Triazolinedione

When the carbonyl groups are present, the transition state for syn attack is sta-bihzed by interactions between the in-phase combination of the NN lone pairs and the antisymmetric n orbital of the CO-X-CO bridge (100). Although the secondary effect (SOI) operates only during syn approach and contributes added stabilization to this transition state, the primary orbital interaction (see 103) between the HOMO of the cyclohexadiene moiety of 100 and the n orbital of the dienophile (NN, Fig. 16) is differentiated with respect to the direction of attack, i.e., syn or anti, of triazolinedione (NN, Fig. 16). 

Gleiter and Ginsburg found that 4-substituted-l,2,4-triazoline-3,5-dione reacted with the propellanes 36 and 37 at the syn face of the cyclohexadiene with respect to the hetero-ring. They ascribed the selectivity to the secondary orbital interaction between the orbitels (LUMO) of 36 and 37 with antisymmetrical combination of lone pair orbitals (HOMO ) of the triazolinediones (Scheme 24) [29]. 

Chen, J., Houk, K. N., Foote, C. S., 1998, Theoretical Study of the Concerted and Stepwise Mechanisms of Triazolinedione Diels-Alder Reactions , J. Am. Chem. Soc., 120, 12303. 

Bis-triazolinedione compounds such as bis(p-l,2,4-triazoline-3,5-dione-4-ylphenyl)methane, (TD)2DPM, have been used to crosslink... 

This investigation was undertaken to study the important variables in the hydrophilization of polydiene surfaces by ene reaction with triazolinediones (Step 1) followed by neutralization (Step 2) as shown below. These variables included the nature of the... 

The low temperature ene reaction of triazolinediones with polydienes occur under heterogeneous conditions to yield hydrophilic surfaces, especially after neutralization of the resulting pendant urazole groups. Permanent hydrophilic surfaces can be obtained when (TD)2DPM is used. The use of the other RTDs tested results in surfaces that lose their hydrophilicity within 5-20 days. In applications such as improving the adhesion of rubber to other substrates, these reagents are probably sufficient (18). However, when more permanent hydrophilic surfaces are desired a bis-triazolinedione such as (TD)2DPM would be required. 

Formate esters behave as typical carbonyl compounds in reactions with a number of ylides, eliminating phosphine oxide and forming vinyl ethers, e.g. (33).35 Stabilized phosphoranes are able to condense with the carbonyl group of cyclic thioanhydrides (34).38 Quinoline derivatives, e.g. (35), are obtained from the condensation of dicar-boalkoxy-ylides with isocyanates.37 Benzoyl isothiocyanates and keto-phosphoranes give quantitative yields of (36), which are unreactive in Wittig reactions but can be readily oxidized by selenous acid.38 The products obtained from reactions (Scheme 9) with the triazolinedione (37) depend upon the stability of the ylide used.39... 

The triazolinedione adds to cycloheptatriene and cyclooctatetraene to yield the valence-isomeric adducts 265 and 266, respectively (equations 143 and 144)136. 

Chlorocyclononatetraene 267 rapidly rearranges in liquid sulfur dioxide to 1-chloro-8,9-dihydroindene 268, which forms the cycloadduct 269 with the triazolinedione 264 (equation 145)137. The vinylimidazole 270 affords the purine analogue 271 (equation 146)138. 

A selection of the many applications of cycloaddition with the triazolinedione 264 follows. 

Density functional theory has been used to investigate the Diels-Alder reactions of triazolinedione with s-cis- and. y-fran -butadiene. " Combined quantum mechanics-molecular mechanics calculations have been used to investigate the asymmetric Diels-Alder reaction of cyclopentadiene with the complex dienophiles AICI3-methyl acrylate and methoxyaluminium dichloride-acrolein.Equilibrium constants have been determined for the molecular complexes formed from 1-alkyl-1-(2-naphthyl)ethenes and 1-vinylnaphthalene with TCNE in C1(CH2)2C1 at 27.1 °C ... 

The total synthesis of ( )-ancistrofuran has relied on the ene reaction of N-phenyltriazolinedione (PTAD, 564) with the alkylidene lactone (563) (81JOC1198,80JOC4287), Upon completion of this room temperature reaction an attempt was made to acetylate the free NH group in (565) (2 1 mixture of diastereoisomers). The cyclized ethers (566) and (567) were, however, obtained instead. The triazolinedione thus functions as a very good... 

A3-Triazolines (7A-7E) Prepared from Vinyl Azides (A-E) and Triazolinedione... 

A reaction mechanism in which the / carbon of the vinyl azide attacks the N-N double bond of the triazolinedione to give an intermediate which cyclizes with loss of nitrogen to the triazoline has been proposed (Scheme 3).6... 

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