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New routes to polyfunctionally substituted pyridine pyridopyridine quinoline and pyridazine derivatives.

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Nitriles in Heterocyclic Synthesis
Nitriles in Heterocyclic Synthesis
New Routes to Polyfunctionally Substituted Pyridine, Pyridopyridine,
Quinoline, and Pyridazine Derivatives
Mohamed H.Elnagdi' and Ayman W. W. Erian
Department of Chemistry, Faculty of Science, Cairo University, Giza, A.R. Egypt.
Received August 25,1990
The pyridine derivatives 4 and 10 are obtained by condensing paminocrotononieile (la) with malononib'ile. Compound 4 affords the pyridylpyridadne
7 on coupling with aryldiazonium salts. The reaction of la with cyan*
thioacemideaffords which
the ae,,,,[2,34iP~h
13 on treatmcm with @nacylb,.&de, and p,,&o[2&bIpyridine 15 on treatment with
A variety of new pyridines. cyclohexadiene. and pyridopyridinederivatives
wen obtained from d o n of2-~l-propene-l,1,3-tricarbonieille(it,)
and diethyl 3-amino-2cyanopent-2-enedioate.
(lc) with Mlcht-systems.
Reaction of l b with acrylonib'ile afforded an acyclic diadduct 25 which
could be c y c l i to the aminoquinolhe 26.
NitrUe in der Heterocyden-Synthese: Neue Wege zu polyfunktiond substitulerten Pyrldinen, Pyrldopyridinen, Chinolinen und Pyrldazlnen
Die Wdine 4 und 10 wurden durch Kondensationvon &Aminocrotonnitril
(la) Illit MalOnS&URdini~erhalkL AUS Verbindung4 entsteht daS W d y l pyridazin 7 durch Kupplung mit Diazoniumsalzen Reaktion von la mit
~ O t h i o a c e t a mlief&
das seinerseitsIllit Phv'bom
zu dm
menot23-blpyridm 13 re@* Das Pyrido[23-blpyridin 15 e n w h t
u mit B e m y l i d e n - m a l o d t .
zahlniche new Pyridine, Cyclohexadiene und Pyridopyridine entstanden
durch Reaktion von 2-Amino-l33-tricyanopropen (lb) bzw. dem Diethylester der ~ A m i n o - ~ x y m e t h y l - a c r (lc)
y I ~mit cgfhngesilaigten
Carbonylverbiiungen. Die U m s e m g von l b mit Acrylnitril fIUute zu
einem Diaddulct 25. das m Aminochinolin26 zylclisien wurde.
Diverse biological activities have been reported for polyfunctionally substituted pyridines. pyridopyridines, and quinolines. For example pyridoxal
phosphate is a coenzyme for a variety of biological transformations. Nalidixic acid is bactericidal to most of common gram-negative bacteria that
cause urinary tract infections2$). Several quinoline derivatives are utilized
as antimalarialdrugs'.5'. The biological activities of these polyfunctionally
substituted pyridine derivatives depend on the nature of substituentson the
aromatic ring. However, only a limited number of functionally substituted
derivatives of the above mentioned biologically interesting pyridines ha9
been prepared as no simple general mutes for derivatives of these a m pounds am available. As a part of our programme directed for developing
simple and efficient procedures for the synthesisof functionally substituted
e f i c i e n t heterocycles as potentid antischistosom~agents'.') we report
here on the synthesis of several new pyridines. pyridyl-pyridazines.pyridopyridines. and quinolines utilizing readily obtainable lac"-") as starting
via JappKlingemunn CN-group cleavage from intermediately formed coupling product 5. This pyridylpyridazine
structure 7 is preferred over the possible isomer 6 based on
the stability of the product on treatment with reagents reported to effect cyclization of hydrazones of similar structure. For example, compounds 7a-c were recovered unchanged after refluxing for a long time in acetic acid. Heating of 7b in acetic anhydride at reflux affords the N-acyl
derivative 8. The W specaum of 8 is very similar to that of
7b. indicating that both compounds have a similar ring
In contrast to formation of 4 from l a and malononitrile,
compound l a reacted with malononitrile in refluxing sodium ethoxide to yield aproduct CllHllNs (m/z = 213, Mt).
