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Enamines reactions with

The formation of heterocycles derived from quinones is an important synthetic technique. The reaction may be intramolecular, eg, the reaction of (92). Either nitrogen products, eg (93) (yields of 85—91% for R = H, CH, and C H ) or oxygen products (94) are obtained (92,93). Reactions with enamines have been especially important. [Pg.415]

The exploration of the chemistry of azirines has led to the discovery of several pyrrole syntheses. From a mechanistic viewpoint the simplest is based upon their ability to behave as a-amino ketone equivalents in reactions analogous to the Knorr pyrrole synthesis cf. Section 3.03.3.2.2), as illustrated in Schemes 91a and 91b for reactions with carbanions. Parallel reactions with enamines or a-keto phosphorus ylides can be effected with electron-deficient 2//-azirines (Scheme 91c). Conversely, electron-rich azirines react with electron deficient alkynes (Scheme 91d). [Pg.139]

Reaction of benzonitrile A-oxide with alkynic phosphinate (343) gave exclusively 5-phosphinylisoxazole (344), whereas reaction with enamine phosphinate (345) gave the otherwise inaccessible 5-unsubstituted 4-phosphinylisoxazole (346) (80JOC529). [Pg.69]

Fluorme-containing Michael addition acceptors have been used as synthons, a portion of a molecule recognizably related to a simpler molecule, for the introduction of fluorine into the organic molecules Their reactions with enamines and ketones lead to a condensarion-cyclization process... [Pg.634]

Bis(trifluoromethyl)-substituted pyrimidines are also available fromtrifluoro-acetonitrde on reaction with enamines and ynamines [d ] With dimethylami-nocrotonates, a cyclocondensation takes place to give 2-pyridones. 5-Cyano-6-trifluoromethyluracil is available via a similar route [95] (equation 18)... [Pg.848]

At higher temperatures the mixture of 10 and methyl vinyl ketone yields the 1,4-carbocyclic compound as described previously. Methyl isopropenyl ketone (5), ethyl acetylacrylate (d), 2-cyclohexenone (21), and 1-acetyl-1-cyclohexene (22) also undergo this type of cyclization reaction with enamines at higher temperatures. This cycloalkylation reaction occurs with enamines made of strongly basic amines such as pyrrolidine, but the less reactive morpholine enamine combines with methyl vinyl ketone to give only a simple alkylated product (7). Chlorovinyl ketones yield pyrans when allowed to react with the enamines of either alicyclic ketones or aldehydes (23). [Pg.216]

Olefins conjugated with electron-withdrawing groups other than a carbonyl group undergo reactions with enamines in a manner similar to the carbonyl-conjugated electrophilic alkenes described above. Namely, they condense with an enamine to form a zwitterion intermediate from which either 1,2 cycloaddition to form a cyclobutane ring or simple alkylation can take place. [Pg.222]

Terminal alkynes with no electron-withdrawing group next to the acetylenic linkage when treated with enamines merely add across the double bonds of the enamines (9i). But electrophilic alkynes (those with an electron-withdrawing group next to the acetylenic linkage) undergo cycloaddition reactions with enamines. [Pg.230]

The bicyclic system quinazoline undergoes intermolecular inverse cycloaddition reactions with enamines RRiNCR2=CHR3 (RRi=(CH2)3, R2 = Ph, R3 = H) yielding 2,3-disubstituted quinolines. [Pg.54]

The Michael reaction with enamines is exemplified in this procedure. In a second (spontaneous) step of the reaction, an aldol-type condensation occurs resulting in cyclization. Finally, the morpholine enamine of the product forms and is hydrolized by the addition of water to yield a mixture of octalones, which is separated by fractional crystallization. J -Octalone-2 can be reduced by lithium in anhydrous ammonia to the saturated tra/i5-2-decalone (Chapter 3, Section III). [Pg.82]

Aliphatic or aromatic aldehydes RCHO can be transformed, in situ, via their iminium iodides, on reaction with enamines of ketones, to give /9-aminoketones. Thus, 4-methoxybenzaldehyde reacts with dimethylammonium chloride, triethyla-... [Pg.118]

The reactions of nitroalkenes (42) with various enols (43b) (vinyl ethers, silyl, and acyl enolates, ketene acetals) have been studied in most detail (110, 111, 125—154). As a mle, these reactions proceed smoothly to give the corresponding nitronates (35f) in yields from high to moderate. As in the reactions with enamines, the formation of compounds (44b) is attributed to the ambident character of the anionic centers in zwitterionic intermediates analogous to those shown in Scheme 3.43. [Pg.465]

We shall consider the sequence as firstly imine formation (an abbreviated form of this mechanism is shown), followed by imine-enamine tautomerism. This provides a nucleophilic centre and allows a subsequent aldol-type reaction with enamine plus ketone. The pyrrole ring is produced by proton loss and a dehydration. [Pg.669]

