COMMUNICATIONS TO THE EDITOR
March 5 , 1961
1261
residual molecule is identical with that of the initial state. To obtain further insight into the structure of this transition state, we compared the rates of addition of methyl radicals to hydrogen containing substrates with those observed in reactions involving deuterated analogs. If the configuration around the reactive center is changed considerably in the transition state, a variation in the rate constant of the respective addition reaction might be expected, and its magnitude then may be used to gauge the extent of deformation. Using the approach developed by Streitwieseraq4 we calculate that a change of configuration a t the reaction center from a trigonal t o tetrahedral should lead to a ratio k ~ l k= ~1.82 for CHa addition to CaH&D=CDn and CsH&H=CHz respectively a t 50". The actual data were obtained by determining the k 2 / k l ratio for each of these compounds, where reaction (1) describes a hydrogen abstraction reaction
that of the initial state. Hence, we confirm the tentative assumption made in previous papers from this laboratory.2 The smallness of the effect observed here suggests also that the incipient C-CH3 bond, formed in the transition state, is comparatively lorlg. Furthermore, i t is clear that the concept of addition close to the nodal plane, which was advocated in our previous papert6is definitely erroneous. In conclusion we give thanks to Dr. Leo Wall for the gift of deuterated styrene, to Dr. A. Streitwieser for his helpful discussions, and to the National Science Foundation for a grant.
CH3
A NOVEL REARRANGEMENT OF PYRIMIDINES TO S-TRIAZINES' Sir :
+- iso-octane d CHI + iso-octyl radical
(kl)
whereas reaction (2) describes the investigated addition process
( 6 ) A. Bader, R. P. Buckley, F . Leavitt and M. Szwarc, J . A m . Chcm. SOC.,79, 8621 (1957).
DEPARTMENT OF CHEMISTRY OF FORESTRY STATEUNIVERSITY COLLEGE AT SYRACUSE UNIVERSITY M. MATSUOKA SYRACUSE 10, NEWYORK M. SZWARC RECEIVED JANUARY 26, 1061
5-Nitroso-6-aminopyrimidinesare widely employed intermediates for the synthesis of purines, or pteridines and other condensed pyrimidine heteroCH, 4 CDzZCDPh +CHaCDzCD(Ph)* (k2.D) cycles and are prepared readily by a variety of ' 3 wish to report a novel The experimental technique and the methods of synthetic m e t h o d ~ . ~e*% calculationof the results are described fully in a recent rearrangement of these intermediates to 2-cyanopaper by \Steel and S z w a r ~ . ~All the pertinent s-triazines. Heating a mixture of 2-phenyl-4,6-diamino-5data are given in Table I. nitrosopyrimidine (I, R = Ph, X = NH) for one TABLE I hour with 1.1 equivalents of benzenesulfonyl chloMETHYL AFFINITIESOF STYRENE AND DEUTERIOSTYRENEride and excess pyridine, or with 1.1 equivalents Solvent, iso-octane; T is 50"; CH, radicals generated by of phosphorus oxychloride and excess pyridine, or simply with excess thionyl chloride, gave 2photolysis of azo-methane; X 3600 8. cyano-4-phenyl-6-amino-s-triazine, m.p. 207' (V, Compound hlole Yo CHdNa kdki R = Ph, X = NH)4 in 30% yield. The structure ..... 0.0 0.560 .. of this compound was confirmed by sulfuric acid .... 0.0 .554 .. hydrolysis to 2-carboxamido-4-phenyl-6-amino-sAv. 0.557 .. triazine, rn.p. 324", then treatment with potassium Styrene hypochlorite to give benzoguanamine (2-phenylStyrene 4,G-diamino-s-triazine), identical with an authentic Deuterostyrene .189 ample.