The lH-Nh4R-spectrum revealed two methyl, a methylene
p-Aminocrotononitrile (la) reacts with malononitrile in and methine protons at 6 = 1.41, 2.30, 2.81, and 3.39, rerefluxing dioxane to yield a product C1J-I1&, (m/z = 262 spectively, in addition to an amino signal at 6 = 7.30. The
Mt). The 'H-NMR-spectrum reveals two 3H-singlets at 6 = 13C-NMR-spectmmrevealed the two methyl carbons at 6 =
1.50 and 6 = 2.17 and a 1H-singletat 6 = 6.17. In addition, a 18.68 and 27.74 ppm, the methylene carbod at 6 = 34.96
one-proton DzOexchangeable signal at 6 = 5.40 and two- ppm and the methine carbon at 6 = 31.23, sp3 carbon not
protons D2Oexchangeable broad signal at 6 = 8.72 were linked to any protons appeared at 6 = 57.08 in addition to
also revealed. Based on these data, structure 4 or the tau- cyan0 carbons at 6 = 115.53, 117.55. and 117.63, as well as
tomeric form 5 is suggested for the product. Compound 4 or two low field carbons at 6 = 154.21 and 160.49 were ob5 is assumed to be formed by condensationof la with male served. Based on these data structure 10 was suggested for
nonitrile via ammonia elimination and twofold decarboxyla- the product. Formation of 10 is assumed to proceed by fortion to yield 2 which then dimerizes to give 3. Compound 3 mation of intermediate 2. This then reacts with an other molcyclizes then to 4. Structure 4 was preferred over the cule of la to yield 10 via the intermediate 9.
possible tautomer 5 based on the IR-spectrum, which reCompound l a condensed with cyanothioacetamide (11)to
veals bands for NH, NH2 and CN.
yield the pyridinethione 12. Compound 12 was converted
Compound 4 couples with aryldiazonium salts: Formation into the thienopyridine 13 by reaction with phenacylbroof 7 from 4 and aryldiazonium salts is assumed to proceed mide in refluxing acetone/KzCO3.This is similar to the re-
Arch. Phurm.(Wcinheim)324.853-858(1991)
OVCH VerlagsgesellschaftmbH, D-6940 Weinheim. 1991
0365-6233/91/1111-0853S 3.50 + .25m
Elnagdi and Erian
1 1
- CN
$- c = q c
Ar NzN Cl
Scheme 1
ported behaviour of thiopyridyl carbonitriles on treatment
with this reagent6).
Compound 12 reacts with benzylidenemalononitrile (14)
to yield a 1:l adduct. This is formulated as 15 based on its
IH-NMR-spectrum which indicates that ring N-H and CH3
group are not involved in the reaction.
l b reacts with cinnamaldehyde to yield a product of condensation by water and H2 elimination. This may be formulated as 16 or its isomere 17. Compound 16 is assumed to be
formed by addition of the active methylene moiety in l b to
the activated'double bond in cinnamaldehyde to yield an
acyclic Michael adduct. This then undergoes cyclization by
water elimination yielding a dihydropyridinederivative that
undergoes autooxidationyielding 16.
Structure 16 was preferred for the reaction product based on 'H-NMRand "C-NMR-spectra: The 'H-NMR-spectrum revealed a signal for CH at
= 4.31. two 1H doublets at 6 = 6.94 and 6 = 8.21 (J = 7.5 Hz) and five
protons signal at 6 = 7.66. These signals can only be intelligibly interpreted
for structure 16. If the reaction products were 17 one would expect the one
proton doublet to appear at higher field. Moreover, the five protons signal
at 6 = 7.66 should split into two signals as phenyl oltho protons should be
deshielded by ring nitmgen lone pair anisotropy. "C-NMR of the reaction
product revealed a pattern that can only be intelligably interpreted for
structun 16.
Compound l c reacts with cinnamaldehyde to yield a condensation product by water elimination. The IR-spectrum
revealed that the amino function was not involved in the
reaction. Thus the isomeric structures 18 and 19a.b were
suggested. Compound 18 is assumed to be formed by condensation of l c with the aldehydic group in cinnamaldehyde, while 19 might be formed by intramolecular 4+2 cyclization of 18.
