.\NTITUUOR
Journal of Medicinal Chemistry, 1970, Vol. 13, S o . 0 431
THIOSEMICARBAZONES
Potential Antitumor Agents. IV. 4-Substituted 1-Forniylisoquinoline Thiosemicarbazonesl KRISHNAC. AGRAWAL, ROBERT J. CUSHLEY,~ WALTERJ. MCMURRAY,~ AND ALANC. SARTORELLI Department of Pharmacology and Section of Physical Sciences, Division of Health Science Resources, Yale University School of Medicine, New Haven, Connecticut 06510 Received Xovember I d , 1969 To ascertain the structural requirements for the biological activity of 1-formylisoquinoline thiosemicarbazone (I), a potent antineoplastic agent, substituents such as OH and OAc, two groups that increased therapeutic potency when substituted a t the 5 position of I, have been introduced a t the 4 position. Syntheses were accomplished by rearrangement of 1-methylisoquinoline N-oxide (11) with AclO; acid hydrolysis resulted in two major products, Phydroxy-1-methylisoquinoline(111) and 1-hydroxymethylisoquinoline (IV). A third compound was isolated in relatively small yield and was characterized by nmr and mass spectroscopy t o be a,@'bis(1-isoquinoly1)ethylene glycd (IX). Oxidation of 4acetoxy-1-methylisoquinoline(VJII) with YeO, produced the corresponding 1-carboxaldehyde, which on acid hydrolysis yielded the Chydroxy derivative. Treatment of heterocyclic aldehydes with thiosemicarbazide produced the desired thiosemicarbazones. The Csubstitrited derivatives were less effective than I as antineoplastic agents against Sarcoma 1SO ascites cells in mice; however, the N a salt of the 4 0 H derivative was considerably more efficacious than I on the L1210 lymphoma. The findings in this system compared with those previously reported indicate that the N a salt of 4-hydroxy-1-formylisoquinoline thiosemicarbazone ( X I I I ) possessed the highest therapeutic index of the active antineoplastic agents in the isoquinoline seeies.
cy-(N)-Heterocyclic carboxaldehyde thiosemicarbazones have considerable potential as antineoplastic agent^.^ One of the compounds in this class, l-formylisoquinoline thiosemicarbazone (I), has been shown4 to cause pronounced inhibition of the growth of a relatively wide spectrum of transplanted rodent tumors. The biochemical basis for the carcinostatic activity of I has been studied in our l a b ~ r a t o r y ;this ~ agent caused marked inhibition of the synthesis of DNA by preventing the conversion of ribonucleotides into deoxyribonucleotide forms, and lesser blockade of the formation of RNA and protein. As part of a program designed (a) to develop antineoplastic agents with greater therapeutic efficacy and (b) to define the structural requirements of this new class of compounds for inhibition of growth, I has been subjected to systematic structural modification. The initial approach employed was the synthesis of a series of 5-substituted derivatives of I.B The overall dimensions of I in this position could be modified with the retention of high activity, since substituents such as &OH and 5-OAc were found to confer therapeutic indices to the resultant derivatives that were higher than for the parent compound. A number of alterations were also made in the formyl thiosemicarbazone side chain;7 modifications made a t the various positions (1) Presented in part before the Division of Medicinal Chemistry a t the 156th National Meeting of the American Chemical Society, Atlantic City. N. J. Sept 1968; This work was supported by Grant CA-02817 from the National Cancer Institute, U. 9. Public Health Service, and Grant T-23 from t h e American Cancer Society and t h e National Institutes of Health (HE 03558 and FR 00356) and tbe National Aeronautics and Space Administration (N.IS 9-8072 and NGL 07-004-008) (Section of Physical Sciences). (2) Section of Physical Sciences. (3) F. A. French and E. J. Blanz, Jr., J . Med. Chem., 9, 585 (1966). (4) F. A. French and E. J. Blanz, Jr., Cancer Res., 26, 1454 (1965). (5) (a) A. C . Sartorelli, Biochem. Btopkys. Res. Commun., 27, 26 (1967): (b) A. C. Sartorelli, Pharmacologist, 9, 192 (1967); (c) A. C. Sartorelli. M . S. Zedeck, K. C. Agrawal. and E. C. Moore, Fed. PTOC., 27, 650 (1968): (d) A. C. Sartorelli, K. C . Agrawal, B. 8 . Booth, and E. C. Moore, International Congress of Pharmacology, Basal, Switzerland, July 1969, Abstract 195. (6) K. C. Agrawal, B. A. Booth, and A. C. Sartorelli, J . Med. Chem., 11, 700 (1968). ( i ) I ield; this wirl1:iracterized by nmr :tiid maqs spectra to hcl @,cy'~)i-il-isoquinolyl)eth?.leiieglpcol (IX). Formation of (1
trum of IX changed after being dissolved in the DIISOd6 solution for a relatively long period of time; this effect was most likely due to slow oxidation of the vicinal diol moiety by the solvent. The nmr spectrum of XI1 gave a singlet a t 6 8.49 nhich was assigned to H-3, and a three-proton singlet at 2.53 which was assigned to the OAc group of XII. Mass Spectrometry.-The mass spectrum of IX was characterized by a weak molecular ion (-l> animals were employed in each group.
TABLE I1 EFFECT OF I-FORMYLISOQUIKOLINE THIOSEMICARBAZONE A N D ITS4-HYDROXY DERIVATIVE O N THE SCRVIVAL TIME OF
MICEBEARING THE L1210 LYMPHOMA Daily
Compound
dose (rng/kg)=
Control 1-Formylisoquinoline thiosemicarbazone (I) 4-Hydroxy-1-formylisoquinoline thiosemicarbazone IXIII) Sodium salt of XI11
Sone 20 40 30 40 60 32.7
Av A w t (%)*
Av survival (days) =tSE
-5.2 +10.5 +2.4 -2.8 -1.0 -1.8 -2.9
8 . 4 +c 0 . 0 7 11.8 i 0.33 16.6 i 0.91 1 1 . 4 i.0.46 13.4 i 0.23 12.1 & 0.22 25.4 =t1.13 (10)C 43.6 -1.9 26.7 i 0.72 (13) 65.4 -1.4 26.2 i 1.05 hdministered twice daily for 4 consecutive days a t 12-hr intervals beginning 24 hr after tumor transplant,at,ioii. * Average weight change from onset to termination of drug treatment. percentage of mice surviving over 50 days. These were calculat,ed as 30-day survivors in determinat,iori of the average survival time; 10-15 animals were employed in each group. Q
tive, which caused a 14.5Yc loss in body weight at the daily dose of 120 mg/kg.6 It has been reported13 that the Na salt of the &OH derivative of I caused a greater prolongation of the survival time of mice bearing the L1210 lymphoma than did the parent derivative. Therefore, the Na salt of XI11 was synthesized and tested in the same system; the results are shown in Table 11. The parent compound I was also evaluated under these conditions. Untreated control tumor-bearing animals had an average survival time of 8.4 days. Compounds I and XI11 at a daily dose of 40 mg/kg increased the survival time to 16.6 and 13.4 days, respectively, whereas the l l a salt of XI11 caused a pronounced increase in the life-span of the tumor-bearing mice; with a maximum effective level (43.6 mg/kg per day) this soluble derivative (13) K. C . hgraival and A . C . Sartorelli, .I. Phnrm. Sei., 57, 1948 (1968).
c:tused it proloiigatiuri of survival time to 2 B . i days. Since little toxicity, tis nmtsurecl by lobs i11 lmdy weight. :ir c~ncountered,it would appear that the Na salt of XI11 has the higheqt therapeutic index observed t o datcl of the active compound;. iri the isoyuinoline series, and is tliercfore the prime cundidatc of thir series for rlinicnl cvnluntion for :ititiricopln~ticactivil y i r i man. Since thc S:t inlt 1~011ld 1)c c-qwted t o >iclcl XI11 o it i. tlificult to exphiit rc>:itlilv thc. rc4:itivcl\. high poic'ncy of' t h i i tlcriv:itivcs.
