ID Name References
C1

an oxidized electron donor

C2

a reduced electron donor

C3

a deaminated amino group acceptor

C4

an aminated amino group acceptor

C5

Charged-LEU-tRNAs

C6

LEU-tRNAs

C7

a 2-oxo acid

C8

an amino acid

C9

an acyl-CoA

C10

a carboxylate

C11

an oxidized ferredoxin [iron-sulfur] cluster

C12

a reduced ferredoxin [iron-sulfur] cluster

C13

NAD(P)H

C14

NAD(P)+

C15

an L-tyrosyl-[tRNAtyr]

C16

a tRNAtyr

C17

(2Z,4Z)-2-hydroxy-5-carboxymuconate-6-semialdehyde

C18

4α,14α-dimethyl-porifersta-8,25(27)-dienol

C24

2-amino-4,5-dihydroxy-6-oxo-7-(phosphooxy)heptanoate

C26

4-methylcyclohex-1,5-diene-1-carbonyl-CoA

C27

isoshowacene

C29

2-hydroxyhexadecanal

C30

16-sinapoyloxypalmitate

C31

3-methylquinolin-2-ol

C32

(22R)-hydroxycholesterol

C37

N-(2-methylpropyl)hydroxylamine

C38

chloroeremomycin

C39

3-hydroxy-3-methylbutanoate

C40

2',3',4'-O-methyl-rhamnosyl tetracyclic spinosyn pseudoaglycone

C41

2',3'-O-methyl-rhamnosyl tetracyclic spinosyn pseudoaglycone

C42

2'-O-methyl-rhamnosyl tetracyclic spinosyn pseudoaglycone

C43

rhamnosyl tetracyclic spinosyn pseudoaglycone

C44

rhamnosyl tricyclic spinosyn pseudoaglycone

C45

spinosyn tricyclic macrolactone

C46

11-dehydro-15-oxo spinosyn macrolactone

C47

15-oxo spinosyn macrolactone

C48

spinosyn macrolactone

C51

diethylamine N-oxide

C52

triethylamine N-oxide

C53

UDP-2-acetamido-2-deoxy-α-D-ribo-hex-3-uluronate

C55

nitroxyl

C57

trans,octacis-decaprenylphospho-β-D-arabinofuranose

C58

1,3-dihydro-2H-imidazol-2-one

C63

2-phenylethyl β-D-glucopyranoside

C64

formyl hopane

C65

ribosyl hopane

C66

adenosyl hopane

C70

(2Z)-2-hydroxypenta-2,4-dienoate

C72

(2S,4S)-4-hydroxy-2,3,4,5-tetrahydrodipicolinate

C73

(2Z)-2,4-dihydroxypent-2-enoate

C75

(2E,7Z,10Z,13Z,16Z,19Z)-docosahexaenoyl-CoA

C76

(3R,5Z,8Z,11Z,14Z,17Z)-3-hydroxydocosapentaenoyl-CoA

C77

(5Z,8Z,11Z,14Z,17Z)-3-oxodocosapentaenoyl-CoA

C79

(+)-3'-hydroxylarreatricin

C80

(+)-larreatricin

C81

2-trans,4-trans-xanthoxin

C1538

2-C-methyl-D-erythritol 4-phosphate

C1449

2-C-methyl-D-erythritol-2,4-cyclodiphosphate

C928

CO2

C11604

thiamine diphosphate

C1552

2-(α-hydroxyethyl)thiamine diphosphate

C11543

H2O

C11873

N-succinyl-L,L-2,6-diaminopimelate

C1184

5-phospho-β-D-ribosylamine

C11802

4'-phosphopantetheine

C11710

(R)-4'-phosphopantothenoyl-L-cysteine

C11874

N-succinyl-2-amino-6-ketopimelate

C12368

(S)-2,3,4,5-tetrahydrodipicolinate

C12351

2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one

C6359

(S)-2-acetolactate

C6369

(S)-2-aceto-2-hydroxybutanoate

C1621

(R)-2,3-dihydroxy-3-methylpentanoate

C873

coproporphyrinogen III

C11715

quinolinate

C11857

β-nicotinate D-ribonucleotide

C2191

carbamoyl phosphate

C1231

5-aminolevulinate

C10349

glycerone phosphate

C11690

S-acetyldihydrolipoamide

C12333

dihydrolipoamide

C891

citrate

C6444

oxaloacetate

C12355

dethiobiotin

C12350

7,8-diaminopelargonate

C11800

(R)-pantothenate

C13723

arsenite

C1172

5-amino-1-(5-phospho-β-D-ribosyl)imidazole

C11774

5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate

C1180

N1-(5-phospho-β-D-ribosyl)glycinamide

C1171

2-(formamido)-N1-(5-phospho-β-D-ribosyl)acetamidine

C1182

N2-formyl-N1-(5-phospho-β-D-ribosyl)glycinamide

C12352

(S)-dihydroorotate

C3821

5-methylcytosine

C12364

isopentenyl diphosphate

C12139

preuroporphyrinogen

C12162

hydrogen peroxide

C11930

N-acetylglutamyl-phosphate

C14074

prenyl diphosphate

C651

3-(4-hydroxyphenyl)-3-oxo-propanoyl-CoA

C371

3S-(4-hydroxyphenyl)-3-hydroxy-propanoyl-CoA

C184

3-[(3aS,4S,5R,7aS)-5-hydroxy-7a-methyl-1-oxo-octahydro-1H-inden-4-yl]-3-oxopropanoyl-CoA

C185

3-[(3aS,4S,5R,7aS)-5-hydroxy-7a-methyl-1-oxo-octahydro-1H-inden-4-yl]-3-hydroxypropanoyl-CoA