^ Similarly, heating 2-dimethylamino-4Deuterostyrene .189 ,167 1214 hydroxy-5-nitroso-6-aminopyrimidine(I, R = k n / k B = 1.07 N(CH3)2, X = 0) and 2-methylthio-4,6-diamino-5.... .0 .582 ., nitrosopyrimidine (I, R = SCH8, X = NH) for Styrene '229 5-30 minutes with excess acetic anhydride gave Av. 1084 .143 .227 Styrene 2-cyano-4-dimethylamino - 6-hydroxy-s - triazine, m. Deuterostyrene .142 I2O8 p. 262' (V, R = N(CH3)2, X = 0), 84% yield, Av. 1208 .I42 .214 1208 Deuterostyrene and 2-cyano-4-methylthio-6-acetylamino-s-triazine, k D / k B = 1.11 map. 213' (V, R = SCH3, X = NCOCH,), 100% yield, respectively. 2,4-Diamino-5-nitrosoThe results listed in Table I show clearly that, 6-hydroxypyrimidine (I, R = "2, X = 0) rearas has been expected, the deuteration accelerates ranged to 2-cyano-4-amino-6-hydroxy-s-triazine, the rate of methyl radical addition. The magni(1) This work was supported in part by a grant (C-2551) to Princetude of the observed effect (7-11y0)is much lower University from the National Cancer Institute of the National Inthan that calculated on the assumption of the ton stitutes of Health, Public Health Service. tetrahedral transition state (82%). We conclude, (2) E. C. Taylor, 0 Vogl and C . C. Cheng, J. A m . Chem. Soc.., 81, therefore, that these results indicate only a slight 2442 (1959). (3) A. Bendich in "The Nucleic Acids, Chemistry and Biology." deviation of the transition state configuration from CH, f CHzECHPh
CH?CHACH(Ph).
(k2.a)
-
(3) A. Streitwieser and R. C. Fahey, Chcm. and Industry, 1417 (1957). (4) A. Streitwieser, R . H. Jagow, R. C . Fahey and S.Suzuki, J . A m . Chem. Soc., 80, 2326 (1958) (5) C. Steel and M.Szwarc. J . Chcm. Phys., 35, 1677 (1960).
ed. by E. Chargaff and J. N . Davidson, Vol. I, Academic Press. Inc., New York, N. Y.,1955, p. 81. (4) Acceptable microanalytical results were obtained for all compounds reported. (5) We are indebted t o the American Cyanamid Company for a generous gift of authentic material.
COMMUNICATIONS TO THE EDITOR
1262
1701. 83
m.p. > 350" (V, R = "2, X = 0) upon heating strong bands near 1900 cm.-' in the infrared specfor a few minutes with trifluoroacetic anhydride. trum which are attributed to yc=o. In view of We believe that these transformations are initi- these observations, and particularly since we have ated by esterification of the 5-nitrosopyrimidine found similar strong absorptions at 1800-2100 in its oxime form (11) to give I11 (2 = S02CeH5, cm.-' in the spectra of a number of mono-, diCOCH3, COCF3). Elimination of 20- with and trihalogeno complexes of osmium and ruthecleavage of the C4-425 bond then yields the open- nium, some of which, as we now find, are formed chain intermediate IV in a reaction closely related even a t 25" (including monohalides),6 we have to the "fragmentations" discussed by Grob.'j undertaken a study of these reactions by using Recyclization gives the observed products (V). radiocarbon and deuterated alcohols as solvents. This interpretation is consistent with the observaAccording to the evidence obtained from these tion that the transformation is facilitated markedly experiments, summarized below, we now wish to by the introduction of electron-releasing substi- reformulate the monohalogeno complexes of Os tuents (e.g., N(CH&, SCH3) in the 2-position of and Ru as containing also hydrido and carbonyl the pyrimidine ring. groups, [MHX(CO)L3](cf. ref. 4). TABLE I Compound
Infrared spectrum (cm.-I)Q vM-n
YDLD
YC-o
Oxygen, 5% Found Calcd.
No. of 14C/ f . w . of compd.
