Butadienyl

Write out the coefficients of the butadienyl system, as they are produced by program MOBAS, in matrix form. Is the matrix symmetric If not, can it be made symmetric by exchanging rows only ... 

Draw charge density diagrams for the positive ion, free radical, and negative ion of the butadienyl system. 

Draw bond order and free valency index diagrams for the butadienyl system. Write a counter into program MOBAS to detemiine how many iterations are executed in solving for the allyl system. The number is not the same for all computers or operating systems. Change the convergence criterion (statement 300) to several different values and determine the number of iterations for each. 

Methyl-lf 2-butadienyl acetate (l-acetoxy-2-methyl-1 2-butadiene)... 

The reaction of the vinylcyclopropanedicarboxylate 301 with amines affords an allylic amine via the 7r-allylpalladium complex 302[50]. Similarly, three-membered ring A -tosyl-2-(l,3-butadienyl)aziridine (303) and the four-mem-bered ring azetidine 304 can be rearranged to the five- and six-membered ring unsaturated cyclic amines[183]. 

The reaction of 2,3-butadienyl acetate (843) with soft carbon nucleophiles such as dimethyl malonate gives dimethyl 2,3-butadienylmalonate (844)[520]. On the other hand, the reaction of the 2,3-butadienyl phosphate 845 with hard carbon nucleophiles such as Mg and Zn reagents affords the 2-allcyl-1,3-butadiene 846[520,521]. The 3-methoxy-1,3-butadiene 848 is obtained by the reaction of the 2-methoxy-2,3-butadienyl carbonate 847 with organozinc reagent. 

The 3-alkyi-1,3-butadiene-2-carboxylate (2-vinylacrylate) 850 is obtained in a high yield by the carbonylation of the 2-alkyl-2,3-butadienyl carbonate 849 under mild conditions (room temperature, atm)[522]. The corresponding acids are obtained in moderate yields by the carbonylation of 2,3-alkadienyl alcohols under severe conditions (100 °C, 20 atm) using a cationic Pd catalyst and p-TsOH[523],... 

A. E)-(2-Methyl-l,3-butadienyl)dimethylalane. An oven-dried, 1-L, twonecked, round-bottomed flask equipped with a magnetic stirring bar, a rubber septum, and an outlet connected to a mercury bubbler is charged with 7.01 g (24 mmol) of dichlorob1s(n -cyclopentadienyl)z1rconium (Note 2) and flushed with nitrogen. To this are added sequentially at 0 C 100 mL of 1,2-d1chloro-ethane (Note 3), 12.48 g (120 mtiol) of a 5016 solution of l-buten-3-yne in... 

Acetoxy-1,3-butadiene (1,3-butadienyl acetate) cis-trans mixture [1515-76-0] M 112.1, b 42-43 /16mm, 51-52 /20mm, 60-61 /40mm, d 4 0.9466, n g 1.4622. The commercial sample is stabilised with 0.1% of p-/er/-butylcatechol. If the material contains crotonaldehyde (by IR, used in its synthesis) it should be dissolved in Et20, shaken with 40% aqueous sodium bisulfite, then 5% aqueous... 

Methyl vinyl dichlorosilane (dichloro methyl vinyl silane) [124-70-9] M 141.1, b 43-45.5 /ll-11.5mm, 91 /742mm, 92.5 /743.2mm, 92.5-93 /atm, d 1.0917, n 1.444. Likely impurities are dichloromethylsilane, butadienyl-dichloromethylsilane. Fractionate through a column packed... 

The product can be recrystallized readily from dimethyl-formamide to give yellow leaflets, m.p. 290-293°. However, it is pure enough to be used in the next step. This synthesis has also been applied to the preparation of l,4-bis-[4-( -tolyl)buta-dienyljbenzene (100%), l,4-bis-[4-(3-nitrophenyl)butadienyl]-benzene (56%), and l,4-bis-(3-methyl-4-phenylbutadienyl)ben-zene (87%). 

This procedure has been applied to the synthesis of 4,4"" dimethylquinquephenyl and 2, 3" -dimethylquinquephenyl from l,4-bis-[4-(j>-tolyl)butadienyl]benzene and l,4-bis-(3-methyl-4-phenylbutadienyl)benzene, respectively. 

Desoxyleukotriene D4 was synthesized to determine whether the 5-hydroxyl group is necessary for biological activity. It is, since the bioactivity of 5-desoxyleukotriene D4 is less than % that of LTD4 itself. An interesting synthetic equivalent of the 4-formyl- , -l,3-butadienyl anion was utilized in the synthesis. 

