Gabriel reaction


A related aziridine synthesis is the Gabriel reaction (a.k.a. Gabriel-Cromwell reaction), which involves an intramolecular Sn2 reaction of a P-amino halide. However, the reaction has become so common that the name Gabriel is not tightly related to the transformation.  [c.63]

Chapter IV. a-Chloromethylnaphthalene (IV,23) benzylamine (Gabriel synthesis) (IV,39) i r.N -dialkylanilines (from amines and trialkyl orthophosphates) (IV,42) a-naphthaldehyde (Sommelet reaction) (IV,120) a-phenyl-cinnamic acid (Perkin reaction using triethylamine) (IV,124) p-nitrostyrene (IV,129) p-bromonaphthalene and p naphthoic acid (from 2 naphthylamine-1 -sulphonic acid) (IV,62 and IV,164) diphenic acid (from phenanthrene) (IV,165).  [c.1191]

A method that achieves the same end result as that desired by alkylation of ammonia but which avoids the formation of secondary and tertiary amines as byproducts is the Gabriel synthesis Alkyl halides are converted to primary alkylamines without contam mation by secondary or tertiary amines The key reagent is the potassium salt of phthal imide prepared by the reaction  [c.929]

The Gabriel-Colman reaction can be used to prepare isoquinoline-1,4-diols regioselectively by the use of unsymmetrically substituted phthalimides. Reaction of phthalimide 32 with sodium ethoxide in ethanol provides a 1 7 mixture of 33 34. It was rationalized that attack at carbon b is preferred because of its greater steric accessibility and diminished electron density compared to carbon a. In spite of the reasonable regioselectivity observed m this reaction, the Gabriel-Colman reaction has not been substantially investigated in the preparation of non-symmetrically substituted isoquinolines.  [c.419]

For a review of the preparation of naphthyridines, including use of the Gabriel-Colman reaction, see [R] Allen, C. F. H. Chem. Rev. 1950, 47, 275. For the use of the Gabriel-Colman reaction in the preparation of 1,6-naphthyridines see p. 284, and for the use of the Gabriel-Colman reaction in the preparation of 2,7-naphthyridines see p. 287.  [c.422]

GC reaction.Gabriel-Colman reaction  [c.570]

The Gabriel synthesis is often carried out by heating the starting materials without a solvent for several hours at a temperature of 150 °C or higher. The use of solvents like dimethylformamide can lead to better results. In a number of solvents—e.g. toluene—the phthalimide is insoluble the reaction can however be conducted in the presence of a phase transfer catalyst."  [c.132]

Gabriel s reaction The conversion of a halogen compound into the corresponding amino compound by treatment with potassium phthalimide and subsequent hydrolysis of the intermediate phthalimide compound. Thus chloroethanoic acid gives glycine. The method is of general application and has the great advantage of giving a pure primary amine free from mixture with secondary and tertiary products.  [c.185]

Gabriel synthesis Gattermaim aldehyde reaction Gattermann reaction Gattermann-Kocll reaction Gomberg-Hey reaction Grignard reaction  [c.1210]

This reaction was first described by Gabriel in 1910 (40), when he warmed an acylaminoketone (197a) with an equimolecular amount of phosphorus pentasulfide. The reaction (Scheme 103) is similar to the preparation of other five-membered oxygen- and sulfur-containing rings from 1,4-dicarbonyl compounds.  [c.278]

The Gabriel-Colman rearrangement entails reaction of the enolate of a maleimidyl acetate (2) to provide isoquinoline 1,4-diol 3.  [c.416]

The Gabriel-Colman reaction has been used to prepare 3-alkyl isoquinoline 1,4-diols. Phthalimides 8 and 9 rearrange as expected when treated with alkoxides. Further treatment with sodium ethoxide results in decarboxylation and the expected isoquinolinone 1,4-diols 12 and 13.  [c.416]

The Gabriel-Colman rearrangement entails reaction of the enolate of a maleimidyl acetate (2) to provide isoquinoline 1,4-diol 3.  [c.417]

The Gabriel-Colman reaction has been used to prepare 3-alkyl isoquinoline 1,4-diols. Phthalimides 8 and 9 rearrange as expected when treated with alkoxides. Further treatment with sodium ethoxide results in decarboxylation and the expected isoquinolinone 1,4-diols 12 and 13.  [c.417]

Shortly after Gabriel and Colman reported cinchomeronylacetic ester, Pels reported a similar quinolinimidoacetic ester (40) to provide a 1,6-naphthyridine (41).The structure of the isolated compound was not unambiguously determined for more than 30 years.More recently, the reaction has been shown to produce both 41 and 42 in a 3 1 ratio  [c.420]

The most widely used variant of the Gabriel-Colman is the conversion of saccharine derivatives to benzothiazine derivatives. The reaction has been extensively studied as benzothiazines are important pharmacophores, particularly in the oxicam class of antiinflammatories. The first reported instance of this transformation was in 1956 where 43 was treated with sodium methoxide to provide 44. The rearrangement also works with esters " and some amides " in addition to ketones.  [c.420]

The mechanism of this variant of the Gabriel-Colman reaction has been investigated. Treatment of saccharine derivatives 45-48 with 1-2 equivalents of sodium alkoxide at room temperature provides esters 49-52 in good yields treatment of 45-48 with sodium alkoxide at reflux provides the expected benzothiazines 53-56. Increased concentration leads to higher yields.  [c.421]

Dihydro-l,3-4//-oxazines (32) are among the best known 1,3-oxazines. Their preparation was first described by Gabriel and Elfeldt in 1891. The reaction consisted in benzoylation of y-bromopropyl-amine in the presence of sodium hydroxide by an intermediate formation of A"-benzoyl-y-bromopropylamine (31). The cyclization of the  [c.325]

Reaction of alkyl halides 1 with hexamethylenetetramine 2 (trivial name urotropine) followed by a hydrolysis step, leads to formation of primary amines 3 free of higher substituted amines. This method is called the Delepine reaction, a comparable method is the Gabriel synthesis.  [c.83]


See pages that mention the term Gabriel reaction : [c.24]    [c.309]    [c.113]    [c.81]    [c.929]   
Name reactions in heterocyclic chemistry (2005) -- [ c.63 ]