Synthetic routes to bis(3-aminophenyl) phosphinic acid

A study on the acidic hydrolysis of cyclic phosphinates: 1‐Alkoxy‐3‐phospholene 1‐oxides, 1‐ethoxy‐3‐methylphospholane 1‐oxide, and 1‐ethoxy‐3‐methyl‐1,2,3,4,5,6‐hexahydrophosphinine 1‐oxide

“…Most of the hydrolyses have not been optimized, and hence, the quantity of the hydrochloric acid and the conditions including the reaction time are excessive. [3,4] This is well demonstrated by the hydrolysis of diethyl arylphosphonates performed in 6 equivalents of concentrated (cc.) hydrochloric acid at the boiling point for 12 hour.…”

“…The ratio of the 1-hydroxy-3-phospholene oxide (2a) and its 2-phospholene isomer (4a) was 1:9 ( Table 1, entries 3 and 4). Decreasing the quantity of water and hydrochloric acid to the half amount, the conversion remained incomplete (92%) ( 4 ] ionic liquid to the reaction mixtures, somewhat lower conversions were obtained. This was surprising, as in other kind of reactions, the use of ionic liquid additives was highly beneficial.…”

“…In most cases, the acid‐catalyzed hydrolysis is preferred, carried out by boiling the mixture of the P‐ester in aqueous hydrochloric acid. Most of the hydrolyses have not been optimized, and hence, the quantity of the hydrochloric acid and the conditions including the reaction time are excessive . This is well demonstrated by the hydrolysis of diethyl arylphosphonates performed in 6 equivalents of concentrated (cc.)…”

Microwaves as “Co-Catalysts” or as Substitute for Catalysts in Organophosphorus Chemistry

“…The opposite reaction of esterification is hydrolysis that is of high importance also in the sphere of P-esters [ 43 , 44 ]. The hydrolysis of phosphinates and phosphonates is carried out, in most cases, under acidic conditions [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ], but, among other possibilities, base-catalyzed cases also occur [ 53 , 54 , 55 , 56 , 57 ]. It was a new approach to perform the hydrolyses under MW irradiation.…”

Optimization and a Kinetic Study on the Acidic Hydrolysis of Dialkyl α-Hydroxybenzylphosphonates

“…The hydrolysis of P-esters (e.g., phosphinates and phosphonates) resulting in the formation of the corresponding acids (phosphinic acids and phosphonic acids, respectively) is an important chemical transformation, and hence it is applied widely in syntheses. Most often, the hydrolyses were performed under acidic conditions [ 1 , 2 , 3 , 4 ], but the application of NaOH or KOH is also common [ 5 , 6 , 7 , 8 ]. An additional possibility is the fission of the P-O-C unit by the effect of Me 3 SiBr [ 9 , 10 , 11 ].…”