Über einige Be‐obachtungen in der Gruppe der Pyridinaldehyde

Mathes, Wilhelm; Sauermilch, Walter

doi:10.1002/cber.19560890620

Cited by 14 publications

(5 citation statements)

References 5 publications

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“…Spectral data were in accordance with those previously published. [45] O-Propionyl-(S)-2-hydroxy-2-phenylacetonitrile (1l): Chiral GC, pressure 25 psi; injection temp. 225 8C; initial column temp.…”

Section: Experimental Section General Remarksmentioning

confidence: 99%

“…[39] The absolute configuration was determined from the sign of optical rotation. [39] O-Cinnamoyl (S)-2-hydroxy-2-phenylacetonitrile (1q): The crude product was purified by column chromatography on silica gel (eluent: EtOAc in hexanes [45] Chiral HPLC, 2-propanol/ hexane, 1/9, flow: 0.7 mL min À1 , detection 212 nm retention time (t R ) of 19.5 min (major), 27.7 min (minor).…”

Section: Experimental Section General Remarksmentioning

confidence: 99%

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Lewis Acid–Lewis Base‐Catalysed Enantioselective Addition of α‐Ketonitriles to Aldehydes

Lundgren¹,

Wingstrand²,

Moberg³

2007

Adv Synth Catal

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Additions of structurally diverse a-ketonitriles to aromatic and aliphatic prochiral aldehydes yielding highly enantioenriched acylated cyanohydrins were achieved using a combination of a titanium salen dimer and an achiral or chiral Lewis base. In most cases high yields and high enantioselectivities were observed. The ee was moderate in the initial part of the reaction but increased over time. This could be avoided, and higher ees obtained, by keeping the titanium complex, in the presence or absence of aldehyde and ketonitrile, at À40 8C prior to the addition of the Lewis base. A mechanism initiated by nucleophilic attack of the tertiary amine at the carbonyl carbon atom of the ketonitile is supported by 13 C labelling experiments.

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Section: Experimental Section General Remarksmentioning

confidence: 99%

Section: Experimental Section General Remarksmentioning

confidence: 99%

Lewis Acid–Lewis Base‐Catalysed Enantioselective Addition of α‐Ketonitriles to Aldehydes

Lundgren¹,

Wingstrand²,

Moberg³

2007

Adv Synth Catal

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“…With benzaldehyde and water at 125°, 2,6-lutidine gives the monocarbinol188, The yields (per cent) of carbinols from 2-picoline and various aldehydes under standard conditions were: p-tolualdehyde (5), benzaldehyde (11), m-nitrobenzaldehyde (25), o-nitrobenzaldehyde (37), p-nitrobenzaldehyde (48). Alkine formation is reversible, and when heated with water at 140°-2000, alkines give 2-picoline and an aldehyde.…”

Section: Menc600mentioning

confidence: 99%

Pyridine (Continued) the Properties of Functional Groups

Schofield

1967

Hetero-Aromatic Nitrogen Compounds

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“…Typical literature procedures utilize SeO 2 (0.5 equiv) under refluxing pyridine. 16 This is a major problem due to the toxicity, cost, product purity and low isolated yields. In our hands, this was a significant issue that could not be overcome by manipulating the experimental conditions.…”

mentioning

confidence: 99%

An Easy Entry into Schiff Base Molecules Bearing a Pendant Primary Alcohol Function for Hydrogen Bonding

Ziessel¹,

Nguyen²

2005

Synthesis

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A series of mono-oxidized pyridine, bipyridine, terpyridine and pyridine/pyridazine frameworks were prepared using MnO 2 as oxidant. Corresponding Schiff bases were prepared with aromatic or aliphatic amines carrying various functions such as paraffin chains, terminal acrylates and a second nitrogen atom. Various flexible tethers have been used for the ditopic ligands synthesis. These ligands formed dinuclear helicates for the shorter chains. The dinuclear copper(I) complex prepared from the CH 2 -CH 2 bridge is aggregated in the solid state by a hydrogen bonded network of the residual primary alcohol groups. For the longer spacers the ditopic ligand wraps around a single copper(I) centre forming a mononuclear complex. A significant merit of this work is that it allows the preparation of ligands and complexes retaining the hydroxymethyl function, which are likely to help to stabilize multidimensional networks in the solid state.The development of the so-called Schiff base compounds has attracted a lot of interest in the fields of coordination chemistry and material sciences. 1,2 Metal complexes derived from such useful derivatives are known to form a large variety of molecular architectures, ranging from macrocyclic helicates to infinite coordination polymers. 3,4 In particular, 2-iminopyridine, 2,6-diiminopyridine and 6,6¢-diimino-2,2¢-bipyridine, readily formed via reversible reaction between an achiral or chiral amine and appropriate aldehydes, are attractive building blocks for assembling intricate supramolecular species and highly stable metallo-helicates. 5,6 The presence of a lone pair on the nitrogen atom of the imino group enables the coordination of numerous metal cations, especially when the imine function is located at the ortho position of the heterocycle such as pyridine. 7 These ligands can display specific binding behavior towards metal cations, some are reminiscent of 2,2¢-bipyridine as in A, 2,2¢:6¢,2¢¢-terpyridine as in B and 2,6,2¢,6¢-quaterpyridine as in C (Figure 1). Notice that in this last case the ligand can adopt a bridging mode of coordination of type D. Recently, various molecules found interesting applications as ligands in various homogeneous catalytic reactions such as hydrosilation, Mukaiyama aldolization and cyclopropanation, 8 homologation of aromatic aldehydes, 9 and ethylene polymerization. [10][11][12] In the domain of material science, the main advantage in the use of Schiff base ligands relates to the availability of a free imino site that can be functionalized with a wide variety of appendages, such as paraffin tails, highly polarized molecular units or fragments bearing specific physical properties. Along these lines we discovered that assembling non-mesomorphic but lipid-like ligands bearing in close proximity to the central core of two imino functions around d-block transition metals promotes the formation of a liquid-crystalline state. 13-15 One of the key element of this approach lies in the helix rigidity and polarizability to counterbalance the flexibility and non-po...

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Über einige Be‐obachtungen in der Gruppe der Pyridinaldehyde

Cited by 14 publications

References 5 publications

Lewis Acid–Lewis Base‐Catalysed Enantioselective Addition of α‐Ketonitriles to Aldehydes

Lewis Acid–Lewis Base‐Catalysed Enantioselective Addition of α‐Ketonitriles to Aldehydes

Pyridine (Continued) the Properties of Functional Groups

An Easy Entry into Schiff Base Molecules Bearing a Pendant Primary Alcohol Function for Hydrogen Bonding

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