3658 ARTHUR C. COPE, PETER KOVACIC AND MARION BURG Vol. 71 ... (18) Iddles, Low, Rosen and Hart, Ind. Eng. Chem., Anal. Ed., 11, 102 (1939). COLLEGE PARK, MARYLAND RECEIVED MAY 18, 1949 ... [CONTRIBUTION FROM THE DEPARTMENT OF CHEMISTRY, MASSACHUSETTS INSTITUTE OF TECHNOLOGY ] ... Spirobarbituric Acids Containing a Six-membered Carbocyclic Ring ... BY ARTHUR c. COPE, PETER KOVACIC~ AND ...