17972-06-4

Upstream product

• 104-87-0 4-methyl-benzaldehyde 
• 75-04-7 ethylamine 

Downstream Products

• 858132-59-9 [PdCl(CH(C₆H₄CH₃)N(C₂H₅)C(C₆H₅)O)]2 

Relevant academic research and scientific papers

Mixed carboxylic-sulfonic anhydride in reaction with imines: A straightforward route to water-soluble β-lactams via a Staudinger-type reaction

The first example of employing a mixed carboxylic-sulfonic anhydride in reaction with imines is reported. Unlike its well-studied isostere homophthalic anhydride, benzo[c][1,2]oxathiin-3(4H)-one 1,1-dioxide gave no product of a formal [4 + 2] cycloaddition and only followed an alternative reaction pathway toward β-lactams, presumably, via a formal [2 + 2] cycloaddition (a Staudinger-type reaction). Optimized reaction conditions involve the use of triethylamine as a base promoter, which also allows isolating the product β-lactam benzene sulfonic acids as respective triethylammonium salts by conventional column chromatography. The reaction shows some preference to trans-isomer formation; pure diastereomers can be isolated in some cases.

Tunable Synthesis of α-Amino Boronic Esters from Available Aldehydes and Amines through Sequential One-Pot Dehydration and Copper-Catalyzed Borylacylation

Copper-catalyzed multicomponent borylacylation of imines with acid chlorides and bis(pinacolato)diboron was developed for the preparation of synthetically useful and pharmacologically relevant α-amino boronic acid derivatives. Starting from a range of acid chlorides and imines with aryl, heteroaryl, and alkyl substituents, most of these ligand-free reactions proceeded smoothly at room temperature in moderate to good yields. Furthermore, a facile and convenient one-pot, multistep access to the direct synthesis of α-amino boronic acid derivatives from available aldehydes and amines was also developed.

α-Acyl-α-diazoacetates in Transition-Metal-Free β-Lactam Synthesis

Thermally promoted reaction of α-acyl-α-diazoacetates with imines has been investigated. The transformation, earlier reported predominantly under transition metal catalyzed conditions, delivers α-alkoxycarbonyl-substituted β-lactams with outstanding diastereoselectivity. DFT calculations performed in order to evaluate energetically feasible reaction pathways revealed the intermediacy of 1,3-oxazin-4-one intermediates hitherto never implicated in the Staudinger synthesis of β-lactams.

A General Way to Construct Arene-Fused Seven-Membered Nitrogen Heterocycles

Imines react with seven-membered cyclic anhydrides (prepared from the corresponding dicarboxylic acids by a recently discovered in-situ cyclodehydration protocol) by the Castagnoli–Cushman reaction pathway to give privileged seven-membered arene-fused nitrogen-heterocyclic compounds with reagent-controlled diversity of the skeleton and peripheral groups.

Unusually Reactive Cyclic Anhydride Expands the Scope of the Castagnoli-Cushman Reaction

In the course of synthesizing and testing various "azole-including" cyclic anhydrides in the Castagnoli-Cushman reaction with imines, a remarkably reactive, pyrrole-based anhydride has been identified. It displayed a remarkably efficient reaction with N-alkyl and N-aryl imines, in particular, with "enolizable" α-C-H imines which typically fail to react with a majority of known cyclic anhydrides. The reactivity of this anhydride has been justified by an efficient resonance stabilization of its enol form. This finding expands the existing arsenal of highly reactive cyclic anhydrides and further confirms the importance of anhydride enolization for an efficient Castagnoli-Cushman reaction.

Acetic anhydride to the rescue: Facile access to privileged 1,2,3,4-tetrahydropyrazino[1,2-a]indole core via the Castagnoli-Cushman reaction

Indole-fused cyclic anhydrides earlier deemed unreactive in the Castagnoli-Cushman reaction with imines have been rendered valid participant in this process. The new reaction format involves the use of respective indole-based dicarboxylic acids and in sit

New Heterocyclic Product Space for the Castagnoli-Cushman Three-Component Reaction

Significant expansion of heterocyclic product space accessible by the Castagnoli-Cushman reaction (CCR) has been achieved via the use of glutaric anhydride analogues containing endocyclic substitutions with oxygen, nitrogen, and sulfur. Incorporation of these heteroatoms in the anhydride's backbone results in enhanced reactivity and generally lower temperatures that are required for the reactions to go to completion. These findings are particularly significant in light of the CCR recently recognized as an efficient tool for lead-oriented synthesis.

Palladium-catalyzed aryl iodide carbonylation as a route to imidazoline synthesis: Design of a five-component coupling reaction

Take five: A new method employing aryl halide carbonylation to directly access heterocycles has been described (see scheme). In a single palladium-catalyzed reaction the catalyst mediates two consecutive carbonylation steps, thereby converting five components (aryl iodide, two units imine, and two units CO) into an imidazoline ring.

Activation of fluorescent protein chromophores by encapsulation

(Figure Presented) Chromophores related to fluorescent proteins, when sequestered into the "octaacid" capsule, recover their fluorescence. The fluorescence recovery is related to the inhibition of torsional motions within the cavity, implicating the single-bond torsion as an important contributor to internal conversion within this important class of chromophores.

Reactions of N-(arylsulfonoxy)-N-alkylbenzylamines with MeONa-MeOH. Steric effect on the structure of the imine-forming transition state

Elimination reactions of N-(arylsulfonoxy)-N-alkylbenzylamines 1-5 with MeONa-MeOH have been studied kinetically. The elimination reactions are regiospecific, producing only corresponding benzylidenalkylamines. The rate equation for the reactions is kobs = k0 + k2[MeONa], indicating that the reactions proceed by competing solvolytic- and base-promoted pathways. The relative rates of elimination for the k2 and k0 pathways are 1, 0.67, 0.53, 0.35, and 0.27 for R = Me, Et, i-Pr, s-Bu, and t-Bu and 1, 4.1, 5.1, and 8.7 for R = Et, i-Pr, s-Bu, and t-Bu, respectively. For MeONa-promoted elimination from 1-5, Hammett ρ and kH/kD decrease but ρ1g and |β1g| increase with a bulkier alkyl substituent. However, the values for the solvolytic eliminations are nearly the same for all substrates and are similar to those for the base-promoted pathway, except for the ρ values, which have opposite signs. From these results, the changes in transition-state structure wrought by variation of N-alkyl substituents are assessed.