C11767

porphobilinogen

C11748

pseudouridine 5'-phosphate

C11479

phosphoenolpyruvate

C1522

3-demethylubiquinol-6

C3264

S-adenosyl-4-methylsulfanyl-2-oxobutanoate

C1130

8-amino-7-oxononanoate

C11606

thiamine phosphate

C3850

5-amino-6-(D-ribitylamino)uracil

C11832

orotidine 5'-phosphate

C9422

nicotinate adenine dinucleotide

C571

4-hydroxy-2-nonenal

C11812

5'-phosphoribosyl-4-(N-succinocarboxamide)-5-aminoimidazole

C14003

N-acetyl-L-glutamate 5-semialdehyde

C1427

5-enolpyruvoyl-shikimate 3-phosphate

C11652

shikimate 3-phosphate

C191

L-selenocystathionine

C13950

pimeloyl-CoA

C1528

2-dehydropantoate

C3262

3-methyl-2-oxobutanoate

C1108

acetyl phosphate

C10274

5-amino-6-(5-phospho-D-ribosylamino)uracil

C13627

DNA without lesion

C12158

(E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate

C11737

(3R,5S)-3-hydroxy-1-pyrroline-5-carboxylate

C1631

3-amino-1-hydroxyacetone 1-phosphate

C1018

4-amino-2-methyl-5-(diphosphooxymethyl)pyrimidine

C1020

4-amino-2-methyl-5-(phosphooxymethyl)pyrimidine

C1268

(R)-4'-phosphopantothenate

C352

2-iminoacetate

C927

carbon monoxide

C12174

4-amino-2-methyl-5-pyrimidinemethanol

C3343

(3R)-3-hydroxy-2-oxo-4 phosphooxybutanoate

C1265

4-phosphooxy-L-threonine

C1548

(2S)-2-amino-3-oxo-4-phosphooxybutanoate

C12325

1,4-dihydroxy-2-naphthoate

C12326

1-deoxy-L-glycero-tetrulose 4-phosphate

C3829

5-amino-6-(5-phospho-D-ribitylamino)uracil

C11826

oxalosuccinate

C12218

α-D-glucosamine 1-phosphate

C12848

N5-carboxyaminoimidazole ribonucleotide

C12369

3-dehydroquinate

C1431

3-dehydroshikimate

C11653

shikimate

C12056

L-arginino-succinate

C1550

2-amino-3-carboxymuconate-6-semialdehyde

C12214

(S)-4-amino-5-oxopentanoate

C13986

pseudouridine

C1417

(1E,2Z)-3-hydroxy-5,9,17-trioxo-4,5:9,10-disecoandrosta-1 (10),2-dien-4-oate

C3376

(S)-4-hydroxy-2-oxohexanoate

C193

(2Z,4Z)-2-hydroxyhexa-2,4-dienoate

C194

3-[(3aS,4S,7aS)-7a-methyl-1,5-dioxo-octahydro-1H-inden-4-yl]propanoate

C188

3-[(3aS,4S,7aS)-7a-methyl-1,5-dioxo-octahydro-1H-inden-4-yl]propanoyl-CoA

C187

5-hydroxy-3-[(3aS,4S,5R,7aS)-7a-methyl-1,5-dioxo-octahydro-1H-inden-4-yl]propanoyl-CoA

C186

(2E)-3-[(3aS,4S,5R,7aS)-5-hydroxy-7a-methyl-1-oxo-octahydro-1H-inden-4-yl]prop-2-enoyl-CoA

