ANALOGSOF TUBERCIDIK
July 1967
Analogs of Tubercidin' JOHN
A.
A I O N T G O h f E R Y AND I < I B T H L E E S
HEWSON
Kettering-;Meyer Laboratory, Southern Research Institute, Birmingham, Alabama
35205
Received February 25, 1967 The synthesis of a number of alkyl analogs of tubercidin has been accomplished via 4,6-dichloro-5-(2,2-diethoxyethy1)pyrimidine (9). Although somewhat cytotoxic, these analogs showed no activity agaiiist leukemia L1210.
.%
Tubercidin (4-amino-7-P-~-ribofuranosyl-7H-pyrro~o[2,3-d]pyrimidine, l), an antibiotic analog2l3of adenosine in which S-7 has been replaced by a carbon atom,
N'
NHz
N
R
3
pyrrolo [2,3-d]pyrimidines (3) .14 The acetal furictioii of ~-(2,2-diethoxyethyl)-4,6-dihydroxypyriniidine,which could be prepared by a modification of Davoll's ring-
OH OH 1, X = CH 2,X=N
is also related to 4-aminopyrazolo [3,4-d]pyrimidine (4-APP) ribonucleoside (2),4,5in which N-7 and C-S have been inverted. Since both these structures have shown a high degree of biologic activity,G-8 arid tubercidin has shown significant anticancer activity in experimental animal system^,^,^ it would appear that S - 7 is not a requirement for activity. Furthermore, both 9-alkylpurines'o and 1-alkylpyrazolo [3,4-d]pyrimidines" are known to have anticancer activity, and certain 9-alkylpurines inhibit the growth of cells resistant to 6-mer~aptopurine.'~Thus it seemed desirable to prepare and evaluate the biologic activity of a series of 7-alkylpyrrolo [2,3-d]pyrimidine analogs (3) of tubercidin. Davoll's procedure13 for the synthesis of 4-amino7H-pyrrolo [2,3-d]pyrimidine (3, R = H), the aglycon of tubercidin, involves ring closure to a 4-amiriopyrimidine arid canriot be used to make the 4alkylamiiiopyrimidines needed to prepare the desired 7-alkyl-
closure procedure, is not compatible with the chlorodehydroxylatioii procedures that would have to be used to convert it to 4,6-dichloro-5-(2,2-diethoxyethyl)pyrimidine, which could be used to prepare the requisite 4-alkylaminopyrimidine intermediates. I t was, therefore, necessary to devise a reaction sequence in which the aldehyde function could be introduced after the chlorodehydroxylatioii step. j-A11y1-4,6-dihydroxypyrimidine (6), prepared by the reaction of formamidirie acetate (4) Jvith diethyl allylnialonate ( 5 ) ,was converted t o S-allyl-4,Ci-dichloropyrimidine (7) by treatment with Poc13 and diethylaniline (Scheme I). The 5-allyl-4,6-dichloropyrimidine (7) was ozonized at -7.5' aiid the resultant ozonide was reduced n-ith sodium thiosulfate to the desired 4,6-dichloropyrimidirie-5-acetaldehyde (10). Since reaction of the acetaldehyde (10) with benzylamine SCHEME I NH
II
+
CH~COOH~HCNHZ 4
CZH~O~C, CHCHzCH=CH2
I
co I
-
OCzHs
HNy N y ~ z ~ 5
(1) This investigation was supported by funds from t h e C. F. Kettering Foundation and t h e Cancer Chemotherapy National Service Center, National Cancer Institute, National Institutes of Health, Contract No. PH43-64-51. ( 2 ) K. hnzai, G. Nakamura, and 8.Suzuki, J . d n t i b i o t . , A10, 201 (1957). ( 3 ) G. Nakamura, ibid., 14, 90 (1961). Kerridge, J. C h e m . S o c . , 2589 (1961). ( 5 ) J. A. Montgomery, B. J. Clayton, and K.E. Fitagibbon, J r . , J . Heterocyclic C h e m . , 1, 215 (1864). (6) J. P. Owen and C. G . Smith, C a m e ? Chemotherapy X e p t . , 36, 19 (1964). (7) L. L. Bennett, Jr., and D. Smithers, Biochem. Pharmacol., 13, 1731 (1964). ( 8 ) L. L. Bennett, Jr., M. H. VaiI, 6. Chumley, and J. A. hXontgomery, ibid., 16, l i l y (1Y66). (9) C. G. Smith, JV. L. Lummis, and J. E. Grady, Cancer Res., 19, 847 (1959). (10) F. >I. Schabel, Jr., J. A. Montgomery, H. E. Skipper, W. R. Laster, Jr., and J. R. Thomson, ibid., 21, 690 (1961); J. A. Wolff. C. L. Brubaker, RI. L. Murphy. M. I. Pierce, and N. Severo, Cancer Chemotherapy R e p t . , 30, 63 (1963). (11) H. E. Skipper, R. K. Robins, J. R. Thomson, C. C. Cheng, R. TT-. Brockman, and F. M. Ychabel. Jr., Cancer Res.. 11, 579 (1957). (12) G. G. Kelles,., G. P. \Vbeeler, and J. A . Montgomery, ibid., 22, 329 1962). (13) J. Daroll, J . Cham. S o c . , 131 (1960).
C1
0
H2CH=CHz
N .'
*
+
N .'