Structure 19 was preferred for the product based on its
13C-Nh4R-spectrumwhich revealed signals for two sp3 carbons other than those of the ester groups. If the reaction
product were 18 it would have been difficult to interpret
these two signals. The I3C-NMR-spectrum revealed also
that 19 exists as two isomers (cf. 19a and 19b). Trials to
isolate each isomer in pure form failed.
Compound 17 could be prepared by nacting l b with 20 in
refluxing DMF. It is assumed that phenyl vinyl ketone is
first produckd from 20. This then reacts with l b by Michael
addition, condensation and dehydrogenation to yield 17. As
expected the 'H-NMR-spectrum of 17 revealed the aryl
protons as two multiplets. 17 reacted with acetic acid/conc.
sulfuric acid to yield the diazanaphthalene derivative 21.
Compound 21 exists in the dione form 21 rather than in the
Arch. Pharm. (Weinheim) 324.853-858 (1991)
Nitriles in Heterocyclic Synthesis
dihydroxy form 22, based on its IR-spectrum which reveals
signals for two carbonyl groups but no OH. In addition, l c
reacts also with 20 to yield a product C~9H2004N2
(M" =
m/z 340). Structure 23 instead of 24 was established for this
product based on spectral data:
Its 'H-NMR-spectrum revealed in addition of signals for two ester
groups and phenyl protons a multiplet for 2H at 6 = 2.7 ppm. a dd for 1H at
6 = 2.9 ppm. a
exchangeable signal for 1H at 6 = 1.60 ppm, and a
multiplet at 6 = 5.5 ppm. These were assigned for H-4, H-3, NH, and H-5
respectively. If the reaction product were 24 it would be difficult to rationalize the observed multiplicity. For example, the NH signal should appear
as a triplet and the dd at 6 = 2.9 ppm should have appeared as multiplets
and should have integrated for two protons. Structure 23 was further confmed by 13C-NMR spectroscopy (cf. formula).
Compound l b reacted with acrylonitrile to yield a diadduct 25. When 25 was refluxed in dioxane in presence of
sodium metal the quinoline derivative 26 was formed. To
our knowledge this is first reported synthesis of aminoquinolines utilising l b as starting material.
Spectroscopic measurements were performed at University of Missouri,
Columbia. Missouri. U.S.A. by Prof. Dr. M. Tempesta and at the City
University London by Prof. Dr. S.A. M a t h Thanks to the support of
International Organization of Chemical Sciencesin Development (IOCD).
Experimental Part
All m.p.3 are uncorrected.- IR spectra: (KBr). Pye Unicam SP 1 I00
Specu0photometer.- 'H-NMR spectra: in Me2S0. Perkin-Elmer R32 90
MHz NMR-spectrometer. chemical shifts in 6 values.- Microanalytical
dakx Microanalytical Data Unit at Cairo University.- Mass spectra: MS 30
and MS 9 (AEI), 90 eV.
A solution of 3-am~nocrotonoNtrilela (0.01 mol) and malononitrile
(0.01 mol) in dioxane (30 ml) was heated at reflux for 30 min, then left to
cool to room temp. The solid product so formed was crystallized from
ethanol. Yield 1.2 g (46%).m.p. 2 3 5 O C , colorless crystals.- IR: v = 3200,
3310-3400 (NU. NH3.2220-2190 br (CN). 1650 (Cd)Ern-'.- 'H-NMR: 6
(ppm) = 1.50 (s. 3H. CH3). 2.17 (s. 3H, CH3). 5.40 (s. 1H. CH). 6.17 (s.
1H. NH), 8.72 (br. 2H. NH3.- M S mh = 262 (M+).- C14HI,,N6(262.2)
Calcd C 64.1 H 3.81 N 32.1 Found C 64.2 H 3.9 N 32.0.
3-(6-Amino=l-cyano-4-methyI-2-pyridinyl-l sryl-6-imino4-methyI
To a solution of 4 (0.01 mol) in ethanol (30 ml) containing sodium
acetate (3 g), an ice cold solution of atyldiazonium chloride (0.01 mol),
prepared by adding Na NO2 (0.01 mol) to the appropriate quantity of
\ r ,CH3
Na O E t
C H3
Scheme 2
Arch. Pharm. (Weinheim)324.853-858(1991)
Elnagdi and Erian
Scheme 3
aniline, p-toluidine. or p-anisidine in HCI acid was added with stirring.