C183

3-[(3aS,4S,5R,7aS)-5-hydroxy-7a-methyl-1-oxo-octahydro-1H-indene-4-carboxylate

C12164

H2

C1010

ammonia

C12274

enol-phenylpyruvate

C1363

(4,5-dihydro-5-oxofuran-2-yl)-acetate

C13689

(2-carboxy-2,5-dihydro-5-oxofuran-2-yl)-acetate

C9077

(2E,6E)-farnesyl diphosphate

C6287

2-octaprenylphenol

C6317

5,10-methenyltetrahydrofolate mono-L-glutamate

C2765

1-oleoyl-2-lyso-glycerone phosphate

C2150

(2R)-2,3-dihydroxy-3-methylbutanoate

C6437

3-phospho-D-glyceroyl-phosphate

C6427

2,3-diphospho-D-glycerate

C6438

3-phospho-D-glycerate

C6425

2-phospho-D-glycerate

C8420

sn-glycerol 1-phosphate

C8419

sn-glycerol 3-phosphate

C7121

oxygen

C7672

coproporphyrinogen I

C7662

uroporphyrinogen-I

C7658

uroporphyrinogen-III

C7676

protoporphyrin IX

C7666

protoporphyrinogen IX

C6624

protoheme

C10799

DNA with lesion

C4632

(glutathion-S-yl)-4-hydroxy-2-nonenal

C8518

γ-L-glutamyl-L-cysteine

C1434

D-alanyl-D-alanine

C6708

2-iminopropanoate

C6596

2-iminosuccinate

C12247

L-homocysteine

C6043

4-methylphenol

C3536

L-α-amino-ε-keto-pimelate

C5642

L-arginine

C5584

L-lysine

C5607

L-glutamate

C8797

D-glutamate

C5609

L-glutamine

C12067

glycine

C5579

L-serine

C5597

L-alanine

C5588

L-leucine

C11441

β-alanine

C5571

L-valine

C2469

L-phenylalanine

C5583

L-methionine

C5612

L-cysteine

C5580

L,L-diaminopimelate

C12073

L-aspartyl-4-phosphate

C12231

L-ornithine

C5573

L-tyrosine

C5596

L-aspartate

C5595

L-cystathionine

C13322

N-carbamoyl-L-aspartate

C15000

N-acetyl-L-ornithine

C12303

L-citrulline

C15292

S-adenosyl-L-methionine

C12239

L-aspartate 4-semialdehyde

C12203

S-adenosyl-L-homocysteine

C12233

L-glutamate-5-semialdehyde

C12245

L-homoserine

C12241

L-4-hydroxyglutamate semialdehyde

C5585

meso-diaminopimelate

C12063

seleno-L-homocysteine

C14973

N-acetyl-L-glutamate

C8799

D-alanine

C7757

ADP

C7844

ATP

C7745

GTP

C7809

AMP

C7827

GMP

C7811

XMP

C7783

dATP

C7823

dADP

C7751

dGTP

C7807

dGDP

C7795

GDP

C7759

ITP

C7817

IDP

C7749

dITP

C7747

dIDP

C5552

5'-deoxyadenosine

C10288

adenylo-succinate

C7741

IMP

C7848

2'-deoxyguanosine

C7813

2'-deoxyadenosine

C7840

dGMP

C7743

dAMP

C8423

4-(cytidine 5'-diphospho)-2-C-methyl-D-erythritol

C10343

2-phospho-4-(cytidine 5'-diphospho)-2-C-methyl-D-erythritol

C7824

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-L-lysine

C7808

UDP-N-acetyl-α-D-muramoyl-L-alanyl-D-glutamate

C7742

UDP-N-acetyl-α-D-muramoyl-L-alanine

C7734

UDP-N-acetyl-α-D-glucosamine-enolpyruvate

