Efficient Synthesis of Novel Coumarin‐3‐carboxamides (=2‐Oxo‐2H‐1‐benzopyran‐3‐carboxamides) Containing Lipophilic Spacers

The novel coumarin‐3‐carboxamides (=2‐oxo‐2H‐1‐benzopyran‐3‐carboxamides) 5a – 5g containing lipophilic spacers were synthesized through the Ugi‐four‐component reaction (Scheme 1). The reactions of aromatic aldehydes 1 , 4,4′‐oxybis[benzenamine] or 4,4′‐methylenebis[benzenamine] as diamine 2 , coumarin‐3‐carboxylic acid (=2‐oxo‐2H‐benzopyran‐3‐carboxylic acid; 3 ), and alkyl isocyanides 4 lead to the desired substituted coumarin‐3‐carboxamides 5a – 5g at room temperature with high bond‐forming efficiency. These novel coumarin derivatives exhibit brilliant fluorescence at 544 nm in CHCl₃.     

An Efficient Approach to the Synthesis of Hydrazinyl Pseudo‐Peptides

New hydrazinyl pseudo‐peptides have been obtained from Ugi four‐component reaction (4CR). The 5‐hydrazinyl‐5‐oxopentanoic acids used as starting materials were prepared by the reaction of hydrazides with anhydrides. Mild reaction conditions, high atom economy, bond‐forming efficiency, and easy workup are advantages of this approach. The products have four amide bonds and high potential for H‐bonding.     

Synthesis of diverse phenylglycine derivatives via transformation of Ugi four-component condensation primary adducts

3-(N-Substituted)amino-4-arylamino-1H-isochromenones (isocoumarins) which can be regarded as the enediamine tautomers of the Ugi four-component condensation primary adducts between 2-formylbenzoic acids, arylamines, and isocyanides undergo a facile ring cleavage with amines to give a series of phenylglycine derivatives. Thus, a synthetically useful post-condensation transformation of Ugi four-component condensation primary adducts is described for the first time.     

Synthesis of peptidomimetic-spirostane hybrids via Ugi reaction: a versatile approach for the formation of peptide-steroid conjugates

A general approach towards the preparation of peptide-steroid conjugates has been addressed. Utilizing the Ugi reaction, five peptidomimetic-steroid hybrids were achieved in good to excellent yields from carboxy- and amino-spirostanes and mono-protected α-amino acids. Diverse synthetic routes, specially focused on the formation of secosteroids, were implemented to introduce Ugi-type functionalities at different positions of the steroidal nucleus. This versatile approach is suitable for the formation of stable conjugates of steroids with other biologically relevant molecules.     

Recent trends in the design of antimicrobial agents using Ugi-multicomponent reaction

Multi-drug resistant (MDR) forms of several bacteria, fungi, viruses, and parasites pose a serious challenge to human health and economy. Hence, the rise of antimicrobial resistance (AMR) requires the expedient discovery of novel antimicrobial agents with a unique mode of action. Ugi multicomponent reaction (Ugi-MCR) and its variants have proved to be an important tool in the hand of a medicinal chemist. Traditional Ugi reaction provides one-step access to peptide-like molecules. However, several modifications of Ugi products are now available, enabling the design of diverse molecular scaffolds. This has tremendously expanded the scope of Ugi-MCR in drug discovery. This review focuses on the recently reported application of Ugi reaction in the design of molecules against important pathogenic microbes and parasites. The design, synthesis, and bioactivities of important lead molecules from the literature is discussed. Towards the end, we also provide our perspective highlighting the overall trends in Ugi-MCR enabled antimicrobial drug design and future prospects.     

Rhodium-catalyzed multicomponent synthesis of chiral oxazolopiperidines

A multicomponent reaction that employs an unsaturated carboxylic acid, a 1,2 or 1,3 amino alcohol and gaseous CO and H₂ has been discovered. Thus, hydrocarbonylation of the carboxylic acid double bond generates a linear aldehyde, that is, immediately transformed into an oxazolidine. Further microwave assisted intramolecular lactamization delivers oxazolopiperidines with the generation of six new bonds in a one-pot single step. Bicylic, tricyclic, tetracyclic, and spirocyclic oxazolopiperidines can be prepared in good yields and acceptable stereoselection. The reaction did not occur under conventional heating even at higher temperature and pressure and for longer time, showing that microwave heating is indispensable to the process.     