After 30 min the solid product was collected by filtration and crystallized
from DhWethanol mixture.
7a: yield 1.5 g (44%). m.p. > 280°C. red crystals.- IR: v = 3450-3220
1640 (GIN) cm-'.-~ 1 9 ~ 1 (341.1)
5 ~ 7 wcd.
C 66.9 H 4.41 N 28.7 Found C 66.8 H 4.1 N 28.6.
7 b yield 1.6 g (45%), m.p. 275'C. red crystals.- IR:v = 3450-3200 (NH2.
NH), 2230,2190 (CN). 1650 (GN~m-'.) 'H-NMR: 6 = 1.40 (s. 3H, CH3).
2.39 (s. 3H. CH3.2.43 (S.3H. CH3h 2.76 (SV2H. NH3.7.25-7.50 (m 5H,
aromatic H). 8.0 (br. lH, NH).- MS: m/z = 355 (Mc).--17N7
Calcd C 67.6 H 4.78 N 27.6 Found C 67.7 H 4.8. N 27.5.
7c yield 1.5 g (W),
m.p. > 280°C red crystals.- IR: v = 3480. 3230
(NH2. NH), 2225. 2190 (CN). 1650 (C=N) ~m-'.- C&l17N7O (371.2)
Calcd. C 64.7 H 4.58 N 26.4 Found C 64.7 H 4.5 N 26.2.
dition of 30 ml ethanol, was crystallized from DMF. Yield 1.2 g (30%). m.p.
> 28OOC. brown crystals.- IR:v = 3400-3300 (NH2).2225,2190(CN), 1670
an-'.-'H-NMR: No spectrum. 8 is soluble in common solvents.CuH19N7O(397.4) Calcd C 66.5 H 4.78 N 24.7 Found C 66.5 H 4.8 N 245.
To a solution of l a (0.02 mol) of ethanol containing NaOEt (0.02 mol).
malononitrile (0.02 mol) was added. The mixture was heated at reflux for
15 min, then the solvent was evaporated in vacw. m e remaining product
was refluxed with CHCIs and the chloroform layer was decanted and evap
orated. The resulting product was crystallized from ethanol to yield colourless crystals. Yield 1.5 g (37%); m.p. 176OC.- IR: v = 3400-3200 (NH2),
2950,2940 (CH3). 2240,2215,2200 (CN),1680 (C&) cm-'.- 'H-NMR: 6
= 1.41 (s. 3H. CH& 2.24 (s. 3H. CH& 2.81 (s. 2H. CH& 3.33 (s. IH.
6 - A r e ~ l ~ n o - 3 - ( 6 ~ ~ ~ - 3 - ~ a n o ~ - m e t h y l - 2 - p-p-tolyly r ~ i n y CH).
l ~ - ~7.33
~ y(s.2H.
i - ~ NH3.- MS: m/z = 213 (M+).-"C-NMR 160.99 (C-2);
92.0 (C-3); 57.08 (C-4); 31.23 (C-5); 159.21 (Cb); 18.68 (C-7); 117.55
A solutionof 7b (0.01 mob in acetic anhydride (20 ml) was reacted at re(C-8); 27.74 (C-9): 34.56 (C-10): 115.53 (C-11). and 117.63 (C-l2).flux for 1 h then left to cool at mom temp. The solid product. formed on ad- CIIHIINS (213.2) Calcd. C 62.0 H 5.16 N 32.9 Found C 62.0 H 5.1 N 32.6.
Arch. Pharm. (Weinheim) 324,853458 (1991)
Nitriles in Heterocyclic Synthesis
A solution of la (0.03 mol) and cyanothioacetamide 11 (0.03 mol) in
dioxane (30 ml) was refluxed for 15 min. then left to cool to room temp.
The solid product was crystallized from ethanol as yellow crystals. Yield
2.0 g (41%). m.p. > 280°C.- IR.3400-3200 (NH2,NH). 2200 (CN) cm-'.1
H-NMR: 6 = 2.18 (s, 3H. CH3k 5.90 (s, IH. CH); 7.25 (br. 2H, NH2).
