1134 Journal of Medicinal Chemistry, 1971, Vol. i4, N o . ii
NOTES
TABLE I a-Naphthylacetyl ,~',N-Dimethylhydrazide (4).--a-Naphthylacetyl chloride, bp 136" (1.5 mm), n z 51.6209 ~ [lit.6 bp 175-76O EFFECTIVENESS OF DERIVATIVES oF h',N-DIMETHYLHYDRazl~~ (1.5 mm)] was prepd from a-naphthylacetic acid and SOCl,. It AGAINST L1210 LEUKEMIA I N BDF, MICE was treated with Me2NNHz in a mixt of Et20 and EtaN and after Dose,a Number extn with C6H6 and concn, the recovered solid was recrystd from Compd
mg/k
of doses
400 400 400 7.i
1 2 3 3
1 9 1 9
Survivors
616 616 0 16 6: 6
EtOH t o give 4 as a white solid, mp 139.5-140.5'.
T I C , %b
100 110 101
Itoute of administration ip, h Y,,C is ratio of survival time of test animals to survival time of cont,rol animals.
Acknowledgments.-The author wishes to thank Dr. Harry B. Wood, Jr., of the Cancer Chemotherapy National Service Center for making the LIZ10 leukemia screening data available. He also wishes to thank Dr.
TABLE I1 DERIVATIVES OF IV,N-DIMETHYLHYDRA~INE
1
M p or bp ("), OC
Compd
NO.
CH~CCH&OOC~HS
c/o yield
n%
Analyses
dzs
S5 (8.1)
76
1.4750
0.9655
MR 50. la
90 ( 7 . 3 )
65
1 .4640
0.9352
M R 59. O b
NK(CH3)2 OCONHN(CH,)
3
d 05
136-137
58
C,c H, N
139.5-140.5
24
C, H, N
CH,CONHS(CHJ.
4
ti
Calcd 48.7.
Calcd 57.7.
c
C : calcd, 67.81; found, 68.51.
Compds 1, 2, and 3 in Table I1 were evaluated against L1210 leukemia in BDF, mice.2 Results are given in Table I. Ethyl acetoacetate N,N-dimethylhydrazone (1) was tested against Plasmodiuwi beryhei in ICR/HA Swiss mice.3 At 640 mg/kg the survival time of the mice was increased 1.8 days (mean survival time of controls was 6.2 days; mean survival time of treated animals was 8.0 days). Compd 1 showed some toxicity in this test w-hic~hdid not appear when it was tested against L1210 leukemia at a much higher total dosage. Experimental Section Ethyl Acetoacetate S,S-Dimethylhydrazone (l).--Lk mixt of 100.0g (0.77 mole) of eth,vl acetoacetate and 48.6 g (0.81 mole) of 1\IerXStI2iii 150 nil of EtOH %'a>allowed to st,aiid at room temp for 18 hr. At the end of this period the niixt was coned under vacuum and distd through a 30-cm vacuum-jacketed Vigreux column to give 100.3 g (73% yield) of 1, bp 8.5" (8.1 mm). This material was collected in .i fractions, nZ5D 1.4747-1.4751, terf-Butyl Acetoacetate -Dimethjlhydrazone ( 2 ) . - - f e r t BiLty1 acet,oacetate 197.1 g, mole) and L\Ie2SNH2 (38.4 g, 0.64 mole) were dissolved i n 150 nil of lerf-BuOH and the mixt was allowed t o stand a t room t e m p for 1S hr. It, was coned under . product (2) vac'iiiim arid the residiie wad dihtd BJ a 1 ) o ~ ~ The (79.2 g, 65yc)was collected iri 4 friictioii.>, n Z 5 D 1.4639-1.4641. or-Naphthyl SjAY-Dimethylcarbazate(3).--.4 mist of a-naphtho1 rtiid CsH:,Nlle? was treated with C'OCI, to give a-naphthyl rhloroformate in ?VC( yield as a iiearly colorless liquid, bp 101.5-104..:' (0.5 mm), nZ51)1..XWl [lit.4bp 117" (1 mm)]. This vias treated with 121eLNN in EtiO atid the resultant, solid oil extii with EtOAc aiid re( t i i fi.om E t O F T yielded 3 ( 3 8 % ) , mp 136-137". ( 2 ) Cancer Chemotlierapy Sational Service Center 9062 Protocols for screening chemical agents and natural products against animal tumors and other tnological systems are described in Cancer Chemofher. R e p . , 26, 1 (1962). ( 3 ) T . 9. Osdene, P.1 3 , Russell, and L. Rane, J . .\fed. Chem., 10, 431 (1967). (4) Kvan-Chung Tsoii, J . . I m i r . Chem. Soc., 76, 6109 (1954).
