PTEILIDINECARBOXAMIDE DIURETICS
Narc11 1967
165
YteriLliiiecarboxainide Diuretics. 11. Reaction of ~E,G-l)iaiiiiiio-5-nitrosopyrimidines with N- Substi tuted Cyanoace tamidesl rY. S. OYI)ENE, k ' P H C r R A. SAKTILLI,~ LEE E. ~ ~ C A R D AND L E ,;\IARVIN E. ROSENTHALE IVyeth Laboratories, Inc., Research and Development Division, Ratlnor, Pennsylvania Received September 2.4, 1966 Several new 4,6-diamino-2-substituted 5-nitrosopyrimidines and S-substituted 2-cyanoacetamides were prepared and used as intermediates in the base-catalyzed preparation of a number of 4,7-diamino-2-substituted Nsubstituted 6-pteridinecarboxamides. Many of these pteridines were examined for diuretic activity in rats after oral administration. Increased activity was associated with certain specific structural characteristics. The more active compoundb were those in which the 2 position of the pteridine nucleus bears an aromatic group, preferably pheiij 1 or m-chloiophenyl, and in which the carbamoyl nitrogen bears a 2-dialkylaminoethyl or 2-(S-heterocyclic amino)ethyl grolip, e.g., 2-diethylaminoethyl or 2-morpholinoethyl. 111 tlie preceding paper of this series3 the structurediuretic activity relationship of 4-amino-2-substituted 7-substituted amino-S-substituted 6-pteridinecarboxamides prepared from 4,6-diamino-2-substituted5nitrosopyrimidines and N,X'-bis-substituted malonamides was discussed. I n the present work a number of new 4,7-diamino-2-substitutedN-substituted 6pteridinecarboxamides were prepared by the reaction 5-nitrosopyrimidines with of 4,6-diamino-2-substituted N-substituted 2-cyanoacetamides (see Chart I and
CHARTI
(Tables 1-11)
(Table 111)
(Tables IV-V)
Tables I-V). The first descriptions of this type of synthesis were reported several years ago.* hlany of the 6-pteridinecarboxamides given herein were fourid to be active diuretics when tested orally in rats. These compounds differ from those presented in the previous paper by having substituted in the 7 position of the pt'eridine nucleus an amino group rather than a hydroxy or substituted amino group. Slight modifications in structure a t the 2 and 6 positions resulted in significant changes in activity and a systematic study was undertaken to determine the relationship between these structural changes and diuretic profile. Certain generalities have been observed and are presented in this report. Chemistry.-The method used for the earlier syntheses of 4,7-diamino-6-pteridinecarb~xamides~ has now been expanded to include the preparation of 4,7diamino-IT-substituted 6-pteridinecarboxamides. The N-substituted cyanoacetamides required as intermediates were prepared generally by heating ethyl cyanoacetate with 1 equiv of a primary amine (Table I) or secondary amine (Table 11) in refluxing ethanol. Various 4,6-diamino-2-substituted 5-nitrosopyrimidines (1) This work was presented in part before the Division of Medioinal Chemistry, 150th National Meeting of the American Chemical Society, Atlantic City, N. ,J., Sept 1965, v 16 P. ( 2 ) T o whom inquiries stioiild he addressed. (3) T. S. Osdene, A . A. Santilli, L. E. McCardle, and RI. E. Rosenthale, J . .?fed. Chem., 9 , 697 (1966). (4) (a) T. S. Osdene and G . 11.Timmis, Chem. Ind. (London), 405 (1954); (b) T. 9. Osdene and G. RI. Timmis, J. Chem. Soc., 2036 (1955).
