Koveiiiber, 1961
P I P E R I D I N E C b R B O X A M I D E S .4SD P L A S J L 4 C H O L I S E S T E R A S E .
11
TABLEI PROPERTIES O F
CARBAMOTLPIPERIDIKE DERIV.4TIVES
Method No.
I
of prepn. A
Yield.
%" 100
Salt HBr
Recrystn. solvent*
E
I1
B
75.6
HBr
E
I11
A
83 6
HBr
EA
IX
B
78.3
HBr
E-EA
x
B
53.8
HBr
E-EA
SI1
B
90.9
HBr
E-EX
XI11
B
65 3
HBr
E-EA
xx
c
80 3
2HBr
E-EA
a
Crude yield.
* E, ethanol;
M.P., OC. 164.4164.6 77.2i8.3 102.5103.0 167.3167.8 186.2187 1 1i4.8175.3 133.2134.5 209.0209.1
-- C,%---
--H, Calcd.
%----
---N , 4 10
-.
Found
Calcd.
Found
22.87
22.90
8.02
3.08
9.54
21.99
22.05
7.71
7.84
9.88
10.07
21.17
21 20
7.42
7.62
51 16
8.28
S.27
26.18
26.18
9.18
9.35
46.91
46.83
7.55
i.47
26.01
25.84
9.12
9.17
CzIHdiBrSzO
00.42
60.39
9.90
9.71
19 14
19.18
6.71
6.69
C?oH39BrSzOz
j7.26
57.18
9.37
ii 48
19 05
18.92
6.68
6.54
Cd?HwBrzSiOz
55.49
55.31
8.73
S 65
23.07
22.85
8 09
i.83
Calcd. Formula C I ~ H ~ ~ B T N Z O55.01
Found 54.86
9.52
9.65
CiiH36RrxaO
56.19
56.01
9.71
CisHmBrSzO
5i.28
57.00
CiaHzsBrSzO
51.15
CizHz3BrX-10~
EA, ethyl acetate.
then subjected to hydrogenation and subsequent purification as described under procedure A. Procedure C. l,lO-Bis[3-( piperidinoformy1)piperidinoldecane Dihydrobromide (XX).-3-(Piperidinoformyl)pyridine (50.6 g., 0.266 mole) and 1,lO-dibromodecane (39.9 g., 0.133 mole) were dissolved in 200 ml. of anhydrous benzene and refluxed for 35 hr. The precipitate formed during the reaction was then treated as described under procedure B. While the inhibitory properties of the following coinpounds are still in the process of being determined, their synthesis is reported a t the present time. Procedure D.14 l-Methyl-3-(pyrrolidinoformyl)-1,2,5,6-tetrahydropyridine Hydrochloride (XXIII).-l-?\Iethyl-1,2,5,6-tetrahydropyridine-3-carboxylic acid'5 (39 g., 0.276 mole) was covered with 250 ml. of anhydrous benzene, and thionyl chloride (164.2 g., 1.380 moles) was added gradually. The reaction mixture was refluxed for 3 hr. after which excess thionyl chloride and benzene were removed by distillation in vacuo. The residue was dispersed in 250 ml. of anhydrous benzene, and pyrrolidine (98.2 g., 1.380 moles) was added gradually. The reaction mixture was refluxed for 6 hr., cooled, treated with 400 ml. of cold, aqueous 40;: potassium hydroxide solution, and extracted with benzene. The combined benzene extracts were dried (llgSO4) and filtered, and the benzene was removed by distillation under reduced pressure. Distillation of the residual dark oil gave a yellow oil, b.p. 122" (0.17 mm.), which was dissolved in dry ether and converted to the hydrochloride by the addition of a solution of dry hydrogen chloride in dry ether. The hydrochloride ( 5 5 g., 86.4'7,) was then purified by recrystallization from absolute ethanol-ethyl acetate. It melted at 194.6-195.4'. Anal. Calcd. for ClIHI9C1S2O:C, 57.26; H, S.30; C1, 13.3i; S , 12.14. Found: C, 57.25; H, 8.37; C1, 15.20; K, 12.11. 1-Methyl-3-(morpholinoformyl)-1,2,5,6-tetrahydropyridine Hydrochloride (XXIV).-This compound was prepared by procedure D. The free base distilled a t 150" (0.7 mm.). The hydrochloride (40.5 g., 59.OC;;), recrystallized from absolute ethanol-ethyl acetate, melted at 227.0-227.8'. 9 n a l . Calcd. for Cl1Hl9C1S,O2: C, 53.55; H, 7.76; C1, 14.37; 3 , 11.35. Found: C, 53.80; H, i.92; C1, 14.13; 9, 11.21. 1,IO-Bis [ 3 4 morpholinoformyl )piperidino] decane Dihydrobromide (XXV).