- Substituent effects on partition coefficients of barbituric acids
-
Precise partition coefficients in 1-octanol-water at 25°C were determined for three 2-thiobarbituric acids and 14 barbituric acids with a wider range of substituents. The experimental log P values (log P(exp)) of barbituric acids were correlated with the carbon number and the branching effect of the C5 substituent(s) by linear regression analysis. The carbon number term makes a major contribution to the partition coefficients. The contribution of the polar effect of the C5 substituents was insignificant in contrast to a previous report. Hydrophobic constants (π) were determined for allyl, phenyl, and chloro-substituents, and these emperical π values gave much closer predicted calculated log P (log P(calc)) values when applied to the reported log P(exp) values.
- Wong,McKeown
-
p. 926 - 932
(2007/10/02)
-
- Synthesis of 4,4-Disubstituted 1,3-Thiazol-5(4H)-thiones
-
An easy synthesis for the 1,3-thiazol-5(4H)-thiones 5, a class of heterocycles which have hitherto only been available with difficulty, is described.Reaction of 3-amino-2H-azirines 25 with thiocarboxylic acids at 0 deg yields monothiodiamides of type 20 (Scheme 6) which, on treatment with Lawesson reagent at 100 deg, undergo thiation and cyclization to give 5 in good yield.
- Jenny, Christjohannes,Heimgartner, Heinz
-
p. 374 - 388
(2007/10/02)
-
- A Facile Displacement of Tertiary Nitro Group by Hydrogen with Sodium Hydrogentelluride
-
Sodium hydrogentelluride is a useful reagent for replacement of a class of tertiary nitro group by hydrogen.
- Suzuki, Hitomi,Takaoka, Koji,Osuka, Atsuhiro
-
p. 1067 - 1068
(2007/10/02)
-