Butadienes diaryl

Variously substituted siloles of type 129 could be synthesized by Tamao and coworkers by the reaction of l,4-diaryl-l,4-dilithio-l,3-butadienes of type 128 with chlorosilanes . The l,l -spirobisilole 130 was accessible by reaction of the diphenyl snbstitnted dilithium compound 128a with tetramethoxysilane (Scheme 47). All of the dilithium compounds 128a-e were obtained by reaction of 2,5-diaryltellurophenes 127a-e with i-butyllithium in diethyl ether. 

Hexatriene may be arylated similarly to 1,3-butadiene. Iodobenzene and aryl halides with electron-donating substituents require more catalyst (as in the butadiene reactions) than aryl halides with electron-withdrawing substituents to give 1,6-diarylated hexatrienes in a reasonable time. 

Other nucleophiles than amines which have been employed in the reaction are malononitrile and cyanoacetic ester anions. Both of these anions undergo a preliminary reaction with the aryl halide to form the C-aryl derivatives before they attack the ir-allylpalladium intermediate, so that diarylated products are formed (equation 31).86 Phenylmalononitrile anion reacts with iodobenzene and butadiene to give the same product in 70% yield. 

Diaryl butadienes 69 can be made by method 61b as the ylid from 68 is conjugated and will give one -alkene while the other comes from an aldol condensation used to make the enal.15 (chapter 19). 

Diaryl ethers are cleaved rapidly. Polyethylene tereph-thalate) is cleaved at 300°C. Vegetable oils can be hydrolyzed in more than 97% yield with water in 15-20 min at 260-280°C.211 The nitrile, amide, and ester groups in various copolymers of butadiene and ethylene can be hydrolyzed to carboxylic acid groups with water at 250-300°C.212 Phenols can be alkylated with secondary and tertiary alcohols in water at 250-350°C, but the reac-... 

Die oxidative Gyclisierung von 1,2-Diaryl-athylenen laBt sich auch auf 1,4-Diaryl-butadiene und auf hdhere konjugierte , -diarylsubstituierte Polyene, iibertragen3-5 ... 

Diaryl-1,3-butadienes are obtained from ArCOMe directly by the reaction with Sml2 and AC2O in refluxing THF. ° Transannular addition of ketyl species generated from meso-cyclic ketones to a double bond is quite efficient. 

A significant development in 1,2,3-oxadiazine chemistry is the preparation, in moderate yields (30-55%), of the 3,6-diaryl-2-arylsulfonyl-2,3-dihydro-6/f-derivatives (28) by a [4 -I- 2] regiospecific cycloaddition of 1,4-diaryl-1-aza-1,3-butadienes (26) with arenesulfonyl nitrosites (27 Ar = Ph or... 

There is a solitary report on the synthesis of 2,5,6-triaryl-5,6-dihydro-2//-l,2,6-thiadiazine 1-oxides (275) by Diels-Alder [4 + 2] cycloaddition of 1,4-diaryl-l-aza-l,3-butadienes (273) with arylsulfinylamines (272) (Equation (37)). Yields are in the range of 60-80% <88IJC(B)843>. 

Equally rare are 1,2,6-thiadiazine 1-oxides, however, they are available by cycloaddition of 1,4-diaryl-1-aza-1,3-butadienes with arylsulfinylamines (Section 6.16.9.2.2.1). 

The alternative direction ((b) on page 124) is suitable for 1,4-diaryl butadienes (28). These were needed with a variety of substituents for a systematic study of electronic effects on the Diels-Alder reaction. Disconnection to give benzyl phosphonium salts (30) and easily made cinnamaldehydes (29) (see Chapter 18) is best. 

A novel method for preparing l-phenylthio-2,3-disubstituted butadienes (313) involves reaction of 3,4-diaryl-2,5-dihydrothiophenes with benzyne. The mechanism probably involves initial betaine formation, followed by conversion to the ylide. Disrotatory ring opening would then give the product. The major product has the Z configuration (Scheme 59). A minor product is the thiophene (314) this may be formed by a symmetry allowed hydrogen transfer <89TL847>. c -2,5-Dimethyl-... 

Compounds tested and found active in vitro against M. tuberculosis include 5-arylamino-3-pheny1thiazolidin-2,4-diones 2,3-diaryl-5-arylazo-4-thiazolidinethione-1,1-dioxides N-substituted benzisothia-zolin-3-thiones 5 4-(indol-3-yl)-imidazoles , indol-3-ylcarboxylic acids and hydrazides 3-halophenylazoindoles , 3,4-dihydropyrido[2,3-d]pyri-dazin-1[2H]-one 5, Schiff bases from isoniazid and substituted benzalde-hydes °, 5-n-butylpyridine-2-carboxylic acid hydrazide, 4-thiosemicar-bazido-2-[(5-nitrofuryl)vinyl]quinolones and butadiene analogs3-thio-4 3H)quinazolone derivatives, and N- ji-tolyl)-N -(2-benzothiazolyl)-N "-alkylquanidines. ... 

