THE CONSTITUTION OF VITAMIN Kz*

The isolation of vitamin Kz as a yellow crystalline compound melting at 53.5-54.5” has recently been reported from this laboratory (McKee, Binkley, MacCorquodale, Thayer, and Doisy, 1939; McKee, Binkley, Thayer, MacCorquodale, and Doisy, 1939). From the analytical data it was impossible to decide definitely on a formula for vitamin Kz. The formula C&H5402 was used for all calculations, although C&H6002, GH6202, Cd1HbG02, and C42H6802 agree with the analytical data equally well. In this paper we shall present evidence to show that the correct empirical formula is C41Hse02 and on the basis of degradation studies propose a structural formula. Upon catalytic hydrogenation the vitamin absorbed 9 moles of hydrogen to produce a colorless compound which on exposure to the air was oxidized to a yellow compound. This yellow compound absorbed 1 mole of hydrogen to give a colorless solution which on oxidation with air returned to the original yellow color. This behavior on hydrogenation as well as its instability toward light and alkali indicated that the vitamin is a quinone. The yellow color of the vitamin is characteristic of 1,4-quinones. Further evidence for the quinone structure of the vitamin was obtained by preparation of the white crystalline diacetate of dihydrovitamin KS (Binkley, MacCorquodale, Cheney, Thayer, McKee, and Doisy, 1939). Catalytic hydrogenation of this diacetate caused an uptake of 8 moles of hydrogen. The addition of 12 atoms of bromine by the diacetate of dihydrovitamin Kz