C7822

UDP-N-acetyl-α-D-muramate

C7780

UDP-α-D-glucose

C7444

UDP-N-acetyl-α-D-glucosamine

C5150

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimelate

C5094

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine

C5090

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanyl-D-alanine

C5848

UDP-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanine

C8739

uracil

C8707

cytosine

C10601

thymine

C9540

preQ1

C4020

NAD+

C4018

NADP+

C14500

NADH

C14497

NADPH

C8755

dCMP

C8770

dUMP

C8744

dTMP

C8733

dCDP

C8720

dTDP

C8752

dUDP

C8772

dCTP

C8764

dTTP

C8724

dUTP

C8732

CDP

C8714

UDP

C4243

β-nicotinamide D-ribonucleotide

C8761

CTP

C8760

UTP

C2245

CMP

C2241

UMP

C6945

5-fluorouracil

C9773

5-fluorocytosine

C11619

decaprenyl-diphospho-N-acetylmuramoyl-pentapeptide

C10338

5-phospho-α-D-ribose 1-diphosphate

C15289

D-sedoheptulose 7-phosphate

C10340

D-erythrose 4-phosphate

C10356

4-phospho-D-erythronate

C8811

α-D-glucopyranose 1-phosphate

C3186

N-acetyl-α-D-glucosamine 1-phosphate

C2082

β-D-fructofuranose 1-phosphate

C2129

β-D-glucopyranose 1-phosphate

C10326

β-D-fructose 1,6-bisphosphate

C2989

β-D-fructofuranose 6-phosphate

C15303

D-fructose 6-phosphate

C2125

α-D-glucose 6-phosphate

C2123

β-D-glucose 6-phosphate

C8704

D-xylulose 5-phosphate

C8708

1-deoxy-D-xylulose 5-phosphate

C10604

D-ribulose 5-phosphate

C5615

D-glyceraldehyde 3-phosphate

C6673

sucrose 6F-phosphate

C3137

undecaprenyldiphospho-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine

C3138

undecaprenyl-diphospho-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-L-lysyl- D-alanyl-D-alanine

C10362

undecaprenyl-diphospho-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-L-lysyl- D-alanine

C10372

a peptidoglycan dimer (S. aureus)

C10379

a peptidoglycan dimer (E. faeciums)

C10374

decaprenyl-pyrophosphoryl-(N-acetylglucosamine)-N-acetylmuramyl-(pentapeptide)

C10381

a peptidoglycan dimer (mycobacteria)

C3120

ditrans,octacis-undecaprenyldiphospho-[(N-acetyl-β-D-glucosaminyl)-(1,4)-]-N-acetyl-α-D-muramoyl-L-alanyl-γ-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine

C3131

ditrans,octacis-undecaprenyldiphospho-N-acetyl-(N-acetylglucosaminyl)muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanine

C3122

ditrans,octacis-undecaprenyldiphospho-N-acetyl-(N-acetyl-β-D-glucosaminyl)muramoyl-L-alanyl-γ-D-glutamyl-L-lysyl-D-alanyl-D-alanine

C361

a peptidoglycan with D,D cross-links (meso-diaminopimelate containing)

