KOTES
November 1961)
1115
TABLE I a - ~ C E T A ~ I I D l t A Z O N I U MTHIOSULF.ZTES
NH2
+
CH2/hNHit
I
szo3-
R 11
Compd
I11 IV
yield
oc
Mp, dec
Formulaa
Approx LD~Q, mdkg
Antiradiation act.--Drug dose, Ing/kgd
30-day survival,
7Oe
13 132-163 CsHiiN303Sn pOnNCaHc 37 178-179 CsHioNiO&* 130 80 20 V O-CH~OCOH, 19 136-137 C9Hi3N30& 110 25 13 19 143-144 CsHiaFN303Sn VI p-FCJL VI1 EtOnCCHz 17 143-144 C6Hi3N30jSnC 750 400 13 N : calcd, a Analyt.ica1 results obtained for C, H, and N were within 3k0.4Yc of the theoretical values unless listed otherwise. Compounds were suspended in a physiological saline solution containing 0.3% 18.3; found, 17.8. c C: calcd, 26.6; found, 26.1. carboxymethylcellulose and 0.1 Tween 80 and administered intraperitoneally to mice, which were subjected t.o lethal radiation of No survival among control mice. 960 R. c6115
was triturated Kith boiling absolute EtOH and dried to give 2.9 g
(377,) of orange product, mp 178-179" dec.
Acknowledgments.-The authors are indebted to Drs. D. P. Jacobus and T . R. Sweeney for antiradiation data and to 3Ir. P. E. Olson, 3Ir. G. J. Lillquist, and the members of the Analytical Research and Services Laboratory of the 311 Company for microanalytical and spectral analyses.
5-Nitro-8-quinolinols and Their Copper(I1) Complexes. Implications of the Fungal Spore Wall as a Possible Barrier against Potential Antifungal Agents' HERMAN GERSHOK, ~IAYNA W.RAICNEIL, D .\SD YvolvN~HINDS Boyce T h o m p s o n Institute f o r Plant Keseurch, Yonkers, ?;ew Y o r k 10701
Ifcceived A p r d 95,1969
A hypothesis was proposed by Gershon, et a1.,'v3 which suggested that the fungal spore wall acted as a barrier against certain potential antifungal agents. If the geometry and charge distribution of a molecule are not compatible with geometry and distribution of charge around the periphery of the holes in the fungal spore wall, the compound cannot penetrate the wall and cause toxic reactions in the spore. It was deduced from the shapes and dimensions of the Cu(I1) chelates of substituted 8-quinolinols that the holes cannot be circular but may be elliptical or hexagonal. If the hypothesis is sound, and the explanation of the liontoxicity of certain compounds is due to the long axes being greater than the major axes of t,he spore holes, alteration of a secondary axis of the compound should not cause the derivative to become toxic. Bis(ti-nitro-8-quinolinolato)copper(II)was shown to be nontoxic to five fungi, Aspergillus niger, Trichoderma viride, Aspergillus oryxae, Myrothecium verrucaria, and ( 1 ) This work was supported in p a r t by the U. S. Public Health Service, Grant No. AI-05808. (2) H . Gershon. R. Parmegiani, A . Weiner, and R. D'Aaooli, Contrib. Boyce Thompson Inst., 1 8 , 219 (1966). (3) H. Gershon, J . M e d . Chem.. 11, 1094 (1968).
Trichophyton nientagrophytes.2 The explanation was that its long axis was greater than the diameter of the holes in the spore walls and penetration of the spores could not be effected. Consequently, any 7-substituted 5-nitro-8-quinolinol Cu(I1) complexes should also be nontoxic to the same fungi. To test this, the Cu(I1) bischelates of 7-fluoro-, 7-chloro-, 7-bromo-, and 7iodo-5-nitro-8-quinolinol were prepared and screened against the same five fungi. Although the chloro ligand4mas previously preparcd by a Skraup synthesis, the present preparation mas obtained by treatment of 5-nitro-8-quinolinoIj with NaOC1. The bromo6 and iodo7 compounds were also prepared from 5-nitro-8-quinolinol. The respective copper(I1) complexes mere prepared from the ligands by treatment with cupric acetate in aqueous JleOH, or aqueous XeOH containing DNF. The data characterizing the new compounds are contained in Table I. All of the compounds were screened for antifungal activity in shake cultcrz a g r h s t the spores of the five fungi previously mentioned, according to published methods.8 The data of Table I1 show that the 7-substituted ~-1~tro-8-quinolinols possess significant antifungal activity but weaker than that of the parent compound, .j-nitro-8-quinolinol.2 The Cu(I1) bischelates were all inactive. Thus, these results were found to be consist ent with our hypothesis. * It should be mentioned that in certain cases the freshly prepared chelate caused inhibition of mycelial development. On repeated boil-up of the chelate with DNF, the inhibitory effect was eliminated. Upon cooling the D X F solution, a chelate was obtained which was inhibitory. When both the soluble and insoluble chelates were decomposed with H2S and the Cu(I1) removed, followed by recovery of the ligands, gas chromatography of the trimethylsilyl derivatives indicated that both chelates appeared to possess the same component parts. We cannot interpret this observation properly, but a reasonable explanation may be that in the formation of the chelate, a small amount of cis F. X. Wiederkehr and E. Hofstetter, Helu. C h i n . Acta. 86, 468 (1952). V. Petrow a n d B. Sturgeon. J . Chem. Soc., 570 (1954). (6) H. Vogt and P. Jeske, Arch. Pharm., 191, 168 (1958). (4) (5)
(7) K . RIatsumura, J . A m . Chem. Soc.. 49, 810 (1927). ( 8 ) H . Gershon and R. Parmegiani, A p p l . X w w b a o l . , 11, 62 (1963).
