Triethylene glycol derivatives

Monoethylene glycol derivatives ate termed "ceUosolves" diethylene glycol derivatives, "carbitols" and triethylene glycol derivatives, triglycols. CELLOSOLVE and CARBITOL ate registered trademarks of EFnion Carbide Corp. 

Among the 1,4-di-O-substituted-L-threitol derivatives (Figure 14a) the one that has found most use in chiral crown ether synthesis is the 1,4-dibenzyl ether. Not only has it provided (88, 106, 107) a ready entry into the chiral tetrasub-stituted 18-crown-6 derivatives ll-31 to ll-34, but it has also proved to be a usehil chiral precursor for the preparation of chiral disubstituted 9-crown-3 (107), 12-crown-4 (108), 15-crown-5 (108), and 18-crown-6 (109) derivatives l-57, l-58, l-59, and l-60, respectively. In the preparation of l-S8 the base-promoted cyclization with triethylene glycol ditosylate is best carried out (108) with a... 

Compomers contain no water, but rather are mainly formulated from the same components as conventional composite resins. Typically this means macromonomers, such as bis-glycidyl ether dimethacrylate (bisGMA) or its derivatives and/or urethane dimethacrylate, blended with viscosity-reducing diluents, such as triethylene glycol dimethacrylate (TEGDMA). These polymer systems are filled with non-reactive inorganic powders, for example, quartz or a silicate glass [271]. 

Fig. 11 Some selected cycloaddition derivatives of Ceo with more positive reduction potentials than unsubstituted Ceo- TEC = Triethylene glycol monomethyl ether(-CH2CH20CH2CH20CH2CH20CH3).

The diacid is commercially available but the purity has to be checked. Purity can be improved by the preparation of a dianilide derivative (see an example in Ref. 2). This diacid can also be synthesised from triethylene glycol.2... 

Acid-catalyzed dehydration of aldoses and ketoses yields furan derivatives in 40-80% yield. Recently the reaction has been carried out in an organic solvent, e.g., dioxan or triethylene glycol,5 or with I2 in dimethylformamide at 100°. Often D-fructose is employed as starting material. This ketose gives glucose via an enediol, which yields 5-hydroxymethylfurfural or its O-acyl derivative by dehydration.7-10... 

Fig. 8 (a) Reversible formation of cyclic and linear acetal oligomers from triethylene glycol and 4-nitrobenzaldehyde. (b) Reversible formation of hemithioacetal (HTA) from reaction between a thiol and an aldehyde derivative... 

Saccharine can be used to convert an alkyl halide into a primary amine. Saccharine is reacted with the alkyl halide followed by a mild acidic cleavage of the resulting benzenesulfonylcarboxy residue (Abe, 1955 Eckenroth and Koerppen, 1896, 1897). This reaction has been used in cyclizations by first treating the dichloride derivative of a di- or triethylene glycol with the sodium salt of saccharine in DMF in the presence of sodium iodide to form the bis-... 

The A,A -bis(p-toluenesulfonamide) derivative of diaza-18-crown-6 was prepared by treating the ditosylate ester of triethylene glycol with the N,N -bis(/7-tolucnesulfonamide) derivative of a diamino ether in base (method... 

Diaza-18-crown-6 derivatives (24-42) can be prepared by using a unique, single-step reaction of primary amines with triethylene glycol diiodide (42) ... 

The incorporation of two aryl bridgeheads, both linked in turn through the 2,6-substitution of a pyridine nucleus has provided an intermediate which has been converted to a crown ether. Thus, 2,6-bis(2, 6 -dimethoxyphenyl)pyridine after demethylation with boron tribromide or hydrogen bromide in 65% yield was reacted in dimethylsulphoxide containing potassium carbonate with the a,o)-diiodo derivative of triethylene glycol to afford a crown ether system in 22% yield (ref. 199). 

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