Journal of Medicinal Chemistr?,, lY79, Vol. 22, N o . 1 99
Kojic A m i n e
number of mice which lost the reflex over 20 s. Rotating Rod Test. Groups of six mice were injected intraperitoneally with the test compounds. After 30 min the mice were placed for 1 min on a rotating rod (3.5 cm in diameter, 14 rpm). The EDso value was estimated from the number of mice which fell off the rod twice during the test. Maximal Electroshock Test. Groups of six mice were injected intraperitoneally with the test compounds. After 30 min the alternating current of 25 mA was delivered for 0.15 s through corneal electrodes. The EDjo value was estimated from the number of mice which were protected against the tonic extensor component of the hind limbs. Pentylenetetrazole Convulsions. Groups of six mice were injected intraperitoneally with the test compounds. After 30 min pentylenetetrazole was injected subcutaneously at a dose of 125 mg/kg. The EDa value was estimated from the number of mice which were protected against death due to tonic extensive convulsions within 1 h after administration of the convulsant.
Acknowledgment. T h e authors t h a n k Drs. I. Chibata, M. Miyoshi, Y. Kowa, a n d -4.Kiyomoto for their encouragement t h r o u g h o u t t h e present study. References and Notes (a) K. Okumura, T. Oine, Y. Yamada, G. Hayashi, and hl. Nakama, J . Med. Chem.. 11, 348 (1968); (b) K. Okumura, T. Oine, Y. Yamada, G. Hayashi, M.Nakama, and T. Nose. ibid., 11, 788 (1968); (c) K. Okumura, Y. Yamada. T. Oine, J. Tani. T. Ochiai, and I. Inoue, ibid., 15, ,518 (1972); ( d ) Y. Yamada, T. Oine, and I. Inoue, Chem. Pharm. Bull., 22
Kojic Amine-a
(3),601 (1974); (e) Hull. Chem. Soc. J p n . , 47, 339 (1974); (f) ibid., 47, 343 (1974).
(a) K. H. Boltze, H. D. Dell, H. Lehwald, D. Lorenz, and M. Ruberg-Schweer, Arzneim.-Forsch., 13, 688 (19633, and references cited therein; (b) S. S. Parmar, K. Kishor, P. K. Seth, and R. C. Arora, J . M e d . ('hem., 12, 138 (1969); (c) P. A. Petyunin and Yu. V. Kozhevnikov, Khim. Geterotsihi. Soedin., 415 (1967); (d) C. Saito, S. Sakai, Y. Yukawa, H. Yaniamoto, and H. Takagi, Arzneim.-Forsch., 19, 1945 (1969); (e) C. M. Gupta, A. P. Bhaduri, and N. M. Khanna, Indian J . Chem., 7,866 (1969); (fi H. Breuer and A. Roesch, Arzneim.-Forsch., 21, 258 (1971). T . Ochiai, R. Ishida. S.Nurimoto, I. Inoue. and Y . Kowa, J p n . J . Pharmacol., 22, 431 11972). I. R. Ager, D. R. Harrison, P. D. Kennewell, and .J. B. 'Taylor, J . Med. Chem., 20, 379 (1975). 1%'. J . Hickinbottom in "The Chemistry of Carbon Compounds", Vol. IIIA, E. H. Rodd, E d . , Elsevier, New York-Amsterdam, 1954, p 580. R. Graf and W. Langer, J . Praht. Chem., 143, 161 (1937). T. Kametani, T. Higa, C. V. LOC,M. Ihara, M. Koizumi, and K. Fukumoto, J . A m . Chem. Soc., 98, 6186 (1976). The displacement reaction was also attempted in diniethylformamide or dimethyl sulfoxide under varieties of conditions. However, the yield of the fluorinated product was poor. The direct comparison of 24 with its parent compound in the CNS depressant activity was not made. However, the higher activity of 24 is supportedly shown by the values reported in the ref 2a. (10) T. Ochiai, Y. Kudo, and R. Ishida, unpublished data.