12.35 (s, 1H. NH).- M S m/z = 165 (M3.- "C-NMR 155.12 (C-2): 98.96
(C-3): 153.50 ((2-4): 109.20 (C-5); 175.33'(C-6): 118.05 (C-7). and 20.24
((24.- C7H7N3S (165.1) Calcd. C 50.4 H 4.24 N 25.4 S 19.4 Found C 50.8
H 4.2 N 25.3 S 19.2.
To a solution of 12 (0.01 mol) in 100 ml of acetone containing 1 g
KzCO3, phenacylbromide(0.01 mol) was added. The mixture was refluxed
for 3 h and poured into ice water. The solid product was crystallized from
ethanol as yellow needles; yield 1.2g (42%), m.p. = 152°C.- IR:v = 34503200 (NHz), 1680 (C=O) cm-'.- 'H-NMR 6 = 2.2 (s, 3H, CH3); 6.10 (s,
1H. CH). 6.9-7.22 (m. 9H. aromatic H and 2 NH3.- CISH1f130S(283.2)
Calcd.C63.6H4.59N 14.8s 11.3FoundC63.4H4.6N 14.9s 11.3.
ring): 5.29-5.70 (m,lH, H4); 6.53-6.80 (m. IH. H-3): 7.10-7.36 (m. 5H,
aromatic H); 10.33-10.60 (br. 2H, NH2).- MS: m/z = 340 (MC).C19H2fl204 (340.3) Calcd. C 67.1 H 5.88 N 8.23 Found C 66.9 H 5.7 N
Compound 17 (0.01 mol) was heated with conc. sulphuric/aceticacid l:3
mixture for 30 rnin. The mixture was poured into ice water. The precipitate
was collected and crystallized fromethanoVDMFas brown crystals; m.p. >
250°C; yield 36%.- IR (KBr. ad): 2200 (CN): 1675-1700 (C=O).- 'HNMR: insoluble.- C1sHfl302 (263.2) Calcd. C 68.4 H 3.42 N 16.0 Found
C 68.1 H 3.2 N 15.9.
.6J,4-tetrahydro-2-phenylpyridined-ylidenecyanoacetafe (23)
To lc (0.01 mol) in dimethylformamide(20 ml). 0.01 mole of compound
20 was added. The mixture was refluxed for 30 min then poured into
ice-cold water. The solid product is crystallized from ethanol as white
crystals; m.p. 105°C; yield (47%).- IR (KBr. cm-'): 2200 (CN): 1720-1750
(CO) cm-'.- 'H-NMR (DMSO): 6 = 1.2 (2t.6H. 2 CH3h 1.6 (s. IH. NH);
2,6-Diamino-7,8-dihydro-5-methyl-4-phenyl-7-thioxopyrido[23-b]pyridine2.7 (m, 2H, H4): 2.9 (dd, JI = 4 Hz, J2 = 6 Hz, IH, H-3): 4.2 (2q. 4H. 2
CH2); 5.5 (m, 1H. H-5): 7.2-7.5 (m, 5H, aromatic H).- MS: m/z = 340
A mixture of compound 12 (0.01mol) and equivalent of benzyledenema(M3.- I3C-NMR 124.12 (C-2); 74.89 (C-3); 22.64 (C4); 41.83 (C-5):
lononitrile (14)(1.4 g, 0.01 moll in dioxane (20 ml) was refluxed with
161.97 ((2-6): 104.48 (C-7): 116.68 (C-8): 167.48 (C-9): 61.75 (C-10):
pipendine for 3 h. After dilution. the solid product was crystallized from
14.1 1 (C-1I); 167.53 (C-12): 60.98 ('2-13). and 13.86 (C-l4).-C19Hd104
dioxane, yield 1.5 (51%), m.p. = 237OC.- IR:3470-3210 (NH3.2210 (CN)
(340.3)Calcd.C67.1 H5.88N8.2FoundC67.0H5.9N8.0.
cm".- 'H-NMR: 6 = 1.61 (s, 3H. CH3); 6.90-7.6 (m, 9H, aromatic H and 2
NH2); 9.2 (s, IH, NH).- Ci&I13NsS(307.2) Calcd. C 62.5 H 4.23 N 22.80
S 10.4 Found C 62.4 H 4.2 N 22.0 S 10.0.
