LIV.—The action of aldehydes on the Grignard reagent

Marshall, Joseph

doi:10.1039/ct9140500527

Cited by 9 publications

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“…Actions of the Series Me4N, Me3EtN, Me2Et2N, etc. Boehm [1910] and Marshall [1914] studied the curariform action of the compounds intermediate between Me4N and Et4N. Their results are shown in Table IV.…”

Section: Ravent6smentioning

confidence: 99%

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Pharmacological Actions of Quaternary Ammonium Salts

Raventós

1937

Exp Physiol

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THE curariform action of the quaternary ammonium salts was recognised by Crum Brown and Fraser in the remarkable researches which they carried out in 1869. Ever since that date these salts have been a favourite subject for pharmacological investigations, and consequently the literature is very extensive. It has, however, been summarised by Trendelenburg [1923], Kulz [1923], Gasser [1930], and Ing [1936]. Furthermore, most of the pharmacological actions of these salts are well established, and hence references will be only given regarding points of special importance.The author has studied the actions on a variety of isolated muscles of four series of compounds, namely (i) the series Me4.N, Me3EtN, etc., which is termed the Me3.N.R series; (ii) the series Me4.N, Et4.N, etc.; (iii) Me4N, Me3EtN, Me2Et2N, etc.; (iv) Me3.N.Phen, Me3N.CH2Phen, Me3N-CH2-CH2-Phen.METHODS. The following isolated muscles were used: (a) Frog's auricle, (b) frog's rectus abdominis, (c) rat's gut, (d) dorsal muscle of leech.These preparations were used immersed in Ringer's fluid, Tyrode's fluid, or Locke's fluid modified for the leech, and their isotonic movements were recorded in the usual manner.(a) The following technique was employed in the case of the frog's auricle. Rana esc. Hung. were used, and a strip of auricle free from sinus was isolated and driven at about 12 contractions per minute by break induction shocks. The Ringer's fluid had the percentage composition: NaCl 0 65; KCi 002; CaCl2 0'018; Na2HPO4 0 05 (pH 7.5).The movements were recorded by a light lever on smoked paper. This preparation was found to be very suitable for comparative quantitative estimations of the action of drugs which produced depression of the mechanical response.(b) Frog's rectus abdominis, (c) rat's gut, and (d) dorsal muscle of leech.Standard techniques [Gaddum, 1936] were employed with these

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Section: Ravent6smentioning

confidence: 99%

“…Marshall [1914] found in cats that the series Me4N to Et4N produced a fall of blood-pressure. The relative activity of the different members of the series was as follows: Me4N was slightly more powerful than Me3EtN, whilst Me2Et2N was much weaker.…”

Section: Ravent6smentioning

confidence: 99%

Pharmacological Actions of Quaternary Ammonium Salts

Raventós

1937

Exp Physiol

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“…The chief disadvantage is a conconlitant oxidation-reduction of the Meerwein type (9), because the benzyl alcohol so produced is difficult to separate from 1-phenylethanol by distillation or absorption chron~atography on alumina. Moreover the by-product formation Can.…”

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The Significance of Halide in Grignard Reagents

French¹,

Wright²

1964

Can. J. Chem.

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The optical activity of 1-phenylethanol from benzaldehyde and methyl chloride Grignard reagent coordinated with (+)2,3-dimethoxybutane is about one fourth of that found for the same product when bis-methyimagnesiun is the reagent. The difference has been attributed to the relative coordinating power of magnesium chloride versus the optically active ether.Grigilard reagents usually contain bound halogen because they are commonly prepared by corrosion of magnesium by means of an organic halide. Indeed, this process historically defines the reagent. However, these reagents may be rendered halogen free by the dioxane precipitation technique of the Schlenks (I) and the resultant solution of bis-organomagnesium also has been considered to be a Grignard reagent. We adhere to this extended definition largely because the amount of magnesium halide in a Grignard reagent is dependent on the type of halide and upon the method of reagent preparation. Thus a reagent series may exist with bis-organomagnesium a t one extreme and Grignard reagent saturated with magnesium halide a t the other. Such a series would be important only if there is a difference in reactivity in time or type between the extremes. Interest in these differences has increased during recent years (2, 3, 4). In this report the difference in coordination of the organometallic compound with an ether has been investigated.The method we used is the induction of optical activity in a product of Grignard reagent addition (5, 6, 7) by use of (+)2,3-diinethoxybutane to effect an asyinrnetric synthesis. We synthesized 1-phenylethanol from methyl Grignard reagent and benzaldehyde and compared yields and optical rotation when either bis-methylmagnesium or nlethyl chloride Grignard reagent is used. For the coinparison to be meaningful it is important that the first of these reagents be quite free from halide. Mosher (4) found it difficult to attain this condition. By contrast, our precipitate initially contains not only the halide in toto but also some of the halogenfree complex. T o obtain a reasonable yield of bis-methylmagnesium we must wash the precipitate thoroughly. Subsequently a small amount of white precipitate tends to appear in the solution, presumably because of temperature variations. I-Io~vever, both the solution and the slight precipitate are halogen free by silver halide test. The difference between our results and those of ibIosher may be due to our specific reagent or else to the dioxaneGrignard ratio or to our use of heat during the precipitation.The halide-free solution contains bis-methylmagnesium dioxanate or dioxanateetherate, so these ethers must be removed to ensure that the optically active ether will be fully effective. htlost of the diethyl ether is removed easily a t 50 "C under 1 atm of nitrogen, leaving a solid residue. Co~nparison of the weight of this residue with the basic magnesium equivalence, according to titration (S), indicates a composition of one-half dioxane per inole of bis-inethylmagnesium.

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Studies on the Grignard Reaction‐VII (¹) on the Mechanism of the Grignard Reagent Formation and the Wurtz Side Reaction in Ether

Anteunis

Schoote

1963

Bulletin des Soc Chimique

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In contradiction with accepted views about Wurtz coupling reactions during the preparation of Grignard solutions, the highly accurate Volhard titrimetric and the complexometric method show no difference. Checking the amount of coupling product by direct GLC the obtained results are discussed on the basis of a new mechanistic scheme, which assumes the formation of univalent magnesium radicals. These either disproportionate after preparation, or stay bonded as subhalide.

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LIV.—The action of aldehydes on the Grignard reagent

Cited by 9 publications

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Pharmacological Actions of Quaternary Ammonium Salts

Pharmacological Actions of Quaternary Ammonium Salts

The Significance of Halide in Grignard Reagents

Studies on the Grignard Reaction‐VII (¹) on the Mechanism of the Grignard Reagent Formation and the Wurtz Side Reaction in Ether

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LIV.—The action of aldehydes on the Grignard reagent

Cited by 9 publications

References 0 publications

Pharmacological Actions of Quaternary Ammonium Salts

Pharmacological Actions of Quaternary Ammonium Salts

The Significance of Halide in Grignard Reagents

Studies on the Grignard Reaction‐VII (1) on the Mechanism of the Grignard Reagent Formation and the Wurtz Side Reaction in Ether

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Studies on the Grignard Reaction‐VII (¹) on the Mechanism of the Grignard Reagent Formation and the Wurtz Side Reaction in Ether