Synthese und Eigenschaften einiger tert‐Alkylmalonsäurederivate

Abstract

Aus den Alkylidenmalonsaurederivaten 1 -8 wurden durch 1,4-Addition von Grignard-Reagenzien die tert-Alkylrnalonsaurederivate 9 -18 hergestellt. Aus den Estern 9 -17 wurden die Sauren Synthesis and Properties of Some tert-Alkylmalonic Acid Derivatives1,4-Addition of Grignard reagents to the alkylidenemalonic acid derivatives 1 -8 affords the tertalkyl malonic derivatives 9 -18. The esters 9 -17 give the acids 19 -26 and from these the corresponding chlorides 27 -34 are obtained. Bromination yields the bromo acids 35 -36, the brominated acyl bromide 43, the bromonitrile 44, and the bromoacyl chlorides 37 -42. The trimethylsilyl esters 50 -52, the bis(2-bromoethyl) esters 53 -54, the ethyl ester 14, and the tert-butyl ester 16 are brominated via the corresponding ester enolates giving the bromo esters 45 -46 in pure form. -The dealkylation of malonic esters with chlorotrimethylsilane/sodium iodide has been carried out.Anregung zur hier beschriebenen Arbeit war die von Gripenberg I ) beobachtete anomale Hydrolyse der 2-Brorn-2-tert-butylmalonsaure, wobei Trimethylacrylsaure, Methylmalonsaure und Aceton entstehen. Diese Wagner-Meerwein-Umlagerung wird aber nicht bei der Hydrolyse von 2-Brom-2-terf-butylessigsaure beobachtet, sondern es wird nur das normale Hydrolyseprodukt Trimethylmilchsaure erhalten '). Daher war es interessant, das Verhalten hoher substituierter 2-tert-Alkyl-2-brommalonsauren zu studieren.Die Synthese von Alkylidenmalonestern, die unentbehrliche Zwischenprodukte auf dem Weg zu den tert-Alkylmalonestern sind, war bis vor kurzem schwierig. Mit den iiblichen Knoevenagel-Katalysatoren wird aus Ketonen und Malonsaure-diethylester nur Isopropylidenmalonsaure-diethylester in praparativ interessanter Ausbeute erhalten3s4). Mit Ethylmethylketon betragt die Ausbeute an 1-Methylpropylidenmalonsaure-diethylester hochstens 19% '). Die von Lehnert6) gefundene Variante der Knoevenagel-Kondensation liefert aber mit verschiedenen Ketonen die entsprechenden Kondensationsprodukte in guten bis sehr guten Ausbeuten. 1,4-Addition von Grignard-Reagenzien an Liebigs Ann. Chem. 1981

Anionic N‐Heterocyclic Carbenes with N,N′‐Bis(fluoroaryl) and N,N′‐Bis(perfluoroaryl) Substituents

“…tert-Butylmalonyl chloride was prepared according to the published procedures. [34] All other reagents were purchased from commercial suppliers. NMR spectra were collected on a Bruker Advance RDQ-400 spectrometer and calibrated with respect to [D 7 19 F NMR spectra were calibrated with respect to C 6 F 6 ( 19 F, d = À164.9 ppm).…”

“…Upon stirring for several minutes, the mixture solidified, yielding the desired formamidines in near quantitative yields after washing with hexanes. tert ‐Butylmalonyl chloride was prepared according to the published procedures 34. All other reagents were purchased from commercial suppliers.…”

Biomimetic Copper(I)-Mediated Activation of Dioxygen and Redox Non-Innocence in Copper(II) Complexes of Bis(oxazoline)s

“…With regard to limited availability of diethyl tert-butylmalonate, an alternative route was developed: The prepared diethyl tert-butylmalonate was hydrolysed and the resulting tert-butylmalonic acid converted to the corresponding acyl chloride with thionyl chloride (Scheme 3.4). [129] The corresponding malondiamide could be obtained in good yields by the reaction of tert-butylmalonic acid with 2-amino-2-methyl-1-propanol in presence of triethylamine.…”

“…The ester was hydrolysed, yielding the corresponding malonic acid which in an additional step was transformed to tert-butylmalonyl chloride as it is described in literature. [129] NH HN O O tBu H OH HO 2-(tert-Butyl)-N,N'-bis(1-hydroxy-2-methylpropan-2-yl)malonamide. The synthesis follows a related description.…”

“…13 C{ 1 H}-NMR (75 MHz, CDCl 3 ): δ (ppm) = 158.3 (C N),129.0 (C C),79.4 (CMe 2 ), 68.5 (CH 2 ),28.0 (Me).15 N-NMR (30 MHz, CDCl3 ): δ (ppm) = −120.4 (C N). FTIR (neat): ν (cm −1 ) = 2969 (m, ν CH), 2933 (w, ν CH), 2898 (w, ν CH), 2870 (w, ν CH), 1671 (m, ν C=N), 1611 (m, ν C=C), 1465 (w), 1385 (w), 1363 (m), 1315 (m), 1275 (w), 1253 (w), 1210 (w), 1173 (w), 1188 (w), 1007 (m), 980 (w), 937 (w), 910 (w), 898 (w), 820 (w), 774 (w), 748 (w), 720 (w), 641 (w), 612 (w), 550 (w).…”