-This compound was prepared by procedure C. The product (35.2 g., 51.8y0), recrystallized from absolute ethanol-ethyl acetate, melted a t 241.0-242.0'. Anal. Calcd. for C&56Br?N404: C, 51.72; H, 8.10; Br, 22.94; N, 8.04. Found: C, 51.80; H, 8.20; Br, 22.80; S, 7.97. l,2-Bis [3-(morpholinoformyl)piperidino] ethane Dihydrobromide (XXVI).-This compound was prepared by procedure C. The product (11.2 g., 18.47,), recrystallized from methanol, melted at 278.1-278.6" dec. Anal. Calcd. for C22H40Br2K404: C, 45.21; H, 6.90; Br, 27.35; N, 9.59. Found: C, 45.28; H, 7.11; Br, 27.20; N, 9.45. 1,2-Bis [3-(piperidinoformyl)piperidino] ethane Dihydrobromide (XXVII).-This compound was prepared by procedure C. The (14) A. Lasslo and P. D. Waller, J . Org. Chem., 22, 837 (1957). (15) E. Jahns, Arch. Pharm., 229, 680 (1891).
product (12.7 g., 19.0(.;), recrystallized froin absolute ethanolethyl acetate, melted at 269.4-269.7" dec. Anal. Calcd. for CaaHa4Br,X40r:C, 49.66: H, 7.64: Br, 27.54: S , 9.65. Found: C, 49.45: H, 7.60; Br, 2i.42; S , 9.66. Biochemical Evaluation.-;\lanometric determinations were carried out on a GNE-Lardy RWB-3 Warhurg instrument, using 15-ml. flasks. Predominantly, acetylcholine iodide was used as a substrate (8.2% X 10-3 111 concentration in t,he final h Krebs-Ringer bicarbonate buffer, reaction mixture). .TI SaC1, consisting of 2.3 X lo-' J I SaHCOs, i . 3 X 7.3 x lo-* .I[ KC1, and 4.0 X lo-* -11 lIgCl,.AH,O was prepared according tf) Coheii'e" : the final reaction mixture was calculated16bto yield a p H of T.6 with the indicated SaHCOa concentration, in a gas phase of 5 7 , CO? and %yo N:, :it 37" (740 mm.). The displacement of air i n the reaction vessels with the above gas mixture vias carried out by nieans of :i gasexchange technique16c under reduced preseure. The reaction volume totaled 3.20 nil., with 0.60 nil. of substrate sohition in the side arm and all other reaction components in the main winpartment. The compounds were introduced in 0.06 rill. of aqueous solution appropriately concentrated t o yield the desired dilution of the compounds in the final reaction mixture. Equilibration w-as initiated at -60 niin. with readings every 5 niin. beginning at - 2 5 niin. Dumping was effected a t 0 nrin., with the side arm being washed twice with the reaction mixture. Each manometer was read precisely at electrically timed 10.0niin. intervals during the reaction period of 0 t o +60 min. The rate is expressed as T' = [ ( p l . of COS at : 3 0 niin.) - (PI. of CO, a t 10 min.)]/20 X 60, where T 7 signifies pl. of COS/hr. evolved within the reaction interval Of + l O to +30 niin., during which time the rate is linear in all instanc,es. The percentages o f inhibitioii are reported as I = [(T, - T7i)/Yc] X 100, where V, represents the coiitrol rate and T-l the inhibited rate. All reagents were prepared using redistilled water, registeriiig a t least 7 3 dynes/ciu. (uncorrected) i n surfare tension nieasurements on a Kahlsico TE03 du S o u y interfacial tensiometer. Cholase (Cutter Laboratories, Berkeley, Calif.), a lyophilized cholinesterase preparation obtained through extensive alcoholic fractionation of large pools of nornnnl human plasma, WAS the enzyme used. It n'as stored a t -23" with the temperature being continuously registered by a spring-activated temperature recorder. .Is reported previously, l7 our system was kinetically characterized18and the system's response checked against established inhibitors. -411 compounds were screened first for inhibitory properties at, .I1 concentration. For purposes of our evaluation. 1.0 X
I