OH
C1 7
6
c1
C1
10
9
3a,R = CzH5
C1
a
b, R = CsHsCHz c,R=
R 11
(14) Recently the methylation of 4-chloro-TH-~~yrrolo[2,3-dlpyrimidine was described.15 (15) R. 13. Hammer, J . I'harm. S c i . , 66, 1096 (1966).
AKALOGS OF TUBERCIDIK
July 1967
667
TABLE I1 D.kT.4 O N
Compd
Yield,a
9
%
Recrystn solvent
hfp,
oc
Calcd
Benzene 137-138 37* 177-179 Et,hanol 50 Acetone 169 C 58 160-162 Acetone d 31 I n addition a 16% yield Analytically pure material. a b
a
ULTRAIIOLET
AND
COMPOUNDS 3
-c.
%Found
---H, Calcd
59.23 59.35 69.61 69.56 65.31 65,23 62.04 61.87 of the hydrochloride salt of
%---Found
6.42 6.22 5.3 5.40 6.78 6.98 7.01 6.93 3a was obtained.
--Xmax, rnfi ( e X 0.1 .Y HCI
230(24 4) 275.5 (9 4) 230 (27.4) b 274 (10 4) 231 ( 2 7 . 0 ) C 276 (9 4) 231 (27.0) d 275 (9.4) a NII and OH stretch.
lO-3)--
PH 7
224 sh 273 (9.1)
a
b
272 (10.6) 228 (17.6) 275 (9.3) 225 sh 273 (9.4) OH bend.
yo----. Found
34.57 24.98 2 7 . 70 24.12
34.49 25,25 27.79 23.92
TABLE I11 INFR LRED SPECTR 1 OF TUBERCIDIN AN LOGS
-----
c,----m e -l-
Compd 3
-N, Calcd
N H stretch
C H stretch
3400,3320, 3140 3410,3300, 3080 3340,3160
2980,2930, 2860 3020,2920, 2850 2950,2865
1645
3380," 3320," 3140a
2950,2870
1650
ayer was evaporat,ed to dryness in vacuo and the residue was dissolved in ligroin (ethanol for l l d ) . The amorphous insolubles were removed by filtration through dry Celite and the filtrate was evaporated to dryness in vacuo to give the pyrrolopyrimidine as a n oil in 60-100% yield. Thin layer chromatography indicated the presence of only t,race impurities. The pmr spectrum confirmed the pyrrolo[2,3-d]pyrimidine st'ructure and, therefore, the product, was iised as an intermediate without further purification. The ultraviolet, infrared, and pmr spectra of l l a , c, and d were all very similar, with the expect'ed differences, t'o t'he spectra of l l b (vide infra). On concentration of the ligroin solution, the 4-chloro-7-benzyliH-pyrrolo[2,3-d]pyrimidine ( l l b ) crystallized. The crystals were collected by filtration, washed with ligroin, and dried in vacuo to give the pure product in 53% yield; mp 6 6 4 7 " ; Xmax in mp (E x 10-3): p H 1, 226 (26.6), 273 broad (4.3); ethanol, 224 ( 2 8 . 2 ) , 272 (4.8); pH 7, 13, 226 ( 2 7 . 2 ) , 273 broad (4.4); u, in cm-1, 3100-2900 (CH), 1573, 1340, and 1500 (C=C, C=X), 915 d, 84.5, and 710 d (ring CH deformation); 6, in ppm, 8.6 (H2),7 . 2 d (H6),6.6 d (H6),3.4 (benzyl CHg), 7.2 m (phenyl H). H j and HE appear as a n AB pair VO(& - 6s) = 36 cps and J b . 6 = 3.7 cps. Anal. Calcd for Cl3Hl0C1X3:C , 64.07; H, 4.14; K, 17.24. Found: C, 64.01; H, 4.16; ?;, 17.21.
N H bend
1645 1650
C=C, C=N stretch
1590,1550, 1SOB 1590, l5S0, 1510 1590, 15.50, l30j 1590,1550, 1505
-
CH bend
1470, 1430,940 d, 900,790 1473,945,000, 795 1470,940,895, 790 1475, 101O,b950, 900,795
7-AIkyl-4-amino-7H-pyrrolo[2,3-d]pyrimidines (3).-A solu tion of the 4-chloro-7-alkyl-7H-pyrrolo[2,3-d]pyrimidine in ethanol saturated at 5" with XH3 (100 m1/20 mmoles) was sealed in a glass-lined Parr bomb and heated a t 100-110" for 18 hr. The reaction solution was evaporated to dryness and the oily residue was triturated wit,h ligroin to remove impurit,ies. The insoluble solid was washed wibh water and recrystallized from the appropriate solvent to give the pure aminopyrrolopyrimidine (Table 11). Compounds 3b and 3c were washed with water and recrystallized (Table 11) to give the pure compounds; 3a was dissolved in CHCl,, and the CHC13 solution was extracted with wat,er before evaporation to dryness. The residue was recrystallized to give pure product. Compound 3d was dissolved in acet,one, and the acetone solution was filtered before evaporat,ion to dryness. The residue was recrystallized to give pure product. Ultraviolet and infrared dat,a for 3a-d are given in Table 111.
Acknowledgments.-The authors are indebted t'o Dr. W. J. Barrett and his associates for the microanalytical and spectral determinations reported and t'o Dr. L. L. Bennett, Jr., and Ptlrs. AI. H. Vail for the cytotoxicity data.
