'The Bacteriostatic EfTectiveiiesh of I -Alk>1-3-(3, i-dichloropheny1)ureas
iiito 2 1. of vracketl iw :illti viater. T h e crude prodi1c,t collected by fillration arid led tlioroiighly with Taler. Ilecrystallization from glacial ai.etic* m.id (charcoal) gave the prodikct as short yellow needles. Other tlt,rivativel: of I11 were prepared similarly. 6 45-Nitro-2-furyl)-3(2H)-pyridazinone(IVa).----I riiisture i l f 41.8 g (0.2 mole) of IIIa ill 200 nil of glacial :tc,etic acid uxc heated to 90". Bromine ( 2 nil) w:is added with drriiig. W'heii HI3r evolutioa began, the reriiainilig bromine (total of 32 g, 0.2 mole) was added :it siich a rate as tn maintain a temperature of 90-96". When he zidditiorr \vas completed, the mistine XLY he:ited a t 100" for 30 min. The mixture was rooled, diluled vith waler, :tnd filtered, and the r e d u e was washed thoroughly with m ~ t e r . The yield of critde protiiirt melting at 293-295' n i s :N.0 g (94:; ). Foiir rec allizat ions from climethylformnniiclc. (1~11:ircoal)gave pale yellow rryst:ils. IT% mis prepared 5iniii ~ r o i i stirring i
wts
1:1rIy.
2-Ethyl-6-(5-nitro-2-furyl)-3(2Hi-pyridazinone(IVc).----A 111istiireof 50.0 g (0.24 mole) of IVa and 13.0 g (0.24 mole) i ) f s i ) i l i i i m methoxide iii 1000 1111 of methanol was refluxed with .tiwing for 3 hr. E ~ h y iodide l ( 5 0 nil) \\-as added and refluxiiig was cont iriiml overnight. The solvents were evaporated under diriiiiiished pressure on n steam b a t h arid the residue was shaken wit11 500 nil of cold .5(,-;, SaOH soliilion. T h e rrude pro(1uc.t \vas filtered, uadied thororighl>. with Iv:itPr. aiid recryatdlizetl from ~ l l l l l ~ ~ lc>t~lalloi ~lls i l ~ ~ i : i r c ~1. o : lmlr. ~ l l r . l l t ~ l l l ~ t ~s e p n r a i ~ t:~ iq p:ii~ y c ~ l l iievtlle~. i~~~ I\'h t i i i ~ l1T.d x v ( w 1 ) i ~ ~ p ; i from r ~ d the sippropri:it~ :I11;y I i I idi iIC>.
Acknowledgments. --\\-c \\.ish to express our gmtit utlc i o lJT. 0. Smith and 73. F. Stel-eii.zoii and grou]> f o r tecaliiiicd assistaticc tluriiig t 1 1 ~1)rei)aratioli of I ~ K W
SOTES
May 1966
Recently, we had occasion to prepare 1-(3,4-dichlorophenyl)-3-n-nonylurea. Although there was no reason to expect unusual bacteriostatic activity, this compound was routinely tested against X. aureus 209. Since it was found to be nearly as effective as I and 11. a series of 1-alkyl-3-(3,4-dichlorophenyl)ureas was prepared and the activity was determined against S. aureus 209. Experimental Section The 1-alkyl-3-(3,4-dichlorophenyl)ureaswere obtained by the reaction of 3,4-dichlorophenyl isocyanate with the proper alkylamine by the method of Beaver, et al.' These compounds were white crystalline solids, soluble in alcohol, benzene, and dimethylformamide; slightly soluble in ether; and insoluble in water. Several alkylene-a,w-bis( 3,4-dichlorophenylureas) were prepared by the reaction of 2 equiv of 3,4-dichlorophenyl isocyanate with the appropriate diamine in dimethylformamide. The following preparation is representative. 1,5-Bis(3,4-dichlorophenylureido)pentane.-To a stirred solution of 10.2 g (0.1 mole) of cadaverine in 150 ml of dimethylformamide was carefully added a solution of 40.4 g (0.22 mole) of 3,4-dichlorophenyl isocyanate. A white precipitate began to to form, whereupon the reaction mixture was heated until a clear solution again resulted. After 15 min, water was added to precipitate the crude product. This material was filtered and washed with water; yield 38 g (74%). Recrystallization from dimethylformamide-water gave white crystals, mp 208-210'. The compounds were tested by the agar streak dilution technique, in the presence of soap.2 A 24-hr broth culture of S. aureus 209 was used as the test organism. The concentrations of soap used (100 times the concentration of the test compound) would not inhibit this organism under our test conditions.
