| S-Ribosyl-L-homocysteine | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Salicin 6-phosphate | Organic compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Glycosyl compounds | Details |
| Sedoheptulose 1,7-bisphosphate | Organic compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Monosaccharides | Details |
| Shikimate 3-phosphate | Organic compounds | Organophosphorus compounds | Organic phosphoric acids and derivatives | Phosphate esters | Details |
| Siroheme | Organic compounds | Organoheterocyclic compounds | Tetrapyrroles and derivatives | Metallotetrapyrroles | Details |
| Sirohydrochlorin | Organic compounds | Organoheterocyclic compounds | Tetrapyrroles and derivatives | Not Available | Details |
| Sucrose-6-phosphate | Organic compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Disaccharides | Details |
| Trans-2,3-Dihydroxycinnamate | Organic compounds | Phenylpropanoids and polyketides | Cinnamic acids and derivatives | Hydroxycinnamic acids and derivatives | Details |
| Trans-4-Carboxymethylenebut-2-en-4-olide | Organic compounds | Organoheterocyclic compounds | Dihydrofurans | Furanones | Details |
| UDP-2,3-Bis(3-hydroxytetradecanoyl)glucosamine | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleotides | Pyrimidine nucleotide sugars | Details |
| UDP-N-Acetyl-D-mannosamine | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleotides | Pyrimidine nucleotide sugars | Details |
| UDP-N-Acetylmuramoyl-L-alanyl-D-gamma-glutamyl-meso-2,6-diaminopimelate | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleotides | Pyrimidine nucleotide sugars | Details |
| UDP-N-Acetylmuramoyl-L-alanyl-D-glutamyl-6-carboxy-L-lysyl-D-alanyl-D-alanine | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleotides | Pyrimidine nucleotide sugars | Details |
| UDP-N-Acetylmuramoyl-L-alanyl-D-glutamyl-L-lysyl-D-alanyl-D-alanine | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleotides | Pyrimidine nucleotide sugars | Details |
| UDP-N-Acetylmuramoyl-L-alanyl-gamma-D-glutamyl-L-lysine | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleotides | Pyrimidine nucleotide sugars | Details |
| Undecaprenyl phosphate | Organic compounds | Lipids and lipid-like molecules | Prenol lipids | Polyprenols | Details |
| Undecaprenyl-diphospho-N-acetylmuramoyl-(N-acetylglucosamine)-L-alanyl-D-glutaminyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine | Organic compounds | Lipids and lipid-like molecules | Prenol lipids | Polyprenols | Details |
| Undecaprenyl-diphospho-N-acetylmuramoyl-(N-acetylglucosamine)-L-alanyl-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine | Organic compounds | Lipids and lipid-like molecules | Prenol lipids | Polyprenols | Details |
| Undecaprenyl-diphospho-N-acetylmuramoyl-(N-acetylglucosamine)-L-alanyl-gamma-D-glutamyl-L-lysyl-D-alanyl-D-alanine | Organic compounds | Lipids and lipid-like molecules | Prenol lipids | Polyprenols | Details |
| Undecaprenyl-diphospho-N-acetylmuramoyl-L-alanyl-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine | Organic compounds | Lipids and lipid-like molecules | Prenol lipids | Polyprenols | Details |
| Ureidoglycine | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| 1-Deoxyxylonojirimycin | Organic compounds | Organoheterocyclic compounds | Piperidines | Not Available | Details |
| 1-Ethyladenine | Organic compounds | Organoheterocyclic compounds | Imidazopyrimidines | Purines and purine derivatives | Details |
| 2'-(5-Triphosphoribosyl)-3'-dephospho-CoA | Organic compounds | Nucleosides, nucleotides, and analogues | Purine nucleotides | Purine ribonucleotides | Details |
| 2-Carboxymuconate | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Tricarboxylic acids and derivatives | Details |
| 2-Deoxy-D-glucose 6-phosphate | Organic compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Monosaccharides | Details |
| 2-Hydroxydeoxyadenosine 5'-triphosphate | Organic compounds | Nucleosides, nucleotides, and analogues | Purine nucleotides | Purine deoxyribonucleotides | Details |
| 2-Hydroxymalonate | Organic compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Sugar acids and derivatives | Details |
| 2-Thiouridine | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleosides | Not Available | Details |
| 3-Hydroxyadipyl-CoA | Organic compounds | Lipids and lipid-like molecules | Fatty Acyls | Fatty acyl thioesters | Details |