(16) "lIanometric Techniques." \V, \V. Umbreit. R. H. Burris, and .J. F Stauffer,Ed., 3rd Ed., Burgess Publishing Co.. llinneapolis, Zlinn.. 1957: (a) p. 149: (b) p. 2 5 : ( c ) p. TI. (17) i. Lasslo P. D. \Valler, .IL. . 3Ieyer. and B. V. R a m a Sastry. J. M e d . Pharm. Chem., 2 , 617 (1960). (IS) (a) H. Lineaeaver and D. Burk, J . A m . Chem. Soc., 6 6 , 658 (1934); (b) 11. Iliuon, Biochem. J.. 65, 170 il95Xj: (c.1 .J. 11. Reiner, "Beha\-ior of Enzyme Systems." Burgess Publishing C o . , llinneapolis. hlinn., 1959, p. 28: ( d j G. E. Briggs and J. B. d. Haldane E m h e m . J., 19, 339 (1925).
j.
C,H, 1:
=
-s
----f
11 =
--s C,H
I
\
tIupIic*ate determinations wei'e run t o confirm responses of less t h a n 13: inhibitory :tctiiin. Conversely, an observed inhibition of 15:; or higher at 1.0 x 1 0 - 3 .lI concentration wits deemed sufficient to warrant further evaluation. 'The of s,lcil c o I l l p o u l l ~ sMS:l' a t four aPPr,,priate concentrations, with itt least two independent duplicate determinations for each concentration, and the ISO (Inolarity of coinpound effecting 505~;inhibition) was graphically determined. In most instances, the standard error computed according to
fullc+ioll is i l l correspolldillglJ~suk)s+it,ltej creasing. By applying these principles t o the amide fuiici ioiis of these cholinest(2rasic inhibitors. one may arrivr at ;ill (19) G. IT. Snedecor and W. G . Cocilran, "dtatistiral AIetliods," 5 t h I.: i . Iowa, lyj6, gp, 42-d5, state College Press, (20) R. JT. Taft. .Jr.. in "Steric Effects in Organic Chernistrv." 11. d. \ I . * man, Ed.. J o h n Kileg m d sons. Inc., S e n York, S. T.,1956, 1) 5r)l.
THYROXINE ANALOGS.XI
November, 1964
expected order of activity, expressed in terms of the -KR1R2 segment, paralleling that of the respective I:,, values (see Table 11). Indeed, the significant parallel of these relationships holds true when it is considered in three additional sets of compounds listed in Table I11 (VI and YIl, XIV and XV, and XVII and XYIII). Xii additional factor which should be considered in predicting coniparative anticholinesterase activities of alkyl-substituted amides is the lipophilic-lipophobic iiature of the substituent groups. As the S-substituted group becomes more fat soluble, the lipophiliclipophobic ratio for the substituent should increase in the order H < CHI < C2Hj. This leads to the same order of activity suggested earlier. Our study of variations in the amide structure was extended to include cyclic pyrrolidide, piperidide, and inorpholide substituents. As expected, the piperidides (Table 111, compounds I X , XII, and X X ) were in all iiistaiices more powerful inhibitors than the corresponding pyrrolidides (YIII, XI, and X I X ) . Likewise, as anticipated, the niorpholides (X and XIII) were weaker inhibitors than the similarly constituted pyrrolidides or piperidides. Thus, replacement of a methylene group in the &position of the piperidine ring by an electronegative oxygen (or introduction of oxygen into the pyrrolidine ring) results in a marked lesseiiing of activity. This may be due to two factors: (1) the ring oxygen coiiipetes with the electron-attracting part of the amide function for the electrons of the niorpholide’s alkylene units, and or ( 2 ) the de-
701
