Two series of new crown compounds [4 : CpAsp (n), CpGlu (n), p=10-16, n=5, 6] were prepared by the cyclization of oligoethylene glycol ditosylates with the dicaesium salt of N-acyl-aspartic or -glutamic acids (Scheme-1). The yields of CpGlu (n) were generally better than those of CpAsp (n) (Table-1). The yield and specific rotation ([α]
25D of the cyclization products depended on reaction temperature (2080 °C), type of alkali metal cation (M : Li, Na, K, and Cs), and leaving group (X : TsO, Cl, and Br) in the ω, ω′-disubstituted oligoethylene glycols. The results for the synthesis of C
10Glu (5) are as follow : 1) under M =Cs and X=TsO, the reaction at 40 °C gave a good yield (41%) and that at 20 °C, the largest [α]
25D, 2) at M=Cs and 60 °C, the dibromide gave the best yield (74%) and the dichloride, a larger [α]
25D.
All the products except C
10, 12 Asp (6) were water-insoluble. The cloud point, cmc (critical micelle concentration), and surface tension at cmc (cmc) were determined for the aqueous solution of C
12 Asp (6). These values were lower than those of the corresponding open chain compound, C
12Asp (6) OH, indicating a decrease in hydrophilicity caused by cyclization of oxyethylene chains. C
16Asp (5, 6) was highly efficient as a phase transfer catalyst in the halogen-exchange reaction.
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