(Table 111) n-ere prepared by previously described procedures.5 Reaction of the latter compounds with K-substituted cyanoacetamides in refluxing ethanol containing catalytic amounts of sodium afforded the pteridinecarboxamides (Tables IV-V) used in this study. I n those pteridines prepared from 4,6-diamino5-nitrosopyrimidines bearing a 2-amino function, it mas necessary to use a higher boiling solvent for reaction t o occur. 2-Ethoxyethanol was found to be suitable for this purpose. An examination of the infrared spectra of the pteridines thus prepared revealed the expected carbonyl and amino absorption bands. A typical example is given below. Biological Methods.-The procedure used for evaluating the diuretic profiles of the pteridinecarboxamides in male Sprague-Dawley rats has been previously described in detaiL3 The results in Tables VI-X are expressed as the average ratios of urine volume and sodium levels in test (T) animals to those of the control urea-dosed (V) animals. ,411 ratios (T/G) greater than unity for volume and sodium output represent statistically significant diuretic responses. This preliminary screening procedure was quite useful in that it afforded a means of rapidly evaluating the action of each drug on a quantitative basis. Further biological evaluation of the more active compounds has been carried out and is typified by other reports cited below. Structure-Activity Relationships.-Table VI gives the relative diuretic response of a number of 4,7diamino-2-phenyl-6-p t eridinecarboxamides having various substituents (Rz) bonded to the K atom of the 6carbamoyl group. I n general, the more active pteridines are those in which Rz contains an amino group, e.g., 96, 103, 109, 116, and 118. The most active of these are 103 and 118 where R2 = 2-diethylaminoethyl and 2-morpholinoethyl, respectively. A more detailed account of the diuretic action of 118 in rats and dogs has recently been given.6 The action of this drug has been compared with several other diuretic agents. Table VI1 shows the results of retaining an active moiety such as the 2-diethylaminoethyl group on the carbamoyl nitrogen hut varying thc siibstitnent in the ( 5 ) 0.Vogl and E:. C . Taylor, J . A m . Chem. Sac., 79, 1518 (1957); E. C . Taylor, 0. Vogl, and C . C . 0 1 m g , ihid.. 81,2142 (1959), and other soiirces given in ref 3. (6) M . E. Rosentliale and C. G . Van .Irman, .I. Pharmacol. E z p f l . T l ~ r a p . , 142, 111 (1963). ( 7 ) 11.E. Rosenthale, ibid., 147, 399 (1965).
166
2 1)o-it i o i t of (lie ptc>ridiiicb i i u i ~ l c ~ i - . 'Yhc oiily :rc*tivcs ni(wilwi- of thi. w r i ( ~is~ 103 ( I l l = pliniyl). r l ' l i ~ i otlicr t oiiipoutitl, I\ c w iii:ic.tivcb :It t 1 1 ~(lose levc.15 4 1 0 \ \ 11.
Iri l':ible VI11 are giveii cwiiipounds in which t h c i\-e group i, rc>t:iinctl on the carbamoyl iiitrogwi h u t the siibstitucrit It' on the '-phenyl group is v:iiictl. 'l'hc most active compounds in this series are 103 and 155 in u-hich It' = H aiid m-C'l, respectively Substitiition generally diniinislicd the activity. Coi1i~ ) o i i i i c l h145, 148. a n d 165 \I crc iiinrtivc. w i i i ( > :wt
Table IX dciiioiihtriit ES t lie cffcct of Iiuinologatioii diurCti(4 responbc \I itliin RII active \erics. The, optimal iiiethylciic chain length attac*lietl t o tlic varbamoyl nitrogen appears t o be two (103). *lctivity decreased with a third methylene group (104) arid i v a 5 nonexistent for conipourids rontainirig four (105) or five (106) methylenc. groups in the alkyl chain. Similar results were observed with higher homologs (ti > 2 ) in other active pteridine TabIe X h h o n the uretic effect in 4,7-diairiin( 1-2~ ~ h c n y l - 6 - p t c r i c l i r i c ~ ~ : ~ ~ l which ~ r ~ ~ a nhave i i d ~ ~1 ~1 i ~~ 3 1 ' oii
167
JIarch 1967