\'Ill. I "
I I Ifi
OH
Experimental Srction I"
7-Fluoru-8-yuiiiuliiiol.
-
lic*iiii-
~ - . \ I ~ ~ ~ I I I I - ~ - I ~ ~ I ~ I I: It iI ~ ~ 1110 IIII~~' liiil
ilir
\ \ u r k uf C. F. Marks. I. J .
i t d . . 2 2 , 321 (1968). be conaideieil o u r IiypotlieAa on tlie tiingal spore n-all a s a possible barrier
$\iiiirekjiect i c i against 1,otrntiai antifungal agentb. These authors attempted t o implicalr B iulicuticulur membrane as the actual barrier 10 penetration in nematode.. rather tlian tire cuticle itself. .\ltIiuugh this study deals with the rates of Iii,netration of t h e animal organi-m hy nematocides and other compounds, n o rrork \Pa.- regiirted on the nuntosicits of imtential nematocides. The reawns f u r o u r choice of fungal spore wall irn tlie barrier against the class (11 ,,urnpounds in o u r study r a t h e r tlian tlie memlhrane are presented in ref ! a i t i l :i. I t h l i u i i l i l 18,. no!rranr c n i i l e - o i i ! liic. 1t.i1al functiuns attriliiiteil t u i t . b i i t tliat \ \ a l l itlnu acts aa a harrirr uf a sori I 1 0 ) JIelttnrr priints i w r c takrn i n R Alel-Teiiiii rneltinr point apixiratti; n i ~ di t w i i n c t ~ r r e v t ~ r l .
Sovember 1909
XOTEH
c*oiitiniied. When the temperatiire i'ose t o 15-20', all of the irihc~liible material went, iiito solutioii. The clear solution was poured int,o 500 ml of H20 and the mixture wa. adjusted to pH 5 . The product was removed by filtration, washed with deionized H20, and dried overnight at i o " . The crude product melted a t 219-220' dec. Bisi7-fluoro-5-nitro-8-quinolinolato)copper (11) (IIa).-Two soIritions containing 0.41 g (0.0018 mole) of i-fluoro-5-nitro-8quiiiolitiol in 10 ml of MeOH and 0.21 g (0.0010 mole) of Cli(OAc,),.H?Oi n 20 nil of 75qi aqueoria 1teOH were mixed and $tined for 1 hr. The product was removed by filtration, boiled i i i 1)lIF .*everal times, and t.he insoluble material was washed with acetone arid dried lindei, vnciium a t 100" overnight. The componitd was FiifYiciently pure for anal! 7-Chloro-5-nitro-8-quinolinol (Ib).-Tu 400 ml of H20 xvas added 5 . i g 10.028 mole) of 5-iritro-8-quirioliiio14and 1.8 g 10.026 mole) of 85c; ROH. Soliitioir was effected by stirring and heatiiig. After cooling t o 30", 50 ml of SaOC1 ( 5 . 2 5 % ) \vas added :tiid stirring was contiillled 1 hr loiiger. The mixture was brought to pH 5 with 25 ml of AcOH. The pt,odiict was obtained by tilt,ratioii, wishing with deionized H20, arid dryiiig at i o " over-
guanosine disulfide was also found to be a more potent inhibitor on a molar basis than either 2 or thioguanosine. Despite these rather intriguing results there does not appear to have been any further study upon the effects of disulfide formation on biological activity in 6-t hiopurinyl nucleosides. In an effort to explore this aspect further we have prepared the disulfides of several 6-t hiopurinyl nucleosides. The candidates chosen for conversion to their disulfideb were a- and P-9-(2-deoxy-u-erythro-pentofuranosy1)-9H-purine-6-thio12 (3), a- and P-2-amino-9-(2deoxy-i)-eryth ro-pent ofuranosy1)-9H-purine-6-thiol6 (4), 9-B-1)-arahinofurariosyl-9H-purine-G-thiol~ ( 5 ) , and 2amino-9-(3-deoxy-p-r, -erythro-pentofuranosyl) -9H- purine-&thiol8 (6). All of the compounds chosen with the exception of a-3 have previously demonstrated significant activity in the leukemia L1210 test system" (Table I).
tiight.
