March 196ti
fkWIVIlthL
11.
Antiviral Agents.
AGENTS. 11
21 1
Substituted Morpholiniunl Quaternary Salts
ELVINL. ANDERSON,JOHN E. CASEY,JR.,E L I Z s B E T H E. F O H C E , EELIXGAI. JETU'SEN, RALPHS. ~ I A T ZAND , DONALD E. RIVARD 19101
Reseurch and Development Diaision, Smith Kline and French Laboratories, Philadelphia, Pennsylvania Received October 21, 1965
A aeries of substituted morpholinium quaternary salts was prepared by the reaction of substituted phenacyl halides with various dialkvlaminoalkanols. The chemical and antiviral activities of these compounds are discussed.
Kuriierous workers have reported the forination of heterocyclic coinpounds from ethanolaniirie derivatives. For instance, Hill and Powell1 reported a cyclization and dehydration of S-(3,4-dihydroxyphenacyl)PI;-benzoylethanolarine to 2- (3,4-dihydroxyphenyl)-4benzoyl-5,6-dihydro-l,4-oxazine. Norpholine ring formation froni a-(P-hydroxyethy1aniino)deoxybenzoins was studied2 and the observation was made that the nionoethanolamino compounds either were open chain or involved a relatively labile ring-chain tautonierism. Additional studies in keto-hemiacetal tautonierism3 of N-phenacyl-N-substituted ethanolamines established that compounds of this type exist largely in the cyclic hemiacetal forms. When S-ethylethanolamine was treated with an excess of pheriacyl bromide, the quaternary derivative, 4-ethyl-2-hydroxy-4phenacyl-2-phenylmorpholiniuni bromide, was obtained in high yield. I n the course of a program of testing compounds for anticholinesterase activity, Long and Schueler4 prepared a series of bisphenacylammoniuni compounds. The reaction of a,a'-dichloro-4,4'-bisacetophenone with diniethylaminoethanol was foriiiulated to give 1.
w
CICHLCO\
COCHLCl
+ 2(CH ),NCH,CH,OHL.
'+
\ /
2C1°
2
Subsequent ~ o r established k ~ that this product existed as the hemiacetal (2) rather than as the open-chain coiiipound previously suggested. Although additional structures of this type were prepared,6 the open-chain formula was consistently employed. (1) R. Hill and G. Powell, J . Am. Chem. Soc., 67, 1462 (1945). (2) R. E . Luts, J. A. Freek, and R. S. Murphey, ibid., 70, 2015 (1948). (3) (a) R. E. Lutz and R. H . Jordan, ibid., 71, 996 (1949); (b) N. H. Cromwell and K. C. Tsou. ibid., 11, 993 (1949). (4) .J. 1'. Long and F. \\'. Srliuelei., .I. Am. I'knrtrr. .lsuoi,., S c i . Ed., 43, 7:) (1954). (5) E'. \V. Sclineler, d . Pharmncol Ezpll. T h e m p . , 115, 127 (1955). ( 6 ) 1:. N. Marshall and J. P. Long, ibid., 137, 236 (1959).
Since spontaneous ring closure of quaternary aniinoriium salts to niorpholine derivatives does not appear to be well defined, we undertook a series of experiments to study the scope of this reaction inore completely. It was found that ring formation followed the general schenie proposed by Cronmell and Tsou3' (Scheme I). SCHEME I
RQCOCH,Br
+
R:NCH2CH20H
@
€ t o COCH,yCH,CH,OH
Br"
R:
'
Br@ OJ
Exaniination of the infrared spectra of the 1)roducts provided a convenient method for establishing the structure, since the carbonyl absorption bonds disappeared and strong ether bands appeared in the 9-10-p region. Additional confirmation was afforded by the ultraviolet absorption spectra. The niaxiinuni shifted from the 300-310-mp range for the open-chain conipounds to a characteristic maximum a t 252 inp for the hemiacetals. The coiiipounds thus prepared are listed in Table I. The requisite phenacyl halides were generally prepared by bromination of the corresponding ketones in carbon tetrachloride. I n some instances, it was more convenient to prepare theni by acylation of the aroniatic compound with chloroacetyl chloride under normal Friedel-Crafts reaction conditions.' The quaternizations were carried out by refluxing equimolar quantities of reactants in chloroform or acetone for 4 or 5 hr. The products usually precipitated as solids which could be separated and purified by recrystallization froni isopropyl alcohol or an alcoholether mixture. Occasionally it was necessary to concentrate the solution until an oil or a solid separated. Decantation and trituration with alcohol or acetone hastened crystallization. Formation of the niorpholine ring system appeared to be yuitc general with tlic variety of dia1kyl:tniino and \V. H. ( 7 ) (a) C. C. Price, Oru. Reatlzorrs, 3, 1 (18.161, ( b ) R . ~1n1orioff Hartung, J . Am. Pharm. Assoc., Sct. Ed., 35, 306 (19413).
