Condensationen zwischen Malonester und Aldehyden unter dem Einfluss von Ammoniak und organischen Aminen

Abstract

Obgleich die geschilderten Versuchsergebnisse noch vie1 zu wiinschen iibrig lassen, glanben wir docb aus denselben schliessen ZII konnen, dass unsere Siiure eine gepaarte Glykuroneiiure ist. Somit ist rnit Sicherheit erwiesen, dass das Kaninchen befiihigt ist, einen Theil des aufgenommenen Thymols rnit der in seinem Korper gebildeten Glykoronsiure zu vereinigen und als Thymolglykuronsaure im Hnrne auszuscheiden.O k a y a m a (Japan), den 20. Juli 1898.

Silica Bonded N-(Propylcarbamoyl)sulfamic acid (SBPCSA) Mediated Expeditious Approach to C–C Bond Formation: An Innovative Pathway for Acrylonitrile Derivatives

“…Carbon-carbon (C-C) bond formation reactions are of significant importance in organic synthesis as they unlock new pathways to new chemical entities [16][17][18]. The Knoevenagel condensation between aldehydes and ketones with activated methylene compounds is one of the reactions which facilitates C-C bond formation [19,20] and has been exploited in the synthesis of some vital drugs such as entacapone [21] pioglitazone [22] and lumefantrine [23].…”

Visible light induced Knoevenagel condensation: A clean and efficient protocol using aqueous fruit extract of tamarindus indica as catalyst

“…The reaction was further explored for the synthesis of p-bis-2-(phenylidene) malononitrile in 98% yield by the condensation of terephthalaldehyde (entry 23) with two moles of malononitrile under similar reaction conditions. In the present instance, we speculate that the reaction may plausibly be initiated by homolytic C-H bond cleavage of malononitrile (2) in the presence of visible light to produce a radical A and hydrogen radical which is trapped immediately by water molecule to form radical B. Aldehyde (1) becomes activated by protonation from tamarind juice to produce a protonated species C. One electron transfer from B to D produced a radical E, which couples with radical A to form F. Protonation of F followed by dehydration from G to form the title compound 3 as depicted in Scheme 2.…”

“…Knoevenagel condensation [1] is one of the most important and widely employed methods for the formation of carboncarbon bonds [2][3][4]. It has been used for the preparation of a wide range of substituted alkenes, and for the synthesis of intermediate such as coumarin derivatives which are useful in perfumes, cosmetics and bioactive compounds [5][6][7][8].…”

Synthesis and bio-evaluation of novel 7-hydroxy coumarin derivatives via Knoevenagel reaction

“…These compounds have also been reported in clinical trials to demonstrate activity against prostate cancer, malignant melanoma, and metastatic renal cell carcinoma [11][12][13]. 7-hydroxy coumarin was condensed with N,N-dialkyl substituted cyano acetamide derivatives to get the novel knoevenagel products, which are expected to be biologically active.…”