Journal of Medicinal Chemistry, 1970, Vol. IS, N o . 6
NOTES drate (3.73 g, 20.0 mmoles). The resulting red soln was stirred under Nz a t room temperature for 72 hr, then refluxed for 1 hr. After treatment with charcoal the soln was evapd in vacuo to give a dark gummy residue that was dissd in HzO (300 ml) containing concd HC1 (5 ml). The resulting soln was warmed, treated with charcoal, and filtered through Celite. The orange filtrate was adjusted to pH 11 with 50% NaOH and extracted with CHC13 ( 3 x 1.50 ml). The combined extract was washed wit,h H 2 0 , dried (Xa,SO,), and evapd to dryness. An EtOH soln (100 ml) of the residue was acidified with 3 X ethanolic HCl (10 ml) and dild with EtzO (300 ml). After vigorous stirring for several hours, an orange powder deposited slowly. The mixture was dild to 1 1. with Et20 and filtered under h ' ~ . The orange powder was recrystd under the same conditions to give a hygroscopic orange solid that was collected by filtration and dried in uacuo over P20ja t 78": yield 3.85 g (46%): mp sintering and gradual decpn 220-250" (Mel-Temp); Amax nm ( E X l o w 3 ) ,pH 7, 243 (27.4), 293 (21.4), 338 (12.6), 3% (10.0); pmr (8% DMSO-ds wiv), 6 1.28 (m, 9, CH,), 1.82 (m, 4, CHZ),3.03 (m, 6, CH*K), 4.24 (m, 1, CHX), 7.22 (d, 1, 7-CH), 8.04 (9, C&), 8.55 (&CHI, 9.57 (XH), 9.63 (2-CH). Anal. (C22H&lS6. BHC~.HIO)C, H, C1, N.
Acknowledgments.-The authors are indebted t o Dr. W. C. Coburn, Jr., and members of the i\lolecular Spectroscopy Section of Southern Research Institute \vho performed most of the microanalytical and spectral determinations reported.
Hydroxylamine Derivatives as P o t e n t i a l Antimalarial Agents. 1. Hydroxamic Acids1 JOHN B. HYNES Department of Pharmaceutical Chemistry, College of Pharmacy, Medical Cniversity of South Carolina, Charleston, South Carolina 29401 Received X a y 1 , 1970
Hydroxamic acids have been found to exert a number of diverse pharmacologic actions including antituberculous, antifungal, and antileukemic activities.* I n addition, certain arylhydroxamic acids inhibit nucleic acid biosynthesis in Since the quinoline type antimalarials such as chloroquine, quinacrine, and quinine have been reported to function a t least in part by blocking enzymatic synthesis of DSA and RNAJ6a series of hydroxamic acids was synthesized and evaluated as a potential new class of antimalarial drugs. A total of 33 mono- and dihydroxamic acids and related compounds was prepared and tested for in vivo antimalarial activity against Plasmodium berghei in mice.'J Pertinent physical and chemical data for new compounds or those for which the melting points were significantly different from the literature values are summarized in Table I. The preparation and properties of other compounds have been described earlier. Of the compounds tested, two showed an increase in mean survival time of infected mice of greater than 100%. They were terephthalohydroxamic acid (2) and (1) ment 9066. (2) (3)
1235
dibenzoylterephthalohydroxamate (15) and the pertinent testing data for them are summarized in Table 11. The most probable structure of 15 is based upon ir data. p-HONHCOCeH4CONHOH 2
The similar level of activity of these two compounds suggests that 15 is enzymatically converted into 2. However, the lack of activity of the diacetyl derivative 14 is difficult to explain on this basis. All of the derivatives of 2 involving ring substitution, 4, 5, 6, and 7, were inactive with the exception of the tetrafluoro analog 3 which was slightly active (A = 2 days a t 640 mg/kg). Similarly, alkylation of the hydroxamic acid portion of the molecule (11, 12, and 13) resulted in inactive compounds. Compounds 8,10, and 20 as well as adipohydroxamic acide were prepared in order to evaluate the effect of altering the distance separating the two hydroxamic acid functions. Since none of these showed appreciable activity, one may conclude that this value is extremely critical. The pyridine analog of 2, 2,5-pyridinedicarbohydroxamic acid (16), as well as its 3-position isomers, 17, 18, and 19, were also prepared and evaluated for antimalarial activity. As would be expected from the inactivity of 8, only 16 showed appreciable activity but was also toxic.10 I n addition to 4-carboxybenzohydroxamic acid (1) two related compounds, terephthaldihydrazide" and terephthaldioxime,12 were also prepared and found to be devoid of activity. A series of 4-substituted benzohydroxamic acids [p-XCsH,CONHOH (X = S02NH2,X02, Br, C1, I ) ] mas prepared as described in the l i t e r a t ~ r e . ~ .Only '~ the 4-Br derivative showed appreciable activity (A = 3.1 days a t 640 mg/kg). In addition, 3,4,5-trimethoxy-, 2-bromo-3,4,5-trimethoxy-, 2-hydroxy-3,4,5-trimethoxy-, and 3,5-dichlorobenzohydroxamic acids ab well as 3,4,5-trimethoxyphenylacetohydroxamic acid were prepared ab described earlier5 and found to be inactive. Compound 21 was synthesized as an analog of the highly potent antimalarials, the quinoline methanols. l 4 It was also inactive.