Results and Discussion The minimum concentrations (hIIC) of these compounds able to inhibit the growt'h of S . aureus 209 are listed in Tables I and 11. These results confirm the observations of Beaver, et aZ.,I that 1-(3,4-dichlorophenyl)-3-ethylurea (1) is relatively ineffective against this organism when compared with I or 11. As the length of the alkyl chain is extended from ethyl to n-octyl, the bacteriostatic activity increases regularly. l-(3,4-Dichlorophenyl)-3-n-octylurea(10) is as eff ective as I or 11. With further increase in chain length, however, the activity decreases. The n-undecyl derivative (15) is no more effective than the n-propyl compound (2). The tridecyl (17), tetradecyl (18), and octadecyl (19) derivatives showed no inhibition at t'he highest concentrations tested. Such a relationship of bacteriostatic activity t o t'he size of an alkyl substituent is not an isolated phenomenon. A similar effect has been observed for the activity of n-alkylbenzoylacrylic acids against staphy l o c ~ c c i where , ~ ~ the most effective compound is the nonyl, and for n-alkylphenols against Xalnzonella t y p h ~ s awhere , ~ ~ the optimum chain length is amyl. However, there is no certain explanation why the n-octyl cornpound should be more effective against the test organism than compounds with longer or smaller alkyl chains. A second finding of interest is the fact that the minimum inhibitory concentrations of 3, 4, 5, (2) D. R. Noel, R. E. Casely, W.M. Linfield, a n d L. A. Harriman, A p p 1 . Microbial., 8, 1 (1960). A commercial toilet soap consisting of t h e sodium salts of mixed tallow a n d coconut oil f a t t y acids (80% tallow) was used (Ivory@). (3) (a) F. Kirchner, J. Bailey, and C. Cavilito, J. Am. Chem. Soc., 71, 1210 (1949); (b) E. G. Klarman a n d E. S. Wright i n "Antiseptics, Disinfectants, Fungicides, and Chemical and Physical Sterilization," G. F. Reddish Ed., Lea a n d Fehiger, Philadelphia, Pa., 1954, p 429.
427 TABLEI 1-.4LKYL-3-( 3,4-DICHLOROPHEISYL)URE.%S
ANHCONHOcP
No.
R
1Ip,
oca
-Chlorine, ACaicd Foundb
111c. dmlc
Ethj 1 179-18Ud 30.4 30.6 20 n-Prop) 1 129-13 l C 28 7 10 28.5 n-Butyl 121-123' 27 2 5 27.3 27 2 sec-Butyl 27 4 > 132-134 5 I5obut) 1 27 2 138-139I 27 0 5 6 I-Butj 1 27 2 5 27 5 194-195 7 n-Pentyl 25 9 26.0 1. 0 117-1 18 24 6 8 n-Heq 1 104- 106' 0.5 24.4 9 n-Heptyl 0.3 23 4 23 4 97-98 10 n-Octll 80-828 22.4 22.5 0.2h 11 1,1,3,3-Tetra22 4 145-147 22.4 0.4h methylbutyl 12 n-Sonj 1 S7-88 0.4 21 5 21 7 20 6 13 n-Eec)1 S9-90 1.0 20 s 8-83 14 9-n-Uecenyl 1 .o 20 6 21 0 94-96 10.0 15 n-Uridecyl 19.5 19 8 19 0 15 94-95 16 n-Dodec? 1 18 8 17 n-Tridecyl si-88 18 3 >20 lb 5 96-97 17 7 18 n-Tetradecyl 18 0 >%0 19 n-Octadec) 1 I 1-79 16.0 16.3 >20 All melting points were taken on a Fisher-Johns melting point, apparatus and are uncorrected. Chlorine analyses were by the Schoniger combustion technique. c Minimum inhibitory concentration against Staphylococczls aureus 209. d Lit.' mp 180". e?;. E. Good [Plant Physzol., 36, 788 (1961)] reports mp 128-129", 121-122', arid 104-105' for 2, 3, and 8 , respectively. f A second crystalline modification, melting 122-124', was observed. On melting and refreezing, it reverted to the 138 139 O form. A second crystalline modification, melting 10010lo, was observed. Its analyses, infrared spectrum, and 111C against S.aurezls 209 were identical with those of the 80-82" form. Compounds 10 and 11 were also tested in the abseiice of soap. The M I C under these conditions were 0.3 arid 0.4 pg/ml, respectively. 1 2 3 4
--
TABLE I1 ,&LKYLENE-ap-BIS( 3,4-DICHLOROPHENYLUREhS)
NO.