C13230

a peptidoglycan dimer (meso-diaminopimelate containing)

C10383

a peptidoglycan with L,D cross-links (mycobacteria)

C10364

a peptidoglycan with D,D cross-links (mycobacteria)

C14591

a peptidoglycan with D,D cross-link (S. aureus)

C14587

a peptidoglycan tetramer with a D,D cross-link (Enterococcus faecium)

C8835

β-D-fructofuranose

C2858

glycolaldehyde

C9494

D-glyceraldehyde

C10693

sucrose

C9304

trans,octacis-decaprenyl phosphate

C9075

mono-trans,octa-cis-decaprenyl diphosphate

C8321

geranyl diphosphate

C8322

di-trans,octa-cis-undecaprenyl phosphate

C1813

di-trans,octa-cis-undecaprenyl diphosphate

C5383

all-trans-octaprenyl diphosphate

C5364

all-trans-decaprenyl diphosphate

C5382

all-trans-heptaprenyl diphosphate

C5368

all-trans-hexaprenyl diphosphate

C15301

all-trans-nonaprenyl diphosphate

C4553

3-octaprenyl-4-hydroxybenzoate

C4550

3-decaprenyl-4-hydroxybenzoate

C4549

3-heptaprenyl-4-hydroxybenzoate

C7060

3-hexaprenyl-4-hydroxybenzoate

C4545

3-nonaprenyl-4-hydroxybenzoate

C4334

1-oleoyl-2-palmitoyl-phosphatidylglycerol

C5904

phosphatidylglycerophosphate (1-octadecenoyl(9Z), 2-palmitoyl)

