Aug. 20, 19.5;
?-sVBSTITUTED
DERIVATIVESOF
4x5
Acknowledgments.-U'e are indebted to Drs. ilifred Holtzer and E. Peter Geiduschek for furnishing the apparatus and solvents used in the viscosity studies and for helpful WiXestions.
reagent of Overell and Petrow12was fairly effective. There was sume indication that more vigorous conditions were required for t h e 2,5-series than t h e 3,4-series. The polymers prepared by this method of deacetylation analyzed poorlJfor carbon, hydrogen and nitrogen. ..\ summary of results is given in Table I .
[CUSTRILILTTIOS FROM
3,4-DX€.~SDRoXSPllE?;UL.~L.\~~s~~
A-EW
'THE L)EPARI'MENT O F
HAVES,COSN.
CHEMISTRY,
C X I V E K S I l Y OF \ - I K G I S I A ]
2-Substituted Derivatives of 3,4-Dihydroxyphenylalanine BY CARL KAISER^
AND
-ILFRED BURGER
RECEIVED MARCH 6,19,57 Because 2-methyl- and 2-chloro-3,4-dil1~~droxyp11enylalanine inhibited the niultiplication of influenza virus in the allantoic fluid of the chick embryo, the following additional 2-substituted derivatives of DOPA and their dimethyl ethers have been synthesized for biological screening: 2-bromo-, 2-fluoro-, 8-ethyl- and 2-nitro-DOPA. I n addition, the synthesis of &(2meth~-l-3,4-dih~drox~.phenyl)-~-n~ethyl-a-alanine and ~-(2-chloro-3,4-dil~~.~rox?.phen~.l)-~-al.~nine has been performed,
3,&Dihydroxyphenylalanine (DOP,A) is the substrate of several enzyme systems such as dopa oxidase and dopa decarboxylase which convert i t to melaninsL and to 3,4-dihydroxyphenethylamine and norepinephrine.3 , 4 These reactions play an important role in animal and plant metabolism and have been studied extensively in oitro and in oiao. Interference with these reactions should prevent the accumulation of the respective reaction prod ucts in certain pathogenic conditions and for this purpose inhibitors for dopa decarboxylase have been sought repeatedly.j-'O IVhen 2-methyl-3,4CH,O+ CH30v X
in vitvo, and the same substance and its 2-chloro analog" were screened for anti-phenylalanine behavior in various biological systems. Since several analogs of amino acids had been found to possess antiviral activity," I 4 i t seemed desirable to test the effect of both coinpounds against influenza virus. In the course of these experiments i t was observed t h a t both compounds inhibited the multiplication of the PR-8 strain of influenza virus in the allantoic fluid of the chick embryo.'" *\lthough in rats infected with the virus these two compounds were inactive, additional 2-substituted derivatives
cH30(j
y$cH2c13(
CH.,O\
ROi\~
x
Y
R
Br (1) F (VI) C2H5 (XIX)
CH.4 Br CHzCl (11) CHI F CH2CI (1-11) CH:< CzHj CH*Cl*(XX) CH.4 SO2 CH2C1 ( S I ) CHs Br CHaC(SHCOCHa)(COrC?H5)2 (111) H F CH2C(XHCOCH3)(COX2Ha)z ( V I I I ) IS C2H5 CH?C(SHCOCH?)(COzCsH5)1*( X X I ) H SO* CHaC(SHCOCH~)(CO2CeHs)a (SII) H * T h e position of this group has not been coilfirmed conclusively. Fig. 1.
dihydroxyphenylalaninei',12became available, i t was included in a series of some two hundred compounds in tests for dopa decarboxylase inhibition (1) Smith, Kline and French Laboratories Fellow. ( 2 ) F. Hanrowitz, "Biochemistry," J o h n Wiley and Sons, Inc., h-ew York. N.Y . . 1955, DD. . 161. 392. (3) D. J. Dernis, H. Blaschko and A . D. R-elch, J . P!?armeco2. E-tbll. l ' h e r a p . , 117, 208 (1956). ( 4 ) A . B. Lerner, Adisatices in F u s y m o l , 14, 116 (1953). ( 3 ) W. J. Hartman, R . 1. Akawie and W. G. Clark, J . R i d . C h n . , 216, 507 (1955). (6) G. .4. Stein, H. A. Bronner and R. Pfister, 3rd, THISJ O U R N A L , 77, 700 (1955). (71 T. L. Sonrkes, Avch. Biockeni. Biophys.,61, 414 (1951). (8) G . j. Martin, R . Brendel and J. h i . ~ ~ i l .wed. ~ ~ s i, I v g8,,
5 (1950). (9) G. .J. Martin and J . &f. Reiler, J . A m P h n i m . k!s.TO< , .Sei. Ed., 37, 3 2 (1948). (10) G. J. Martin and J . .\I. Beiler, Avch. H i o ~ h e n 7 . ,15, 201 (1947). (11) E . D . Hornbaker and A . Burger, THISJOURIZAL, 7 7 , 5314 I%X. ( 1 2 ) K I . T. Cromartie a n d J . H n r l c p h l a w n , J . C ' h r v . S o r . , 10.52 ; I Cl,j2I .