creased lipophilic character of the inhibitor molecule resulting from replacement of the piperidide with the more polar morpholide. Isomers containing the amide function in the 4position (Table 111, footnotes d and f, compounds X X I X and XXXI) were less effective inhibitors than their 3-substituted counterparts (V and VII) ; this is in accordance with Wilson and Quan’s conclusion, 2 1 relative to interatoniic distances between the pertinent reactive functions. The 3,4-unsaturated analogs of derivatives V and VI1 (Table 111, footnotes c and e , compounds XXVIII and XXX) mere less effective than the corresponding saturated conipounds, confiriiiiiig our earlier findings2 concerning the introduction of 3,4-unsaturation into the piperidine moiety. An iinportant objective of this study was to substantiate further the data obtained in our preceding experinients.2 We consider it an important observation that, in each instance, (1) among the decanes the monosubstituted one is the inore powerful inhibitor, and ( 2 ) among the ethanes the his-substituted derivative has the more potent inhibitory action. more comprehensive interpretation of this work and that currently in progress will be reported at a later date. Acknowledgment.-We wish to acknowledge valuable discussions with Dr. Andrew Lasslo which contributed to the successful completion of this phase of our study. (21) I. B. Wilson and C
. Quan, B i c h . Bzochem. B i o p h y s . , 73, 131 (1958)
-
Thyroxine Analogs. XI.’
Structural Isomers of 3,5,3’-Triiodo-~~-thyronine
EUGESEc. JORGESSEN ASD JAMES A. M7. REID Department o j Phari~iacezitztalCheuiistry, School of Pharmacy, Cnivcrsity of California, San Fi,ancisco, California Received June 21, 1964 The synthesis of two structural isomers of 3,5,3’-triiodo-~~-thyronine is described, namely, 3- [‘L-( 3-iodo-4hydroxyphenoxy)-3,5-diiodophenyl]-~~-alanine (VIIa) and 3-[5-(3-iodo-4-hydroxyphenoxy)-2,4-diiodophenyl] m-alanine (VIIb). Both isomers were found to be inactive in an antigoiter assay in the rat which would have determined activity greater than 1.5% that of L-thyroxine.
-
The L-alanine side chains of the thyroid hormones, thyroxine (Ia) and triiodothyronine (Ib), have been replaced by a variety of ionizable groups with retention of thyroxine-like activity.2 However, no such side-chain-substituted analog has proven more potent than the naturally occurring hormones with respect to the major physiological effects in the intact animal. Unusually high activity found for the aliphatic carboxylic acid side-chain congeners in inducing metamorphosis in tadpoles appears to be related to the absorption of the analogs from test solutions in which the (1) (a) Paper X: E. C . Jorgensen and R. A. Wiley, J . M e d . Chem.. 6, 459 (1963). (b) This investigation was supported by Research Grant Ahl04223 from the National Institute of Arthritis and hIetabolic Diseases, U. S. Public Health Service. (0) Presented before the Division of hfedicinal Chemistry, 148th National Meeting of the American Chemical Society, Chicago, Ill., Sept., 1964. (2) (a) H. A . Selenkow and S. P. .4sper, Jr., Physiol. Rev., 36, 426 (1955); (b) T. C. Bruice, K. Kharasch, and R. J. Winaler, Arch. Eiochem. Biophys.. 69, 305 (1956).
I
\
I
SH,
R3
Ia, RI = b, R3 = C, RB = d, RB =
H3’
= I I ; RS’ = H R3’ = H H; R3’ = I
tadpoles were i n i m e r ~ e d . ~S o analogs have been reported in which the side chain is nioved t o other positions on the same ring, although an approach to the synthesis of such isomers has been r e p ~ r t e d ,as~ have analogs with alanine side chains in both phenyl rings.5 The nature and position of substituents in the ring bearing the side chain (“inner ring”) is important to (3) E. Frieden and G . Westmark, h e n c e . 133, 1487 (1961). (4) E. L. Jackson, J . Or@ Chem., 96, 2227 (1960). (5) E. C. Jorgensen and R. Cavestri, J . Pharm. Scz., 62,481 (1963).