Novel y-Aminobutyric Acid Analogue
J o s e p h G. Atkinson,* Yves Girard, J. Rokach.* C. S. €looney,* Medicinal Chemistry Department
C. S. M c F a r l a n e , A. R a c k h a m , a n d N. N. S h a r e * Pharmacology Department, Merck Frosst Laboratories, Pointe ClairelDorcal, Quebec, Canada H9R 4P8. Received Jul, 13, 1978 A series of compounds containing the 3-hydroxy-4H-pyran-4-one nucleus has been synthesized and tested as potential skeletal muscle relaxants. Reduction of 2-(azidomethyl)-5-hydroxy-4H-pyran-4-one (4) with HBr in HOAc- phenol (kojic amine, 3) in 8170 yield. Reaction of 2-1 (tosy1oxy)yielded 2-(aminomethyl)-5-hydroxy-4H-pyran-4-one methyl]-5-(benzyloxy)-4H-pyran-4-one ( 5 ) with NH, gave a 40% yield of the 0-benzyl ether of kojic amine, which
was N-acylated with a series of carbobenzyloxy-protected amino acids. Complete deprotection with HBr-HOAc gave the following amino acid amides of kojic amine: glycyl (23), a-alanyl (24), B-alanyl (25), *,-aminobutyryl (26), and glycylglycyl (27) Among the analogues of kojic amine prepared was a series of one-carbon homologues: 2-[(methylamino)methyl]-5-hydroxy-4H-pyran-4-one (7a), 2-(l-aminoethyl)-5-hydroxy-4H-pyran-4-one (a), 6(aminomethyl)-3-hydroxy-2-methyl-4~-pyraii-4-01ie (121, and 2-(2-aminoethyl)-5-hydroxy-4H-pgran-4-one (16). Kojic amine (3) has been found to possess certain of the properties to be expected in a 7-aminobutyric acid mimetic agent, notably skeletal muscle relaxant activity. In the chronic spinal cat preparation, EDio values for reduction of flexor spasms of 2.2 and 4.0 mg/kg by iv and PO routes of administration, respectively, were observed for kojic amine, which was the most potent of the various hydroxypyrone derivatives investigated. y-Aminobutyric acid (GABA, I ) is believed t o play a
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major role in vertebrates as a n inhibitory neurotransmitter, both at t h e brain a n d spinal levels.'S2 As GABA itself does
n o t cross t h e blood--brain barrier, there is considerable i n t e r e s t in t h e d e v e l o p m e n t of s y s t e m i c a l l y active GABA-mimetic agents. T h e s e a g e n t s m i g h t have t h e r a peutic utility in neurological disorders such as H u n t i n g don's ~ h o r e a schizophrenia,4 ,~ a n d epilepsy,5 as well as in analgesia6 a n d in t h e t r e a t m e n t of skeletal muscle spasticity. Muscimol (2), a p o t e n t , orally active, naturally occurring GABA-like agent, is toxic a n d has been reported t o cause hallucinations in man.7 T h e very recent reportX t h a t muscimol is a p o t e n t blood pressure lowering a g e n t when administered intracerebroventricularly indicates a possible involvement of GABA receptors in t h e central regulation of blood pressure. T h e structure of muscimol, which corresponds t o t h e e x t e n d e d conformation of
0022-26231'79 ~1822-O099SOl.OO/O G 1978 American Chemical Society
Scheme I
Scheme I1 n
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of' t h e azide (41, using palladium, also gave 3. In an alt e r ii a t ive r ( ) ut e. 5- ihenz y l o x y 1- 2 - [ ( p - t olue nesulfonyl-
7a. I: b. I
90% yield. T h e latter was converted by hydrogenation with Raney nickel catalyst in acetic a n h y d r i d e , followed by hydrolysis, t o 16. I n a n alternative a p p r o a c h , 5 when reacted with n i t r o m e t h a n e gave, unexpectedly, the hydroxynitroethane derivative 17." T h i s probably results from initial aldehyde formationI6 followed by condensation of t h e aldehyde a n d nitromethane. Compound 18, with the chain extended t o three carbons, was prepared by alkylation of ethyl cyanoacetate with 5, followed by hydrolysis, decarboxylation, a n d reduction. s y n t h e s e s of t h e pyridine analogues of kojic a m i n e , 19a a n d 19b, were carried o u t by a s t a n d a r d displacement of t h e ring oxygen with N H ? a n d CH,NH2. P r e p a r a t i o n s of derivatives 20a,b, 21, a n d 22 were uncomplicated a n d are described in t h e Experimental Section. T h e peptide-like derivatives of kojic amine, 23-27, were p r e p a r e d f r o m 2 - ( a m in o m e t h y 1) - 5 - ( b e n z y l oxy) - 4 H pyran-4-one using either t h e p - n i t r o p h e n y l ester or t h e e t h y l chloroformate procedure with t h e a p p r o p r i a t e Boc-protected a m i n o acid intermediate, followed by hydrolysis of t h e protecting groups.
Pharmacology. ( A ) Skeletal Muscle Relaxant Activity. Kojic a m i n e effectively reduced flexor spasms in chronic spinal rat a n d cat preparations. In the rat, 70%
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reduction of flexor spasms occurred after a cumulative dose (ED70) of 8 m g / k g iv of kojic amine. For muscimol, a similar reduction of flexor spasms was observed only after cumulative doses of 16 m g / k g iv, which were ultimately lethal. I n t h e cat, ED70for reduction of flexor spasms by kojic a m i n e was 2.2 m g / k g iv, whereas doses u p t o 7 . 5 m g / k g iv of muscimol were ineffective. An ED7,, of 4 m g / k g PO obtained for kojic a m i n e indicated good oral absorption in this preparation. B o t h t h e glycinamide derivative 23 a n d t h e alaninamide derivative 24 of kojic a m i n e h a d ED70 values of a b o u t 8 m g / k g iv in t h e rat model a n d a b o u t 12 m g / k g iv in t h e cat.