This work was supported b y t h e U. S. Army Research a n d DevelopCommand, Contract No's. DADB17-67-C-7055 a n d DADA17-69-C-
R . T. Coutts, Can. J . Pharm. Sei., 2, 1 (1967). G . R. Gale, Proc. SOC. E z p . B i d . ,Wed., 122, 1236 (1966). (4) G. R. Gale and J. B. Hynes, J . M e d . Chem., 11, 191 (1968). ( 5 ) G . R . Gale. J. B. Hynes, and A . B. Smith, ibid., 13, 571 (1970). ( 6 ) L. G. Hunsicker, Arch. I n t . .Wed., 123, 645 (1969). (7) T. S. Osdene, P. B. Russell, and L. Rane, J . ,lfed..Chem., 10, 431 (1967). (8) Testing was carried out by L)r. L. Rane of t h e University of Miami.
(9) M. E. Cupery. U.S. Patent KO.2,346,665 (1944). (10) A t 640 mg/kg 2 mice died on day 4 (mean survival time for controls was 6.1 days). Deaths due to toxicity of drugs occur in 3-5 days. (11) E. Davidis, J . Prakt. Chem., 54, 81 (1896). (12) L. A. Errede and S. L. Hopwood. J . A m e r . C h e m . SOC..79, 6507 (1957). (13) C . H . Andrems, H. King, and J. Walker, Proc. Roy. Soc.. Ser. E , 138, 20 (1946). (14) E. R. Atkinson and A . J. Puttick, J . .\!fed. Chem.. 11, 1223 (1968).
Experimental Section': lfnsubstituted Hydroxamic Acids.--Each of t,tiose coiiipoiiiidh .n1 hesized from its corresponding Me or E t est,er, which iii 'e cif 1 (rnoiiobiit,yl ester), 2, 7, 8, 9, 17, atid 20 was obtained from commercial :oiirce~. Dimethyl tetrafluorot,erephthalate wtts prepared i i r (is(,; yield from the corresponding acid by reeOIT satitrated with atihyd HCl for 14 hr. The lline solid melted at. 78-80" (lit.16 mp 79-80'), (15) Melting points tuneor) Irere taken on a Fisher-Johns melting point apparatus. The ir spectra were determined using a Beckman IR 8 spectrophotometer. (16) 13. Getiiinx, ( ' . 11. l'atrieh, and J . ( > .'l'atlow, J . Chern. Soc., 1 5 i % , (1961).
