330598-06-6Relevant academic research and scientific papers
Aminophosphonic derivatives of chromone. synthesis of novel chromone-3-(α-amino) methanephosphonic acids
Boduszek, Bogdan,Lipinskp, Margin,Kowalska, Maria W.
, p. 179 - 189 (1998)
Reactions of 3-formylchromones with benzyl carbamate and triphenyl phosphite in acetic acid lead to the corresponding diphenyl chromone-3-[α(-N-benzyloxycarbonyl)amino]methanephosphonates 2 in high yields. Deprotection of the Z-substituted diphenyl esters 2 by means of acetic hydrogen bromide solution and the subsequent hydrolysis by means of 20% aq. HCl, lead to the final chromone-3-(a-amino)methanephosphonic acids 4. Attempts of synthesis of the corresponding chromone-2- aminophosphonic derivatives by this way, have failed. On the other hand, chromone-2-(α-amino)methanephosphonic acid (6) was successfully obtained by an addition of tris(trimethylsilyl) phosphite to the aldimine, which was formed from the 2-formylchromone.
Acid-catalyzed cleavage of some chromone, coumarin and pyrone derivatives of aminomethylphosphonic acid. Products and kinetics of the reaction
Boduszek,Latajka,Walkowiak
, p. 63 - 69 (2007/10/03)
Treatment of chromone-2, coumarin-4 and pyrone-2 derivatives of N-benzylaminomethylphosphonic acid with strong mineral acids leads to formation of the corresponding heterocyclic amines and phosphoric acid. Kinetic studies of this cleavage reaction demonstrate that protonation has a remarkable influence on a cleavage of C-P bonds. In aq. H2SO4, cleavage of the acids 1-3 exhibits a kinetic dependence on [H+]. The measured solvent isotope effect (kH/kD) was about 1.5 for the 1 and 2 and only 1.1 for the 3. The existence of the isotope effect shows that protons are involved on the rate-determining step. The data obtained suggest that the protonated phosphonate molecule is split by a dissociative mechanism with A-SE2 character and this is combined with an elimination of the phosphonate group as a positive-charged phosphorus moiety.