B. T. Poon of the Walter Reed Army Institute of Research, Walter Reed Army Medical Center, for the data for the antimalarial test. ( 5 ) Invtituto De .ingel1 Societa per iziom (by Gianfranco Pala), British Patent 1,016,968 (1966)
Comparisons of Butyrylcholinesterase Inhibitory Potencies of Selected 3-Substituted-1-decylpiperidinesw i t h Their Electron Charge Densities? 0. E L M O
l \ I l L L N I It,
J R . , L~h D
WlLLI \ h l
P.
PWRCELL'
Deparfnient of 3fdeczilai and Quantum Bzology, Coilege oj' Pharmacy, I'nzcerszfy of Tennessee Bfedzcal Unzts, .If c m p hz s, Tennessee ,3810 1 12ec.ciLu-i January ?, 1971
and Purcell, et U Z . , ~ have investigated Beasley, et the inhibitory potencies against butyrylcholinesterase k t This research is being supported
by t h e U. S. Army Medical Research and Development Command (D.~-49-193-~1D-2779),t h e Cotton Producers Institute (through the National Cotton Council of America), the National Science Foundation (GB-7383).and a grant from Eli Lilly and Company. Computer facilities were provided through Grant HE-09495 from t h e National Institutes of IIealth. f T h e work reported in this paper constitutes a segment of the thesis to be submitted by 0. Elmo 1Rlillner, J r . , t o the Graduate School-Medical Sciences of t h e Unirersity of Tennessee in partial fulfillment for t h e degree of Doctor of Philosophy. S I H Trainee, U. S. Public Health Service Grant TO1 GI%-02052from t h e National Institute of General Medical Sciences. Bethesda, Md. (1) (a) J. G. Eeasley, 11. P, Quintana, and G . G. Nelms, J . M e d . Chem., 7 , 698 (1964); (13) J . G. Beasley and W. P. Purcell, Biochin. B i o p h y s . Acta, 178, 176 (1969). ( 2 ) (a) W ,P. Purcell. J . G. Ileasley, and It. P. Quintana. %bid., 88, 233 (1961); (h) W.P. Purcell. J . G . I3easley. R . P. Quintana, and J. A . Singer, J . M e d . Clcem., 9, 297 (1966); ( e ) \V. P. Purcell and J. G . lieasleg, M o l . Phormacol., 4, 404 (1968).
Journal of Medicinal Chemistry, 1971, Vol. 14, N o . 11 1135
NOTES
(acylcholine acylhydrolase, E C 3.1.1.8) of 3-(l-alkylpiperidyljcarboxamides (I) in which the R1 substituent varied from a C1 to a Clo chain and in which the structural variation at R2 included the substituents NH2, NHCH3, NHC2H5, N(CH3j2, N(CH3)(C2H5), and N(CzH&. Mathison, et C T Z . , ~ have reported the synthesis and evaluation of the butyrylcholinesterase (BuChE) inhibitors I1 and I11 in which the carboxamide function in I is replaced by the acetamide moiety and by the urea moiety, resp. R varies in I1 and 111 as did R1in I. It was shown by Mathison, et u Z . , ~ that, although an increase in the alkyl chain length of the N' substituent increased the BuChE inhibitory potencies of I, 11, and 111, the effect of chain length was far less pronounced for series I11 than for series I and II.3
6, and qPv, resp, used in the Huckel method are given in Table I. All calcns were carried out on the IBM Systems 1620" computer.
