Journal of Medicinal Chemistry, 1971, Vol. 14, No. 6 557
NEWCOMPOUNDS 340 mg (59%); mp 238-240'; [ a ] l D D +41.5' (C 1, DMF); lit.4 (L isomer) mp 239-240"; [ c x ] " ~-42" (c 1, DMF). Procedure B.-Octapeptide. HBr, obtained in a run identical with the one described in procedure A, was dissolved in 60 ml of MeOH and treated with 100 mg of imidazole. The resulting soln was evapd to a solid residue which was dried over PZOS under vacuum. The dry residue was dissolved in 2 ml of D M F and condensed with p-nitrophenyl S-benzyl-p-mercaptopropionate as described in procedure A: yield 485 mg (84y0); mp 241243"; [CZ]'~D+41.6" ( C 1, DMF). Anal. (CmH?s"i012S2) C, H , N. Deamino-o-oxytocin.-The debenzylation of 200 mg of amide I was performed with Na in 400 ml of liq NH3 freshly distd from Na.5 The soln was concd, and the last 30 ml of liq NH3 was lyophilized. The residual white powder was dissolved in 150 ml of 0.257, AcOH, the pH was adjusted to 6.8 with 1 N ",OH, and the resulting clear soln was titrated with 0.011 M KaFe(CN)s until a yellow color began to appear (27 ml). Then excess ferricyanide (8 ml) was added. After 30 min the soln gave a negative Ellman test, and it was passed through a column of AG3-X4 (Cl-). The soln of the crude product thus obtained was divided into 2 equal portions, each of which was purified by a different method. One half of the soln was concd to 15 ml and subjected to countercurrent distribution in the solvent system n-BuOHn-PrOH-0.5% AcOH contg 0.1% pyridine (6: 1:8). After 200 transfers a main peak ( K = 4.4) was obtained, as detd by measurement of the Folin-Lowry color values.14 The contents of tubes 155-170 were combined, concd, and lyophilized to yield 25 mg of a white fluffy powder. A sample was hydrolyzed in 6 (14) 0. H. Lomry, N. J. Rosebrough, A . L. Farr, a n d R . J. Randall, J . B i d . C h e m . , 193, 265 (1951).
N HC1 a t 120' for 20 hr for amino acid analysisI15and the following molar r:ttios were found, with the value of Gly taken as 1.0: Gly, 1.0; Leu, 1.0; Pro, 1.0; Asp, 1.0; Glu, 1.1; Ile, 0.93; aIle, 0.07; Tyr, 1.0; Cys, 0.24; the mixed disulfide of cysteine and p-mercaptopropionic acid, 0.67; "3, 2.9. The other half of the crude soln of deamino-D-oxytocin was concd to a low vol and purified by partition chromatography by the method of Yamashiro.8 A Sephadex G-25 column (2.15 x 113 cm) was Pmployed with the solvent system n -BuOH-C6H63.570 AcOH contg 1.5% pyridine (1:1:2). Elution with the upper phase was performed a t a rate of 30 ml/hr. The FolinLowry color values showed a main peak with Rr 0.19. The correspg value for deamino-L-oxytocin is 0.19.l1 Fractions correspg to the main peak were combined, concd, and lyophilized: yield 37 mg of white fluffy powder; [ ~ ] W D +104' ( c 0.5, 1 N AcOH); lit.4 (amorphous L isomer) [ a I z 1-107' ~ (c 0.5, 1 N AcOH). A sample of deamino-D-oxytocin was hydrolyzed in 6 N HC1 a t 120" for 20 hr for amino acid analysis. The following molar ratios were obtd, with the value of Gly taken as 1.0: Gly, 1.0; Leu, 1.0; Pro, 1.0; Asp, 1.0; Glu, 1.0; Ile, 1.0; aIle, 0.02; Tyr, 1.0; Cys, 0.34; the mixed disulfide of cysteine and p-mercaptopropionic acid, 0.62; "3, 2.9. Anal. (C13HGNIIOIZSZ) C, H , N.
Acknowledgments.-The authors wish to thank the following people for their assistance : Mr. Joseph Albert for the elementary microanalyses, Mr. Roger Sebane for the amino acid analyses, and Dr. W. Y. Chan, under whose direction the biological assays were performed. (15) (1958).