z
Testing Methods Virus Preparation. A. Mouse Hepatitis Infection.---'l'hc, -Ioi.k viriis 1)rqi:tratioli cmiit:tilicd 1 0 7 . 4 I,I>50/ml:is tieterniiiittd i i t 14-g 11iic.e. Fur iritraperitoiieal iiifectiolt, approximately 8 Ll):,, values of the v i i u s i* emplo>-ed. Deaths occur beginning at 72 hr with the maximum rale at 96 lir after infection. B. Herpes Simplex Encephalitis Infection.--!i rubbit kitltrt~)~ wll vulture prepar:itiotr of virus i. u4ed for tectiiig. Stork vir\\~jreparatioric o i r t ainctl 1 0 T,U5~/lnl ~ ~ ~ti5 deteriniiietl i i i 14-g rniw. For i1itrac:raiiial i1rfec.tiou, approximately 5 L l h values is used. i f t w itlfectiori with the maximum per cent) death at 10 d a w .
ANTIVIRALAGEXTS. I1
March 1966 TABLE I1 I n Vivo ANTIVIRALACTIVITY(3)
Virus
hIHV3a
Virus dose X LDao value
Route
Toxic concn, mg/kg/ dose
Ip
10
Concn, mg/kg/ dose
% 1)rote+
tion
5.0 2.5 1.23 0 , 63 0.32
0 0 20 :3 5 0 0 Herpes' :id IC in ..i 0 0 simplex 2,5 encephalitis 1.26 40 0.63 40 0.32 25 Average of four experiments. * Stock virus contained LD,,/rnl for 1 4 g mice. c Average of two experiments. Stock virus contained 104.8 LD,,/ml for 14-g mice. 8*
Compound Testing.-Swiss, albino mice (14-15 g) are treated suhrutaneoualy with 0.25 nil of each of 5 twofold dilutions of compound, starting at one-half the toxic concentration. Treatments are given 1 hr before and 1 hr after infection and continued twice daily for 4 days thereafter. Ten mice are used for each dose level of compound. Evaluation of Drug Efficacy.-The compound is considered effective if, over a 1Cday observation period, the per cent protection (per rent survival of the drug-treated groups miniis per rent survival of untreated controls) is greater than 20yo at any given dose level. Duplicate tests are run on compounds found effective in the initial experiment, to confirm the data.
Experimental Section12 3,5-Dimethyl-4-hydroxyphenacylChloride.-To a cooled, stirred mixture of 183 g (1.5 moles) of 2,6-dimethylphenol and 220 g (1.5 moles) of AlC1, in 800 ml of tetrachloroethane was added 180 g (1.5 moles) of chloroacetyl chloride at such a rate that a temperature of 0-6" was maintained. When the addition was roniplete, the reaction mixture was stirred a t room temperature for 4 hr and poured into a mixture of 250 ml of HCl and crushed ice. The organic layer was separated, washed with water, and dried. The residue remaining after removal of solvent was recrystallized twice from isopropyl alcohol t o give 121 g (41%) of white solid, mp 109-11Oo. Anal. Calcd for ClOHllClOz: C, 60.46; H, 5.58. Found: C, 60.39; H, 5.53. Cyclic Quaternary Salts.-The procedures described are typical for those used to prepare the compounds listed in Table I. (12) All melting points were taken on a Thomas-Hoover melting point apparatiis. Calibration of t h e ttiprmometer against standard rompounds shou-ed no need for rorrection.
