Dioxalones

Several examples of the binding of enzymes to poly(vinyl alcohol) are in the literature. These could possibly be used to treat enzyme deficiency diseases. In a recent example, trypsin was immobilized on poly(vinyl alcohol) fibers using maleic dialdehyde or bromal. While the reaction was more complete with bromal, the reaction with maleic dialdehyde gave a better support which showed decreasing activity with increasing enzyme content. The activity of the bromal activated system was independant of the enzyme content (52 ). Trypsin and papain were attached to poly(vinyl alcohol) by the reaction sequence shown in Equation 13. In this case, the crosslinked poly(vinyl alcohol) is treated by the 1,3-dioxalone derivative and then converted to either the isothiocyanate or the diazonium salt for coupling with the enzyme. The bound enzymes showed significant, altho reduced, activity in each case (53). 

In this reaction, acetals are used as dication equivalent of one-carbon unit 72, whereas 71 provides a dianion 73 <95TL5581>. A new stereocontrolled synthesis of substituted tetrahydrofiirans starts with dioxalones 74. A titanium-mediated methylenation using dimethyltitanocene (THF, 60 C) with subsequent treatment of 75 with trialkylaluminium reagents results in the formation of tetrahydrofiirans 76 <95JA6394>. 

Michael type reaction. Chlorosulphonyl isocyanate adds to epoxides to generate the carbon dioxide inserted oxazolidines (74) or dioxalones (75) depending on the substitution pattern of the epoxide. 

Methyl-4-methylene-l-3 dioxalene, 2,2-dimethyl-4-methylene-l,3-dioxalane, 2-phenyl-4-methylene-l,3-dioxalone... 

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