March, 1964 10.31; 11.98.
237
XOTES
X, 12.23. Found: C, 62.77; H, 5.42; C1, 10.14; N,
Pharmacology. Methods.-The calculated amount of the products, dissolved in a fixed volume of saline 7-Chloro-2-dimethylamino-5-phenyl-3H-1,4-benzodiazepine (0.2 ml.), was added to the oxygenated Tyrode solution (VI).-To 4.5 g. (14.25 mmoles) of I11 dissolved in 75 ml. of of the bath chamber, in which the isolated rat intestine chloroform was added 9 ml. of phosphorous trichloride. The mixture was maintained a t reflux for 1 hr. and then was extracted was suspended, 1 min. before the introduction of acetyltwice with water. The aqueous extracts were made basic with choline. The recorded effects were evaluated as yo saturated sodium carbonate solution and were extracted with reduction of the contractile response elicited by acetylether. The ether was evaporated on a steam bath under reduced choline. Dose-response curves were found to be suffipressure. The residue, after recrystallization from absolute ciently parallelto allow a direct comparison of potency. ethanol, gave 3.3 g. (78%) of material m.p. 178-179", vi::"' 1602 (s), la73 ( w ) , 1462, 1455, 1420, 1400, 1390, 1330, 1310, 129.5 To indicate the anticholinergic activity, the concentracn,.-'; xQ5Yo ethanol (PH '251 mp ( e 3200). tion of each compound that reduces the contractile effect Anal. m?h,lcd. for C,,H,,ClNs: C, 68.56; H , 5.42; C1, 11.91; of acetylcholine by 50% was recorded. N , 14.11. Found: C, 68.32; H, 5.64; C1, 12.03, 12.04; N, 1)
13.82. The same compound, as shown by mixture melting point and infrared spectrum, was obtained in 60% yield when V was subjected to the methyl iodide-sodium hydride procedure described earlier.
Structural Changes and Anticholinergic Activity in a Class of Tropic and a-Methyltropic Acid Derivatives VENIERO SCARSELLI, GIORGIOCIGNARELLA, AND GIULIORIAFFII
Departments of Pharmacology and Organic Chemistry of Lepetit S . p . A . , Research Laboratories, Milano, Italy Received June 20,1963
As a continuation of the studies on a-methyltropic acid carried out in our laboratories, the optically active isomers of tropine a-methyltropate were synthesized. The replacement of the a-hydrogen atom with a methyl group in the tropate moiety allowed the isolation of stable optically active forms,' which were pharmacologically investigated. (-)-Tropine a-methyltropate was shown to be twice as active as atropine in antagonizing the acetylcholine-induced contraction in isolated gut.2 This result prompted us to investigate the relationship between the pharmacological activity and certain structural changes in a series of tropic and a-methyltropic acid derivatives. We first investigated the relation of optical activity and anticholinergic action. In order to answer the question whether molecular asymmetry is essential for such activity, tropine a-hydroxymethyl tropate,3 devoided of optical activity because of the presence of two hydroxymethyl groups on the a-carbon atom, was studied. Furthermore, we investigated the influence of the basic moieties of the molecules on the anticholinergic activity. For this purpose, some tropoyl and a-methyltropoyl derivatives of 3- and 8-methyl-3,8diazabicyclo [3.2.1]octane mere prepared by Cignarella, et a1.4,6 The tropoyl and a-methyltropoyl derivatives of K-methy lpiperaxine have also been synthesized in the course of the present investigation. (1) G. Melone, A. Vecchi, G. Pagani, and E. Testa, J. Ore. Chem., 26, 859 (1960). (2) G. Maffii and G . Bianchi, Nature, 186, 844 (1960). (3) E. Testa and L. Fontanella, Ann. Chem., in press. (4) G. Cignarella, E. Occelli, G . hlaffii, and E. Testa, J . Med. Chem., 6, 29 (1963). ( 5 ) G. Cignarella, E. Occelli, G. hlaffii, and E. Testa, {bid., 6, 385 (1963).
Results Compound I1 (.4,R = CHzOH) was found to possess marked anticholinergic activity although quantitatively it was less effective than atropine. In the 8-methyl3,s-diazabicyclo[3.2.1]octane amides (ITr-J r ) , the racemic tropoyl derivative (117) was 4 to 5 times less effective than the racemic a-methyltropyl derivative (1'). As previously r e p ~ r t e dthe , ~ anticholinergic activity of V was found to reside in the (-) isomer T'a, which is twice as active as the racemic form, thus indicating a close parallelism with the behavior of tropine a-methyltropate2 (111). Nore detailed in vivo investigations on compound Va are still in progress and will be reported elsewhere; however, it may already be mentioned that Va appears twice as active as atropine in preventing methacholine-induced hypersalivation when orally administered to mice. The X-methylpiperazine amides of tropic and a-methyltropic acids (YII, 17111, VIIIa) showed weak anticholinergic activity. The ratio of equally effective doses of racemic VI11 and of the (-) isomer (VIIIa) was 3: 2, which suggests a greater activity of the (f)isomer; however, these results seem scarcely significant because of the low activity of the products. The racemic tropoyl amide (VII) is about 3 times more effective than the corresponding a-methyltropoyl derivative (VIII) . Finally, ( =k)-3-methyl-8-a-methyltropoyl-3,8-diaaabicyclo[3.2.l]octane (VI), which differs from T' by having the substituents on 3- and 8-nitrogen reversed, was found to be about 0 times less active than T' as an anticholinergic agent. Discussion In contrast with a hypothesis of Cushny,6 the presence of an asymmetric carbon atom in atropine is not essential for parasympatholytic activity. In fact,, the disappearance of the center of asymmetry in I1 reduces the activity only a little. This result agrees with the statement of Kreitmair7 that optically inactive tropine benzylate has anticholinergic properties. On the other hand, the anticholinergic activity of the present dl derivatives of a-methyltropic acid is due to the (-) isomer. The basic moiety of the compounds tested seems to determine the degree of anticholinergic activity. In fact, when tropine is replaced by 8-methyl-3,8-diazabicyclo [3.2.1]octane and, especially, when replaced (6) A. R. C u s h y , J . Pharmacol. E z p t l . Therop., 16, 105 (1920) (7) H. Kreitmair, Klin. Wochachr., 16, 676 (1936).