I )irnethyl ",3-dinietli?.lterepht,halatc w i s obtitiiietl i i i TSf yiel(l by refluxing a mist ure of 2,3-dimeth>-lterephthalicacid in Me01 1 i i i the preaeiice of coricd H,S04 for 9 hr. The estc'r melted : i t 11:J---114..i0 i1it.I; nip 114"). 1)irnetIiyl broiiiotrrephthal:ite w:iobtained by t,he HC1-ratalyzed e..terification of the rorrespoiidiiig acid, nip 53-.i4..io (lit.17 inp 5 7 ' ) . The prepararioli of dimethyl L',.i-dichloroterephthal:~l e was also coiiducted iiyiiig HC1 :IS t h v cs;r,talyst rather than H2SOcas ( in the literature. I k c~iystallixationfrom B large volu OH yielded the desired mp 1Xi0, yieltl cwmpound in 77':; yield, nip 1 .50(5; ). The ciimeth>-l esters of 2,:- 3,5-, a i d 2,G-pyridiiietlirarboxylic acids wetx prepared by the I12804-c,atalyzed ehterifiw1 i o n technique. T h r meltiiig poiiiti K re:p 1(3A-16io (lit." nip ltil--163°), 54.; h 4 0 ) , :lilt1 123 .12:1* (lit .?" nip 121 "). .\Iothyl %-(4-~l1lor~~pheiiyI)-(i,S-t~i1net hylciilc~lioriiiiate, t r i p 147.- 1 4!1°, K ~ Ssupplied hy Walter Reed A I ' I ~ ~ ) Iiist,itute of Research. The hynt,heses of hydroxiniic acids 3 , 4 , 5, 6, 7, 9, 10, 16,17, 18, :iiid 19 all were carried out living MeOH as the solvent and bot ti S a O H and NH20H.HCI in excess of the theoretical anioiiiitrequired to produw the disodium salt of the corresporidiiig dihydroxamic acid. The reactions were 1-oiiducted at room ten1pcrature for periods of 2-5 days. Compounds 2 a~icl8 wen' prepared in the same niaiiner as :il)ove exrept that the mlvc~lt ('on1W B S EtOH- HZ0 while 1 was prepared iii RIeOFI-lid). poiuids 20 aiid 21 w t w prepared nsirig excew NI-IzOH i i i 11eO11 with 11eON:t :ts thc I) In (he latter cas+ Et,O was lttltietl t o the reaction m i x t u r ~t iprove the >oliibility of the ester. N - and 0-Alkylated Hydroxamic Aeids.--C:i,mpoliiids 11, 12, aiid 13 were prepared from their vorrespoiidilig hytiroxylaiiii~i~~ hydrochlorides by a niodific-atiuii of the method of Koeiiig :i11(1 I)eiiiaer.21 The followiiig descriptio11 of the preparation o f 0,U'tliethgl1,erepht h a l ~ h ~ ~ i i ~ o set i is i i irepre,eiit ~t ative of this techeiii lmivicletl with :i N2 purge were placed 6.4 g iif .~. .
ilij 118) tl9) (20) (21)
M. Cachia anti If.Ralil, Dull. S O C . Chirn. F r . , I415 (1958). T . 0. Soine, J . d m e r . I ' i i a r n i . A s a . , 33, 223 (1954). .I. liuthan, C'zechoslo\-akian Patent 1119,895 (1964). 11. Anderson and 1'. 0 . Puine, J . Anrcr. Phnrm. . I b s . , 39, 160 ( I X O ! . T. Roenig aiid 31. I)ein;.ar. J . A i f i c r . ('hem. Soc., 90, 7014 (1CJfBl.
Noms EtONH2.HC1, 8.6 g of imidazole, and 100 ml of anhyd MeCN. Next, 6.1 g (0.03 mole) of terephthaloyl chloride was added portionwise over 0.5 hr and the stirring was cont,iiiued for an additional 3 hr. The solid which formed was sepd by filt'ration, suspended in 200 ml of H20, and then refiltered. An analytically pure sample was obtained with one recryst'allization from H20. As expected, this substance, as well as 13, gave a negative color reaction with 1% FeC13 solutioii. Conversely, 11 gave a dark maroon color with t,his reagent. Diacetyl Terephthalohydroxamate (16).-A mixture of 3.3 g of 2, 20 ml of AcrO, and 20 ml of AcOH was heat,ed at 100" until a iiegative FeC13 test, was obt,ained (approx l . . 5 hr). The solid was sepd by filtration, m s h e d with HsO, and then t'hroughly vacuum dried. Recrystallization from 900 ml of MeOH produced 2.4 g of a whit8ecryst,alliiie solid. The ir spect.rum (Nujol mull) exhibited characteristic bands at 3122 (broad), 1783, and 1640 cm-1. Dibenzoyl Terephthalohydroxamate (15).-This compound wab prepared by two different, techniques. One involved the reaction of 2 with 2 equiv of BzC1 in pyridine at, ambient, temperature. procedure However, a better yield was obtained by employing tmhe of Renfrow and Hauser.22 The disodium salt, of 2 was prepared by adding the required amount of 2 t,o 2 equiv of NaOH in anhyd MeOH. After stirring for 0.5 hr, the solid was sepd by filtration, washed several times (EtsO), and thoroughly vacuum dried. Yext,, 1.2 g (0.005 mole) of this material was suspended in 12 ml of dioxane and 1.4 g (0.01 mole) of BzC1 was added. The resulting mixture was stirred rapidly at 100" for 0.5 hr. Aft,er cooling, ('he product was added t o 100 ml of cold H20 and the resulting solid was sepd by filtration and washed with H20 and EtzO. Recrystallization from dioxane yielded the desired mat,erial in analytical purity. Significant ir bands were located a t 3140, 1770, and 1650 cm-1.