102
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(€3) Anticonvulsant Activity in Mice. Intraperitoneal injection (~f':i-mercaptopropioiiic acid has been shown t o elicit a rapid and dramatic decrease in hrain GARA levels immediately prior to the onset of tonic extensor seizures.'' Oral doses required t o prevent t h e induction of tonic extensor seizures in e-holldC - H coupling constant parallel those reported h y Horsley and Sternlicht"' in a s t u d y of a series of amino acids and indicate clearly that the nitrogen is not protonated in >le?SO or aqueous SIe,SO solution. 'The esseiitially un-ionized character of kojic amine in solution may t h u s he a contrihuting factor t o its ready penetration to the ('SS. T h e very narrow structureeactivity picture in whole a n i m a l t e s t s is p e r h a p s not surprising in retrospect. Kruysgaard-Larsen and co-workers')] have reported in vitro a n d microelectrophoretic studies of a series of muscimol analogues. arid a relatively narrow structureeactivity relatiunship is seen in these much simpler biological systems. Koiic, a m i n e h a s been shown t o be a potent a n d specific inhibitor of sodium-independeiit ["HIGABA binding to rat brain niemliranes.2' and iontophoretic applications of kojic a rn in e ca II sed a pronounced . bi cu cull ine sen s i t ive . i 11hihit ion of t h e firing of spontaneously active cerebral cort i d aiid cerehellar Purkinje cells in anesthetized rats.'.'
Atkinson et a l .
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Kojic Amine T h u s , kojic a m i n e constitutes a novel s t r u c t u r e possessing m a n y of t h e properties, both in vivo a n d in vitro, t o be expected of a GABA-like compound. S t u d y of its properties a n d applications are continuing.
Experimental Section Melting points were determined using a Thomas-Hoover melting-point apparatus and are uncorrected. 'H NMR 60-MHz spectra were recorded with a Varian Associates EM-360 instrument. Chemical shifts were recorded in parts per million (6) relative to Me4Si as an internal standard. 13C NMR spectra were obtained on a Varian CFT-20 spectrometer, and the chemical shifts are reported relative t o internal Me4Si. IR spectra were determined on a Perkin-Elmer 257 spectrophotometer. Mass spectral analyses were provided by Morgan-Schaffer Corp., Montreal, and elemental analyses by Dr. C. Daessle, Montreal. T h e 13C NMR and pK, determinations were performed by Mr. S. C. Ho and associates at Merck Frosst Laboratories. 2-(Aminomethyl)-5-hydroxy-4H-pyran-4-one(Kojic Amine, 3). Method A. A mixture of 2-(azidomethyl)-5hydroxy-4H-pyran-4-one (4)13 (143 g, 0.86 mol), mp 128-130 "C, and phenol (72 g) was dissolved in 700 mL of HOAc. The solution was cooled in an ice bath and saturated with HBr gas. The mixture, after being stirred for 3.5 h, was cooled with ice and filtered. T h e solid was washed with a small quantity of HOAc and then freely with T H F and then Et,O. Crude 3a (287 g) was obtained: mp 206-207 "C; 'H NMR (MepSO-d& b 4.2 (2 H , quartet, CHz, collapses to a singlet on D 2 0 exchange, JCH2-NH3+ = 5 Hz), 6.68 (1 H, s. H:J, 8.22 (1 H, s, H6),8.72 (3 H , br, +NH3), 9.45 (2 H, s, 20H). Anal. Calcd for C6H9Br2N03:C, 23.78; H , 2.99; N, 4.62; Br, 52.76. Found: C, 24.80; H, 3.44; N,5.58; Br, 49.54. 3a (287 g) was dissolved in MeOH (1500 mL), and T H F (1000 mL) was added. The solution was concentrated to 500 mL, and 1000 mL of T H F was added. On filtration, 3-HBr (154 g, 81 % ) was obtained: mp 220-222 "C; 'H NMR (Me$O-d6) d 4.10 (2 H, s, CHJ, 6.68 (1 H , s, H3),8.22 (1 H , s, H6),8.65 ( 4 H , hr s, OH and NH3+). Anal. (C6HBBrN03)C, H , Br, N. Metathesis using Amherlite AG 1-X8 resin (C1- cycle) gave 3.HC1: mp 24&245 "C; 'H NMR (Me2SO-d6)6 4.02 (2 H, s, CH2), 6.65 (1 H , s, HJ, 8.12 (1 H, s, H6),9.10 (4H, hr s, OH and +NH3). Anal. (C6HBC1N03)C, H , C1, N. An aqueous solution of kojic amine hydrobromide was passed through a column of AG 50W-X8 resin (acid cycle) and eluted Upon concentration of the eluate, free kojic with 1 N ",OH. amine (3) crystallized from the aqueous solution: mp 181 "C dec; 'H NMR (Me2SO-d6)6 3.57 ( 2 H , s, CH,), 5.58 (3 H, br s, OH and NHJ, 6.43 (1 H, s, H3),8.02 (1 H, s, H6);IR (KBr) 3200-2150 (hr, OH-",), 1630, 1595, 1560 cm-' (strong, C=O, C=C). Anal. (CeH;NO,) C, H , N. The 13C NMR spectral data of 3 and 3.HC1 are collected in Table I, along with the published dataz4for kojic acid. Method B. Into a refluxing solution of 5 (500 g, 1.26 mol) in CHCI, (5.5 L-MeOH (3.5 L ) was passed NH3 gas for 9 h. The solvent was evaporated and the residue slurried with CHC1, (1.5 L) and filtered to give 240 g of a mixture of salts. These solids were dissolved in H 2 0 (1.0 L), and the solution was made basic with K 2 C 0 3and then extracted with CHCI3. The CHC13 extract on evaporation gave 2-(aminomethyl)-5-(benzyloxy)-4H-pyran4-one (27.6 g). The CHC13 solution from the initial slurry was shaken with 1 N HC1 (1.5 L) and the salt which formed filtered (80 g). The solid was partitioned between CHC1, and aqueous K2C03solution. The CHC1, solution on evaporation afforded bis[5-(benzyloxy)-4-oxo-4H-pyran-2-yl]methylamine, mp 163-165 "C (60 g). Anal. (C.LOH23NO6) C, H , N. The aqueous HC1 phase, which was made basic with aqueous K2C03and extracted with CHCl,, provided an additional 79 g of 2-(aminomethyl)-5-(henzyloxy)-4H-pyran-4-one (total yield 106.6 g, 38%), mp 84.5-86.5 "C. Anal. (C13H,,N03) C, H, N. A solution of 2-(aminomethyl)-5-(benzyloxy)-4H-pyran-4-one (8.9 g, 0.038 mol) in HOAc (200 mL) was made strongly acidic with anhydrous HBr and then heated at 100 "C for 20 min. On cooling there was obtained 3a. Recrystallization from MeOHT H F gave 3.HBr. A similar HBr-HOAc treatment of the crude his[j-(benzyloxy)-4-oxo-4H-pyran-2-yl]methylamine gave 6.HBr: mp 270-275
Journal of Medicinal Chemistry, 1979, Vol. 22, No. 1
103
"C dec; 'H NMR (MezSO-d6)6 4.36 (4H, S, 2CHz), 6.77 (2 H, s, 2H3),6.5-8.0 (4 H, br s, 2 0 H and +NH2),8.27 (2 H , s, 2H6). Anal.
