TETRAHYDROFURANS: I. 2,2-DIMETHYL-4-SUBSTITUTED-4-HYDROXYMETHYLTETRAHYDROFURANS AND RELATED COMPOUNDS

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Abstract
Substituted methallylmalonic esters (I) were reduced with lithium aluminum hydride to the corresponding 2-methallyl-1,3-propanediols (II). These diols II underwent cyclization on treatment with a mineral acid to the isomeric 2,2-dimethyl-4-substituted-4-hydroxymethyltetrahydrofurans (IV). II and IV were converted to the respective carbamates III and V, which exhibited pharmacological activity. The assigned structures of the cyclic compounds IV were proved by infrared analyses and the following transformations. Ring scission of 2,2-dimethyl-4-allyl-4-hydroxymethyltetrahydrofuran (IVe) with acetic anhydride – pyridine hydrochloride yielded 2-allyl-2-methallyl-1,3-propanediol diacetate (Xe). Catalytic reduction of IVe gave 2,2-dimethyl-4-n-propyl-4-hydroxymethyltetrahydrofuran (IVd). Reductive cleavage of the tosylate VIIIb of 2,2,4-trimethyl-4-hydroxymethyltetrahydrofuran (IVb) with lithium aluminum hydride yielded the known 2,2,4,4-tetramethyltetrahydrofuran (IXb).