Benzylidene malononitrile, reaction

Some TICT-forming fluorescent probes containing the / j - /V. /V - cl i a I k I a m i n o benzylidene malononitrile motif (usually related to 30 in Fig. 11) have been applied to monitor and quantify polymerization reaction, crosslinking, chain relaxation,... 

Nucleophilic attack of hydroxide ion on the a-carbon atom, with subsequent cleavage of the Ca—Cp bond, has been proposed to account for the kinetics of retro-aldol reaction of substituted benzylidene malononitriles with hydroxide ion in 90%... 

The 4-aminopyrimidines 367 and 368 were prepared by the reaction of the benzylidene malononitriles with thiourea or S-methylisothiourea, respectively. Nucleophilic substitution at the 2-position of 368 with hydrazine gave the 2-hydrazino derivative 369, whose treatment with carbon disulfide yielded the triazolopyrimidine 373 rather than its isomeric compound [83ZN(B)1686]. Heating 369 with benzoyl chloride in anhydrous dioxane,... 

Various unsaturated compounds, such as CO2, isocyanates and aldehydes, undergo Pd-catalysed cycloaddition with vinyl epoxides. Reaction of CO2 with 127 affords cyclic carbonates 128 with retention of the configuration at C(3), offering a method of cis hydroxylation of epoxides [66], and has been used for the synthesis of the side-chain unsaturated (—)-exo-brevicomin (129) [67], The tetrahydrofuran 131 was prepared by [3+2] cycloaddition of activated alkenes such as benzylidene malononitrile (130) with vinyl epoxide via Michael addition and allylation [68],... 

Reaction of 91 and 92 with 88 furnishes the arylidene products 89 [81S635 84ZN(B)824 87IJC(B)216], whereas the condensation of 92a with cyanoacetic acid hydrazide yields the parent bicyclic product 93 (84JHCI885). Arylidene product 89 is presumed to have been obtained via the intermediate 5-benzylidene derivative of 91 and 92 formed by the addition of the active methylene in 91 and 92 to the activated double bond of benzylidene malononitrile with concomitant elimination of malononi-trile, which subsequently adds to the activated double bond of the interme-... 

Pyrimido[4,5-fr]quinolines 344 were obtained from 2-amino-3-cyanoqui-noline 280 (R = Ar1) upon reaction with benzoyl isothiocyanate (96IJC(B)608) (Scheme 67). Reaction of enamine 31 (R = o-CNC6H4) with benzylidene malononitrile in the presence of DBU gave the pyrimidoquinoline 345 via the respective quinoline 280 (01ARK73). A series of pyrimidoquinolines were prepared by cyclization of the... 

Solvent Effects on k0. Only a few studies so far allow an assessment of solvent effects of k0. The change from water to 50% (CH3)2SO-50% water enhances log k0 from 2.10 to 2.55 in the reaction of piperidine and morpholine with P-nitrostyrene (22) and from 4.55 to 4.94 with benzylidene-malononitrile (C. F. Bernasconi and R. B. Killion, unpublished results). On the other hand, the change from water to acetonitrile either leaves k0 unaffected or even decreases it slightly in the reaction of benzylidene-substituted Meldrum s acid with the same amines (23, 24) the uncertainty is due to a lengthy extrapolation in water that renders k0 uncertain in this solvent. 

A more versatile method than most of those previously available for the synthesis of triaryloxazolopyridine is based on the cyclization of 4-benzylidene-oxazol-S-one with N-phenacylpyridinium bromide [3152]. Hot phosphorus oxychloride promotes C—C lx>nd formation between a lactam carbonyl and a ring-carbon and the pyrimidinone ring is chlorinated [3093]. Malononitrile in a basic medium converts an alkenyl-lactam into a fused 3-cyanopyridine ring. Yields in this reaction are low and heating for 16 h is necessary [3427]. 

In this reaction, k0 for benzylidene-substituted Meldrum s acid is higher than for benzylidenemalononitrile log [fc0(CN)2/fc0XY] —0.7, while for benzylidene-l,3-indandione, k0 is about the same as for the malononitrile derivative (19). This finding contrasts with the normal behavior where k0 for benzylidene-substituted Meldrum s acid and benzylidene-l,3-indan-dione should be much lower than that for benzylidenemalononitrile (Table III). 

Dithiins are produced by the reactions of geminal dithiols with enones such as chalcone and benzylidene acetophenone (Equation (54)) <62JOC4488, 66BSF1920>. Treatment of geminal dithiols with malononitrile also gives rise to 1,3-dithiins (Equation (55)) <62JPR2ll>. 

The dialdehydes from periodate oxidation of methyl 4,6-0-benzylidene-a-and -p-D-glucopyranoside reacted with appropriate Wittig reagents to give such dienes as (400) that afforded cyclized products [e.g. (401)] with nitromethane by a double Michael condensation, whereas only one of the olefinic linkages was attacked, without cyclization, with ethyl cyanoacetate and malononitrile. Details of the reactions of these dialdehydes with nitroalkanes (see Vol. 8, p. 108), ethyl cyanoacetate (see VoL 8, p. IlOX and other carbanions to give various branched-chain heptoseptanosides have also been reported. ... 

The reaction of 2-C-hydroxymethyl glycals with phenols or phthalimide under Mitsunobu conditions to produce 2-C-methylene glycosides has been reported (See Vol. 27, p. 178, ref. 51 for the same reaction under Lewis acid conditions). The condensation of malononitrile and methyl 4,6-( -benzylidene-3-deoxy-a-D-crytAro-hexopyranoside-2-ulose under basic conditions affords the corresponding methyl 4,6-0-benzylidene-2-(dicyanomethylene)-2,3-dideoxy-a-D-eryt/iro-hexo-pyranoside. This latter compound on reaction with 3-benzyl-2-methylthio-2-thiazolinium iodide affords butadiene 58 whilst with 3-benzyl-4,5-dihydro-2-methylthio-l,3-thiazinium iodide, 59 is produced. ... 

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