Febrifugine antimalarial agents. I. Pyridine analogs of febrifugine

Journal of Medicinal Chemistry 2006 49 (15), 4698-4706. Abstract | Full ... Potent Antimalarial Febrifugine Analogues against the Plasmodium Malaria P...
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XOTES

January 1970

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centrated to an oil, which was didilled under high vacuum. Compoiind 6 solidified after the reaction mixture was poured into 2 .\- S a O H and left overnight and was crystallized from Et'OHH?O. The same was the case with 14, which was crystallized from DAIF-H,O. Compounds 10 and 11 solidified aft8er the dried Et,O extract, was concentrated and were crystallized from EtOAc and petroleiim ether (bp 30-60°), respectively.

showed an improved chemotherapeutic index against Plasmodium lophume in ducks;2 one analog was tested in limited clinical trails, but was ineffective against P. vivax and P. falciparum. We have now prepared 3- [p-keto-y-(3-hydroxy-2pyridyl)propyl]-4-quinazolone (3c) (Table I), in which 7-Chloro-l,3-dimethyl-4-(3-diethylaminomethyl-4-hydroxy- the piperidine ring of the side chain has been replaced aniIino)-lH-pyrazolo[3,4-b]quinoline (15).--A solution of 3by pyridine. Baker and 1 I c E ~ o y?ynthebized ~ the diethylaniiiionieth!l--l-h~drosyaniliiie (5.7 g, 0.02 mol) in a mini-

niiim anioiiiit uf H 2 0was neiitralized with dilute SaOH to congo red paper. To this ivaA added 4,T-dichloro-1,3-dimethyl-lHpyran110 [:3!4-b] qiiiiioliiie (5.0 g, 0.02 mol) and 100 ml of ethoxyethaiiol. The niistiire \vas refluxed for 4 hr. .S clear solution formed after 2 hr aiid then a yellon- solid separated. The reactioii \vas cooled, mid the yellon- solid v a s filtered and crystallized from Me.CO-HyO.

0

2

Acknowledgment.-This n-orli n-as supported by the E. S . Army Medical Research and Development Command under Research Contract S o . DA-49-193-AID2369. This ie Contribution So. 387 from the Army Research Program on llalaria.

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Febrifugine Antimalarial Agents. I. Pyridine Analogs of Febrifugine M O R R FISHV I~ ix

.ISD

a.S=H b ?i=OCH e. X = O H

PHILIP A . CRLTICKSH.GK

Ctntrnl Restarch Dtpartment, Chcw ical Resrarch and Devclopment Center, F J I C Po/porcifion, 8, Princeton, .\-ew Jersey 08540

Rccc iced S c p f ~ m b e12, r 1969

7 he dlialoid febrifugine (1) has been shown to be the active iiigredieiit of the aricieiit antimalarial preparation Ch'xng Shall.' Although 1 is effective against avian malaria-,2 Plasmodiuna cynomolgi in monkey^,^

pyridinium derivative 2b, and described hydrogenolysis of the corresponding free base to the methyl ether 3b using Raney S i catalyst. However, no attempt to prepare SC by cleavage of the Ale0 group was reported. Working with the desoxy analog 2a8 as a model compound, we found that hydrogenolysis of the benzyl group could be effected smoothly over Pd-C, affording 3 - [p- keto-7 - ( 2 -pyridyl)propyl] -4 - quinazolone (3a). The N e 0 derivative 2b gave 3b under identical conditions.

TABLE I 3-[~-Kb.10-~-(3-SUBSTITCTED 2-PYRIDYL)PROPYL]-4-QUIN4ZOLONbS

s

C ompd

a

*3a 3b 3c Washed with AcMe,

Iield,

70

Mp,

59 OCHa 41 OH 53 Et,O. * Recrystallized from RIeOH; lit.' H

and Plasnaoclium berghei in mice,4 it has poor activity against Plasmodium falcipamm and Plasmodium ~ i v a x ; ~in- ~addition, it is a powerful emetic and has a low chemotherapeutic i ~ i d e x . ~Several analogs of 1'

oc

209-212a 151-155' 211-214 deca mp 157-158'.

FormulaC

CiuHi&302 '2HCI.HL0 Ci7Hi&& CisHi~N303.2HCl.1.5HiO All compounds were analyzed for C, H, S .

For the preparation of 3c, the intermediate l-benzyl3-hydroxy-2- [p-keto-y- (4- quinazolon-3- yl)propyl]pyridinium chloride hydrochloride ( 2 ~ was ) hydrogenolyzed over Pd-C. Compounds 3a-c were assayed against P. beryhei in mice and Plasmodium yallinaceum in chick^.^ S o antimalarial activity was observed. Experimental Section

1 (1) J. R. Koepfli, J. A. Brockman, Jr.. and J . hloffat, J . Am. Chem. Soc., 74, 3323 (1950). (2) R. Hewitt, E. R . Gill, W. S. Wallace, and J. H. Williams, Am. J. T r o p . .Wed. H u g . , 1, 768 (1952). ( 3 ) F. G . Henderson, C. L. Rose, P. H. Harris, and K. K. Chen, J . Pharmr~col.Ezptl. Therap., 96, 191 (1949). (4) R. h-. Chaudhuri, B. N . Dutta, and N. K . Chakravarty, I n d i a n M e d . G m . , 89, 660 (1954). (5) G. R . Coatney. W. C. Cooper, W.B. Culwell, IT, C . White, and C . A. Imhoden, J r . , J . X a t l . Malaria Soc., 9, 183 (1950). (6) V. .4.Trevino, L. 4.Reyes, and h l . F. Mendoza, Rev. Inst. Salubridad Enfermedndes T r o p . (Mex.), 13, 253 (1953). ( 7 ) €3. R. Raker, R. E. Sohauh, J. P. Joseph, F. J. McEvoy, and J. H. Williams, .I. O r g . Chem., 17, 141, 149, 157, 161 (1952): 18, 133, 138 (1953).

Melting points were determined on a Thomas-Hoover "OniMelt" capillary melting point apparatus and are not correcfed. The ir and nmr spectra were as expect,ed. 1-Benzyl-3-hydroxy-2- [P-keto-~-(4-quinazolon-3-yl)prc~pyl] pyridinium Chloride Hydrochloride (2c).-A solution of 2b (13.T g, 0.029 mole) i n 573 ml of 487( aqiieoiis HBr was refluxed for 18 hr. After cooling, the solution was evaporated t o dryness in L~UCUO. A saturated solution of K a H C 0 3 was added to the residue; the resulting mixture was extracted (CHCL), and the

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(8) B. R. Baker and F. J. MoEvoy, ibid., 20, 118 (1955). (9) The screening tests v e r e carried out a t the University of Miami. Miami, Fla., under the direction of Dr. L. Rane. Details of the mouse screen with P. berghei have been published [T. S. Osdene. P. B. Russell, and L. Rane, J . M e d . Chena.. 10, 431 (196711.