Straightforward stereoselective synthesis of polyfunctionalised cyclohexenols using a multicomponent approach

An intramolecular Ugi 5-centre-4-component reaction (U-5C-4CR) followed by a palladium-catalysed ring-opening has been employed to transform oxabicycloheptene-based β-amino acids into two families of regioisomeric polyfunctionalised cyclohexenols. The whole process is completely stereoselective and enantiomerically pure products are obtained in high overall yields.     

One-pot four-component synthesis of 4-hydrazinothiazoles: novel scaffolds for drug discovery

One pot ring synthesis of novel 4-hydrazinothiazoles through sequential four-component route employing carbonyl compounds, aminoguanidine, isothiocyanates, and α-haloketones was accomplished under mild reaction conditions. Base-assisted eliminative aromatization in the [4+1] ring synthesis shed light on interesting leaving group propensities of amine versus hydrazine resulting in the exclusive formation of the title compounds with immense potential as scaffolds for drug discovery. Hydrazone deprotection was effected by acylation which subsequently provided a new set of diacylated molecular systems with a wider scope as chemical handles in the design of thiazolyl drug candidates.     

Synthesis of 3,5-Dichloro-4-(1,1,2,2-tetrafluoroethoxy)phenyl Containing 1,2,3-Thiadiazole Derivatives via Ugi Reaction and Their Biological Activities

A series of novel 3,5‐dichloro‐4‐(1,1,2,2‐tetrafluoroethoxy)phenyl containing 4‐methyl‐1,2,3‐thiadiazole derivatives were designed and synthesized via Ugi reaction. Their structures were confirmed by IR, ¹H NMR, ¹³C NMR and high‐resolution mass spectroscopy. The preliminary bioassay results indicated that some title compounds had good fungicide activity at 50 µg/mL; most of the compounds presented a certain degree of direct inhibition activity, good inactivation and curative activity against tobacco mosaic virus at 500 µg/mL and 100 µg/mL; some compounds showed good larvicidal activity against Plutella xylostella L. at 200 µg/mL and excellent larvicidal activities against Culex pipiens pallens at 2 µg/mL.     

First Diastereoselective PasseriniSmiles and UgiSmiles Reactions Using Chiral Aldehydes

A diastereoselective O/N‐arylative Passerini/Ugi reaction of chiral aldehydes with commercially available isocyanides affording O‐aryl amides and N‐aryl amides, respectively, as products in moderate to good yields, together with de values, is reported.     

U-4C-3CR versus U-5C-4CR and stereochemical outcomes using suitable bicyclic β-amino acid derivatives as bifunctional components in the Ugi reaction

Intramolecular Ugi reactions with bicyclic β-amino acids have been performed and the effects of the configuration and N-alkylation have been studied. We have proven that preferential ring contraction or nucleophilic attack by the solvent depend not only on the presence of N-alkylation but also on the relative disposition of the carboxyl group and the amine. Excellent results in terms of stereoselectivity have been obtained in the case of N-alkyl-3-exo-amino-7-oxabicyclo[2.2.1]-2-endo-carboxylic acids.     

Fluorous Synthesis of Biaryl-Substituted Proline Analogs by 1,3-Dipolar Cycloaddition and Suzuki Coupling Reactions

A solution-phase synthesis of bicyclic prolines containing four points of diversity has been developed by a two-step synthesis involving 1,3-dipolar cycloaddition of perfluoroalkylsulfonyl-protected hydroxybenzaldehydes followed by Pd-catalyzed Suzuki coupling reaction of fluorous sulfonates with boronic acids. Both reactions are conducted under microwave irradiation and reaction mixtures are purified by solid-phase extractions without performing chromatography.     

Studies on the Synthesis of a Natural Product—Piceatannol and its Analogs

Piceatannol,(E)-3,3′,4,5′-tetrahydroxy stilbene, a natural polyhydroxy stibene, possesses many biological activities, its synthesis has been reported. We designed another route of its synthesis, which can be controlled more easily. The synthetic product was characterized by elemental analysis,IR,MS and ^1H-NMR. Its analogs were synthesized by the similar method.     