C3117

dioleoyl phosphatidate

C6241

1-oleoyl-sn-glycerol 3-phosphate

C10025

1-C16:0-α,ω-dicarboxyl-2-lysophosphatidate

C11421

protocatechuate

C3450

ethanol

C3523

1-propanal

C3500

acetaldehyde

C10143

menadione

C2040

diacetyl

C3308

pyruvate

C3301

2-oxoglutarate

C3351

glyoxylate

C3345

3-phenyl-2-oxopropanoate

C8974

4-aminobenzoate

C11517

acetate

C11482

(R)-pantoate

C11481

orotate

C4985

(S)-1-pyrroline-5-carboxylate

C6371

3-oxoadipate

C3421

formate

C6185

(R)-lactate

C8534

cis-aconitate

C8536

3-carboxy-cis,cis-muconate

C8531

D-threo-isocitrate

C8950

chorismate

C6442

succinate

C6443

fumarate

C2802

(S)-malate

C6934

4-hydroxybenzoate

C2915

menadiol

C9501

6-methoxy-3-methyl-2-all-trans-octaprenyl-1,4-benzoquinol

C1868

3-demethylubiquinol-9

C1867

3-demethylubiquinol-8

C1865

3-demethylubiquinol-7

C1866

3-demethylubiquinol-10

C1860

demethylmenaquinol-7

C1857

demethylmenaquinol-6

C1863

demethylmenaquinol-8

C1672

menaquinol-7

C1679

menaquinol-6

C1680

menaquinol-8

C5551

ubiquinol-9

C5543

ubiquinol-8

C5559

ubiquinol-6

C5535

ubiquinol-7

C5563

ubiquinol-10

C13354

preQ0

C12680

(7,8-dihydropterin-6-yl)methyl diphosphate

C12728

6-(hydroxymethyl)-7,8-dihydropterin

C12730

7,8-dihydroneopterin 3'-triphosphate

C12664

7,8-dihydroneopterin

C12696

7,8-dihydromonapterin

C12708

7,8-dihydroneopterin 3'-phosphate

C10609

7,8-dihydropteroate

C10597

7,8-dihydrofolate monoglutamate

C7129

5,6,7,8-tetrahydrofolate

C4599

(6S)-5-formyl-tetrahydrofolate mono-L-glutamate

C8565

5-methyltetrahydropteroyl mono-L-glutamate

C414

10-formyl-tetrahydrofolate mono-L-glutamate

C6250

5,10-methylenetetrahydropteroyl mono-L-glutamate

C10052

FMN

C10988

riboflavin

C10053

FAD

C10049

FMNH2

C1659

6,7-dimethyl-8-(1-D-ribityl)lumazine

C10994

thiamine

C10982

nicotinate

C10996

nicotinamide

C4210

pyridoxal 5'-phosphate

C4188

pyridoxamine 5'-phosphate

C4214

pyridoxine 5'-phosphate

C4208

pyridoxine

C4200

pyridoxal

C4216

pyridoxamine

C10614

coenzyme A

C5394

(R)-NADHX

C5392

(S)-NADHX

C11516

glycine betaine

C4901

succinyl-CoA

C5298

acetyl-CoA

C4913

malonyl-CoA

C5276

3-oxo-2-(cis-2'-pentenyl)-cyclopentane-1-(3-oxooctanoyl)-CoA

C5278

3-oxo-2-(cis-2'-pentenyl)-cyclopentane-1-(3R-hydroxyoctanoyl)-CoA

C5270

3-oxo-2-(cis-2'-pentenyl)-cyclopentane-1-(3-oxohexanoyl)-CoA

C5272

3-oxo-2-(cis-2'-pentenyl)-cyclopentane-1-(3R-hydroxyhexanoyl)-CoA

C5263

3-oxo-2-(cis-2'-pentenyl)-cyclopentane-1-(3-oxobutanoyl)-CoA

C5265

3-oxo-2-(cis-2'-pentenyl)-cyclopentane-1-(3R-hydroxybutanoyl)-CoA

C5308

(3S)-hydroxyadipyl-CoA

C5186

(3R,11Z,14Z,17Z)-3-hydroxyicosatrienoyl-CoA

C5182

(11Z,14Z,17Z)-3-oxoicosatrienoyl-CoA

C4937

3'-dephospho-CoA

C5635

oleoyl-CoA

C10758

3-oxoadipyl-CoA

C6198

3-oxodecanoyl-CoA

C6200

3-oxohexanoyl-CoA

C6197

3-oxooctanoyl-CoA

C2008

acetoacetyl-CoA

C6562

hexadecanedioyl-CoA

C1177

propanoyl-CoA

C7162

cerotoyl-CoA

C7169

2-carboxy-cerotoyl-CoA

C10775

(S)-3-hydroxybutanoyl-CoA

C7353

(S)-3-hydroxydecanoyl-CoA

C5922

(S)-3-hydroxyhexanoyl-CoA

C15307

(S)-3-hydroxyoctanoyl-CoA

C5919

(S)-methylmalonyl-CoA

C4560

3,24-dioxocholest-4-en-26-oyl-CoA

C4513

24-hydroxy-3-oxocholest-4-en-26-oyl-CoA

C10538

androsta-1,4-diene-3,17-dione

C10542

androst-4-ene-3,17-dione

C10545

9α-hydroxyandrosta-1,4-diene-3,17-dione

C10544

3-hydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione

C10548

3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione

C8039

5-formamido-1-(5-phospho-D-ribosyl)-imidazole-4-carboxamide

C8043

5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide

C3574

spermidine

C3548

putrescine

C6524

2-aminoprop-2-enoate

C1689

trimethyl sulfonium

C7036

hydrogencarbonate

C8958

superoxide

C6097

phosphate

C6093

diphosphate

C7006

chloride

C11005

Zn2+

C11023

Fe2+

C4320

H+

C4328

ammonium

C4734

dimethyl sulfide

C4678

glutathione

C12637

3-sulfopyruvate

C12587

L-cysteate

C5750

2-[(2R,5Z)-2-carboxy-4-methylthiazol-5(2H)-ylidene]ethyl phosphate

C5744

5-(2-hydroxyethyl)-4-methylthiazole

C5753

4-methyl-5-(2-phosphooxyethyl)thiazole

C5759

2-(2-carboxy-4-methylthiazol-5-yl)ethyl phosphate

C4658

2,4-dinitrophenyl-S-glutathione

C13114

1-chloro-2,4-dinitrobenzene