Hydroxy base

We have shown that the reaction of PtL (L=P(i-Pr).j) with water in acetone or pyridine produces a strong hydroxy base (7). The reaction is described in terms of equilibria (eq. 6-9). By adding NaBF to the solution of PtL in aqueous pyridine, trans-... 

Iboga alkaloids devoid of the 19-hydroxy group are significantly more stable toward oxidation than are the corresponding hydroxy bases. Abstraction of the hydroxy proton of 7-hydroxyindolenines by bases leads to concomitant carbon migration and formation of pseudoindoxyls. In some cases the rearrangement is better accomplished by warm HC1. The interrelationship among indoles, 7-hydroxyindolenines, and pseudoindoxyls has been exhaustively treated by Cordell (see Ref. 6). 

Tropine and pseudo-tropine both possess the same structural formula, for, on oxidation, they each 3deld tropinone, whilst the latter, when reduced, gives a mixture of the two hydroxy-bases (Willstatter and Iglauer, Ben, 1900, 33,1170). Willstatter concluded, therefore, that a cis-/rans-isomerism, dependent on the relative positions in space of the hydroxyl and methyl groups, existed between tropine and pseudo-tropine. Objection to this explanation might be made on the ground that no quite parallel case of isomerism seems to have been observed, and it therefore appeared to the present authors that it should not be accepted unreservedly so long as another explanation is possible. 

The Arrhenius theory of acid-base behavior satisfactorily explained reactions of protonic acids with metal hydroxides (hydroxy bases). It was a significant contribution to chemical thought and theory in the latter part of the nineteenth century. The Arrhenius model of acids and bases, although limited in scope, led to the development of more general theories of acid-base behavior. They will be considered in later sections. 

Treatment of the quinol acetates derived from 5-, 6-, or 7-hydroxytetra-hydroisoquinolines with lead tetraacetate (LTA) in acid gives different types of alkaloids. LTA oxidation of 7-hydroxy bases 82b,c,f,g in acetic... 

The absolute configurations of thalidastine and berbastine, the two known 5-hydroxy-berberines, have been determined by inference from the observation that the analogue (23) is dextrorotatory as are these alkaloids. The hydroxy-base (23) was prepared from (+)-tetranydrojatrorrhizine by oxidation with lead tetraacetate, followed by hydrolysis to give a 2 1 mixture of the alcohols (24 R = H, R" = OH) and (24 R = OH, R = H), the configurations of... 

The reaction of a poly hydroxy base with less than a stoichiometric amount of an acid forms a basic salt, that is, a salt that contains unreacted OH groups. For example, the reaction of aluminum hydroxide with hydrochloric add can produce two different basic salts ... 

D. L. Whitehouse, S. N. Savinov, D. J. Austin, An improved synthesis and selective coupling of a hydroxy based photolabile linker for solid-phase organic synthesis. Tetrahedron Lett. 1997,38, 7851-7852. 

Figure I. PEG grafted polystyrene supports - TentaGel S RAM resin 1. PEG-PS resin 2, Argo-Gel-OH 3, ArgoGel-NHj 4, -hydroxy based PS-g-PEG resin 5 and Merrifield based PS-g-PEG resin 6.

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