60.85 7.30 20.28 60.91 7.26 20 09 B 67 1-Pyrrolidiiiyl 71 Piperidinob 87 B 76 A4-J 73 65.03 8.49 16.85 65.19 8 . 6 0 17.10 74 l-Hexahydroazepiii31 F-C 27 XIorpholinob 82 16.46 49.72 16 $4 1) 70 5.93 49.39 5.92 93 Thiomorpholiiio 57.46 7 . 8 4 25.13 57.59 8 . 0 8 24 96 113 J 40 4-XIethyl- 1-piperaz in)-1 54. SO 7.67 21.31 55.09 7 . 5 1 21 41 4- (2-Hydroxyethyl)-l-piperF 83 84 azinyl 64 B 92 $2 K(CH3)s' 36.78 s . 9 4 24. 83 56,44 8 . 9 9 24 i 1 66 I ~ C H ~ ( C H ~ ) S ( C H J ) ~ 147 ( 0 . i ) 33 8.93 15.54 67.09 A-1) 66.63 99 S.66 15 37 82 34 KCHBCGHII-C ;"~'CH~(CH~)~N(CLH~)L~ 55 9.35 22.93 58. 65 23 14 147-130 21 58. 99 9.1; 56 KCaHa(CH:!)2N(CH3)2 (0.7) 57 NC~H~(CHZ)~N(CZH~)Z~ 66.36 10.74 16.59 66.28 10.63 16 36 86 79 38 K(i-C3H;)(CH2)25(i-C3H7)2 C. JV. Whitehead aiid J. J. Tiaverso, J . Am. Chem. Soc., 77,5867 (l955), ieported inp S i " for both 46 See footnote u of Table I. Compoulid used without purification. :tiid 48. E. L. Eliel, ibid., 73, 43 (195l), repoited mp 85-66". 45 46 47 48 49 50 51
(1
NH2
---
-----yc calcd----? 'yo fuund----"C Formula C I1 N C H N >360 Rf-D I CbH4F3N50 29.01 1.95 28.55 2.16 59 CF, A 11 C8H12N602 42.85 5.39 37.48 43.03 5.41 37.20 60 Nlorpholinod 236dec A I CiiHiiNs02 57.63 4.84 30.54 57.87 5.00 31.44 61 o-CH~CGH~ 219dec 62 V Z - C F ~ C ~ H ~ ~211 H I CiiHJ?aNgO 46.81 2.50 24.82 46.90 2.78 24.56 63 3,4-CLCsH3 279dec E I CloH7C124'sO 42.29 2.49 24.65 42.53 4.75 24.40 64 o - C H ~ C ~ H ~ C H 210 ~ A I C12H13N60 59.25 5.39 28.79 59.51 5.41 28.80 65 p-CICsH4CH2 216 E-D I CiiHloClNjO 50.10 8.32 26.56 50.02 3.88 26.67 a The sources for the 4,6-diamino-5-nitroso-2-(substituted) pyrimidines in which RI is H, n-CaH7, CH& C6H, p-CH3OCsH4, m-ClCsHa, p-C1C6&, and 2-thienyl were previously given in paper I of this series.3 Other preparations: m-CH&&, J. Weinstock, s. Patent 2,963,478 (1960); p-CH3CsH,, E. C. Taylor and T. S. Osdene, C . S.Patent, 2,975,180 (1961); CHI, E. C. Taylor, 0 . l'ogl, and c. c. See Cheng, J . -4m. Chem. Soc., 81, 2442 (1959); m-CF3C6H4,obtained from Arapahoe Chemicals, Inc. See footnote a of Table I. Experimental Section. See ref 10. Compd
R:"
Mp,
Recrystn solventb MethodC
u.
bamoyl nitrogen disubstituted. At the doses indicated compounds 184-186 were only mildly active and all other compounds were inactive. It is interesting to note that further substitution on the carbamoyl nitrogen bearing the active 2-diethylaminoethyl moiety (180, 182) eliminated the diuretic response. In summary, the diuretic profiles of several 4,7dianiino-2-substituted N-substituted B-pteridinecarboxamides, as determined in male Sprague-Dawley rats, show that activity is related to specific structural requirements. The more active compounds are those in which the 2 position of the pteridine nucleus bears an aromatic group, preferably phenyl or 772-chlorophenyl, and in which the carbamoyl nitrogen bears a 2-dialkylaminoethyl or 2-(N-heterocyclic amino)ethyl group such as 2-diethylaminoethyl or 2-morpholinoethyl. Experimental Section8 The examples given below illustrate procedures used for the prepurntion of the compounds given in Tables I-V.
The 4,6-diamino-5-nitrosopyrimidinesgiven in Table I11 were prepared in general by the reaction of a suitably substituted amidine hydrochloride with the silver salt, of isonitrosomalononitrile (method I ) or by the direct riitrosation of the 4,6-diaminopyrimidine (method 11). Illustrative examples follow. Method 1.O 4,6-Diamino-2-triAuoromethyl-5-nitrosopyrimidine (59).-To a solution of 24.5 g of trifluoroacetamidine hydrochloride in 450 ml of absolute ethanol was added portionwise 33.6 g of finely powdered silver salt of isonitrosomalononitrile. The reaction mixture was stirred for 2 hr and the AgCl was removed by filtration. The filtrate was evaporated to dryness in 2;uczio on a rotary evaporator to give the trifluoroacetamidiiie The material thiis salt of isonitrosomalononitrile, mp 95-96'. obt,ained was dissolved in 150 ml of dimethylformamide ( D l I F ) and boiled under reflux for 10 min. An excess of water was added, resulting in the deposition of a dark green powder. Recrystallization from aqueous DRIF followed by recrystallization from aqueous acetic acid gave 13.5 g of the product, mp > 360". (8) Rlrlting points mere determined on a Thomas-Hoover capillary melting point aj,paratiis and are corrected. r i e l d s reported in Tables I-V are the results of single experiments. Infrared spectra were determined in I i U r disks on a Perkin-Elmer Model 21 spectrophotometer. (9) Other 6-nitrosopyrimidine intermediates prepared by this method h a r e been preriously cited in ref 3.