TABLE I SEMIEMPIRICAL PARAMETERS USEDIN MO CALCULATIONS Parameters Employed in HMO Calculations4 c a; ?PV N: Piperidyl 1 . 6 +CN< 0.8 C: >c= 0 . 0 >c=o 2.0 0: 0.7
=o
Parameters Employed in Del Re Calculations c
PV
C:
3 C-C f -(=)C-Cf
1.0 1.0
0. lb 0. lb
N: Tetrahedron 0.31b CN:
+ C-N
C=O 0.70 0.10 a From Berthod and Pullman, J . Chim. Phys. Physicochim. Biol., 62,942 (1965). From Del Re.6
Results and Discussion Results of the molecular orbital calculations along with the BuChE inhibitory activities are given in Table 11. Calculations were made on the molecules in TABLE I1 BUTYRYLCHOLINESTERASE INHIBITORY POTENCIES AND TOTAL CHARGE DENSITIES
IS0,b
KiQ x Compd 1 2
3 4 5 6 i
8
Experimental Section
c-o+
I
The experimental evidence presented makes it apparent that the dramatic change in inhibitory potency found when one compares the shorter alkyl chain derivatives of I1 with the corresponding shorter alkyl chain derivatives of I11 is associated with replacing the acetamide (SHCOCHsj moiety with the urea (NHCON11e2) moietyS3 It was suggested by Xathison, et al., that the urea moiety "provides a better "fit" in the vicinity of the esteratic site" of BuChE than either the acetamide moiety or the N,N-diethylcarboxamide m~iety.~ It is the purpose of this paper to report further interpretations of the differences in the contributions to activity of the urea, acetamide, and carboxamide moieties in I, 11, and 111. I n order to investigate the contribution of electronic charge densities to the activity of BuChE inhibitors, it was decided that, in accordance with Rogers and Cammarata's emphasis of the importance of the u electron charge densities as well as the x electron charge densities in describing the partitioning p h e n ~ m e n o n the , ~ total charge densities of the inhibitors I, 11, and I11 should be calculated. It would then be possible to compare the BuChE inhibitor potencies with the net charges a t various centers that have been proposed as important in the interaction of inhibitors with cholinesterase^.^
YPV
CPV
CC: CC:
Tetrahedron 0 . 07b 0.24a N: Aniline
9
R
NHCOCHa NHCON(CHs)z CON(CzHs)z COSHCHa COX (CHa)z CON(CHa) (CzHs) CO-N-pyrrolidyl CO-N-piperidyl CO-N-morpholinyl
&I x
106 105 9,381 0.501 1.461 0.53h 11.321 3.48* 2.96f 2.1ih 0.98h
QN'
-0.2776 - 0.11580 -0,1235 - 0.2747 -0,1185 -0.1210 0 . i i h -0.1240 0 . 3Zh - 0.1240 2 . 57h -0.1200
Qcd
Qo"
0.2821 0.3365 0.2726 0.2807 0.2731 0.2728 0.2725 0.2665 0,2729
-0.3168 -0,3675 0.3186 -0.3170 0.3185 -0,3186 -0.3186 -0.3186 -0.3185
-
K , is the inhibitor dissociation constant as calcd by the method of Bergmann and Segal. [Riochem. J., 58,692 (1954)]. * 1 5 0 is the molarity of compd effecting 50% inhibition. Net charge on amide N . Net charge on carbonyl C. e Net charge on carbonyl 0. f J. G. Beasley, unpublished data. 0 Net charge on the dimethyl-substituted N of the urea moiety. h From ref 2b. a
u Electron charge distribiitions were determined using a com-
puter program writteii by Ilr. G. E. Bass of t'his laborat'ory, utilizing the method of Del The T electron charge distributions were determined using a computer program writt'en by lh. K . Sundaram, utilizing the Hiickel method.8 The total charge was obtained as a sum of the u electron charge densities and T electron charge densities. The values used for the atomic parameter, a,,' and the bond parameters, ye" and eu, used in the Del Re method and the Coulomb and resonance parameters, (3) I . IT. Mathison, J. G. Beasley, K . C . I:owler, and E. R . Peters, J . M e d . Chem.. l a , 928 (1969). (4) K . S. Rogers and A . Cammarata. B i o c h i m . B i o p h y s . Acta, 193, 22
(1969). (5) (6) (7)
I. U. Wilson and C . g u a n . A r c h . Biochem. B i o p k g s . , 73, 131 (1958). G.Del Re, J . C h e m . Soc., 4031 (1958). G. Del R e , B. Pullman, and T. Tonezawa, Biochini. B i o p h y x . A c t a ,
76,153 (1963): Bull. C h e m . Sac. J a p . , 37,985 (1964). (8) E. Hackel. Z.Physik., 70,204 (1931).
which the piperidine h' is prot,onated since t'his species is expected to predominate a t p H 7.4, the pH maintained during the enzymatic evaluation. 5 Some calculations 6 Quintana and Smithfield have determined the pKs' for the piperidine N in a series of substituted l-bensyl-3-(hT,N-diethylcarbamoyl)piperidine hydrobromides in which the average pKa' value is 7.55.8 Since the s u b stituents examined are classically considered as electron-withdrawing groups, one would expect the piperidine N t o be less hasic (have %lowerpK,') t h a n in t h e compds considered here. (9) R . P.Quintana and W. R. Smithfield, J . M e d . Chem., 10, 1178 (1967).