D. H. Spackman, W. H. Stein, and 9. Moore, Anal. Chem., SO, 1190
New Compounds a-Bromo- and a-Chloropyridylalanines' P. TIMOTHY SULLIVAX A N D
s. J. NORTON*
Department of Chemistry, Xorth Texas State University, Denton, Texas 76103 Receieed January 7 , 1971
Phenylalanine analogs have exhibited biological activity in certain mammalian phenylalanine, tryptophan, and tyrosine hydroxylase system^.^-^ p-Chlorophenylalanine depletes brain serotonin in the rat6 thus causing an abnormal psychic behavior of the animal.' The synt,hesis of the a-fluoro- and a-hydroxypyridylalanines has been described in an earlier study and certain of these compounds are toxic t o the growth of various microorganisms.* I n this report the synthesis of the bromo and chloro analogs is described. (1) This work was supported by grants from the Robert A . Welch Foundation of Texas (0-133) and from a Faculty Research Grant of North Texas S t a t e University (2024). ( 2 ) J . I. DeGram, VI.Cory, W.A . Skinner, M . C. Theisen, and C. Mitoma, J . M e d . C h e m . , 10, 64 (1967). (3) R . W.Fuller, Life S c i . , 4, 1 (1965). (4) W. S.Saari, J. Williams, S.F. Britcher, D . E. Wolf, a n d F. A . Kuehl, Jr., .I. M e d . Chem., 10, 1008 (1967). (5) W.F. Coulson, E. Wardle, and J. B. Jepson, B i o c h i m . B i o p h y s . Acta, 167, 99 (1968). (6) B. K . K o e a n d A. Weissman, J . Pharmacol. E z p . Ther., 184,499 (1966). (7) A . Tagliamonte, P. Tagliamonte, G. L. Gessa, a n d B. B. Brodie, Science, 166, 1433 (1969). (8) P. T. Sullivan, C . B. Sullivan, and S.J . Norton, J . M e d . Chem., 14, 211 (1971).
Experimental Section A Thomas-Hoover capillary melting point apparatus was employed for all mp determinations, and the melting points reported are uncorr. Uv spectra were determined with a Beckman DBG recording spectrophotometer. Where analyses are indicated only by symbols of the elements, analytical results obtained for those elements were within f 0.4Y0 of the theoretical values unless otherwise specified. The aminopicolines were obtained from Aldrich Chemical Co., Inc. and J. T. Baker Laboratory Chemicals. The following reaction procedures are given for specific compds; compds indicated by reference to the particular table were prepared in like manner. a-Bromopico1ines.-The appropriate aminopicoline was diazotized as previously reported' utilizing HBr, Biz, and NaN02. The boiling points and melting points agreed in all cases with those reported above. a-Chloropico1ines.-The appropriate aminopicoline was diazotized as reportedlo employing HCl and NaNO2. The boiling points were in agreement with those reported in the literature. 2-Bromo-3-bromomethylpyridine~ HBr (Table I, 1-8).-2Bromo-3-methylpyridine (29.2 g, 0.17 mole), NBS (30.2 g, 0.17 mole), and 1.5 g of benzoyl peroxide in 500 ml of MgSO4-dried CCL were refluxed several hours. The succinimide was removed by filtration, and the filtrate was concd in uucuo to about 100 ml. The soln was washed with 100 ml of each of the following: 474 NaOH, H20, and 2 7 , aq HBr. EtzO was added to the org layer to make a total of 175 ml, and the dried soln was satd with anhyd (9) For syntheses a n d physical constants of t h e a-bromopicolines see F. A. Case, J . A m e r . C h e m . Soc., 88, 2574 (1946); P. Adams a n d S. Miysno,
zbzd., 76, 3168 (1954). (10) For syntheses a n d physical constants of the a-chloropicolinea d. 0. Seide, Ber., 87B, 1802 (1924): 0. Seide, zbzd., 67B,791 (1924); 0. A. Zeide, Z h . Russ. F i r . - K h i m . Obshchest., 80, 534 (1920); W.Herz and D. R . K. M u r t y , J . Ore. Chem., %8, 122 (1961).
