COMMUNICATIONS TO THE EDITOR 1553 I R = Otos 11 R = I 111 R = H IV VI1 V R = HV I R = CHa num catalyst, barium hydroxide and then formic acidformaldehyde into the crystalline a-methyl glycoside of amosamine VI, identical with the natural product by mixture melting point determination and examination of the infrared spectra, which were superimposable. Hydrolysis of the a-methyl glycoside gave the free sugar, 4,6-dideoxy-4-dimethylamino-~-glucose (VII) , which traveled with the same R r values as amosamine upon paper chromatography in a pyridine-ethyl acetate-water (*5 : 12 : 4) system and in a pyridine-ethyl acetate-acetic acid-water (5 : 5 : 3 : 1) system. The free sugar VI1 was converted to the itol VI11 using sodium borohydride. The crystalline itol hydrochloride was identical with the natural derivative as shown by mixture melting point determination and paper chromatographic comparisons.Acknowledgment.-This investigation was made possible by Research Grants CY 3772 and A 769 of the
Sir :The observation that dimethyl sulfoxide enhances the base strength of potassium t-butoxide has led to rather extensive use of this system for carbanion reactions.2 Noteworthy applications are the recently described isomerization of 2-methyl-1-pentene3 and the study of endo iS exo kinetics with alkylidenecycloalkanes. While these studies dealt primarily with isomerization rates, equilibrium compositions appeared to be in qualitative agreement4 with data available from other investigations. The present investigation was in fact initiated on the premise that product ratios would reflect relative thermodynamic stabilities of the isomers.The thermal isomerization of allenes to mixtures of acetylenes and 1,3-dienes is well known.5 More recently, 1,2-cyclodecadiene was I eported to undergo isomerization to 1,3-and 1,4-cyclodecadiene when heated a t 190" in diethyl carbitol containing notassium hydroxide.6(1) The authors are indebted to the Robert A. Welch Foundation for the financial support of this study. Generous quantities of cycloktene, 1,scycloiictadiene and 1,5wycloiictadiene were kindly provided by the Petrochemical Research Laboratory, Cities Service Research and Development Co., Lake Charles, La. (2) D. J. Cram, B. Rickborn and G. R. Knox, J. A m . Chcm. Sor., 82, 6412 (1960). (3) A. Schriestleim and C. A. Rowe, Jr., ib{d,, 84, 3160 (1902). (4) A. Schriesheim, R. J. Muller and C. A. Rowe, Jr., ibid., 84, 3104 (6) Ya. M. Slobodin, J . Gen. Chem. USSR, 2 2 , 1958 (1952); Chem. Abotv., (19G2). 47, 8630 (1953!, and preceding papers.We have found that 1,5-cyclooctadiene is converted rapidly and essentially quantitatively to 1,3cyclooctadiene by potassium t-butoxide in dimethyl sulfoxide (1 hr., 70"). Similarly, 1,2-cyclononadiene (I)' under identical conditions gave rise to 1,3-cyclononadiene (11) which is 98%. pure by vapor-liquid chromatography. The properties of I1 are in good agreement with those reported.8 Extending the reaction time t o 3 hr. afforded a mixture comprised of 70% of I1 and 23% and 7% of two new substances. Th...