(CI2Hl2BrNO6) C, H , Br, N. 5-Hydroxy-2-[(methy1amino)methyl1-4H-pyran-4-one (7a). The procedure of method B, when repeated using methylamine in place of NH,, gave 7a.HBr.H20: mp 187-188 "C; 'H NMR (Me2SO-d6)b 2.65 (3 H, s, CH,,),4.26 (2 H, s, CHz), 6.73 (1 H , s, H3), 8.27 (1 H, s, H6), 9.42 (3 H, hr s, OH and 'NHJ. Anal. (C7H12BrN04)C, H, Br, N. 2-[ (Benzylamino)methyl]-5-hydroxy-4H-pyran-4-one (7b). When benzylamine was substituted for methylamine in the above procedure, 7b.HBr was obtained: mp 270-273 "C; 'H NMR (Me2SO-d6)6 4.22 and 4.66 (4 H, 2 s, CH2NHz+CH2Ph),6.66 (1 H, S, HJ, 7.25-7.70 (5 H, m, CsHj), 8.21 (1 H , S, He), 8.0-10.0 (3 H, br s. OH and NH2+). Anal. (C13H14BrN03)C, H , Br, N. D L - ~ - l-Aminoethyl)-5-hydroxy-4H-pyran-4-one ( (8). T o a suspension of 5-(benzy10xy)-4-oxo-4H-pyran-2-carhoxa1dehyde1' (35 g, 0.152 mol) in T H F (1.0 L) was added in portions a 1.5 M solution of MeMgI (80 mL, 0.12 mol). After the mixture was agitated for 0.5 h, H,O (200 mL) was added t o decompose the complex. Following evaporation, the residue was extracted with CH2CI2(3 x 200 mL). The extract was concentrated and the residue reextracted with EtOAc and with CHC1,. The oil (20 g) obtained on evaporation of the combined extracts was chromatographed (silica gel, EtOAc-C6H6, 1:l) to give as an oil (5.5 g, 14.7%) 2-(l-hydroxyethy1)-5-(henzyloxy)-4H-pyran-4-one. A mixture of this intermediate (5.0 g, 0.02 mol) and Na2Cr207(5.0 g, 0.02 mol) in HOAc (50 mL) was heated for 10 min a t 100 "C. Ice was added and the mixture extracted with CHCI,. The CHCl, extract, after washing with H 2 0 and drying over MgSO,, was evaporated to yield 4.0 g (80%) of 2-acetyl-5-(benzyloxy)-4Hpyran-4-one, mp 145-147 "C. Anal. (Cl4HI2O4)C, H. A mixture of this intermediate (3.8 g, 0.015 mol). NH20H.HC1 (6.0 g, 0.086 mol), and N-ethylpiperidine (9.0 g) in MeOH (60 mL) was stirred for 2 h. Addition of ice, followed by filtration, gave 2.3 g (5970)of solid oxime, mp 220-221 "C, which was not further purified. A mixture of oxime (2:l g, 0.008 mol), Zn (2.1 g ) , and HOAc was stirred for 6 h. .4fter filtration of inorganic solids and evaporation of the filtrate, the residue was slurried with EtzO to give 2.46 g of solid amine acetate. T o the solid was added 4870 HBr (80 mL), and the mixture was heated at 110-120 "C for 0.25 h. The cooled solution was extracted with E t 2 0 . The aqueous portion was evaporated to an oil which was dissolved in H 2 0 and passed through a resin column (AG 50W-X8, acid cycle). The residue from evaporation of the eluate was recrystallized from EtOH to give 8 (0.52 g, 42%): mp 170-174 OC; 'H NMR (Me2SO-d6)6 1.24 (3 H, d, CH3, LI,-H~cH = 7 Hz), 3.78 (1 H, quartet, CH, J C H C H 3 = 7 Hz), 4.12 (3 H, hr s, OH and NH,), 6.47 (1 H , s, H3), 8.07 (1 H, s, H6). Anal. (C7HgN0,)C, H, N. 2-(Aminomethyl)-3-hydroxy-4H-pyran-4-one (9a). A (2.6 g, mixture of 2-(chloromethyl)-3-hydroxy-4H-pyran-4-onez5 0.016 mol) and NaN, (1.1g, 0.016 mol) in DMF (30 mL) was stirred for 18 h at 20 OC. Following filtration and evaporation of the filtrate, the residue was extracted with CHC1,. On evaporation there was obtained a roughly 1:l mixture of 10a and 2-(azidomethyl)-3-hydroxy-4H-pyran-4-one, as shown by NMR, TLC, and mass spectral evidence. This mixture (0.88 g) in HOAc (20 mL) was saturated with gaseous HBr with ice cooling. After 2 h, 9a.HBr was