4180
COMMUNICATIONS TO THE EDITOR
Vol. 78
At: 246 mp, e 1.57 X lo3; YE;' 1684 cm.-l). When (I) was treated with excess bromine water, Sir: followed by boiling with lead oxide, 5-hydroxy-1,31,3-Dirnethyluracil ( I ) z was used to study the dimethyluracil (V) m.p. 198-199' (found: C, interesting but poorly understood ultraviolet ir- 46.15; H, 5.38; N, 17.83; A,": 285 r n p , E 7.35 X radiation effects on nucleic acids.3 (I) (m.p. l o 3 . :A;: 248 mp, e 1.78 X lo3; &' 3215 cm.-l, 121-122'; : : A 267 mp, E 8.67 X lo3: :;A: 235 v?;',"' 1669 cm.-l) was obtained. Hydrogenation of rnp, E 1.68 X lo3; A250/A260, A280/A260; 0.62, (V) a t two atmospheric pressures gave 5-hydroxy0.62 for p H 2-12; vggl 1701 cm-l) in aqueous solu- 1,3-dimethylhydrouracil (VI), m.p. 109-11 0' tion ( O . O G 7 M ) was irradiated with ultraviolet light (found: C, 45.57; H, 6.40; N, 17.92; ';:v 3390 until SO-SO% of the optical density a t 260 mp had cm.-', YE:' 1704 cm.-l). No reconstitution of disappeared. The irradiated product (60-75y0 (VI) under similar conditions. When (VI) was yield) was recrystallized from chloroform and irradiated, then treated with acid or alkali, there petroleum ether and gave 6-hydroxy-1,3-dimethyl- was no change in ultraviolet spectrum, indicating hydrouracil (11),4m.p. 105-106' (found: C, 45.61; that (VI) was not converted to (11) on irradiation. 1704 These observations suggested strongly that (VI) H, 6.49; N, 18.00; vggl 3344 cm.-', '::v cm.-l). On treating (11) with acid (pH 2 ) ) alkali was not an intermediate. (pH 9, 10, 11, 12) or heat, respectively, the ultraWhen (I) was treated with one mole equivalent violet spectrum of (I) was reconstituted (A250/ of bromine water trans 5-bromo-6-hydroxy-l,3X260, A2SO;A2GO; 0.62, 0.62; 0.61, 0.62; 0.60, dimethylhydrouracil (111) was obtained in solution. 0.62; 0.62, 0.63; 0.61, 0.62). Over 90% yield of There was no detectable change in ultraviolet ( I ) was obtained in the acidic and alkaline recon- spectrum after standing for two hours. However, stitutions. when the solution was allowed to stand overnight or crystallized from the CHC13 extract, only (IV) was obtained. This dehydration probably went by way of the "mutarotation" (IIIA) or (IIIB). Hydrogenolysis of (111) in a non-buffered solution gave only (I) as the product. However, hydrogenolysis of (111) in a phosphate buffered solution, pH 7, gave (11), m.p. 105-106' in over 50% yield. This was identical with the irradiated product as determined by m.m.p. 105-106', infrared and analysis (found: C, 45.56; H, 6.49; N, 17.71). (11) was thus identified by synthesis as 6-hydroxy1,3-dimethylhydrouracilI suggesting a 1,4-addition as the mechanism of the photo-reaction. The kinetics of the photo-addition were zero order as shown by a plot of optical density vs. time. The acid catalyzed dehydration (pH 1.98) (IIA), and the base catalyzed @elimination (pH 9.01) (IIB) were both of the first order as shown by a plot of log C"/C, es. time. ULTRAVIOLET IRRADIATION OF l,&DIMETHYLURACIL'
DEPARTMENT OF PHYSIOLOGY SHIHYI WANG TUFTSUNIVERSITY SCHOOL OF MEDICINE M. APICELLA 136 HARRISON AVENUE B. R. STONE BOSTON11, MASSACHUSETTS RECEIVEDJUNE 22, 1956
sir :
THE BASIC RING SYSTEM OF CRININE
Two recent communications have suggested the likelihood that several alkaloids of the Amaryllidaceue possess structures containing a spiro ring system.'e2 The following results establish a new On treating (I) with an excess of bromine water, spiro ring system for ~ r i n i n e . ~ 5-bromo-1,3-dirnethyluracil (IV) , m.p. 184-1 85', Manganese dioxide oxidation of crinine, C15H14was obtained (found: C, 33.03; H, 3.40; N, N(OzCH2) (OH), m.p. 210') gave an a,p-unsatu12.66; Br, 36.20; 283 mp, E 8.57 X lo3; rated ketone, oxocrinine (m.D. 183-185' : found: (1) This work was done under the terms of Contract No. AT(30-1)C, 71.15; H,. 5.52; N, 5.21; "*: : :A 5.98'fi; XEt,"," 911 of the Physiology Department, Tufts University School of Medi227 mfi (4.20). 296 mu (3.59)). Lithium aluminum cine with the Atomic Energy Commission. hydride'reduction o i oiocrinine afforded epicrinine (2) A. M. Moore and C. H. Thomson, Science, 128, 594 (1955). and references therein. (3) E. Chargaff and J. N. Davidson, "The Nucleic Acids," Vol. I, p. 123, Academic Press, Inc., New York, N. Y. (4) The product of Moore and Thomson, m.p. 102'. Following the nomenclature used in Chemical Abstracts (11) should be called 1,3dimethyl-5,6-dihydro-6-hydroxy-2,4-pyri~dinedione.
(1) S. Kobayashi, T. Shingu and S . Uyeo, Chemistry and Induslry 177 (1956). (2) T. Ikeda, W. I. Taylor, Y. Tsuda and S. Uyeo, i b i d . , p. 411. (3) Crinine was reported by L. H. Mason, E. R. Puschett and W. C. Wildman, THISJOURNAL, 77, 1253 (1955); in Chem. Ber., 87, 1704 (1954), H.-G. Boit reported the same alkaloid as "crinidine."