脂蛋白脂酶激活剂艾溴利平类似物的合成

合成了两个新型的艾溴利平类似物——N-2 -硝基-4-氯苯基-4-[(膦酸二乙酯基)甲基]苯甲酰肼(5,总收率28.1％)和N-2-四氮唑基-4-氯苯基-4-[(膦酸二乙酯基)甲基]苯甲酰胺(7,总收率30.5％).以对氯甲基苯甲酸为原料,经酯化、水解和酰氯反应制得中间体4-[(膦酸二乙酯基)甲基]苯甲酰氯(4);4与2-硝基-4-氯苯肼盐酸盐反应合成了5.4先与2-氨基-5-氯苯腈反应制得N-2-氰基-4-氯苯基-4-[(膦酸二乙酯基)甲基]苯甲酰胺(6);6再与叠氮化钠反应合成了7.其结构经1 H NMR和IR表征.     

Synthesis of Analogs of Phosphoamino Acids and their Biomimic Reactions

Previ0uslyitwasf0undthatphosph0amin0acidscouldstimulatemanyinterestingbioorganicreacti0nsI-3.In0rderfurthert0confirmthesignificanceofph0sphorusinbiochemistry,tw0m0delcomp0unds,anal0gue0fphosphorylaminoacidsc0ntainingP-Cbondandphosphorylglucoaminoacids,weresynthesized.Theirreacti0nswithalcoholandamin0acidwerealsoinvestigatedbyNMRandMSmeth0ds.Theresultsindicatedthatthereactioncharacteristicsofphosphorylbio1ogicalsmallmoleculesweredependentonthe'configuration,functiongroupsandpositions.(O,O-b…     

One-pot synthesis of α-acyloxyaminoamides via nitrones as imine surrogates in the Ugi MCR

α-acyloxyaminoamides can be prepared, with yields ranging from fair to very good (up to 89%), through an Ugi four component reaction by mixing a carbonyl component, a carboxylic acid, an isocyanide and an N-alkylated hydroxylamine in methanol. Preformed nitrones furnish the same final compounds with comparable yields.     

Novel Four‐Component Approach for the Synthesis of Polyfunctionalized 1,4‐Dihydropyridines in Aqueous Media

The four‐component reaction of dimethyl acetylenedicarboxylate (=dimethyl but‐2‐ynedioate; DMAD), aromatic aldehydes, and malononitrile (=propanedinitrile) leads to polyfunctionalized 1,4‐dihydropyridine derivatives. The reaction proceeds at room temperature and in the presence of a catalytic amount (20%) of (NH₄)₂HPO₄ as a base in aqueous media.     

Novel Disubstituted Phenylene‐Linked Bis‐imidazole Derivatives: Facile Synthesis and Optical Properties

Six novel disubstituted phenylene‐linked bis‐imidazole derivatives, 3a – 3f , were prepared by a one‐pot, microwave‐assisted method under solvent‐free conditions, in yields ranging from 61.6 to 85.6%. The new compounds were characterized by ¹H‐ and ¹³C‐NMR, UV/VIS, and fluorescence spectroscopy, and mass spectrometry, as well as by elemental analyses. The influence of substituents and solvents on the optical properties of 3a – 3f was investigated. It was found that there is little influence on absorption and excitation spectra in contrast to emission spectra. Compounds 3a – 3f exhibit strong fluorescence in solution, their fluorescence quantum yields ranging from 0.27 to 0.96.     

Ugi反应在环肽生物碱和小肽衍生物抗生素及细胞毒素类等天然产物合成中的应用

Ugi反应是由1分子醛或酮、1分子胺、1分子异腈和1分子羧酸4个组分通过缩聚反应生成α- 酰氨基酰胺类化合物的反应。 具有反应条件温和、产率高和原子经济性好等特点。 该反应还可与Suzuki、Heck和Smiles等经典反应偶联,使得其在天然产物合成方面得到越来越多的关注。 本文概括总结了近几十年来Ugi反应在一些天然产物合成中的应用。