Hydroxy functional groups

Reactive dyes typically contain the chlorotriazinyl group. The chloro substituent can be displaced by hydroxy functional groups from cellulosic fibres thereby incorporating the dye molecule into the fabric. Bright and lightfast colors are obtained by this approach. Reactive dyes for cotton generally contain a number of sulfonic groups to provide the water solubility which is required to apply the dyes from aqueous solutions. 

Another NHC ligand with a backside hydroxy functional group was introduced by Buchmeiser and coworkers with the intention to use the hydroxy group to attach the NHC ligand to a polymeric support [161,191], Attachment to the polymeric support was achieved... 

Similar cts-bis-carbene chelate complexes of palladium(Il) [327,330,331], but without the hydroxy functional groups on the wingtips, were used by the same research group for the copolymerisation of ethylene and CO. Once again, chelating bisphosphane complexes inspired the synthesis and application of their NHC counterparts [332,333]. The actual, defined catalyst precursors were the cationic complexes formed after haUde abstraction with silver salts in acetonitrile as donor solvent. 

Note Whereas gold(I), silver(I) andpalladium(II) did not show coordination by a neutral hydroxy functional group, copper (11) coordinates the anionic alkoxide functionalities [and even a 0 anion bridging four copper(II) centres]. 

Priihs et al. found an elegant application for a seemingly remote hydroxy group in the sidechain [43]. The remoteness of the hydroxy group implies a mode of introduction to the central imidazole ring different to the epoxide method developed by Arnold (hydroxyethyl) and Thiel (hydroxyhexyl). Indeed, Priihs et al. modilied the classic method of imidazo-lium salt synthesis by using a bromoalkane as carrier for the hydroxy functional group. In this way, they reacted A-mesityl imidazole with l-bromo-ta-hydroxyalkanes to obtain the... 

When the alkyl halide method is used to introduce a hydroxy functional group it can as easily provide two hydroxy functionahties in the same wingtip group. An example comes from Cai et al. who reacted A-methylimidazole with 3-chloro-2-hydroxypropanol to form the corresponding imidazolium salt (see Figure 4.13) that was then used in the palladium catalysed Heck reaction between phenyl iodide and ethyl acrylate [51]. 

Reagents 32c and 32e arc imidazolidines and oxazolidines characterized by sufficient reactivity of the X—CH2—N moiety for pixxlucing substrate aminomethylation. Indeed, when analogous, more stable cyclic derivatives are formed (e.g., 25), the Mannich reaction does not take place. Compounds 32c and 32e are used for synthesizing Mannich bases bearing a further amino or hydroxy functional group in the amine moiety, as depicted in the example reported below for product 37 (Fig. 21).- ... 

Dioxinones Obtained by Resolution or Prepared with a Chiral Auxiliary. 2-Phenyl-4//-1,3-dioxin-4-ones (15) derived from formylacetate or acetoacetate can be readily prepared in enantiopure form by preparative resolution " on cellulose triacetate. These have been used for Michael additions and hydrolysis to long-chain p-hydroxycarboxylic acids, for example the tride-canoic acid (16) from (/ )-(15a). The cuprate adducts formed with the methylphenyldioxinone (i f-flSb) can be hydrogenolyti-cally cleaved directly to p-branched p-hydroxy acids with benzyl protection of the hydroxy functional group see (17) in eq 9. ... 

Hydroxy Functional Group Properties of the Alcohols and Strategic Syntheses... 

Chapter 8 HYDROXY FUNCTIONAL GROUP ALCOHOLS PROPERTIES, PREPARATION, AND STRATEGY OF SYNTHESIS... 

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