A 2-Azapentadienyl Carbanion: a Nonstereospecific Electrocyclization

1975 ◽  
Vol 53 (3) ◽  
pp. 355-365 ◽  
Author(s):  
D. H. Hunter ◽  
R. P. Steiner
Keyword(s):  
Proton Transfer ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Butyl Alcohol ◽  
Open Chain ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Cis And Trans ◽  
Protic Media

Treatment of 1,3,5-triphenyl-4-aza-1,3-pentadiene under selected basic conditions leads to either isomerization among the azapentadienes or to cyclization. Analysis of the products from reaction under aprotic conditions (LiTMP in THF) suggested that the open-chain delocalized carbanion exists in both the W and sickle forms. The open-chain anions were observed to electrocyclize in a nonstereospecific manner to produce a 1:1 mixture of cis- and trans-2,4,5-triphenyl-1-pyrrolines. Reaction in protic media (methanol and tert-butyl alcohol) produced a 1,5-proton transfer as well as cyclization. The details of the 1,5-proton transfer reaction were elucidated using methanol-O-d and the collapse preferences and intramolecularity in this medium were determined.

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

Transfer Thermodynamic Functions ∆Gt0, ∆Ht0 and T∆St0 of cis- and trans-[CoCl2(en)2]+ Isomers in Aqueous Mixtures of Methanol, tert-Butyl Alcohol and Acetonitrile

2000 ◽  
Vol 65 (9) ◽  
pp. 1455-1463
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Enthalpy Of Solution ◽  
Transfer Functions ◽  
Partial Molar Volumes ◽  
Butyl Alcohol ◽  
Aqueous Mixtures ◽  
Aqueous Methanol ◽  
Solvent Interactions ◽  
Tert Butyl Alcohol ◽  
Surface Charge Distribution ◽  
Cis And Trans

The solubility, partial molar volume and standard integral molar enthalpy of solution of cis- and trans-[CoCl2(en)2]Cl in water, aqueous methanol, aqueous tert-butyl alcohol and aqueous acetonitrile are reported. The transfer functions ∆Gt0, ∆Ht0 and T∆St0 as well as partial molar volumes are used to obtain information on the solute-solvent interactions. Results obtained are discussed in terms of differences in the surface charge distribution in isomeric coordination species.

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