213
The infrared spectra of these products shorn-ed no absorption in the carbonyl region and strong ether absorption was observed in the 9-10-p region. A maximum a t 252 m p was observed in the ultraviolet spectrum. 4,4-Dimethylhexahydro-2-hydroxy-2-( p-hydroxyphenyl)-1,4oxazepinium Chloride (15b).-A solution of 26.0 g (0.153 mole) of p-hydroxyphenacyl chloride and 15.7 g (0.153 mole) of N,Sdimethylamino-1-propanol in 200 ml of acetone was stirred at the reflux temperature for 4 hr. The reaction mixture was Cooled and the solid was separated by filtration and washed with acetone to give 36 g Of off-white material. Two rec mixture of ethanol and ether gave 26.1 g (62 nip 189-191". Anal. Calcd for C ~ H t & l N 0 3 : C, 57.03; H, 7.36; K,5.12. Found: C, 57.25; H, 7.66; N, 5.02.
2-Biphenylyl-4,4-dimethylhexahydro-2-hydroxy-l,4-oxazepinium Bromide (Ea).-A solution of 55 g (0.2 mole) of p-phenylphenacyl bromide arid 21 g (0.2 mole) of X,N-dimethylamino-1propanol in 300 ml of CHC13was stirred a t the reflux temperature for 4 hr. The reaction mixture was cooled and the product was collert,ed by filtration, washed (CHCl,), and recrystallized twice from a mixture of isopropyl alcohol and benzene to give 53 g (70%) of white solid, nip 168-170", after drying in 2;uczm at 70" for 24 hr. A n d . Calcd for ClnH*4BrN0z: C, 60.32; H, 6.39; N, 3.70. Found: C, 60.14; H, 6.56; N, 3.76. 2-Hydroxy-2-phenyl-3,4,4-trimethylmorpholiniumBromide (ll).-A solution of 115 g (0.38 mole) of a-bromopropiophenone and 40 g (0.38 mole) of X,K-dimethylaminoethand in 150 nil of CHC1, was stirred at the reflux temperature for 5 hr. The yellow solid was separated by filtration and recrystallized three times from isopropyl alcohol to give 48 g (42%) of white product, mp 216-2 18". 2-Hydroxy-Z-( 4-hydroxy-3,5-dimethylphenyl)-4,4-dimethylmorpholinium Chloride (14).-A solution of 43 g (0.22 mole) of 4-hydroxy-3,5-dimethylpheiiacylchloride and 25 g (0.27 mole) of X,N-dimethylaminoethanol in 150 in1 of CHCla was stirred at the reflux temperature for 5 hr. The reaction mixture was cooled and an amorphous material was collected by filtration. Three recrystallizations from a mixture of isopropyl alcohol and ether gave 17 g (26Yc)of white solid, mp 145-146' dec. 2-Biphenyl-2-hydroxy-4,4'-spirobimorpholiniumBromide (9). -A solution of 55 g (0.2 mole) of p-phenylphenacyl bromide and .2 mole) of K-p-hydroxyethylmorpholine in 500 ml of CHCl3 rred a t the reflux temperature for 5 hr. The reaction mixture was cooled, and the white product was separated by filtration and recrystallized twice from methanol to give 22 g ( 2 7 7 , ) , nip 224-226".
Acknowledgment.-The authors are grateful to 3Ir. J. P. Crumsho and RIr. J. S. Boromski for technical assistance in carrying out many of the preparations. The microanalyses were performed by A h . D. A. Rolston and eo-workers of our laboratories. Dr. IT.E. Thompson and l\Ir. R. J. Warren were very helpful in interpreting the spectral data.
