91-47-4Relevant articles and documents
On the mechanism of a modified Perkin condensation leading to α-phenylcinnamic acid stereoisomers - Experiments and molecular modelling
Palinko, Istvan,Kukovecz, Akos,Toeroek, Bela,Koertvelyesi, Tamas
, p. 1097 - 1104 (2000)
A modified Perkin condensation leading to α-phenylcinnamic acid stereoisomers affords predominantly or exclusively the (E)-isomer. Reaction duration, temperature, and polarity of the solvent affect the isomeric distribution only to a minor extent. However, geometry optimization of the stereoisomers by semiempirical quantum chemical methods revealed that their thermodynamic stabilities in the absolute minimum are the same. (E)-(Z)-isomerization under the conditions of the Perkin condensation resulted in an equilibrium mixture of nearly 1:1 composition, thus corroborating the results of the computations. Comparing the detailed potential energy maps of the isomers obtained at the semiempirical level of theory may explain the controversy. The (Z)-isomer has a structured potential energy surface with few but well-defined minima, whereas that of the (E)-isomer shows an extended flat plateau enabling this isomer to approach a minimum (which is close to the global one) right after its formation.
Click amidations, esterifications and one–pot reactions catalyzed by Cu salts and multimetal–organic frameworks (M–MOFs)
Armentano, Donatella,Ferrando-Soria, Jesús,Greco, Rossella,Leyva-Pérez, Antonio,Palomar-De Lucas, Brenda,Pardo, Emilio,Tiburcio, Estefanía
, (2022/03/17)
Amides and esters are prevalent chemicals in Nature, industry and academic laboratories. Thus, it is not surprising that a plethora of synthetic methods for these compounds has been developed along the years. However, these methods are not 100% atom economical and generally require harsh reagents or reaction conditions. Here we show a “spring–loaded”, 100% atom–efficient amidation and esterification protocol which consists in the ring opening of cyclopropenones with amines or alcohols. Some alkyl amines react spontaneously at room temperature in a variety of solvents and reaction conditions, including water at different pHs, while other alkyl amines, aromatic amines and alcohols react in the presence of catalytic amounts of simple Cu2+ salts or solids. A modular reactivity pattern (alkyl amines >> alkyl alcohols >> phenols >> aromatic amines) enables to design orthogonal and one–pot reactions on well–defined catalytic Multimetal–Organic Frameworks (M–MOFs, M= Cu, Ni, Pd), to easily functionalize the resulting cinnamides and cinnamic esters to more complex molecules. The strong resemblance of the amidation and esterification reaction conditions here reported with the copper–catalyzed azide–alkyne cycloaddition (CuAAC) allows to define this fast, clean and flexible protocol as a click reaction.
Palladium catalyzed 8-aminoimidazo[1,2-: A] pyridine (AIP) directed selective β-C(sp2)-H arylation
Mondal, Biswajit,Ghosh, Prasanjit,Kundu, Mrinalkanti,Das, Tapas Kumar,Das, Sajal
, p. 360 - 364 (2021/01/29)
Palladium catalyzed arylation of the inert β-C(sp2)-H bond of carboxylic acid derivatives is reported herein for the first time utilizing 8-aminoimidazo[1,2-a]pyridine (AIP) as an efficacious and new inbuilt 6,5-fused bicyclic removable directing group. This protocol is scalable, exhibits high levels of β-site selectivity and tolerates a broad spectrum of functional groups. This journal is
