56209-30-4Relevant academic research and scientific papers
A practical approach for spiro- and 5-monoalkylated barbituric acids
Singh, Palwinder,Paul, Kamaldeep
, p. 607 - 612 (2007/10/03)
The single step reactions of N,N′- substituted/-unsubstituted barbituric acids with various alkyl dihalides under phase transfer catalytic conditions using DMF-K2CO3 (base), TBAHSO4 (catalyst) provide spirobarbituric acids
A simple synthesis of 5-spirobarbituric acids and transformations of spirocyclopropanobarbiturates to 5-substituted barbiturates
Singh, Palwinder,Paul, Kamaldeep
, p. 247 - 251 (2007/10/03)
The reactions of barbituric acid and its 1,3-dimethyl derivative with 1,2-dibromoethane, 1,4-dibromobutane, 1,5-dibromopentane and 1,2-bis[bromomethyl] benzene in DMF-K2CO3 (base), TBAHSO4 (catalyst) provide 5-spirobarbitu
First Thermodynamic Dissociation Constants of Barbituric Acid Derivatives in Water at 25 deg C. Part 3. 5,5-Alkylenebarbituric Acid Derivatives. A Comparison with 5,5-Dialkylbarbituric Acids, and with Mono- and Di-carboxylic Acids
McKeown, Robert H.,Prankerd, Richard J.
, p. 481 - 487 (2007/10/02)
The synthesis and determination of the first thermodynamic dissociation constants for three 5,5-alkylenebarbituric acid derivatives (II; n=2-4) is described.A pK1 value for a fourth derivative (II; n=5) is also reported.In a previous study the steric effect of the 5-substituents in 5,5-disubstituted barbituric acids, e.g. (I; R1=R2; Me to Et), was found to be acid strengthening.This acid strengthening effect has been attributed to solvent exclusion in the undissociated molecule.In the derivatives (II) steric effects of the 5-substituents are minimized and remain essentially constant.These derivatives all have high pK1 values (8.73-8.88), similar to that, 8.51, of (I; R1=R2=Me).Polar effects of the 5-substituents in the derivatives (II) were small but in keeping with those expected for 5,5-alkylene groups and pK1 values followed the expected inductive order for electron release in derivatives (II) (n=5 > n=4 > n=3 > n=2).Comparison of the pK1 values for the barbituric acid derivatives with those for certain mono- and di-carboxylic acids reveal similarities in substituent effects which are very pronounced in the barbituric acid reaction series, although not as pronounced as in the malonic acid series.
