Guanidine residues

Add (Nafion or molybdic add)- and base (diamine-based or guanidine residues)-catalyzed reactions in the same pot Sol-gel immobilization of both catalysts... 

Some Gua lesions are characterized by a guanidine residue that can be detected spectrophotometrically using l,2-naphthoquinone-4-suphonate as the reagent (Kobayashi et al. 1987). The resulting product is shown in reaction (19). 

Whilst the fully protonated version of the compound 24a was readily soluble in methanol and water, solubility problems of the neutral zwitterionic form 24b meant that analysis could only be performed in DM SO-c/V, and then only up to concentrations of around 5mM. Further deprotonation of the guanidine residue by treatment of a second equivalent of base allows the formation of the anion 24c that is once again freely soluble in methanol and water. 

NH signal of the guanidine residue should appear at about +200 ppm from CHjNOj. 

Although RNA is ss, it usually does not bind to membranes (Nygaard and Hall, 1963) due to the often considerable secondary structure. Alkali treatment is hardly possible (hydrolysis RNA) and DMSO dissolves nitrocellulose membranes. Glyoxal has been proposed by Thomas (1980) and has been widely used. Glyoxal binds to guanidine residues and the complex binds efficiently to nitrocellulose after which the glyoxal is removed by incubation at lOO C at pH 8.0. However, RNA should be free of protein which may react with glyoxal. 

The medicinal compounds included in this classification essentially comprise of two guanidine residues —C=NH joined together. A few typical examples belonging to this category,... 

NB This value is most likely to be for the 2° amino group. There should be higher values for the guanidine residues. 

Mainly, the common Dendrodoa grossularia (baked bean ascidian, gooseberry seasquirt). Most of alkaloids isolated from spedes of the genus Dendrodoa contain a guanidine residue, often assodated to the a-carboline system. 

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