Aznar, et al. reported a proline-catalyzed imino-Diels-Alder reactions of acyclic a,p-unsaturated ketones 96 with imines 92 for the synthesis of mc50-2,5-diaryl-4-piperidones 98, Scheme 3.35 [50], The 2-amino-1,3-butadiene was generated in situ by the reaction of a,p-unsaturated ketones 96 with L-proline, followed by Diels-Alder cycloaddition with imine 92 to provide tetrahydropyridine adduct which was then hydrolyzed to the 4-piperidone 98. 

E,E)-l,4-Diaryl-l,3-dienes. A mixture of p-bromostyrene, catalytic amounts of dichlorobis(2,2 -bipyridyl)nickel(II) and PbBr2,. 7 and Al in methanol stirred at room temp, for 6 h under argon 1,4-diphenyl-1,3-butadiene. Y 83% (E,E/E,Z 97 3). KI is not essential, but quickens the process BiCl3 is effective in place of PbBr2. F.e. and conversion to terphenyls via diene synthesis s. H. Tanaka et al.. Tetrahedron Letters 30, 26 -A (1989). 

Figure 1 Polymer interpretation chart. PAI, polyamideimide PC, polycarbonate UP, unsaturated polyester PDAP, diarylate phtalate resin VC-VAc, vinyl chloride-vinyl acetate copolymer PVAc, polyvinyl acetate PVFM, polyvinyl formal PUR, polyurethane PA, polyamide PMA, methacrylate ester polymer EVA, ethylene-vinyl acetate copolymer PF, phenol resin EP, epoxide resin PS, polystyrene ABS, acrylonitrile-butadiene-styrene copolymer PPO, polyphenylene oxide P-SULFONE, poly-sulfone PA, polyamide UF, urea resin CN, nitrocellulose PVA, polyvinyl acetate MC, methyl cellulose MF, melamine resin PAN, polyacrylonitrile PVC, polyvinyl chloride PVF, polyvinyl fluoride CR, polychloroprene CHR, polyepichlorohydrin SI, polymethylsiloxane POM, polyoxy-methylene PTFE, polytetrafluoroethylene MOD-PP, modified PP EPT, ethylene-propylene terpolymer EPR, ethylene-propylene rubber PI, polyisoprene BR, butyl rubber PMP, poly(4-methyl pentene-1) PE, poly(ethylene) PB, poly(butene-l). (Adapted from Ref. 22, p. 50.)...

A,iV-diaryl-l,4-diaza-l,3-butadienes also form stable dimethyl- and chloro(methyl)-platinum complexes 16 and 17. Addition of the ligand to Pt2Me4(/i-SMe2)2 and PtMe2(cod) yields the dimethylplatinum(ii) complexes having chelating diimines. 

Efficient photo-isomerization of water-soluble 1,4-diaryl-l,3-butadiene dendrimers (19) occurred in high quantum yield (Scheme 11). " E-Z photoisomerization of benzylidene-oxazolones (Z-20) and ( -20) was also reported as molecular photo-swiches. The ring size effects of aromatics of styrylbenzothiazol (21) were examined (Scheme 12). ... 

Singh et al. (2008) studied a microwave-assisted [4+2] cycloaddition reaction for the synthesis of unsymmetrically substituted 1,4-dihydropyridines. 1,4-Dihy-dropyridine analogs such as Nifedipine and Nimodipine are well known for their potent biological activities. Microwave-assisted [4+2] cycloaddition of 1,4-diaryl-1-aza-1,3-butadienes with allenic esters at 100°C for 5-17 min gave cycloadducts in excellent yields (83-96%), which after a tandem 1,3-H-shift furnished unsymmetrically substituted 1,4-dihydropyridines. 

Dilithio-l,3-dienes 1 could react with diaryl diazomethanes to give multi-substituted 1-imino-pyrrole or indole derivatives 46 in high yields [73]. In this reaction, diaryl diazomethanes reacted as electrophiles. Besides, synthetic methods for Af-imino-pyrrole and indole derivatives are limited. Only when 2,3-cyclic-1,4-diphenyl-1,4-dilithio-l, 3-butadiene 1 were treated with 2.2 equivalents of... 

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