1117
6,6'-L)ithiobispurinyl Nucleosides' ---SH" Dose,
FREDKELLER.\SD JAMES E. B ~ K E K .Ilrtlicinal ChPmistr?/ SPction, Chrniical Research DepaifmPnt, lii?iPr Laboratories, Division of Dart Industries, Inc., Sorth ridge, Ca 1ijorn ia 91324 X i w i w t l Fcbruaiii 5, 1969
rl number of nucleosides of purine-6-t'hiol (1) and 2-aminopurine-6-thiol (2) have been prepared in an effort to modify the toxicity of these clinically useful :inticancer agerit,s and to provide drugs for use against 1- and 2-resistant cancer st,rains. A serious problem which has presented itself in t'he use of these new drug cartdidat'es i R their rapid elimination and metabolism by oxidative pathways to therapeutically inactive products. The metabolism of (%mercaptopurine and some of its deriv:itives hws been the subject of :I recent review.Y 111:LI~ attempt to provide :I "reservoir" source of 1 arid 2 :is well a s their 8-i)-ribofurnnosides, Doerr, ef a/.,4 prepared the disulfides of these compounds using an adaptation of the iodine-buffer procedure of AIiller, et d.: The disulfides could he envisioned as reverting to the corresponding thiol and sulfenic acid through chemical means by the attack of base,4 or alternately an enzymatic system such as that regulating the oxidation and reduction of glut:ithione could prevail t o reduce the disulfide to the thiol. The earlier paper4 did riot record any metabolic data to support directly the "reservoir" hypothesis but did note that the :ictivity of the disulfide of t,hioinosine in the Sarcoma 180 tem was greater than that of 1 while thc corrc~spontlingthiol \v:w in:ictivc. Tlrc thio( 1 1 -\lost of tliir \vork w a a uerfulctied rirldrr the a u s u i c e r uf r l j r ('alicrr
Cliemotlieraps National Service Center. Xational Institutes of Health, Put)lie Health Ssrvice. under Contract PH-43-66404. T h e views expressed in this paper are those of the authors and d o not necessarily reflect those of t h e ('CNSC. (2) See R. H. Iwamoto. E. .\I. h c t o n , and L. Goodman, J . Org. Ckem.. 27, R94Y (19621, and leading references therein for a discussion of t h e rationale for tlie preparation of these compounds. ( : ( I C,. B. Elion. Frrirr,iti,jrb T'rm., 26, 898 ( 1 H t i i ) . (-1) I . I.. I)ocrr. I . \Vein[~eri,L). .i. ('larke, a n d J. .J. 1:o.r. .I. O r y . Cltem.. 26, 3.101 IlYlil). c.5) \V. I{. XIiller. R. 0. Rol)lin, J r . . and E. I%..\stmood. J . A m . Chem. S o c . , 6 7 , 2201 (1945).
Compound
my,'kg
,--s-sh
g,-
ILS, 70
ff-3
3-3 ff-4
200 1.i 20 400 200
36
J)ose, mdkg
400 4-600 400 150 400 to-150
---_ ILS, '/c
16 30 47 3% 40 33
93 Y9 3-.i 63 !3-6 89 Optimal dose. Optimal dose not determined; admiiiistered iiitraperitorieally in saline stispension. 13-4
--
The thiols were smoothly converted to disulfides 111 good yields upon treatment in the iodine-buff er i y + With the exception of a- arid p-3 all oi the nucleohide disulfideq proved t o be quite water insoluble and were recovered by filtration of the reaction mixture and conveniently purified by recrystallization from DlIF-H20 (method -4). The 2-deoxynucleoside disulfides (a- arid 6-3) had significant water solubility :ind were best recovered by lyophilization of the oxidation mixture and recrystallization of the residueq from a minimum of H20 (method R). The physical constant5 of the new compounds are listed in Table 11. -111 of the disulfides exhibited the characteristic uv spectra described prev i o u ~ l ylo. ~ Biological Testing.-The preliminary screening resulth in the 1,1210 system for the neu disulfides are li*ted in Table I along with the optimal dose> for the parent thiol*.$ It n-ould appear from theye data that all of the ( 6 ) R . 11. Iwamoto. E . AI, .leton. and 1,. Goodman, .I. M e , / . C h e m . . 6 , 081 (19fi3). ( T I 1.; .I. Ileist. .\. l%enitv/,I.. G o d m a n , 13. K. Ilaker. ancl \\'. \\ . 1 . w
./. Or
