A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA) in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH) losses. Additionally, the grafting in chitosan with LA produced films with ...

Rearrangement of cholesta-2,4,6-triene in the presence of p-toluenesulfonic acid in acetic acid at 70 C leads to 4-methyl-19-nor-cholesta-1,3,5(10)-triene and 1(10 ! 6)-abeo-14b-cholesta-5,7,9(10)-triene in less than 2 h. Postulated mechanisms of formation of these products are supported by molecular mechanics calculations of the relative stabilities of reaction intermediates. The results sugge...

A three-component reaction between 1,2-phenylenediamine, ferrocenecarbaldehyde, and isocyanides in the presence of a catalytic amount of p-toluenesulfonic acid for the synthesis of 3,4-dihydroquinoxalin-2-amine derivatives containing a ferrocene unit is reported. This approach is an effective procedure because the products have a broad spectrum of biological and pharmacological activities such ...

microwave-assisted three component cyclocondensation reactions of aldehydes, amides and dienophiles in the presence of acetic anhydride and para-toluenesulfonic acid as a catalyst to afford the highly substituted cyclohexene derivatives, in relatively good yields after several minutes are reported.

A series of different 1-monosubstituted and 1,1-disubstituted 1,2,3,4-tetrahydro-isoquinolines was synthesized in high yields from different ketoamides. We have developed a convenient method for the synthesis of disubstituted derivatives by interaction of ketoamides with organomagnesium compounds, followed by cyclization in the presence of catalytic amounts of p-toluenesulfonic acid (PTSA). A n...