The reaction of 77 with alkynes has further been elaborated for the synthesis of substituted phthalonitriles 81. An alternative for the synthesis of these compounds is the cycloaddition reaction of 77 with enamines followed by a retro-Diels-Alder loss of N2 and elimination of the amine (Scheme 16). Generally, more forcing reaction conditions are required and lower yields are obtained in reactions with alkynes than in reactions with enamines, for example, 4-ethyl-5-methylphthalonitrile is obtained in 51% yield from 2-pentyne (xylene, 150°C, 18 days) and in 73% yield from 4-(l-ethylprop-l-en-l-yl)morpholine (CHCI3, 70°C, 7 days) <1998T1809>. The mechanism of the reaction with enamines has been studied in detail. This revealed a [1,5] sigmatropic rearrangement in the cyclohexa-2,4-dien-1-amine intermediates formed after the loss of N2 <1998T10851>. [Pg.29]


See other pages where Enamines reactions with is mentioned: [Pg.617]    [Pg.680]    [Pg.788]    [Pg.790]    [Pg.829]    [Pg.829]    [Pg.831]    [Pg.888]    [Pg.888]    [Pg.474]    [Pg.279]    [Pg.1297]    [Pg.59]    [Pg.82]    [Pg.77]    [Pg.369]    [Pg.460]    [Pg.526]    [Pg.669]   
See also in sourсe #XX -- [ Pg.432 , Pg.433 ]

See also in sourсe #XX -- [ Pg.788 , Pg.1250 ]

See also in sourсe #XX -- [ Pg.601 , Pg.602 ]




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1- Azabutadienes, reaction with enamines

5- Nitropyrimidine, ring transformation reaction with enamines

5- Nitropyrimidines reaction with enamines

Acetylenedicarboxylic acid reaction with enamines, cyclobutene ring

Acid chlorides reaction with enamines

Acrolein reaction with enamines

Acrylamides reactions with enamines

Acyl chlorides reaction with enamines

Alkylation Reactions with Imidazolidinone Enamines

Allylic halides, reaction with enamines

Azadienes reactions with enamines

Azirines reactions with enamines

Azodicarboxylates, reactions with enamines

Benzoquinones reactions with enamines

Benzoyl peroxide reaction with enamines

Benzylic halides, reaction with enamines

Borohydride, sodium reaction with enamines, imines

Carbenes reactions with enamines

Carbonyl Condensations with Enamines The Stork Reaction

Conjugated compounds, reaction with enamines

Cyclohexanone enamine reaction with dichlorocarbene

Cyclopropanes reactions with enamines

Cyclopropenones reactions with enamine

Diazadienes reactions with enamines

Diazines, reactions with enamines

Diazomethane reaction with enamines

Dibromoketones reactions with enamines

Electrophilic reagents, reactions with enamines

Enamine reaction

Enamine reaction with enones

Enamine salts reactions with nucleophilic reagents

Enamines nitroalkene acceptor reactions with

Enamines reaction with electrophilic alkenes

Enamines reaction with thiirene

Enamines reactions with acetylenes

Enamines reactions with alkynic esters

Enamines reactions with diazonium salts

Enamines reactions with isocyanates

Enamines, reaction with acyl halides

Enamines, reaction with alkenes

Enamines, reaction with aryl halides

Enamines, reaction with conjugated carbonyls

Enamines, reaction with cyanoborohydride

Enamines, reaction with formic acid

Enamines, reaction with halo ketones

Enamines, reaction with quinones

Enamines, reaction with ring opening

Enamines, reactions with cyclopropenone

Ethyl chloroformate, reaction with enamines

Fluorinated ketones, reaction with enamines

Halides reactions with enamines

Halides, alkyl reaction with enamines

Immonium ions, reactions with enamines

Inverse-Electron-Demand Reactions with Enamine-Activated Dienophiles

Isoxazoles reactions with enamines

Methyl iodide, reaction with enamines

Methyl vinyl ketone reaction with enamines

Michael reactions with enamines

Nitrenes reactions with enamines

Oxirane reactions with enamines

Pyridazines reactions with enamines

Pyrido pyridazines, reaction with enamines

Reaction with Secondary Amines Enamines

Reactions of Enamines with Acrolein

Sulfene, reaction with enamines

Sulphenes reactions with enamines

Sulphuric acids, reactions with enamines

Tertiary enamines reactions with electrophiles

Tetracyanoethylenes, reactions with enamine

Tetrazines, reactions with enamines

Triazines, reactions with enamines

Trimethylene dithiotosylate, reactions with enamines

Vinyl isocyanates, reaction with enamines

Vinyl ketones reactions with enamines

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