filtered (0.52 g, 14.6%): mp 208--210 "c dec; 'H NMR (Me2SO-d6)b 4.06 (2 H, br S, CHJ, 6.45 (1 H , d, Hg, JH;H~ = 6 Hz), 8.20 (1 H , d, H6, J H ~ - H=~ 6 Hz), 8.50 (4 H , br s, OH and +NH3). Anal. (C6HBBrNOJ C, H , Br, N. 2-(Aminomethyl)-3-hydroxy-6-met hyl-JH-pyran-4-one (9b). When the previous procedure was repeated starting from 2-(hydroxymethyl)-3-hydroxy-6-methyl-4H-pyran-4-one, 9b.HBr was obtained in 27% overall yield: mp 270-275 "C dec; 'H NMR (Me2SO-d6)6 2.32 (3 H, s, CH3),4.10 (2 H, hr s. CH,), 6.40 (1 H , s, H5), 8.5 (4 H, hr s, OH and +NH3). Anal. (C,H10BrN03)C, H, Br, N. In the azide-forming step, the byproduct lobz6was obtained: mp 179-181 "C; 'H NMR (MezSo-d6) 6 2.03 and 2.30 (6 H, 2 s, 2CH3),3.17 (2 H , hr s, -CH2-), 3.43 and 4.15 (2 H , dd, -CH2N3, Jgem = 14 Hz), 5.70 and 6.30 (2 H, 2 s, 2H5),8.53 (1 H , s, OH); IR (KBr) 2100 (strong, NJ, 1695, 1670, 1650-1620 cm-' (strong, C=O and C=C); MS (M+ 319). Anal. Calcd f o r C14Hi3N306:
104 Journal of Mcdicinnl C'hcmistry 1979. L ' d 22, No. I
Athinson et al.
C, 52.66; H, 4.10; N, 13.16. Found: C, 52.51; H, 4.57; N, 12.89. identical with an authentic sample." 6-(Aminomethyl)-2-bromo-3-hydroxy-4H-pyran-4-one (1 I). 3-(5-Hydroxy-4-oxo-4H-pyran-2-yl)propylamine (18). A mixture containing 4 (10 g, 0.06 mol) and N-bromosuccinimide Tosylate 5 (40 g, 0.104 mol) was added to a mixture of the po(12 g, 0.067 mol) in benzene (150 mL) was refluxed for 1 h. After tassium salt of ethyl cyanoacetate [prepared from ethyl cyanfiltration (while hot) and evaporation, 13 g ( 8 8 7 ~of) &(azidooacetate (80 g, 0.71 mol) and potassium tert-butoxide (80 g, 0.71 methyl)-2-bromo-3-hydroxy-4H-pyran-4-01ie was obtained, mp mol)] in DMF (2.8 L). After being stirred for 2-3 min, the mixture 112-114 "C. ,4nal. (C6H,BrN,03) C . H , Rr. N. was poured into ice-H20. Extraction with CHCl:, afforded an oil which was chromatographed (silica gel, CsH6and then EtOAc) A mixture of this azide (5 g, 0.02 moli and phenol (2.5 g ) in to give ethyl 2-cyano-3-[5-(benzyloxy)-4-oxo-4H-pyran-2-yl]HOAc (35 mLi was saturated with HBr with ice cooling. After propionate, mp 65-67 " C (18 g. 53%). Anal. (CI8HliNO5)C. H, standing overnight, the solids were filtered (5.6 g) and dissolved N. in MeOH, and the MeOH solution was evaporated to a small volume to give 3.7 g of 11.HBr (61.5%): mp 300 "C: 'H NMR Dialkylation occurred to a significant extent if a smaller ratio (MepSO-d,) 6 4.15 ( 2 H. s, CH,), 6.73 ( 1 H. s, H:), 8.95 ( 4 H. h r of ethyl cyanoacetate was used in this reaction. s, OH and +NH3). Anal. (CfiHiBr2N0,1iC, H, Rr. N. A mixture ( ~ tethyl 2 - c y a n o - ~ i - [ ~ - ( t ~ e n z ? . l o x v ) - - l - o x t ~ - ~ H 6-(Aminomethyl)-3-hydroxy-2-methyl-?H-pyran-4-one (12). pyran-2-ylIpropionate (12.0 g. 0.037 molJ and KOH (2.06 g, 0.036 12.HBr, mp 241-242 "C. was prepared i n 48% overall yield by mol) in MeOH (SO mL) was stirred for 7 days. Evaporation to method B starting from 6 - ( h y d r o x y m e t h y l ) - : i - h ~ ~ d r o x y - ~ - dryness, followed by trituration with Et,O. gave the potassium rneth~l-4H-pyran-4-one:~" 'H NMR (Me2SO-dfi) 6 2.30 ( 3 H. s, salt which was dissolved in H 2 0 and converted t o the insoluhle CHJ, 4.10 ( 2 H , s. CH2i. 6.63 ( 1 H. s. H 5 ) ,8.77 (-1 H. hr s. OH l'ree acid (8.3g. 75% 1, mp 132 1:35 "C. by acidification ivith dilute and +",I. Anal. (C;HloBrN03)C, H, Br, N. C. H. N. HC'1. Anal. iClfiHIC3NO5~0.5H2O) Heating 8.3 g (0.028 mol) of the above acid at 140-145 "C under 2-(2-Aminoethyl)-5-hydroxy-4H-pyran-?