X
hfp, o c a
Chlorine, % Calcd Foundb
20 21 22 23 24 25 26
0 2 3 4 5 6 8
227-228 255-256 227-228 259-260 208-210 228-229 2 13-2 16
34.8 32.5 31.5 30.6 29.7 28.8 27.3
34.6 32.8 31.8 30.3 29.8 28.4 2i.0
11I c , c i d &g/rnl
>5 >5 >5 >5 >5 >5 >5 lIIC,C
KO.
27
Compd
rg/mi
l-(4-Chlorophenyl)-3-n-octylurea~ >20 I 3,3',4-Trichlorocarbanilide 0.2j I1 3,4,4'-Trichlorocarbanilide 0.21 3,4-Dichloroaniline >5d See footnote a, Table I. * See footnote b, Table I. See Highest, concentration tested. e M p 131footnote c, Table I. 132". Anal. Calcd for CI6H2,Cli\',O: C1, 12.5. Found: C1, 12.3. f These compounds were obtained from the Monsanto Chemical Co. These values for the minimum inhibitory concentrations are higher than those reported by Beaver, et ul.,' for the same compounds (0.033 pg/ml). Slight variations in test method or conditions may account for the discrepancy,
Halonitroanilides and Their Bacteriostatic Activity Experimental Section
The antibacterial activity oi a variety of halo- and Iiitrosalicylanilides is well docunientecl. *\Iariy of thew compounds possess good bacterioLt:itic*activity and also are substantive to skin arid cloth. IT(>wish to report the preparation arid bacterioqtatic artivity of additional anilides in which the o-hydroxyphenyl nioiety ha5 been (+hangedto alkyl, haloalkyl, allrenyl, cyclonlkyl. benzyl phenet hyl, phenoxy methyl, :ind 1Ihenyl groul)i. Th c S-aryl portions of the conil)ound\ po and halo substituents. The methods of preparation depended upon tlw anilide or starting materials arid were gerierally modifirations of known procedures. For the acid anhydride reactions a trace of sulfuric acid wa< added t o catalyze the condensations with tlie :miline. When an acid chloride was employed, it was allowed t o react in :i solvent with the aniline eithw with or without triethylamine as t h e hydrogeii chloride acceptor. It w a i necessary t o reflux the reaction mixture several hours to remove the HC1 when 110 acceptor wa5 used. The n'-methylanilide (15) \\ab prepared by the action of dimethyl sulfate on the sodium salt of 14. (1) H. Litmaire, C. H Schrrtmm. and (1961), a n d references cited therein
\
C'ollrl
.I
Pli,rirn
hii
50, X i 1
Chemical Procedures.---lIost ~ i the ' &(:id :iiiIiydricl~~,:wit1 chlorides, aiid substituted anilines were obtaiiied conimerc*i:illy. 3-Chloro-~-nitroanili1~e~~ :I-bromo-4-nitro:miline,6 R-c*hloro-.i-iiitronniline,? ~,5-d~ch~o~i~-.l-iiitroitnil~iie,~ a-hromonotiai ritle.9 2,4-di~tilorcil.'hPiii)sy~~et?-l chloride, IO and 2,4,5 I)heiicisyacet >,l chloricle t o were prep:treti. in R nianner rhow reported iii the liternture. a-Chlorononanoyl chloride x i s prepared froin llir c i ~ r re~poiidingacid" anct SOC12 by :I proredure eniployed for t hc, preparation of similar acid c-hlorides:12 lip 91-95' 13 mni), ?-iel(l 64c;. This i r i l ~rmrdi:iic~ \-ias vliaracterized 1))- convriuiori t o 23. Anilides. Method 1.---A ~riistureof 0.10 niole of rccluircbtl aniline, IL5-lS nil of the acid anhydride, :ind a drop of ( ~ o i i w t i trated H 2 W , TW. he:ited at reflus for I
~
__ .
ne or :i mixture o f ttie*cL 1 HC1 evoluiioii cra,.ect. . . ~~.
J os I,~"i i ( 2 , I,, ,J, i3ellauiy, "'l'lw Infrared dpri'tra of C o m ~ l r sl l o l e i ~ i ~ l ~, ~ \\ iley a n d Sons, Ini., S e w I;ork, N. Y., 1958. p p 203-223. ( 3 ) 11. J . Heaver, I). 1'. Roman, a n d 1'. .J. Stoffel, J . J l e d . C h e m . . 6 , :Ill ( l Y 6 3 ) ; .I. O r y . C h r m . , 2 4 , 18i6 (1959): .I. A m . Che?n. Soc., 79, 123(i ( 1 9 S i i . ( 4 ) 1%.E . Stensetli, .J. 17.. I3aker, and 11. P. Roman , l963).