[RuHCI(CO) 2020 1457 1916 1 . 8 1 . 7 (PhaPhI 1900 jOsHCl(C0) 2100 1505 1898 1 . 0 1 . 5 (Ph3PhI 1884 1509 1902 1 . 4 1 . 5 [OsHBr(CO) 2105 (Ph3PhI 1886 a 325 cm.-'; halocarbon mull. b ~ ~ - = ~ 1.40; calcd., 1.41.
1.02 1.05 0.85 1.39 / ~ to~
The presence of a metal-hydrogen bond and the The reaction appears to be general for S-nitroso- assignment of V M - H are indicated by the isotopic 6-aminopyrimidines and represents a convenient shift in the infrared spectrum. The metal deutemethod for the preparation of cyano-s-triazines. rides (or hydride-deuteride mixtures) were pre(6) C. A. Grob in "Theoretical Organic Chemistry," Kekuli- Sym- pared by either refluxing a suspension of the composium, Butterworths Scientific Publications, London, 1959, p. 114. plex in C2HsOD, or directly from the metal salt, FRICK CHEMICAL LABORATORY EDWARD C. TAYLORPh3P and deuterium-enriched 2-methoxyethanol PRINCETON UNIVERSITY CHARLES W. JEFFORD (120') or ethylene glycol (180"). PRINCETOP;, N. J. C. C. CHEXG The unusual reaction of Os and Ru halides with RECEIVED DECEMBER 27, 1960 alcohols leading to carbonyl complexes was studied by synthesizing the compounds in the usual manCOMPLEX CARBONYL HYDRIDES OF OSMIUM AND ner except using 14C-ethylene glycol as solvent RUTHENIUM (190"). The products, after being washed extensively (methanol) and dried (vacuum), were Sir : N'e have reported recently the discovery and dissolved in toluene scintillator solution and the some properties of monohalogeno complexes of activity counted. The absolute activity of the osmium and ruthenium with triphenylphosphine samples was compared with that of the starting and triphenylarsine which were obtained from I4C-ethylene glycol by adding standard 14Cthe simple system of metal salt [(NH4)20sXs, toluene to the samples. The results (Table I) indicate that one carbon RuX31, ligand and alcohol (2-methoxyethanol or atom of the ethylene glycol is incorporated per ethylene glycol, 120-190°).1~2 Based on analytical and conductivity data, these compounds were formula weight of the complex. The analytical formulated as containing univalent metal, [MXL3] data do not, except for oxygen, readily distinguish (hl = Os, R u ; X = C1, Br; L = Ph3P, Ph3Xs). between the previous and present formulation of Thus, in the absence of a direct evidence to the these complexes. Repeated oxygen analyses have contrary, decomposition of solvent alcohol and now established that 11 '0 = 1. Xccording to the coordination of its fragments to the metal were infrared spectra this oxygen is not associated with not considered, following the theretofore accepted either -OH or triphenylphosphine oxide (possible assumption in the preparative coordination cheni- forms of oxygen that have been observed to be istry. Since then, however, it has been demon- present in other compounds obtained from the strated that metal-hydrido complexes may be formed same systems), which, altogether, appears to conreadily by reaction with alcohol in similar system^.^ firm the suggested composition and the assignment And Chatt and Shaw4 have reported to have of yc=o. The authors are indebted to Dr. R. H. Schuler obtained also carbonyl complexes from a related of the Radiation Research Laboratories of this environment (ethanol KOH), citing as evidence Institute for valuable suggestions and help in (1) I.. Vaska, 2. Yaluvfoouschg., 16b, 56 (1960). carrying out counting experiments, for supplying (2) L. Vaska and E. hl. Sloane, J . A m . Chem. Soc., 82, 1283 (1960). radiocarbon alcohols and making equipment avail(Io L. Vaska, i b i d . , 83,in press (1961) (4) J. Chatt and B. L . Shaw, C h e m and I i d , 931 (1860). able in his laboratories. They also wish to thank
+
-
~