-one (16). A vacuum until C 0 2 evolution ceased (2 h), followed by dissolution mixture of 5 (78 g, 0.2 mol) and NaCN 19.8 g. 0.2 mol) in DMF in CHC13,and decolorization with charcoal, gave a solid residue. (300 mL) was allowed to react at 0 "C for I h and then quenched Trituration with E t 2 0 left 4.8 g (67.2%) of 3-[5-(benzyloxy)with ice. The red gum which formed after washing with H 2 0was 4-oxo-4H-pyran-2-yl]propionitrile. A mixture of the nitrile (1.76 triturated with MeOH. On filtration the trisubstituted acetonitrile g, 0.067 mol) in Ac10 (150 mL) with Raney nickel catalyst (0.5 derivative 14b (15 g) was obtained and was recrystallized from gl was hydrogenated in a Parr low-pressure hydrogenator for 1.5 i-PrOH: mp 204-205 "C; 'H NMR (Me2SO-dfi)6 3.60 ( 4 H, hr h. After filtration and evaporation to dryness. the residue was S, 2-CH2-)%5.00 (4 H , S. Z-CHpPh), 5.08 ( 2 H dissolved in toluene and reevaporated to give 1.5 g (7170 of crude ( 2 H. s, 2H,j),6.6*5(1 H. s. H3),7.50 (15 H. s, acetylated amine. s! 2H6), 8.42 (1 H, s, Hsi; IR iKBr) 1650 cm iC=Oi: MS ( A I + The crude amide in concentrated HC1 (60 mL) was heated a t 669). Anal. Calcd for CIOH3,N09: C . 71.74: H. 4.67: K,2.09. 130 "C for 5 h to effect hydrolysis. After evaporation, the residue Found: C, 71.52; H. 4.81; N, 2.02. was neutralized with dilute ",OH, and the solution was passed Fractions, obtained by evaporation of the MeOH filtrate and through a column of Amberlite 50W-X8 resin. The eluate was CHCI3extraction of the initial aqueous phase and washings, were evaporated and the residue slurried with H 2 0 and filtered to give combined and chromatographed [silica gel. EtOAc--CfiH,(1:10. 0.2,5 g (1970 of 18.H20: mp 143-145 "C; 'H NMR (Me2SO-ds) 1:4), and then i-PrOH-EtOAc i1:10)] to give 6 g of' recovered Fi 1.70 ( 2 H , quintet. ~CH,CH2CH2NH2), 2.58 ( 4 H , m, starting tosylate, 2.83 g of [~5-(benzyloxy)-4-oxo-?H-pyran-2CH2CH,CH,NHl),4.87 (3 H, s, OH and NH2),6.23(1H , s, H3), yllacetonitrile (15) [mp 150-151 "C; 'H NMR (CDC1.I)d 3.68 ( 2 7.97 (1 H, s. H6). Anal. (CBHI3NO4) C: H, N. H, s, CH2CN).5.15 ( 2 H. s. CH,Ph), 6.57 (1 H, s , H.J, 7.50 (5 H. 2-(Aminomethyl)-5-hydroxy-4( 1 H ) - p y r i d i n o n e (19a). s, CsH& 7.67 (1 H, s, HJ: MS ihI+ 241): IR (KBr)2260 cm (weak. 2-(Aminomethyl)-5-(benzyloxy)-4H-pyran-4-one (5 g, 0.022 mol) CN). 1650-1620 cm ' (s, C=O and C=Ci. Anal. Calcd for in .4c20 (100 mL) was heated on a steam bath for 20 min. The Cl4Hl1NO3:C, 69.70; H. 4.59: N. 5.80. Found: C, 69.78; H, 4.14: residue from evaporation was slurried with Eta0 and filtered to N,5.791, and, finally, 3.13 g of disubstituted acetonitrile derivative give 5.8g (96.570).mp 137-139 "C, of the N-acetyl derivative. i, 14a [mp 164-166 "C: 'H NMR (Me2SO-d,) ii 3.40 (2 H, m. --CH2Anal. tCI;,Hl5NO4iC, H. N. 5.00 (5 H, br s. 2-CH2Phand -CH-), 6.53 and 6.62 ( 2 H. 2 s, 2H,). .A mixture of this intermediate ( 5 g, 0.018 mol), concentrated 7.50 (10 H, s, 2C6H,), 8.30 and 8.42 (2 H. 2 s. 2Hfi);IR (KBr) 1650 ",OH (200 mL), and dioxane (75 mL) was heated to reflux for cm-' (C=O): MS (M+455). .4nal. Calcd for C2;H2,N06:C . 71.20: 8 h with continuous passage of ammonia gas. Following evapH , 4.65; N, 3.08. Found: C . 