Synthesis of 1,4-phenylene-bis-aminomethanephosphonates: The stereochemical aspect

First synthesis of 1,1′-ferrocene bis-aminophosphonic esters

“…Unfortunately, diastereoisomers were not separated due to their fragility to silica gel and neither applied cellulose powder nor aluminium oxide were found to be efficient enough to provide a good resolution of diastereoisomers. The addition of phosphites to terephthalic and isophthalic imines is in 100% stereoselective [38][39][40] leading to the formation of a meso-form and we suggested [39] that this stereoselective addition to completely achiral compounds originated from intermolecular interactions between two molecules of the mono-addition intermediate products and two phosphite molecules (Scheme 2(a)). In case of ferrocene derivative, it takes the most probably the conformation as in Scheme 2(b), which seems to be the most convenient one.…”

Cellulose-SO3H catalyzed synthesis of bis(α-aminophosphonates) and their antioxidant activity

“…[11][12][13] However, all these reactions were not succeed with one-pot single step reaction methodology as they are reversible due to the water liberated from the imine formation reaction will decomposes the product formed and hence deactivates the Lewis acid. 14 This drawback has been limited up to certain extent by some of the recent synthetic methods for the synthesis of α-aminophosphonates by the addition of dialkyl/ diarylphosphites to schiff's bases, 15 N-α-naphthylimines prepared from terephthalic and isophthalic aldehydes to yield corresponding N-α-naphthylamino-phosphonates in good yields. 16 Lewkowski et al, 17 synthesized bis(α-aminophosphonates) via the phosphite addition to N-(o-substituted phenyl) terephthalic schiff's bases.…”

Chemical and biocatalytical methods of determination of stereomeric composition of 1,4-di[(diethoxyphosphoryl)hydroxymethyl]benzene

“…The dependence of stereochemical composition of products on the structures of used terephthalic imines was investigated 14 and a possible mechanism of a predominant formation of one diastereoisomer formation from achiral substrates was supposed. 15 The formation of only one diastereoisomer, namely meso form of this compound was well documented 16 which strongly suggests that the similar stereochemical phenomenon may occur during the synthesis of 1,…”