lW
1 I4
($6116
P'TERIDINECARBOXAMIDE DIUI~ETICS
169
'/c calcd
---._-
I -
C
111
H
N
57.8.5 5 62 28 58.81 3 92 27 55.37 4 63 30 *57.$7 5 42 27 -.I.>,29 3 19 26 33 .28 5 19 26 36.63 5 03 28 .57.75 .i42 27 61.44 6 42 26
- % foulid-
C
41 44 14 75 ,54 34 90 75 40
38 14 55 81 i.5 80 57 91 55 00 54.99 36 32 58 07 61 50
-
"
i6 92 44 49 07 35 91 62 6 74 5 5 4 5 5 5 4 5
28.22 2 i 38 29 77 27.73 26 38 26 44 28.61 27.49 26 08
-- .42
. i . S 3 24.8'7 .iT.42 3.70 24.4;: -57.78 5.42 27.7.5 5 i . ! ) ! ) 5.76 28.01 X . 8 4 5.76 26.6'3 .i!l.l.5 5.77 26.41 .)i
ti0.47
5.08 25.98 60.64 5.11 23.8;;
.i3 27 -.)n 58 61 ,53 59 00 60 89 61 74 58 81 60 89 63.64 59 98 60 89 58 59
.i18 26 .54
4 66 4 46 6 0.5 6.64 6 91 5 92 6 64 6.14 6.36 6 64 6 47
26 22 30 28
,i8.67 58.37 53.56 49.43 56.53 57.26
3.93 6.12 5.17 4.15 5.80 6.49
27.59 23.83 24.09 22.42 29.30 26.i2
38.81 58.34 53.39 49.29 55.87 57.12
.LY2
56.59 52.78 53.93 55.00 56.00 56.94 55.00 52.78 55.00 52. '71 56.00 53.21 52.65 58.84
5.70 4.95 5.28 5.59 5.88 6.14 5.59 4.95 5.59 582 5.88
26.40 28, 97 27.9.5 27.01 26.13 25.30 27.01 28.97 27.01 2.5.89 26.13 4.93 26.13 4 . 6 8 25.28 5 . i 6 26.69
56.67 ;,2. 98 53.77 53.27 56.12 57.11 34.72 $2.64 54.72 52.53 56.02 52.97 52.78 59.15
.,67 i 4.71 5.0 3 5.86 6.31 6.4s 5.35 5.17 5.55 3 . 9.5 6.29 4.93 4.38 5.i7
27 27 28 25 29 28 28
55.41 4 . 4 1 23.81 52.84 50.78 48.35 32.83 50.98 56.32
--
.).I 51 69 .i5 88 53 61 35 5h 58 98 41 61 14 43 61 78 44 58 34 41 60 i 3 98 63 64 46 59 61 41 60 92 78 58 78
.i.11 2G.70
4.i4 4.62 6.06 6.72 6.70
.5.9,j 6.2% 6.40 6 . .54 6.59 6.40
27.44 5.97 24.02 5.19 25.01 4 . 2 3 22.16 5.61 29.03 6 . 4 4 27.25 26.24 %.!I1 S i . '32
27.23 2G.21 25.24 26.89 28.52 26.39 25.94 26.00 26.34 25.46 26.41
55.12 4.18 23.66
5.14 22.70 52.87 5.30 4.94 24.94 50.11 .5.19 4 . 0 6 23.22 48.58 3.97 X i 4 29.00 52.98 3.50 5.03 27.98 51.56 5.03 6 . 1 4 26.27 56.05 6.04
53.23 4.43 25.57
26, 52 22.72 30.28 28.28 27.61 27.43 28.38 26.01 29. 0 i 28.32 29.21
22.47 24.96 23.33 28.95 28.07 25.95
53.47 4.63 25.41
61.74 6 . 9 1 27.43 61.65 59.53 6.08 23.71 60.10 .5ti.00 T,.X8 2ti.13 5 5 . 8 5 .53.80 5 . W 24.40 53.88
7.00 26.93 6 . 1 9 23.04 ,5.80 25.81 ,512 24.28
'I Set, footiiole n of T:hk I. See ref 4b of test. Prepared from 75 a i d 3-diethylniniiiopropyl:iiiiiiie by procsedrireused for the preparation of 77. Prepared i n Zethoxyethanol. e I. J. Pachter and P. E. Semeth, J . Org. Chem., 28, 1157 (1963). f Prepared from 4,5-diamino-5-11it~~oso-2-phen~lpyrimidi1ie and 22 in ethanol usiiig 1.2 equiv of SaOEt. Prepared from 104 aud ethyl iodide in refluxing et hariol. 'I
_.T / V - .
,
Vol
Ya
1.54 1.2s 1.i1 1.46 1.08 I . .?!I I.2:;
1.38 1.25 2.06 1.4; 1 ,:;1 1 (iF 1,:
