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Malononitrile, alkylation

Malononitrile, alkylation of, S3, 24 Malononitrile, ferr-butyl-, 53, 21 Meerwein reaction, preparation of p-acetyl-a-bromohydrodnnamic add, 51,1... [Pg.74]

Scheme 6.70 Mechanistic proposal for the 12-catalyzed asymmetric Michael addition of malononitrile to (J-aryl and alkyl substituted N-acyl pyrrolidinones (cyclic imide) (A) and to a,P-unsaturated N-aryl substituted 2-methoxybenzamides such as N-cinnamoyl-2-methoxybenzamide (acyclic imide) (B). Scheme 6.70 Mechanistic proposal for the 12-catalyzed asymmetric Michael addition of malononitrile to (J-aryl and alkyl substituted N-acyl pyrrolidinones (cyclic imide) (A) and to a,P-unsaturated N-aryl substituted 2-methoxybenzamides such as N-cinnamoyl-2-methoxybenzamide (acyclic imide) (B).
Condensation of ester (44e) with the anion of malononitrile gave the alkene (44g) <91JPR35>. Oxadiazole (43e) and triethyl phosphite gave a methane phosphate which underwent a Wittig reation with aldehydes ArCHO to form alkenes (43f). When the alkyl side chain contained an active methylene group, as in (43g), reaction with arenediazonium salts ArN2X yielded arylhydrazones (43h) <88LA909>. [Pg.276]

The constrained bis(oxazolines) 9a and 9b can be constructed beginning with malononitrile 32 as shown by Ghosh and co-workers. Thus, treatment of 32 with anhydrous hydrochloric acid in dioxane, as shown by Lehn and co-workers, yielded imidate salt 33 (Fig. 9.9). Condensation of the imidate salt with commercially available (15,2/ )-l-aminoindan-2-ol afforded the conformationally constrained bis(oxazoline) inda-box 9a. Alkylation at the bridging methylene of 9a was carried out by Davies and co-workers.Treatment of 9a with lithium diisopropylamide followed by alkylation with methyl iodide afforded 9b. Alternatively, alkylation with diiodoalkanes incorporated ring systems at the bridging position (structures 34a-d). [Pg.537]

A heated solution of 458 in dry EtOH containing hydrazine gives 459b <1995JHC69>. The thienopyrimidine-acetonitriles 459c-f were prepared from 458 through an initial reaction with malononitrile to form a thioureido intermediate, followed by treatment with alkyl halides <2001JHC419>. [Pg.413]

A clean twofold Heck coupling of unsubstituted butadiene 46 (R = H) in the 1- and 4-positions has not been reported. However, the initial carbopalladation product from 46 (R = H) and an in situ formed arylpalladium halide, the cr-allylpalladium halide 47 equilibrating with the corresponding 7r-allylpalladium halide, can efficiently be trapped with the anion formed by arylation of malononitrile or cyanoacetate to give 48, a product of reductive 1,4-arylation-alkylation of 1,3-butadiene 46 (R = H)." /3-Hydride elimination from the intermediate 47 (R H) can be accomplished when the reaction is carried out in the presence of silver acetate or thallium acetate, leading to the... [Pg.318]

The most popular preparations of pyrimido[4, 5 ]pyrimidi nes are based on cyanoethylene or cyanomethylene derivatives. In many of these preparations the appropriate acid chloride (R1 = alkyl, aryl) is reacted with malononitrile to give an enol (250), which is readily alkylated to the enol ether (251). This can be condensed with guanidine or a variety of amidines (R2 = H, alkyl, aryl) to yield the key intermediate 4-amino-5-cyanopyrimidines (252) (81S955). Reaction with a second mole of guanidine or amidine is a convenient preparation of a variety of pyrimido[4,5 ]pyrimidines. Under the appropriate conditions the final ring system can be obtained from the enol ether in one step (68JMC568). [Pg.363]

This preparation illustrates the alkylation of malononitrile under acid-catalyzed conditions, and the use of diborane for the reduction of a dinitrile to a diamine. The procedure for the preparation of tert-butylmalononitrile has been outlined briefly by Boldt and co-workers.2 The generation of diborane in situ and the general method for nitrile reduction is that described by Brown and co-workers.3 Attempts to reduce the dinitrile to the diamine by other methods including catalytic hydrogenation (5% rhodium on alumina, 5 atm.), lithium aluminum hydride, and lithium aluminum hydride-aluminum chloride were singularly unsuccessful. [Pg.24]

For the preparation of MBM, the starting phenol was alkylated to 2-(n)-butoxy-1,4-dimethoxybenzene in methanolic KOH with n-butyl bromide. The benzaldehyde melted at 79.5-81 °C from methanol, and formed a malononitrile derivative that had a melting point of 134.5-135 C. The nitrostyrene from the aldehyde and nitroethane in acetic acid crystallized from methanol with a mp of 71 -72 °C. Lithium aluminum hydride reduction in ether gave the ether-insoluble chloroform-soluble product 4-(n)-butoxy-2,5-dimethoxyamphetamine hydro-... [Pg.179]

A three-component reaction of aromatic aldehydes, malononitrile and phenols leads to 4-aryl-2-amino-3-cyano-4//-chromenes this reaction can be carried out in aqueous media with improvements in yield and obvious environmental advantages (Scheme 35). The aromatic aldehyde undergoes a Knoevenagel condensation with malononitrile, followed by ortho-alkylation of the phenol and cyclization to form the iminopyran intermediate 114, which isomerizes to the 4//-chrorncncs (Scheme 36) <2003SL2001>. High yields for this three-component reaction can also be achieved in aqueous media when mediated by 7-alumina <2004TL2297> or cetyltrimethylammonium chloride <2001T1395>. [Pg.453]


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See also in sourсe #XX -- [ Pg.24 , Pg.53 ]

See also in sourсe #XX -- [ Pg.24 , Pg.53 ]




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