h y lUUS
TABLE I11 DOSERANGEFINDING EXPERIMENTS AND
Cornpd
1
449
L)IALBYLAMIKOETHYL CX-~'RIMETHYLSILYLPHENYL-/~-HYDBOXYPI~OPIOSATES
Dose, mg/k
23 50
GROSSBEHAVIORAL CHANGESa General changes
N o obvious abnormalities.
Spontaneous motility reduced ; piloerection. During first 0.5 hr ataxia, followed by almost complete cessation of spontaneous activity; decreased sensibility to touch; intermittent myoclonic jerks; hypothermia; symptoms lasting about 2 hr. All animals died within 15 min; death was 200 preceded by convulsions. 2 ,? No obvious abnormalities. 2 Spontaneous motility slightly reduced ; slight 50 piloerection. During first 0.5 hr slight ataxia, followed by 100 decrease in spontaneous motility; brief intermittent convulsions; ptosis; hypothermia; symptoms lasting about 3 hr. Four animals died within 60 min; death was 200 preceeded by strong clonic convulsions. 23 N o obvious abnormalities. 3 Slight piloerection; slight ptosis. 50 100 During first 0.5 hr clonic convulsions, follonred by decreased spontaneous motility; reduced sensibility to touch; dyspnea; symptoms lasting for about 3 hr. All animals died within 10 min following 200 strong convulsions. 25 S o obvious abnormalities. 4 Piloerection. 50 Slight ptosis; slight decrease in spontaneous 100 motility; during first 15 min following injection brief strong myoclonic jerks and writhing. 200 Ataxia followed by decreased spontaneous activity; ptosis; symptoms lasting for about 2 hr. 25 No obvious abnormalities. 5 Within 5 min following injection, strong myo50 clonic jerks and writhing, lasting several min; slight piloerection. 100 Slight ptosis; piloerection. Considerable reduction in spontaneous mo200 tility; ptosis; 3 animals died within 18 hr. Groups of five mice of 22-25 g for each dose level were used. 100
until two clear layers were formed. The aqueons layer was extracted ( E t 2 0 ) and the combined ethereal layers were extracted with dilute NaOH. The basic solution was acidified (HC1) and extracted (EtgO). The ethereal extract was dried (MgSO4) and the ether was driven off in vacuo, leaving 11.3 g (83y0) of prodAnal. uct, mp 1.57' (from C6H6-petroleum ether (bp 40-60')). (C14HZZO3Si) C , H, Si, mol wt (anhydrous titration with KORIe). DL-@-N,N-Diethylaminoethyl a-p-Trimethylsilylphenyl-phydroxypropionate Hydrochloride (l).-~~-a-p-TrirnethylsiIy1phenyl-P-hydroxypropionic acid (2.38 g, 0.01 mole) and @-N,Ndiethylaminoethyl chloride (1.35 g, 0.01 mole) were refluxed in dry i-PrOH (15 ml) for 10 hr. The reaction mixture was filtered and the solvent was driven off in vacuo. The residue solidified on trituration with dry EtnO, yield 3 g (80y0),mp 118' (sealed tube) (from EtOhc-petroleum ether). Anal. (C18H32C1N03Si) C, H, Ir;, Si. Preliminary Pharmacological Evaluation.-The DL-p-N,N-dialkylaminoethyl ester hydrochlorides (Table 11) were tested as anticholinergics. Atropine sulfate was used as reference drug. All compounds were dissolved in saline and, regardless of route of administration, the maximal volume administered to mice never exceeded 0.2 m1/20 g. For dose range finding experiments and gross behavioral changes in mice (Table 111), the compounds were administered intraperitoneally to groups of five animals for each dose level. Observations were made for not more than 24 hr following injection. I n vitro acetylcholine antagonism (Table IV) tests were carried out.'O
TABLEI V I n Vitro hCETYLCHOL1NE
ANTAGONISM.
GUINEAP I G
ILEUMa
% redn in ht of contraction elicited by acetylcholine in presence of exptl compd Concn, d m l
Atropine
1
2
3
4
5
... ... ... gj 70 0.04 g j ... ... ... 100 0.1 . . . . . . 100 ..' 10 0.2 ......... 85 SO 85 0.4 ......... ... 80 0.6 . . . 70 . . * 95 90 100 1 . . . 70 . . . 100 100 f . . 2 Figures represent mean values of three experiments for each compound. None of the compounds showed any antagonistic effects toward contractions elicited by histamine or bradykinin. e . .