TARIXI
lL Cloncentration able to reduce to SOc;; the rontractile response o f isolated intestine to wetylcholine. " These ronipounds were
prepared starting frorn S-methylpiperaxine by a proredure similar t o that desrribed'j5 for IJ---T-I. Yield, 48";; n1.p. 102-103" ( K t J ) ) . Anal. Calcd. for C1?H20?jd)2: C , 6i.73; H, 8.12; 11.28. Found: C, 67.92; H, 8.27; SI10.92. Yield, 68 111.p.225-228' (HCI salt) (EtOH). Anal. Calcd. for ClaH23ClS o 0 2 ;S , 9.37; C1, 11.86. Found: SI 9.02; ClI12.0B. e Yield, ,j;j( ,( ',' ., m.p. 21:3-21.5' (HC1 salt) (EtOH). -4naZ. Calcd. for C,~Ho:~C'IK202: X , 9.37; C1, 11.80. Found: S , 9.51; (:I, 11.!)1. [ol~)*fi -Lie ( c I , H20i.
by S-methylpiperazine or by 3-niethyl-3,8-diazabicyclo [3.2.1]octane, a decrease in activity was observed. ;Zs far as a comparison of the anticholinergic activity i n the tropoyl and a-methyltropoyl series is concerned, a-niethyltropoyl amides are more active than the corresponding tropoyl derivative i n the 8-methyl-3,8diazabicyclo f3.2.lIoctane series (B), but are less active in the ?;-methylpiperazine series (D). The weak anticholinergic activity of ( &)-%methyl8-a-methyltropoyl-3,8-diazabicyclo [3.2.1]octane (VI) may be correlated with the lack of structural similarity with the active isomer V. This result offers an indirect support for the assumed4pharmacological analogy of 8-methyl-3,8-diazabicyclo [X.2.1]octane (parent compound of Y)and tropane.
Acknowledgment.-The authors are grateful to 1)r. A . Wittgc'n- for her assistnncc i n revising t h e maiiiisvript .
era1 other groups bare report,ed on st)eroidal[:3,2--tI1pyrimidines. Our method for preparing the st,eroidal[X,'.'-d]pyrimidiiies employed the same intermediat#es, the 2hydroxymethylenesteroids, as used previously wit I t other steroidal licterocycles.2,5,6These intermediates were converted to the corresponding steroidal pyrimidines by the procedure of Raumgarten, ct ( I / . , ; or :I modification of t,his method. With t,his procedure, t h c pyrimidine ring was formed from the 2-hydiosymet,liylenesteroids and an amidine hydrochloride. 'I'riethylamine was generally the catalyst employed and ethanol was usually the solvent. Raumgarten, c,t nl.,? reported yields of 23-43y0 in their preparation of lionsteroidal pyrimidines. Our yields generally ran lower, hut wit11 the aid of chromatography, the steroidal pyrimidiiies could be isolated readily. 1TP-Hydroxq.-a-liydroxymethylene-:?oc-androstan-:2-0ne ( I ) and acetamidiiic hydrochloride gave 17/3-hydroxy-5a-androstano[3,2-d]2'-methylpyrimidine (2). ..I side product \vas isolated from the acid-soluble part of the reaction mixture and shown t o he 2-aminomethylene-17p-hydroxy-3oc-~ntlrostan-3-one (3). Similarly, when l~~-liydroxy-%-liydroxymethyle~i~~17P-methyl-5cr-androstan-3-one (4) was treated wit11 acetamidine and formamidine hydrochlorides, the, pyrimidines 5 and 6, respectively, were obtained. TI](> enamine 7 was isolated from the reaction mixt,ure fro111 (1) Paper I X : P . E:. Stiaw, 1.: JV. ( : \ , l i t i . IC. P. .lenriin Clarke, in press. (2) R. 0. Clinton, A. J . Manson, I:. LV. Stonner, A. I,. Beyler, ( i . 0. I ' u t t H , and A. Arnold, .I. A m . Ciiem. Soc., 81, 1.513 (l!J59). ( 3 ) H. .Intaki and Y. Petrow, J . Chem. Soc., 301 (1951!, have r e p o r t e d l',f~',11'-triazafluoreno(3',2': 2,3)cholestane. (4) (a) T. Colton a n d I. Loas, U. S. Pateut 2,9YY,O92 (Septe~ober5 . 2 U t ; l I : (b) J. Zderic, R . Halpern, €I. Carpio, .\. Riiiz, D. Limon, 1,. Magana, l r . JimBnez, A. Bowers, and FL. Ringold. Chem. I n d . (London), 1623 ( 1 W O ) : (c) P. Ruggeri, C . Gandolfi, and 1). Chiaramonti, Gam. C h i m Ital., 92, 7 6 8
hlanson. 1:. kV, Stonner, t l . C', Neurnann, li. C;. Cliristianst~n, R . L. Clarke, ,J. H. Ackerinan. 1). 1:. Page, . I . u'. I)ean, T). l