70.99; H. 4.60: N, 2.92.1. oration, the residue was slurried with hot EtOAc (50 mL) to The intermediate 15 (1.9 g. 0.008 mol) in A c 2 0 (250 mL) remove traces of starting material and filtered to yield 4.67 g (93%) containing 1.0 g of Raney nickel was hydrogenated in a Parr ( ~ f2-(acetamidomethyl)-S-(benzyloxyj-4(lH)-pyridinone, mp low-pressure apparatus for 2 h. Filtration and evaporation gave 217-220 " C . Anal. (C1:,HI6N2O3) C. H , N. an oil (2.1 g) which by NMR was a mixture of 2-(2-acetamidoA mixture of this intermediate (1.5 g, 5 . j moli in 48% HBr (120 ethy1)-5-acetoxy-4H-pyran-i-one and 2-1'-acetamidoethyl)-nmI,)\vas refluxed for 3 h. 'The reaction mixture was evaporated (benzyloxy)-4H-pyran-4-one.The oil (2.1 p i in 20% HC1 1150 mL) and the residue taken up in 100 mL of H20.treated with charcoal, was refluxed for 2 h. After evaporation. addition of i-PrOH and filtered, and evaporated. The oily residue was slurried with 50 reevaporation were repeated several times to give 16.HC1 (0.8:1 mL of THF?which gave a crystalline solid. Filtration yielded 1.11 g, 5570): mp 207-209 "C dec; 'H NMR (Me2SO-dfi) 6 3.05 ( 4 H. g (65% of 19a as the dihydrobromide hydrate: mp 220 -225 "C br s, CH2CH2i.6.40 (1 H. s, Ha).8.13( 1 H. s. H 6 ) ,8.15 (-1 H, h r dec: 'H NhIR (Me2SO-d,)6 4.30 ( 2 H , s. CH2),7.30 (1 H , s, HJ, s, OH and Anal. (CiH,,lCINO:I)C. H. CI. N. 8.26 (1 H, s, He). 9.60 (6 H, br s. 20H. 'SH and 'NH,). Anal. By addition of tosylate 5 to a 30-fold excess of a 1.:3,5hl SaCN rCtiH,,Br,N,0:3i C, H , Br. N. solution in HMPT, the desired acetonitrile derivative 15 was l-Methyl-2-(aminomethyl)-5-hydroxy-4( 1H)-pyridinone obtained in >90% yield. containing only traces of the dialkylated (19b). When the preceding procedure was followed using aqueous compound 14a. 2-(l-Hydroxy-2-nitroethyl)-5-(benzyloxy)-4~-pyran-4-one methylamine instead of ammonia, there was obtained a mixture o f mono- and dihydrobromide salts. Heating at 180 "C under (17). To 15 mL of nitromethane stirred at 20 "C was added i n vacuum for 18 h converted the mixture cleanly to the monoportions 3 g (0.125 mol) of KaH (caution: the sodium salt of hydrobromide of 19b, mp 264-267 "C dec; which still retained nitromethane can decompose violently). After reaction was H,O of hydration: 'H NMR (Me2SO-d6)b 3.75 ( 3 H, s, CH3), 4.18 complete, the white paste was diluted with 200 mL of HMPT and ( 2 H. s, CH21, 5.65 ( 4 H , hr s. OH and +NH3),6.46 (1 H. s, H3), cooled in an ice bath, and 40 g (0.1 mol) of tosylate t5 was added. 7.67 ( 1 H, s. H6). Anal. (C,H,,BrNlO4) C, H , Br, N. After 2 h of stirring, the reaction was complete (TLCi and was 2-[ (5-Hydroxy-4-oxo-4H-pyran-2-yl)methylthio]ethyldiluted with 1200 mL of H,O. Extraction with 1:l EtlO-EtOAc. amine (20a). TO50 mI, of 2 N NaOH was added 11.3 g (0.1 mol) drying, and evaporation left 20 g \'o.
1
Notes
responses was determined. In 90-100% of Robidoux Swiss male mice weighing 1 8 ~ 2 g, 2 intraperitoneal injections of 25 mg/kg of :~-mercaptoprol,ic,nic. acid induced t o n i c extensor seizures within 3 7 min. Test substances were dissolved in saline and administered by the oral route 30 min prior to injection of the convulsant agent. The dose required to prevent tonic extensor seizures in 507c of the animals (ED,,)was calculated using regression analysis and tiased u p ( m at least three doses with ten mice per level.
