Studies on the Syntheses of the Aliphatic Diamines. XIV.

Chloromethylation of 1, 3-butadiene gave a mixture of 3-chloro-(4-chloromethyl)-tetrahydropyran (1) and 4-chloro-(3-chloromethyl)-tetrahydropyran (2) in 95% yield. The selectively hydrolyzed reaction mixture was hydrogenated to give tetrahydropyran-4-methanol (3) and tetrahydropyran-3-methanol (4). From the amounts of (3) and (4), the ratio of (1) and (2) was calculated to be 1: 2. The higher boiling product obtained by the chloromethylation of butadiene was considered to be chloro-(hydroxymethyl)-tetrahydropyrans (5), intermediates for (1) and (2). Starting from (1) and (2), the following compounds were prepared; 5, 6-dihydro-(4-hydroxymethyl)-2H-pyran, 5, 6-dihydro-(3-hydroxymethyl)-2H-pyran, tetrahydropyran-4-methanol, tetrahydropyran-3-methanol, a mixture of 3-chloro-(4-acetoxymethyl)-tetrahydropyran and 4-chloro-(3-acetoxymethyl)-tetrahydropyran, a mixture of 3-chloro-(4-hydroxymethyl)-tetrahydropyran and 4-chloro-(3-hydroxymethyl)-tetrahydropyran. The reaction of butadiene with dichlorodimethyl ether gave dichlorodipentenyl ethers with some amount of by-products, chloro-(chloromethyl)-tetrahydropyrans. The major product was 5, 5'-dichlorodipentenyl ether (6), and the amount of 1, 2-addition product was much less than that of 1, 4-adduct. From(6), 5, 5'-dihydroxydipentenyl ether and 5, 5'-dihydroxydipentyl ether were also prepared.