m2)copH
s Br ( I V ) F (1x1 C3H5* ( X X I I ) S O 2 (SI11 j CHn (SXT-I) Br (1')
F (S) CnH6* ( X X I I I ) so.! (SIT-)
of 3,4-dihydroxyphenylalanine were prepared with the hope of overcoming this obstacle. For the synthesis of 2-bromo-3,4-dihydroxyphenylalanine, 3-bromoveratrole (I)l6 was- chloroto 2-bromoveratry1 (''1 ; this was condensed with diethvl acetamidomalonate to give 111 which was hydrolyzed to B-(2-bromo3,4-dimethoxyphenyl)-cr-alanine (IV) with hydrochloric acid. P-(2-Bromo-3,4-dihydroxypheny1)-cralanine (V) was obtained b y ether cleavage with 47y0 hydriodic acid. By an analogous sequence (VI VI1 \'I11 -+ X) 3-fluoroveratrole VI)'^ was transformed into P-!2-fluoro-X,4-dihydroxy---f
-
(13) G. J. Martin, "Biological Antagonism," T h e Rlakiston Co.. S e w Ynrk. S . Ti, 1951, p 117. i l l ) D. B. Keisner, THISJ u u K x A L , 78, 2133 (195f1). (15) T\'e are grateful t u t h e A\Zicrobi,>logySection of Smith, Kline and French Laboratories for these tests. Their Section will report elsewhere t h e biological evaluation p f coniponnds described in this paper. (16) 5. L . Sinionsen and hI. G. R a u , J . Chew. .Cor., 113, 781 (1918). ( 1 7 ) J. C n r w ancl 1. 1. ln!:r:iha?n, .I O r e ChC,,!! , 15, 1'44.7 i l ! l > l ! ,
C A R LKAISERAXD ~ILFRED BURGER
01 -r z: ^I Y ' - - . t . Y N
^I :i
c:
.
.
% d Y
-.
:.i
.
I.
3
I
e 4
d
3 i=
i
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-
Z
c;
i3
.lug. 20, 1057
%SUBSTITUTED
DERIVATIVES OF
3,4-DIHYDROXYPHENYL24LANINE
phenyl) -a-alanine (X); here, isolation of the intermediate dimethoxy derivative IX was possible but not necessary. This held also for the similar series (,I steps from 2-nitroveratryl chloride (XI)1' to !3-(l'-nitro-3,~-dihydroxyphen~l)-n-alanine(\XIV). The position of the chloromethyl group in I 1 was proved by oxidation to 2-bronioveratric acid. I i i I n an analogous manner, 2-Auoroveratryl chloride ( V I I ) was oxidized t o 2-fluoroveratric acid. T h e identity of this acid was established by ;I Schiemann synthesis from methyl 2-aminoveratrate.l 8 An attempt was made to syiithesize $-(2-bromo:i,4-dihydroxyphenyl! -a-alanine (IV) by a shorter route starting from the readily accessible 2-bromo.?IJ T h c acetoxy-azlactone from isovanillin (XI-) this aldehyde was hydrolyzed to a-berizaiiiido-2bromo-3-hydroxy-4-methoxycinnnmic acid (XI'I) b u t this compound was debroininatecl to I3OP.l cm heating with hydriodic acid ant1 phosphoriis.