References and Notes C . F. Baxter, Haridh. .Vrlcirocheni.. 3. 289 E. E. Roberts, T. N.Chase. and I). €3. Towe
H. G . Christensen and R. It:. Katcliffe of the Merck Sharp & I h h m e Research Laboratories, Rahway, N.J. 1 I c 5 , .A. F. Thomas. J . C'heni. Soc.. 439 (1962). (16) N.Komblum and 1'. Pink, Trltrahc>dron.19, Suppl. 1. 17 22 (1963i. ( 1 7 1 A Iiarlsson. F. Fonnum. 11. Malthe-S$renseii. and .J. 18) Private comniunication from 13.
t
19)
(20)
in Nervous System Function". Raven Press. New l'ork. N , l ' , , 1976. S. .J. Enna. E. D. Bird, .J. P. Bennett. -Jr., I). €3. Hyluiid. H . I. Yamamura. I,. I,. Iverson. and S . H. Snyder, .V, Eric/, .I ,bled., 294. 1305 il976). E. E. Roberts, Z;cDciro.\c,i. Kc.\. Progruni, H ~ t i i . .I O ( 4 ) . 468 (1972). P.,J. Schechter. l'.'I'ranier. % ,J, I .Tung. . and A , Sjoerdima. J . I'har.1nrJc.ol. E'sp. Thv r... 201. 606 (1977i, D. .A. Cutting and C. ('. ,Jordan. Rr. J . P / I O ~ T ~ U U3-1. J /171 ., (19751. S..J, Emia. quoted in C'hc'ni. E n p . .\(,tc\, 35. 1 7 I.Jutir 1:i.
Storm-Methison. Hiochcm. Pharmacol.. 23, 3053 (1974). Y.Clineschmidt, hlerck Institute for Therapeutic Research. West Point, Pa. F.Eiden and cJ. Pluckham. .4rch. F'harm. i Wcitihcirn. c;tir.), 302. 622 119691. \V..J. Horsley and H. Sternlicht. J . Am. C'hem. Soc.. 90, 3738 (1968,. P Krogsgaard-Iaseii and G. A. R. Johnston. J . .'Veurochem., 2.5, 797 (1975): P. Krogsgaard-Larsen, G. .A. R. Johnston, D.K. Curtis. C. CT. A . Game, and R . M. McCulloch, ihid., 25, 80.3 (1975). I-nput)lished results with 12. I,. Hudgin. Private communication from (>. G. Yarhrough, Merck Sharp & Dohnie Research Laboratories, \Vest Point. 1%. C'. A. Iiiiigsbury. hl. Cliffton. and .J. H. 1,ooker. .J. Orj:. ('hen!., 41. 2777 tI9761, Belgian Patent ti25 114 t o Chas. Pfizer and c'o.: ('hrni.
t
(21
t22i
("3 i 1241) i2.i)
d h t r . . G O . 1065lq (19641. Note Added in Proof': suhseyuent examination i)f the ','C' S\IK >pectrum of 10b i i i ;21e2SO-d,, indicates that. i n 51)lution at leasr. i t actually exists in the hemiketal f o r m , i. f'i,rhumalily loa also exist.; a i thi- cyclized structure.
i "ii
19711.
M. .J. ..\ntonaccio and D.(i. Tayliir. Eu r . J . 1%orn?u(r j t ! . . 46. ' 8 1 (19771, P.Krogsgaard-Larsen. (;. '4. R..Johnhton, I). 1,iidge. a n d I ) . R. Curtis. ,Vattire ( L o n d o n ) .268. .i;C I 1977). P. Krogsgaard-Larsen and G. A. R. .J(ihnstcin../.. \ P U ~ I J ~ / I ~ ~ ~ - I I . . 25, 197 (1975). H. iV. R. \Villiams. ('an.J . ('hi,ni.. 5 Li'. H. Dekker, Recl. Tmi,. ('him, I'n?,\ .J. .A. Durden..Jr.. H. A. Stansbury. nnd \{', H. Catlrrtr. ./. Cht'nl. Elli(. I j U t C i . 9. 8 ' 2 (1964J. The details ofthis procedure were kindly provided l)y I ~ s .
- .-. _* 1
~
,,
10b
SI) deduction concerning the stereochemistry could tie made. I)ut only one isomer is present. as judged from the spectrum.
Notes Synthesis and Evaluation for Diuretic Activity of 1-Substituted 6-Chloro-5-sulfamylindolines E d w a r d .J. Glamkowski* a n d Philip A. Eieitano Chemical Rcwarcii D e p a r t m o i t , H o c ~ c ~ l i . ~ t - l ~ Ii' ~h aur.r~n ,u~w~i i~t ii ai,,, Iric
,.
,Siini(jr!,il/(c
.\'(I!(
./(
The synthesis of a series of' 1-substituted i i - c h l ~ i r ~ ~ - ~ - s ~ i l t a ~ r ~ yisl itirsi~rihetl. n t i ~ ~ l i n e 111 ~ I he 1,ipschitz test for diuretic activity. two of the compounds showed significant excretion ( i f urine mid yodiuiii and \yere apprcixiniately equivalent in potency t o chlorothiazide hut with a Inter onset i ) f ' actir-it!
Furosemide is a potent, high-ceiling diuretic, one of the most widely used in medicine today. We thought it noulcl be of interest to synthesize and evaluate for diuretic a('tivity a series of 1-substituted 6-chloro-S-sulfam~lin~~1linei (7-9) which can be regarded as nonacidic ring-cloird
One of t h e more promising indolines with diuretic properties denionstrated in clinical trials is indapamide.? As p a r t of this present work on 1-substituted Ci-chloro~-sulfamylindolines.an analogue, 12. structurally related t o indapamide was also synthesized and tested.
H21u02swco2h CH2 R
furosemide
7-9 C3zNri2
analogues of furosemide. Recent reports of' indolines'.' anti isoindolines3 with diuretic activity lent encwura,
