Cinnamylidene

Recently a novel reaction between the azlactone 76, R = Ph R = Me, and cinnamylidene aniline yielding the adduct 79 has been described.This result has been interpreted as involving a Diels-Alder cycloaddition between cinnamylidene aniline and the valence tautomeric ketene 78, R = Ph R = Me. 

Cinnamylidene chloride (A) reacts with ethanol (B) to give HC1 (C) and a complicated organic molecule (D) by the reaction... 

In this way cinnamic aldehyde and malonic acid give cinnamylidene malonic acid. 

This latter, like all malonic acid derivatives, loses carbon dioxide on heating, and yields cinnamylidene acetic acid (see Preparation 427). For another and similar condensation brought about by amines, see Reaction XLV. 

At approximately 200°C, cinnamylidene malonic esters react with elemental sulfur and (l,2-dithiol-3-ylidene)malonic esters (27) are obtained (Eq. 4).14 15... 

Structural proofs have been given by comparing some of the preceding condensation products with compounds obtained by reacting elemental sulfur with cinnamylidene compounds. Condensation of 5-p-methoxyphenyl-3-methylthio-l, 2-dithiolium iodide with ethyl cyanoacetate3 5 4 2 folio wed by the ethanolysis of the cyano group gave the same dithiolylidene malonate as the reaction of elemental sulfur on ethyl p-methoxycinnamylidene malonate.15... 

The effect of temperature upon selectivity has been shown in a striking manner by Zafiriadis (54,55) in the hydrogenation of cinnamylidene-methylhexyl ketone with Raney nickel. At 40° the ethylenic bonds were reduced at 130° the carbonyl function was reduced to the alcohol and at 260° the phenyl ring was reduced. 

The data on UV-spectroscopy of nitroisoxazoles are rather scarce. It is known that X for 3,5-dimethylisoxazole is 215-220 ran, whereas that for its 4-nitroderivative lies in a field of 250-270 nm depending on the medium (see Table 3.65) [483,499, 1125, 1159], It is shown [483] that for 5-(p-methoxystyryl)- and 5-cinnamylidene derivatives of 3-methyl-4-nitroisoxazole, the absorption band is moved to the longwave area (290 nm, lg e 4.15). The absorption band maxima of 3-methyl-4-nitro-5--styrylisoxazole photodimers lie in field of 268-272 nm. In works of the Italian authors the electron absorption spectra of some derivatives of nitroisoxazole are described [1160],... 

Generally, as discussed previously, the mechanism involved in the cross-linking of fluoroelastomers is the removal of hydrogen fluoride to generate a cure site that then reacts with diamine [39], bisphenol [40], or organic peroxides [41] that promote a radical cure by hydrogen or bromine extraction. Preferred amines have been blocked diamines such as hexamethylene carbamate (Diak No. 1) or bis(cinnamylidene) hexamethylene diamine (Diak No. 3). Preferred phenols are hydroquinone and the bisphenols such as 4,4 -isopro-pylidene bisphenol or the corresponding hexafluoro-derivative bisphenol AF. 

SYNS ANTHRANILIC ACID, N-(3-(p-tert-BUTYLPHEN-YL)-2-METHYLPROPYLIDENE)-, METHYL ESTER BENZOIC ACID,2-((3-(4-(l,l-DIMETHYLETHYL)PHEN-YL)-2-METHYLPROPYLIDENE)AMINO)-, METHYL-ESTER METHYL-N-(p-tett-BUTYL-a-METHYLHYDRO-CINNAMYLIDENE) ANTHRANILATE VERDANTIOL... 

Poly(methoxymethylstyrene) and co-polymers from (2,2-disubstituted 1,.5-dioxolan-4-yl)methoxymethylstyrene crosslink readily under u.v. light (Scheme 17). Here both the 1,3-dioxolane and benzyl methyl ether structures participate in the crosslinking. o-Nitrobenzyl cholate esters have been used as effective photosensitizers in resists," as have poly-(N-vinylamine) and methacrylate co-polymers with substituted cinnamic or cinnamylidene groups. 

