Tert- Alkyl water-soluble

Alkyl hydroperoxides can be liquids or solids. Those having low molecular weight are soluble in water and are explosive in the pure state. Alkyl hydroperoxides are stronger acids than the corresponding alcohols and have acidities similar to those of phenols, tert-Alkyl hydroperoxides can be purified through their alkali inetal salts. 

Among more complex macrocycles, Li et al. [47-52] reported the preparation and characterization of stationary phases incorporating calixarenes or calix-crowns bonded to silica. With individual columns, high selectivity was observed in the separation of alkylated aromatics, aromatic carboxylic acids, sulfonamides, nucleosides, and water-soluble vitamins. In other work, Sokoliess et al. [53] have characterized calixarene- and resorcinarene-bonded stationary phases similar to those described in the previous section of this chapter. And Huai et al. [54] used an end-capped p-tert-butyl-calix[4]arene-bonded silica phase for HPLC separation of a number of organic compounds. Resorcinarenes have also found application in GC. [55-57] Recently, exotic macrocycles have been used in capillary electrochromatography, as reported by Gong et al. [58]... 

PEG-supported cinchona ammonium salts 54 were applied to the asymmetric alkylation of tert-butyl benzophenone Schiff base derivatives 52 [34]. The use of a water-soluble polymer support allowed the reaction to be conducted in a 1M KOH aqueous solution to give the a-amino acid derivatives 53 in high chemical yields (up to 98%). Ten different types of electrophile have been tested for the reaction, with the best enantioselectivity being obtained with o-chlorobenzylchloride (97% ee) (Scheme 3.15). 

Fully 0-alkylated calix[6]arenes, either lipophilic or water soluble, have been previously synthesized and studied for the complexation of ions and neutral molecules [28]. However, very little work has been done on the selective functionalization of calix[6]arenes both at the upper and the lower rim, to create new structures useful for Molecular Recognition. By treating p-tert-butylcalix[6]arene 2 with CH3I in acetone, in the presence of K2CO3, the symmetrical 1,3,5-trimethyl derivative 18 was prepared in 27% yield [29,30]. This compound shows a very simple pattern in the and NMR... 

Alkyl nitrites can also be used in anhydrous media and, for example, 4-hydroxyben-zenediazonium tetrafluoroborate is isolated in 89% yield after diazotization with isopcntyl nitrite, hydrogen fluoride and boron trifluoride in ethanol/diethyl ether.96 Diazotization can also be performed in dichloromethane or ethers (diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane) with terl-butyl nitrite and boron trifluoride-diethyl ether complex which generates nitrosyl fluoride in situ.229 Excess boron trifluoride is used to trap water and tert-butyl alcohol, so that the reaction can be considered as being performed under complete anhydrous conditions. Yields are higher in dichloromethane, but 1,2-dimethoxyethane is preferred for less soluble amines. This procedure has been successfully applied to the synthesis of mono-and difluorobenzo[c]phcnanthrenes.230... 

The four-carbon dividing line is only an approximate guide because the solubility of an alcohol also depends on the sttucture of the alkyl group. Alcohols with branched alkyl groups are more soluble in water than alcohols with unbranched alkyl groups with the same number of carbons, because branching miiiiinizes the contact surface of the nonpolar portion of the molecule. Thus, tert-butyl alcohol is more soluble than n-butyl alcohol in water. 

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