...
Effects on blood pressure, respiration rate, heart rate, and antagonism to hypotension elicited by acetylcholine were also studied (Table V). Male cats (2-3 kg) anesthetized with pentobarbital sodium (35 mg/kg) intraperitoneally were used. Blood Tables I and 11. Melting points were determined on a Fisherpressure was measured from the left carotid artery with a Hg Johns melting point apparatus and are uncorrected. Where manometer or a statham pressure transducer and recorded on a itnalytical results are indicated only by the symbols of the elekymograph or physiograph, respectively. Respiration rate and ments, the observed values differed from the calculated values heart rate were recorded on the physiograph with impedance by not more than =k0.4%. electrodes and an ECG transducer, respectively. Substances Sodium p-Trimethylsilylphenylacetate.--p-Trimethylsilylwere injected through a cannula in the left femoral vein. phenylacetic acid7 (20.8 g, 0.1 mole) in absolute EtOH (40 ml) I n antiarecoline tests in mice" (Table VI), the compounds was added dropwise with stirring to a solution of Na (2.3 g, 0.1 were injected intraperitoneally followed 30 min later by the g-atom) in absolute EtOH (60 ml). The reaction mixture besubcutaneoiis administration of arecoline (4 mg/kg). For came neutral to litmus, was cooled in an ice-salt mixture for mydriatic tests in mice12 (Table VII) the compounds were injected several hours, filtered, and washed with cold absolute EtOH. subciitaneoiisly. The diameter of the pupils was measured with The salt was dried a t 120°, yield 20.5 g (897,). An additional a micrometer iinder a stereoscopic microscope a t 15-min intercrop of 2.5 g ( l l y c ) was isolated on evaporation of the filtrate. vals, twice before and four times after injection. *Inn/. (C11HlSNaOzSi)Si, mol wt (titration with 0.1 S HCl using Since the combination of atropine and pyridine-2-aldoxime methyl orange). DL-a-p-Trimethylsilylphenyl-~-hydroxy-~,p-dimethylpropionic methanesulfonate (P2S) constitutes the standard treatment against organic phosphate poisoning, the possibility of replacing Acid.-To a solution of isopropylmagnesium chloride [from isoatropine by these compounds was considered. The compounds propyl chloride (8 g, 0.1 mole) and Mg (2.4 g, 0.1 g-atom)] in in combination with a standard dose of P2S (90 mg/kg) were addry Et20 (50 ml), solid sodium p-trimethylsilylphenylacetate ministered intraperitoneally t o mice. T E P P (tetraethyl pyro(11.1 g, 0.05 mole) was added in small portions, and the reaction plio\phate) wwq iiijwtril ~ i r l ) ~ i r ~ ~ rtoi ~t ohi e~ anirna1S ~ l ~ ~ 5 miri i i i i u t i i r r was heated iuider iefliiu cor . i 1ir and tlien cooled to 0". L)ry JIe2CO (5.8 g, 0.1 mole) in dry Et20 (30 ml) was added dropwise, and the reaction mixture was heated for an additional 2 hr (10) H. Edery, Brit. J. Pharmacal., 24. 485 (1965). and cooled to 0". H 2 0 (2.7 ml) followed by (1:1) HC1 (50 ml) (11) A. Hem, Arch. Ezptl. Pathol. Pharnacol., 242,414 (1962). (12) P. Pulewka. ibid., 242, 307 (1962). was added cautiously with stirring, and the mixture was stirred
10 30 100
eo 30
xo 30 q0
40 SO
!10 30 SO 90 Figiires represetit mean valiies obtained fiorn at least three wp:tr:tte esperirnerits. SO atitagoirisni to depi'essor effect ( i f :iwiylc~holiiie:it d o r e s up t o 10 mg was observed. SOeffect. o i l I tie heart rate wah ol)sei,vetf for aiiy c~timpoiiiid.
Acknowledgment. -\VP \visfi t o exprebs our t hiillks to "Yihsuni" Research Develupnient Co. for the grant I\-hich erinbled us to carry out this research. \\ i d i to thank Dr. H. Edery and Dr. Y. Grunfeld of t h e Imtc.1 Institute for Biological Research, Kess-Ziona, ant1 t h v Pharmacological Institute of the Sational Couriril foi liesearch and 1)evelopment for carrying out t 110 pharmacological t e b t s.
