Synthesis of 1-Amino-2,5-dihydro-1H-phosphole 1-Oxides and Their N-Phosphinoyl Derivatives, Bis(2,5-dihydro-1H-phosphol-1-yl)amine P,P′-Dioxides
摘要:
Depending on the molar ratio of the reactants and on the order of mixing, the reactions of a series of primary amines with 1-chloro-2,5-dihydro-1H-phosphole 1-oxides prepared in situ from the corresponding hydroxy-dihydrophosphole oxides afforded 1-amino-2,5-dihydro-1H-phosphole 1-oxides, or their N-phosphinoyl derivatives, bis(2,5-dihydro-1H-phosphol-1-yl)amine P,P'-dioxides. The latter family of P-heterocycles could also be synthesized by the reaction of 1-amino-2,5-dihydro-1H-phosphole oxides with chloro-dihydrophosphole oxides.
A few phosphinicacids, such as phenylphosphinic acids, 1-hydroxy-3-phospholene 1-oxides and 1-hydroxyphospholane oxides are esterified with simple alcohols in the presence of propylphosphonic anhydride (T3P®). If 1.1 equiv of the T3P® reagent is used, the esterifications are fast and efficient at 25° C. In the case of more reactive models it was enough to apply 0.66 equiv of T3P® at 85° C under microwave
Abstract Phosphinic acids may be efficiently esterified in microwave-assisted reactions with alcohols. Especially alcohols with longer alkyl chain are suitable reagents for direct esterifications. At the same time, the directamidation cannot be complete under such conditions. Hence, the tradional amidations via the phosphinic chloride intermediates have to be applied. The values of activation enthalpies