To a solution of lb (2.64 g, 0.02 g) in 20 ml pyridine. 2 ml acrylonitrile
was added. The mixture was refluxed for 30 min. The solid product crystal3-Cyano-Q-phenylpyridine-2-yl-malononitriIe
lized from DMF as yellow crystals m.p. > 25ooC; yield 652.- IR (KBr.
To a solution of lb (2.69 g, 0.02 mol) in 20 ml pyridine. cinnamaldehyde
cm"): 3450-3320 (NH& 2200-2250 (CN).- 'H-NMR (DMSO): 6 = 2.10(2.6 g. 0.02 mol) was added. The mixture was refluxed for 2 h. then poured
3.0 (m. 8H. 4 CH3; 8.1-8.4 (br, 2H, NH2).- MS: d z = 238 (M").into ethanol. The solid product so formed was crystallized from aqueous
C12Hlfl6 (238.2) Calcd. C 60.5 H 4.20 N 35.3 Found C 60.3 H 4.2 N 35.3.
DMF as yellow crystals, m.p. > 280°C; yield 598.- IR (KBr, cm-'): 21952210 (cN): i 6 6 0 . 1 6 ~ )(c=c).-'H-NMR (DMSO): 6 = 4.34 ppm (s, IH,
CH); 6.91 (d, J = 6 Hz. 1H. H4); 7.65 (m, 5H. phenyl-H); 8.15 (d, J = 6 2.4-Diaminoquinoline-6,8-dicarbonitrile(26)
Hz, lH, H-9.- M S m/z = 244 (M+).- 13C-NMR 160.57 (C-2): 98.33
Compound 25 (0.01 mol) was refluxed with Na metal (0.01 mol) in 30
(C-3): 143.45 (C-4); 130.90((2.5): 154.61 ((2-6); 41.44 (C-7); 114.19 (C-8):
ml of dioxane for 8 h. The mixture was poured into ice-water with acidifi114.06 (C-10). and 128.46, 128.61; 128.90. 135.56 (phenyl carbons).cation by conc. HCI. The precipitate was crystallized from ethanoVDMFas
Cl5H8N4 (244.2) Calcd. C 73.8 H 3.30 N 23.0 Found C 73.8 H 3.4 N 22.8.
brown crystals: m.p. > 250°C: yield 34%.- IR (KBr. cm-'): 3420-3300
(NH2); 2210-2220 (CN).- 'H-NMR: insoluble.- CllH7N4(209.2) Calcd. C
63.1 H3.34N33.5FoundC63.1 H3.1 N33.5.
To a solution of compound lb (0.02 mol) in dimethylformamide,0.2 mol
of compound 20 was added. The mixture was refluxed for 30 min. then
poured into ice-cold water. The solid product was washed by hot ethanol
and crystallized from dioxane as yellow crystals: m.p. > 280°C; yield
44%.-IR (KBr, cm-'): 2210 2200 (CN).- 'H-NMR (DMSO): 6 = 3.70 (9.
IH, CH): 7.3-8.2 (m. 7H, aromatic H).- MS: m/z = 244 (M+).- CISHBN4
(244.2) Calcd. C 73.8 H 3.27 N 23.0 Found C 73.6 H 3.2 N 22.8.
To a solution of lb (4.5 g. 0.02mol) in 20 ml dry pyridine, cinnamaldehyde (2.6 g. 0.02 mol) was added. The mixture was refluxed for 2 h, then
poured into ice-cold water. The oil obtained is isolated and treated with 30
ml of cold ethyl acetate. The solid product is crystallized from acetic acid
as white crystals: m.p. = 140°C; yield 38%.- IR (KBr, cm"): 3220-3300
(NH2); 2250 (CN): 1680. 1730 (C=O): 1500-1610 (C=C!).- 'H-NMR
(DMSO): 6 = 1.10-1.40 (m. 6H, 2 CH3): 3.904.33 (m. 5H, 2 CH2 and 1H.
Arch. Pharm. (Weinheim)324.853-858(1991)
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Arch. Pharm. (Weinhcim) 324,853458 (1991)
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pyridin, polyfunctional, pyridazine, pyridopyridine, quinolinic, substituted, new, derivatives, route
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