SOTLS
1136 Journal of Medicinal Chemistry, 1971, Vol. 14, N o . 11
(IV), and would thus be expected to “fit” the active site better than those compds which do not have the
Iv
0 0
b, -0.30
-0.20
0.10
,
-0 00
N e t Charge on Nitrogen, QN
Figure 1.-Butyrylcholinesterase inhibition of some 3-substituted-1-decylpiperidines us. net charge on the N of the substituent group. (Data points included are those for the compds for which K , values have been determined, z.e., 1-5, Table 11.)
were done on the nonprotonated species, however, to see if protonation of the piperidine nitrogen was “felt” by the substituent atoms a t the 3 position of the piperidine ring. Using parameter values for a protonated piperidine nitrogen instead of a tertiary S did not change the charge densities on the atoms attached a t the 3 position. An explanation that has been proposed by Bergmann, et al., for the cholinesterase inhibition of compds containing the RCO function is “that the inhibition is related to the effect of the substituting (R) group upon the electrophilic character of the carbonyl carbon.” l o With this in mind one would expect that an increase in the activity of the compds of series I, 11, and I11 (1-5, Table 11) would be reflected in an increase in the positive value for the net charge on the carbonyl C. This does not seem to be the case, however, as can be seen in Table 11. Although the most active compd does have the most positive value as anticipated, the least active compds do not have the smallest positive charge on the carbonyl C. Thus, it would seem that while the electrophilic character of the carbonyl C is important for BuChE inhibition as illustrated by thp most active compd (2, Table 11), its contribution to BuChE inhibition is modified by the alkyl groups of the carboxamide function as seen in 3, 4, and 5. If one examines the total charge on the carbonyl 0, Qo, of 1-5 in Table 11, it can be seen that the most active compd has the greatest negative charge. The total charge on the carbonyl 0 for the other compds has such small variation, hou-ever, that no conclusion can be drawn concerning a relationship between the total charge on the carbonyl 0 and activity. Purcell has reported that, for a series of 1-decy1-3[(N-alkyl)- and 1-decyl-3- [ (N,N-dialky1)substituted carbamoyl ]piperidines, the BuChE inhibitory activity increased a8 the amide N became more positive.” The activity for the acetamide, urea, and substituted amides (1-5, Table 11) increases as the r\’ in the respective moieties (dimethyl-substituted 9 for 2) becomes more positive (Figure 1 ) . It is interesting to note that, whereas a part of the acetamide V shown by darker bonds is isosteric with the choline ester, acetylcholine (10) F. Herpmann, I I3 Wilson and D Nachmansohn, J 186,693 (1950) (11) W.P. Purcell J. Med Chem , 9 , 294 (1966)
Bzol Chem
0
H
V
ACh “backbone,” it is less active than 2 of the carboxamide compds (3 and 5, Table 11) in which the number of atoms separating the cationic S and the CO group is less than in the choline esters. This points out the dynamic nature of the interaction of inhibitor and enzyme; factors other than the proper positioning of certain atoms which are believed to be :ictive-aitt>directing centers must also be of v i t d importntict.. ,2lso, it is the charge density on t h e dimcth? 1-substituted K of 2 that seems to correlate nith activit;\ (Figure 1); this S is situated differently t h a i t cithcr the K of the acetamide or the carboxaniidcs. Th:ri the charge density on the differently situated ( ? . e . regarding the number of bonds b e t w e n the K and the pii)c1idiriium 1)nitrogens is related t o activity indicates that electronic charge densities ma! affect the m a ~ i n ~11ir n-hich the enzyme and inhibitor molecules fit together so that the piperidinium nitrogens and the nitrogelis examined in Table I1 have similar distances bctn een them. ,1 comparison nas made of BuChE inhibitor! iictivities and amide K charge densities for the series of carboxamide derivatives (3-9, Tablc 11) in :in iittempt to delineate further the role of electrostatic charges in BuChE inhibition. Calcris show that there 15 w r y little variation in the charge distribution of t h r C’OXH, function while there is considerable variation in thrl BuChE inhibitory potencies, thus serving to illustrate that the hydrophobic character of thc alkyl g r o u p on the CONH, function is the controlling factor in thc BuChE inhibition of these compds. These result\ are in agreement with those of I’urcell, t t al., \Tho attributc a major part of the activity of 3-9. Table 11, to re1:1t’Ivt’ hydrophobicities of the molecules.?”
Acknowledgment. -The author< uibh to thaiik 1 1 1 h n 1IcEachran and A i m . .Julia Lntham of tht’ vercity of Terineqsee Computer Project for thcir a ancc in operating thc IBAI 16’20 computer a11d George E. B a s for hi\ a tunce i r i the citlculatlon~. Also, T\ e \ \ o d d 1 1 1 ~to c q r w our gratitudc t o 111. J. G. Beasley for permitting u s t o incluclc w n i ~of unpublished data in Table I1 :md for 111- helpful ~ ~ 0 1 1 1 ments (111 the nianu,cript.
Chemistry of Cephalosporin Antibiotics. 25. 3-Cyanomethyl Cephem Nucleus
Sumcrous structural manipulations have been c a r r i d out at thc 3 position of the cephem nucleus. J1odific.a-