Acknowledgment.-The aut,hor wishes to express his grat'it'ude t'o Dr. Edgar A. Steck for many helpful suggestions and discussions during t'he course of t,his work. The technical assistance of Mrs. Linda G. Hack was invaluable.
TABLE I KTHYLALKYLCY.4NOaC~;Ta'r~;Sn RCH (CK )COOCzH; I
R
Tield,
Rp (mm),
(7i
"C
1125~
Formulac
77(0.43) 1.4277 CloHi7NOz 1.4809 CiiHi9NOz 51 9!j((1.75) 1.4331 g 38 100 (0.40) 109.5 ( 0 . 2 3 ) 1,4358 C13H28xO2 h C S H I ~ 51 76 121 (0.53) 1.4367 CiiHzjN02 i CgH1, 1.4384 CiiHz7NOz j CioH21 66 139 (0.80) 1.4418 Ci7H3iNOz k CizHzj 48 165(1.45) Lit. ref 6, " P,C ,,, N 22.50 em-', P : 1741-1745 ~ ~ ~ cni-' (neat). bp 111-113" (1 mm), n Z 51.4337. ~ All compds except' g were analyzed for C, 11, 9. e f
C,HI1 C6Hla C7Hijh
36
TABLE I1 EETIIYL ALIiYLCYASOFLUORf).\C1.;T.\TI.:Sf"
1tCF(C?i)COOC& '7c
I3p (mm), OC
.)c) -9
67 (0.40)
Yield.
I1
It
e
C,HII C6Hi3 C7Hij
f
lil5Uh
1.4081
l*'ormulac
CIOHI~FN~~
77 (0.2,;) 1.4130 CiiHisFXO? 114 (3.0) 1.4164 C12HzoFXO2 h CsHi, !I2 (0.30) 1.4193 C~~HZ~FXOI i C,H,!, .70 llO(0.40) 1.4230 CI4Hs4FNO3 j CI0H21 30 138 ( 1 . 7 ) 1.4257 CI~HZ~FNOY k C12Hej 36 164 ( 2 . 6 ) 1.4302 Ci7H3oFN02 a Y,,, C = N 22.70 cm-1, v:Eo doublet 1775-1785 and 1730-1760 cni-1 (neat). The refract'ive index must' be taken fairly rapidly, since exposure of t'he compound t'o the N a light causes a series of color changes which range from yellow t o orange, t'o red and eventually t o black. The nonfluorinated analogs do not undergo this react'ion. 811 compounds xere analyzed for C, H, F, N . g
36 24 58
(22) W. B. Renfrow, J r . a n d C . R. Hauser. J . Amer. Chem. Soc.. 119, 2308 (1937).
Organic Fluorine Compounds. IV. Synthesis and Antifungal Properties of 2-Fluor0 Fatty Acid Amides' HLHM.\N GLRSHOX,I L ~ Y M OL. ~ DRODIN,K.\uLo P \RUEGIAINI, AND P.1TRICIA K. GODFRE,Y Boycc Thompaon Instztute .for Plant Research, Inc., Yonkers, A-ew York 10701 Receaved January 28, 1970
Sumerous studies on the antifungal properties of fatty acids have been carried out. These were recently summarized by Gershon and Parmegiani2 who :tlso reported a study on the antifungal action of 2fluoro fatty acids as compared with nonfluorinated fatty acids. Four factors which affect the antifungal activity of these compounds are concentration, chain length, pH of the medium, and presence or absence of materials such as serum albumin in the test medium. The results confirmed, in general, that antifungal activity of nonfluorinated fatty acids was dependent on concentration and chain length, and lowering the pH of the medium enhanced fungitoxicity. The pres(1) P a r t I11 of this series: H. Gershon, s. G. Schulman, a n d A . D. Yge\ack, J . .Wed. Chem., 10, 536 (1967). (2) l i . Gersllon a n d R. I'armegiani, h d . , 10, 186 (1967).
ence of beef serum reduced the :tctivity of the toxicant. The same generalizations held true for the fluorinated fatty acids, except that a longer chain length was required for comparable activity. Whereas, in the test system employed,2 the nonfluorinated fatty acids were most active a t chain lengths of 4-10 C atoms, the fluoro fatty acids were most active at chain lengths of 8-14 C atoms. It was also concluded that the pK, of the fatty acids did not play an important role in their antifungal activity, since the pK, values of 2-
