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Calixarenes stepwise synthesis

Figure 7.2.2. Stepwise synthesis of calixarenes bearing different substituents. Figure 7.2.2. Stepwise synthesis of calixarenes bearing different substituents.
Two general routes are available for the synthesis of calixarenes the base-and acid-promoted one-step synthesis and the convergent stepwise synthesis (fragment condensation).2,3... [Pg.146]

The cyclic phosphinate (96) has been isolated from the reaction of dichloro(methyl)phosphine with the ethoxycarbonylimine derived from hexafluoroacetone. Treatment of trichloro(organo)phosphonium-hexafluorophosphate salts with dichloro(diethylamino)phosphine results in the halophosphonium salts (97). Some reactions of dichloro(-)menthylphosphine have been reported.As usual, nucleophilic displacement reactions of halogenophosphines have received attention as routes to new systems of interest as ligands.Of particular interest in this connection is a report of the synthesis of the phosphorus-functionalised calixarenes (98). Only one chlorine atom of dichloro(phenyl)-phosphine is replaced on treatment with an excess of dicyclohexylamine, enabling the stepwise synthesis of the chiral aminophosphines (99), described as air-stable solids. [Pg.19]

Scheme 3. Convergent, stepwise synthesis of calixarene[4]arenes (Bohmer, Chhim, and Kammerer method). Scheme 3. Convergent, stepwise synthesis of calixarene[4]arenes (Bohmer, Chhim, and Kammerer method).
Calixarenes prepared by one-pot procedures necessarily consist of the same repeating unit (usually a phenol). The stepwise synthesis outlined in Scheme 2 allows one in principle to build up calix[n]arenes with n different p-substituted phenolic units. After protection of one orf/zo-position, usually by bromination, a sequence of hydroxymethy-lation and condensation steps furnishes a linear oligomer which, after deprotection, is... [Pg.1373]

Calixarenes [77] are defined as [l.n]metacyclophanes with its basic structural unit consisting of phenolic groups linked by ortho-methylene groups. Two examples are shown in Fig. 25. Several reviews are available on this subject [77-79]. These compounds can be synthesized by the acid- or base-catalyzed condensation reaction of a substituted phenol with formaldehyde or an aldehyde (Fig. 26). Calixarenes have also been synthesized by a stepwise reaction that sequentially add phenolic groups followed by a cyclization step. More efficient convergent synthesis have also been developed [80-82], The bowl-like structural conformation generally... [Pg.585]

SCHEME 2. Synthesis of calixarenes by the stepwise strategy. In principle, each phenolic unit can have a different substituent (mainly alkyl groups) in the p-position... [Pg.1373]

Many years before Gutsche found effective synthetic procedures for the various calixarenes, Hayes and Hunter [14] reported a stepwise preparation of calixarenes. This method was many years later investigated in Mainz by Herman Kammerer and by Volker Bohmer [15]. Their method comprises the tedious synthesis of linear precursors and their subsequent cyclisation. [Pg.8]


See other pages where Calixarenes stepwise synthesis is mentioned: [Pg.64]    [Pg.64]    [Pg.14]    [Pg.35]    [Pg.100]    [Pg.357]    [Pg.153]    [Pg.156]    [Pg.9]    [Pg.44]    [Pg.14]    [Pg.291]    [Pg.75]    [Pg.153]    [Pg.91]    [Pg.335]   
See also in sourсe #XX -- [ Pg.156 ]




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