Ab initio and density functional theoretical studies of the 4 -b 2-cycloaddition of 2-azabutadiene with formaldehyde predict a concerted reaction that agrees well with experimental evidence. " The azadiene A-phenyl-l-aza-2-cyanohuta-1,3-diene reacts with electron-rich, electron-poor, and neutral dipolarophiles imder nuld thermal conditions. 5,6-Dihydro-4//-l,2-oxazines have been shown to he useful as synthon equivalents of 2-cyano-l-azabuta-l,3-dienes. The intramolecular Diels-Alder reaction of 1-aza-1,3-butadienes (106) can be activated by a 2-cyano substituent (Scheme 37). Stereoselectivity in the hetero-Diels-Alder reactions of heterobutadienes, nitrosoalkenes, and heterodienophiles has been extensively reviewed. The azadiene l-(t-butyldimethylsilyloxy)-l-azabuta-l,3-diene (107) reacts with halobenzo-quinones, naphthoquinones, and A/ -phenylmaleimide to yield low to good yields of various pyridine heterocycles (108) (Scheme 38). The 4 -b 2-cycloaddition of homophthalic anhydride with A/ -(cinnamylidene)tritylamine produces the 3,4-adduct whereas with A/ -(cinnamylidene)benzylidine the 1,2-adduct is produced. ... 

A number of plant toxins are cyclic members of this series. Huratoxin is the piscicidal constituent of Hura crepitans (Euphorbiaceae). X-Ray analysis showed 34 jjg structure [117 R - H, R = CH CH-CH CH(CH2)8Me] was related to daphnetoxin (117 R = H, R = Ph). Mezerein (117) which is the toxic principle of Daphne mezereum, containsthe cinnamylidene acetic ester (R ) and orthobenzoate (R ) units. Ingenol (118), as its 3-hexadecanoic acid ester, is an irritant isolated from Euphorbia ingens Its structure was determined by X-ray analysis of the triacetate. 

Double addition of diazomethane to cinnamylidene cyanoacetic ester 50 (EWG = COOR ) and corresponding dinitriles (51) (EWG = CN) followed by thermolysis gave rise to pyrazoline-substituted cyclopropanes (52) which upon photolysis and acid treatment afforded biscyclopropanes (53) and tricyclic compounds (54) respectively. ... 

The reduction of cinnamylidene fluorene by aluminum amalgam in moist ether to 1-fluorenyl-3-phenyl-l-propene (I), a 1,4-addition, exemplifies the use of Al(Hg) rather than Na(Hg) for the reduction of alkali-sensitive compounds in the presence of Na(Hg), I might be tautomerized to 3-phenyl-1-propylidene fluorene [26]. Another example is the reduction of a cumulene, l,l,6,6-tetraphenyl-l,2,3,4,5-hexapentaene, to 1,1,6,6-tetraphe-nyl-l,2,4,5-hexatetraene by Al(Hg) [27]. 

Methyl 2,3 4,6-di-0-cinnamylidene-Methyl 2,3 4,6-di-O-crotonylidene-Methyl 2,3 4,6-di-O-methacrylidene-Methyl 2,3-O-isopropylidene-6-O-methyl-... 

Another type of chromophore modification can be accomplished by extension of the unsaturated chain length. The spectral responses of poly(vinyl acetate cinnamate) and poly(vinyl acetate cinnamylidene acetate) (Fig. 6) typify this method 39>. 

Fig. 6. Wedge spectrograms of poly(vinyl cinnamate) and poly(vinyl cinnamylidene-acetate)...

The benzylidene and cinnamylidene compounds correspond to oxime-like structures in which the -OH has been replaced by a hydrocarbon group. Because both sides of the CH=N group are sub-stituted by bulky hydrocarbon groups, syn-/anti- isomerism is not ordinarily observed in the NMR spectra. It is assumed that the compounds exist primarily in the anti- form (substituents on op-posite sides of the CH=N bond). 

Scheme 16 Structure of the cinnamylidene malonic ester polymer (CM) before and after cross-linking with 2>395 nm for 20 min and 100 mW cm. REPRINTED WITH PERMISSION OF [Ref. 120], COPYRIGHT (2000) Wiley-VCH Verlag GmbH...

The imaging performance of poly(vinyl cinnamate) when exposed by a medium-pressure mercury arc lamp is poor. This is due to the mismatch between the absorption spectrum of the cinnamoyl group (with absorbance maximum at 280 nm) and the spectral emission of the mercury arc. The absorption spectrum of poly(vinyl cinnamate) does not overlap with most of the strong emission lines of a mercury arc lamp. This problem can be overcome by spectral sensitization, for example, with the addition of 5% of Michler s ketone, or by the replacement of the cinnamoyl group with a chromophore such as in poly(vinyl cinnamylidene acetate) (IV) that absorbs at longer wavelengths. ... 

---