Experimental Section AIeltirig points were determined using n Thomas-Hoover r:ipillary melting point apparatus and are uncorrected. Elemental % w e performed by the Srhwarzkopf 3licr.o:irrnlytical T.al)olaloiy, LYoodside, N e w York. Nrnr spectra were ~)ei~foi~nietl O I L it Briiker IIFX-3 spec*ti,oineter oper:tti!ig at 90 LIHz. Chemical shifts (6) a r e given i n p n r s per million ilowifield froni 1'11s i n DYISO-ds ((1, tloiiblet : h, singlet: (id, doublet of doublets; et r . ) . 3I:i-s spec ti,:^ were obtained o n ail .\ssociated Electrical Iiidnslries (Mairrhester, England) &IS-9 niass spectrometer. 1500) were obtained at i 0 The low resoliitioii spectra (.I[ eV :ind 100 F.\ ionizing current, while the niiw measurement. n-ere obtained at 70 eV and 500 PA ionizing ciirrent and at, a11 inhtriinient resohition of 10,000. The xiiirce temperature varied hetwren 150 riiid 2 0 0 " . AI1 -:iinplcs v e r e int rodiiced via the c1ir.ec.t insertion probe. Biological Methods.-Compoiinds were t.ested for antineoplastic activity in mice bearing either Sarcoma 180 ascites cells or the L1210 lymphoma. Complete details of the biological methods have been described earlier.G Transplantation of t,he neoplasms w i s :tccomplished by inociilating mice intraperitoneally with approximately 4-8 x 106 ascites cells. Ilriigs were administered h y irit,raperitoneal injection heginniiig 24 hr later either as fine siihpensions or :is :t soliltion i n distilled € 1 2 0 ( S a salt of XIII); siich therapy was c~)iitiiiiiednnce daily for ci consecutive dags in the case of mice henririg Sarcoma 1Y0 writes cells. ;\[ice bearing the 1,1210 lymphoma were treated twice daily at 12-hr intervals f ~ i r4 ciiiiserritive days. Determination of the sensitivity of the iiirnors t o these agents $)-a3 based upon the pro1ongat)ion of siirviv:il time afforded hy the drug treatments. Chemical Methods. 1-Methylisoquinoline .V-Oxide (II).---The pi,oc.edureemployed by Robison antl Robisonsa for the fabrication of iwqiiinoline AT-oxide was utilized to prepare TI in 7 2 5 yield. Ilecrystallization (hexane) gave w h i t e needles, which after drying ((':K'I2j under v:i~~i1irni had a nip XS-89" ireportet1l5 82-83'): tinir :is exlwtetl. . 1 n d . (C1,J1gXOi C , 11, S ; lo-s in weight aftw dryiiig at X 0f u r 2 hi,, 1 .17'.;. Rearrangement of 11. ( A ) By Ac20.--Compouitd I1 (5.0 g i v w refiiixed in .iO nil of A c 2 0 f o r '2.3 hr. The ewes3 AcyO w i * I'(:liilJv('d try flash eV:ip(JI'LitiOfi; the resi~ltingdark oily residiip w t s theii tli-;tilled iiritler vaciiiim :ti 100--162" ( I mm) l o yield 4.7 g (7,?7(') of :t mist iirtl i i f ncartatr pale y(4low oil. This oil N
(14) Whf*re analyses are indicated only by symhols of the elements or fiinr~i(rns,[tie analytical results obtained for thme elements or function-: were within &O..lc/, of the theoretical values. ( l a 1 F:, .T. Morironi and F. A , Spano. J . Arnrr. ( : h e m . Soc.. 86, 38 (1SG1).
