-one ( 6 ). Similar results might be expected in vivo should these metabolites of succinimides be formed.     

Ring-Opening 1,3-Aminochalcogenation of Donor–Acceptor Cyclopropanes: A Three-Component Approach

A 1,3-aminothiolation was realized by reacting 2-substituted cyclopropane 1,1-dicarboxylates with sulfonamides and N-(arylthio)succinimides. Under Sn(OTf)₂ catalysis the transformation proceeded smoothly to the corresponding ring-opened products bearing the sulfonamide in the 1-position next to the donor and the arylthio residue in the 3-position next to the acceptor. The procedure was extended to the corresponding selenium analogues by employing N-(phenylseleno)succinimides as an electrophilic selenium source.     

Peptide-Catalyzed Stereoselective Conjugate Addition Reaction of Aldehydes to C-Substituted Maleimides

Catalytic stereoselective additions with maleimides are useful one-step reactions to yield chiral succinimides, molecules that are widespread among therapeutically active compounds but challenging to prepare when the maleimide is C-substituted. We present the tripeptide H-Pro-Pro-Asp-NHC₁₂H₂₅ as a catalyst for conjugate addition reactions between aldehydes and C-substituted maleimides to form succinimides with three contiguous stereogenic centers in high yields and stereoselectivities. The peptidic catalyst is so chemoselective that no protecting group is needed at the imide nitrogen of the maleimides. Derivatization of the succinimides was straightforward and provided access to chiral pyrrolidines, lactones, and lactams. Kinetic studies, including a Hammett plot, provided detailed insight into the reaction mechanism.     

Relationship between enantioselectivity and solute structure on a chiral α1-acid glycoprotein column

Summary The relationship between the enantioselectivity, the retention and the solute structure for N-aminoalkylsuccinimides and 1-alkyl-2′,6′-pipecoloxylidides have been studied using α₁-acid glycoprotein as the chiral stationary phase. Both the enantioselectivity and the retention are highly affected by small changes of the solute structure in series of homologous compounds. For example, increasing the steric bulk on a basic aliphatic nitrogen improves the enantioselectivity. It was also demonstrated for the succinimides that the magnitude of the separation factor was highly affected by the distance between the basic nitrogen and the chiral center. The chiral selectivity was not lost for the succinimides despite the fact that the basic nitrogen was separated from the chiral center with seven atoms, which may be an effect of that these compounds contain more than one strong hydrogen bonding group. Substitution in the aromatic ring of the succinimides also influences both the retention and the chiral selectivity to a large extent. Electronegative substituents can increase the separation factor but introduction of an alkyl or an alkoxy group in the aromatic ring decreases the enantioselectivity for the succinimides.     

NHC‐Catalyzed Asymmetric Synthesis of Functionalized Succinimides from Enals and α‐Ketoamides

The efficient asymmetric synthesis of highly substituted succinimides from α,β‐unsaturated aldehydes and α‐ketoamides via NHC‐catalyzed [3+2] cycloaddition has been developed. The new scalable protocol significantly expands the utility of NHC catalysis for the synthesis of heterocycles and provides easy access to assemble a wide range of succinimides from simple starting materials.     

An efficient synthesis of 3-(guaiazulene-1-yl)succinimides by addition of guaiazulene to maleimides

A facile,efficient synthesis of 3-(guaiazulen-1-yl)succinimides was developed by Michael-type addition of guaiazulene to maleimides in the presence of p-toluenesulfonic acid under mild reaction conditions.     

ArylationofN－VinylsuccinimideandPreparationof2－Arylethylamines

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Direct organocatalytic synthesis of enantiopure succinimides from beta-lactam aldehydes through ring expansion promoted by azolium salt precatalysts

A single-step catalytic ring expansion approach from 4-oxoazetidine-2-carbaldehydes to enantiopure succinimides has been achieved by the use of a base (DBU) and a thiazolium salt precatalyst.     

Studies on pyrrolidinones. Oxidations and rearrangements in the hexahydrobenz[f]indolizine-3,10-dione series

Air oxidation of hexahydrobenz[f]indolizine-3,10-diones in MeOH/MeONa yields alcohols, which are easily and selectively transformed, in very good yields, to succinimides, isoquinoline propanoic acids or dehydrated to ene lactams.     

l-Isoleucine-catalyzed Michael Synthesis of N-Alkylsuccinimide Derivatives and Their Antioxidant Activity Assessment

Russian Journal of Organic Chemistry - N-Substituted succinimides having different alkyl groups were prepared by the reaction of N-substituted maleimide with aldehydes. A two-component catalyst...     

Highly enantioselective Michael addition of α,α-disubstituted aldehydes to maleimides catalyzed by new primary amine-squaramide bifunctional organocatalysts

New bifunctional primary amine-squaramides catalyzed asymmetric Michael addition reaction of α,α-disubstituted aldehydes to maleimides has been developed. This organocatalytic asymmetric reaction provides easy access to functionalized succinimides with a broad substrate scope. Both enantiomers of desired succinimide derivatives were obtained in good to excellent yields (up to 98%) with excellent enantioselectivities (up to >99%?ee).     

Enantioselective synthesis of enol lactones from tandem Michael addition/lactonization catalyzed by a chiral squaramide catalyst

The enantioselective tandem Michael addition reaction of dimedone and related 1,3-dicarbonyl compounds with α,β-unsaturated N-acylated succinimides catalyzed by a chiral squaramide catalyst has been investigated. This reaction provides a new approach for the synthesis of chiral enol lactones in good yields with moderate to high enantioselectivities (up to 88% ee) through the enantioselective Michael addition followed by lactonization and removal of the succinimide auxiliary.