subjected to a Gatterrnann aldehyde synthesis with hydrogen cyanide ; the position of the fornigl group in the resulting ethyldimethoxybenzaldehyclt could not be proved conclusively since oxidation with potassiutn perniariganate or chromic acid only led to an ethyldimethoxybenzoic acid which decomposed on continued oxidation. T h e same acid was obtained from the oxidation of the chloromethylation product of 3-ethylveratrole. Since the chloromethylation of %methyl-, 3-chloro-, il-bromo- and 5-fluoroveratrole introduced the chloromethyl group ortho to the 3-substituent, a similar orientation could be expected for the chloroiriethylation of 3-ethylveratrole. In support of this assumption the infrared spectra of pertinelit dimethoxybenzoic acids are listed in Table I . I t may be significant that 2-methylveratric acid a n d our ethyldimethoxybenzoic acid differ from 5niethylveratric acid in their absorption characteristics a t 1 1 . 0 12.3 p . The aldehyde and chloroBr methyl tlerivati\-es obtained from 3-ethylveratrolc are tentatively assigned the structures ?-ethyl~ 1 0 ! % j i ~ 1 3 0 I , liippuric w i t 1 --f veratraldehyde and 2-ethylveratryl chloride (XX), I 'I 2 , I-aOH CHsO)h respectively. 2-Ethylveratraldehyde gave P-(?-ethyl-3,4-diXY niethoxyphenylj -a-alanine (XXII) by an azlnctone 1-1-1COC i;Hj synthesis followed b y hydrolysis, saturation of the HO/ CH=CCOnH 151 side chain and removal of the benzoyl group. The & DOPA CHsOi,\ ,) ether groups of XXII were cleaved with hydriodic P \ acid (XXIII). XVI In order to study the effect of various structural alterations in the amino group of antiviral 2-suba-Benzamido-2-nitro-3,4-dirnethoxycinnatiiic stituted derivatives of 3,4-dihydroxyphenylalanine, acid (XVII'1 was prepared from 2-nitroveratral- $ - (2-1iiethyl-3,1-dihydroxyphenyl) -S-methyl- a dehyde?' in a similar way and was hydrogenated in alanine (XXIV) and ~-!L>-chloro-:i,-~-dihydro?cythe presence of Adams catalyst in the hope of secur- phenyl')-3-alanine (XXI-) have been synthesized. ing the corresponding saturated ?-amino deriva- Diethyl acetarniclo-(2-methyl-~3,~-dimethoxybeiitive. n'hile this compound was undoubtedly zyl) -malonate11was hydrolyzed arid decarboxylated, formed, i t lactamized spontaneously t o :3-benzamido- the miino acid XXVI was tosylatetl :inti the S T,8-dimetho?cy-3,3-clihy~lrct-2-quiiiol~rie (XT'TIT)
?i
CH; lIC)Y\CH,CHCO,II ItC)'\> '\'\
CH
//
i
l
SHCHi
SSI\-
C1
I~O//~CII(SH,)CH~CC),II
I
IIOq
l~ ,)'
s XI.
tosyl derivative treated with dimethyl sulfate. Scission of the methoxyl groups and the N-tosyl linkage furnished XXTI'. T h e chloro derivative XXT' was prepared by subjecting 2-chloroveratraldehyde" to a Perkin reaction, treating the resulting 2-(!hloro-;3,~-dirnethoxycinnaniicacid with hydroxylamine and cleaving the methoxyl groups. S\.III 3-(?-Fluoro-:i,~-dihydroxyphenyl) - w a h i n e had T h e yields in the preparation of the ethyl sub- activity against influenza virus similar to P - ( L .'-Rronio-, stituted malonate ester X X I from 3-ethylverat-role iiiethyl-:S,-~-dihyclroxpphenyl)-c\-alanine. (XIX) were so low t h a t a different route to p- '-fluoro-, ?-ethyl- and 2-tiitro-I)OP.\ and their (ethyldihydroxypheny1)-a-alanine( X X I I I ) was dimethyl ethers werc screened for bacteriostatic, chosen. 3-Ethylveratrole,?' obtained by the I-Iu- antifungal and anti\-iual activity. In chick eniang-lliriloti inodification of the IVolTf- Kishner bryo protection tests, using the PR-8strain of methode3 from 3,:2-dimethoxyacetophenorie. was the influenza virus, XXIT and X X V I possessetl slight activity. 3-(2-Chloro-:3,1-diliydroxyphenyl, 18) K FI :;lotta and I:. I,auer%,n p r n b ! . ihriai , 139, 2 2 0 : 1'1'31) d-alanine ( X X V ) , i n concentrations of 1 : 500, i n I I ! O n' \ I R o d i o n o v a n d A . h I . ir>rr,a.n. /