558 Journal of Medicinal Chemistry, 1971, V o l . 14, ~l,-o.6
TABLL I SYXTHETIC INTERMEDIATES
:e2
R1= CH2BrHBr;R2 = CH,C(COOC2H,)2SHCOCHJ
4 \
R = CH,CHCOOH I XH2
so.
s
R (position)
AIP, >(' dec
u
T1eld \-
@Inad
Recrystno solvent
purified < '
I'urmula",'
271 ir--h 47 C,1€9IhX2O> 1 "0-201 17 Br ) 269 \v - h 42 C',II9BrS20? 187-189 18 Br '2.7'' \\ti\ (:,ET,Br?J*o? 3 2.53-233 19 Br 271 \v ;. 1 C*II,Br?l',O2 4 230-232 20 Br 21 e1 1 200-201 270 iv -A :5 1 CyHQClN202 267 \v-.4 :3\ (:~H9ClS202 2 203-206 22 c1 271 iv 17 C,II9CIN?O2 3 260-262 23 c1 271 iV-.\ .ii) (&HeCIS202 4 182-184 24 e1 See footnote b , Table 11. The bromopyrid~lalnliilles(17-20)did ni)t give cobinteiitly accept;thlr See footnote a, Table I. C analy,ses. However, the N analyaea were acceptable iii every rase except for 18 for which, ?i: d c d , 11.43: fvilrid, 11.92. I
IIBr at 0". The pptd salt was rapidly filtered by suctiori, wa-hed Quaternary Ammonium Salts of with several portioiis of anhyd Et20,and stored over PrOa. The Tertiary Aminoalkyl Amides product was iinstable t o recrystn, but WI:: sufficiently pure (Table I ) for further synthetic: work. Ethyl 2-Acetamido-2-i2-bromo-3-pyridylmethyl)malonate (TableI. 9-16).-To 1.15g (0.050 g-atom) of X a iii 150 ml of 3Igdried EtOH wa5 added 5.43 g (0.025 mole) of ethyl acetamidomalonate. To this soln was added 8.3 g (0.025 mole) of %bromo3-bromomethylpyridiiie.HBr and the ; o h refluxed riiitil the pII of an aliquot dissolved in distd €I,O had decreased to approximately pH 5-6. The reaction mixt was taken t o tiryiie-; 111 t'ucuo, and the product was extd (Ei20). It Kas then crystd from Quaternary ammonium salts derived from long-chain EtyO-petr ether and recrystd from HsO. The condensation fatty acids are lmon-n to possess antimicrobial nctivit leading to 10, 12, 14,arid 16 was carried out in the ;ism$ v01 (as AIany S-substituted amides of long-chain futty :IC above) of 1: 1 CsHsEtOH. For 12 and 16 a molar excess of ethyl acetamidomalonate and Na was used, and the halide was have been rfported to hnvc antimycotic activity."-" added portionwise over a period of 1 hr. Phyhicnl coiistaiits and (1) A lalioratory of t h e Southern Utilization Research a n d Ilevelopment analyses are given in Table I. Division, .\RS,U. 8. Department of .\griculture. Naming of a company or /3-(2-Bromo-3-pyridyl)-~~-alanine (Table 11, 17-24).-Comproduct does not imply approval or recommendation b y t h e Department over poiind 9 (3.86g, 0.010 mole) was hydrolyzed in the presence of others xliicli mab- also b e suitable. ( 2 ) R. .\, Reck and 11. J . Iiardwood, I n d . Eng. Chcm.. 46, 1022 (1953). The sol11 was evapd to 50 ml of refluxing 6 A- HC1 for 0 hr. (3) 1.F. Kovak, G (', Clark, and 11. P. D u p u y , J . .Imer. Oil Chemists' dryness i n cucuo, and the residue was dissolved ill 100 ml of H?O S o c . , 38, 321 (1961). and rieiitralized t Amberlite 111-45). The ~ieiitralizedsolii was 14) h. F. S o v a k , 11. ,I. Fisher, 8 . P.Fore, a n d 1%.1'. Llupuy, ibid., 41, decolorized (Ilarco G-60) a i d concd t o drylies iu z'acuo. The 803 (1964). aniiiro acid was recrystd from H20-lIe2C0. I'hpical coti.t$itit. (3) .\. F. S o v a k , .J. 11. Solar, H . I?. l l o d , I;. C . l l a g n e , and E . I,. Skau, and aiialyaea are reported in Table 11.