Silver trifluoroacetate is a suitable catalyst for various cationic rearrangements involving multiple carbon-carbon bonds [49 5(1] In the presence of silver trifluoroacetate, 2 propynyl acetates rearrange to the butadienyl acetates to give dienes that are useful in Diels-Alder reactions [49] (equation 22)... 

From Bidens species 5-metbyl 5 -butadienyl-2 -bithienyl (245) has been isolated, the constitution of which was eonfirmed synthetically. Another 2,2 -bithienyl derivative has been isolated as an additional nematodicidal principal of the roots of Tagetes, for which strueture (246) has been suggested. On the other hand Sorensen et aL have isolated from the thistles, Berkheya macrocepkala and Echinops spareocephalm, a compound with very similar UV and IR spectra as (246) for which they suggested structure (247), based on... 

Oxidation of phenyl hexyl sulphide with sodium metaperiodate gave also only a trace amount of the corresponding sulphoxide72. On the other hand, Hall and coworkers73 prepared benzylpenicillin and phenoxymethyl penicillin sulphoxides from the corresponding benzyl esters by oxidation with sodium metaperiodate in dioxane solution with a phosphate buffer. A general procedure for the synthesis of penicillin sulphoxides was reported later by Essery and coworkers74 which consists in the direct oxidation of penicillins or their salts with sodium metaperiodate in aqueous solution at pH 6.5-7.0. 1-Butadienyl phenyl sulphoxide 4475 and a-phosphoryl sulphoxides 4576 were also prepared by the same procedure. 

Butadienyl sulphoxides may be used as diene compounds in the Diels-Alder cycloadditions. For example, butadienyl phenyl sulphoxide 571 gives a mixture of diastereoisomeric sulphoxides 573 upon heating with an equimolar amount of N-methyl tetrahydrobenzindole 572672 (equation 364). 

Lithium dibutylcuprate reacted with ( )-l, 3-butadienyl p-tosyl sulfone affording (Z)-2-octenyl p-tosyl sulfone. In the reaction of allyl ( )- and (Z)-l, 3-dibutadienyl sulfones with lithium dibutylcuprate or lithium (Z)-di(l-butenyl) cuprate, the major compound obtained was of (Z)-geometry around the 2,3-double bond, indicating that (Z)-selectivity is not so high in this reaction (56-79%)408-... 

The Ramberg-Backlund reaction has been utilized for the preparation of polyenes. 1,3-Butadienyl allyl sulfones 398 and 399 were transformed into the tri- and tetra-enes 400 and 401 by alkylcuprate addition and the Ramberg-Backlund-type S02 extrusion449. Julia and coworkers450 carried out the Michael addition of various nucleophiles such as ethanol, t-butyl acetoacetate and phenyl thioacetone to allyl dienyl sulfones 402 and then converted them to diallyl sulfones 403. The sulfones were transformed into isoprenoid, 404 by the Ramberg-Backlund reaction. 

Bunnett and Olsen equation 566 Butadienyl sulphones, reactions of 644, 652 Butadienyl sulphoxides reactions of 360 synthesis of 246, 279... 

Bis(4-hydroxyphenyl) sulphones butadienyl - see Butadienyl sulphones chiral - see Chiral sulphones complexes of 573 cyclic - see Cyclic sulphones cycloalkenyl - see Cycloalkenyl sulphones cycloalkyl aryl - see Cycloalkyl aryl sulphones... 

Bis(4-hydroxyphenyl) sulphoxides butadienyl - see Butadienyl sulphoxides carbamoyl - see Carbamoyl sulphoxides chiral - see Chiral sulphoxides complexes of 567-573 conformational analysis of 84-89 cyclic - see Cyclic sulphoxides cyclopentanone - see Cyclopentanone sulphoxides... 

Very recently, Cook and Danishefsky [24] reported an interesting regioselectivity of intramolecular Diels-Alder reactions reversed by the change in the dienophihc moieties from vinyl to allenyl group (Scheme 19). For R = 2-propenyl group, C is bonded to the methyl substituted carbon Cj of the cyclohexadienone ring. For R = 2,3-butadienyl, C is bonded to Cy... 

The allyl ether has larger amplitnde at than (Scheme 21) as propene does at Cj (Scheme 20). In the 2,3-butadienyl ether the ti bond is perturbed by... 

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