AntibioticMech

pyrimethamine

CHEBI:8673 ·resolve ·ANTIPROTOZOAL ·EXACT SEEDED

An aminopyrimidine that is pyrimidine-2,4-diamine which is substituted at position 5 by a p-chlorophenyl group and at position 6 by an ethyl group. It is a folic acid antagonist used as an antimalarial or with a sulfonamide to treat toxoplasmosis. — ChEBI

Classification

antibiotic without defined classificationARO:3000003

Strictly broader compounds or drug classes this molecule belongs to.

• CHEBI:38338 CHEBI:38338
• CHEBI:83403 CHEBI:83403
• ARO:3000003 ARO:3000003

Chemical structure

Computed structure properties

Molecular formula	C12H13ClN4
Charge	0
Average mass	248.717 Da
Monoisotopic mass	248.08287 Da
Source	ChEBI
InChIKey	WKSAUQYGYAYLPV-UHFFFAOYSA-N

SMILES

CCc1nc(N)nc(N)c1-c1ccc(Cl)cc1

InChI

InChI=1S/C12H13ClN4/c1-2-9-10(11(14)17-12(15)16-9)7-3-5-8(13)6-4-7/h3-6H,2H2,1H3,(H4,14,15,16,17)

Also called

• pirimetamina (INN)— chebi
• pyrimethaminum (INN)— chebi
• pyriméthamine (INN)— chebi
• 5-(4-chlorophenyl)-6-ethylpyrimidine-2,4-diamine (EXACT_SYNONYM)— chebi
• 2,4-Diamino-5-(4-chlorophenyl)-6-ethylpyrimidine (EXACT_SYNONYM)— chebi
• 2,4-Diamino-5-(p-chlorophenyl)-6-ethylpyrimidine (EXACT_SYNONYM)— chebi
• 2,4-Diamino-5-chlorophenyl-6-ethylpyrimidine (EXACT_SYNONYM)— chebi
• 5-(4'-Chlorophenyl)-2,4-diamino-6-ethylpyrimidine (EXACT_SYNONYM)— chebi
• 5-(4-Chlorophenyl)-6-ethyl-2,4-diaminopyrimidine (EXACT_SYNONYM)— chebi
• 5-(4-Chlorophenyl)-6-ethyl-2,4-pyrimidinediamine (EXACT_SYNONYM)— chebi
• CD (EXACT_SYNONYM)— chebi
• Chloridine (EXACT_SYNONYM)— chebi
• Chloridyn (EXACT_SYNONYM)— chebi
• Diaminopyritamin (EXACT_SYNONYM)— chebi
• Ethylpyrimidine (EXACT_SYNONYM)— chebi
• Primethamine (EXACT_SYNONYM)— chebi
• chloridin (EXACT_SYNONYM)— chebi
• diaminopyritamin (EXACT_SYNONYM)— chebi
• pirimecidan (EXACT_SYNONYM)— chebi
• pirimetamin (EXACT_SYNONYM)— chebi
• pyrimethamin (EXACT_SYNONYM)— chebi

Cross-references

Equivalent identifiers for this same structure in other resources.

• ARO:3009163
• cas:58-14-0
• drugbank:DB00205
• drugcentral:2332
• hmdb:HMDB0014350
• kegg.compound:C07391
• kegg.drug:D00488
• lincs.smallmolecule:LSM-3967
• pdb-ccd:CP6
• reaxys:219864
• vsdb:1912
• wikipedia.en:Pyrimethamine
• chembl:CHEMBL36
• pubchem.compound:4993

Activity roles

Every antimicrobial role a source asserts for this compound — the unreduced evidence behind its antimicrobial_class.

• CHEBI:35820 CHEBI:35820
• CHEBI:38068 CHEBI:38068

Source concepts

Every upstream concept that resolved to this record. The merge is the product: this is what shows ChEBI and CARD are describing the same structure.

Upstream concepts merged into this record

Source	Native ID	Label	Minted CURIE	Version
ARO	ARO:3009163	pyrimethamine	antibioticmech:aro-e7e60b9586	2026-08-30
CHEBI	CHEBI:8673	pyrimethamine	antibioticmech:chebi-389df716d8	2026-08-30

Mechanism summary

Mode of action

FOLATE_PATHWAY_INHIBITION host shared target — Assigned from ChEBI role CHEBI:50683 (EC 1.5.1.3 (dihydrofolate reductase) inhibitor). ChEBI asserts the role on the compound. The target it names is one the host has too, so the mechanism is true but is not evidence of selectivity — see mode_of_action_target_scope. Not a curator's mechanistic review.

Clinical status

APPROVED

Resistance mechanisms

2 known routes by which microbes resist this compound, grounded in ARO where CARD models them. Grouped by mechanism type — expand a group to see its determinants.

ANTIBIOTIC_TARGET_ALTERATION 2

ANTIBIOTIC_TARGET_ALTERATION

Determinant	ARO ID	Organism	Gene families	Evidence
Pneumocystis jerovecii dhfr with mutations associated with resistance to Trimethoprim sulfamethoxazole combined with Pyrimethamine atovaquone	ARO:3009290	not organism-specific	—	ARO:3009290 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3009163 (pyrimethamine); database assertion, not a primary citation.)
Pneumocystis jerovecii dhfr with mutations associated with resistance to pyrimethamine-sulfadoxine	ARO:3009285	not organism-specific	—	ARO:3009285 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3009163 (pyrimethamine); database assertion, not a primary citation.)

Curation history

1. SEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Seeded from data/raw/ inventories (ARO, CHEBI)

2. RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

3. RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

4. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

5. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

Provenance

Seeded by scripts/seed_from_sources.py from the committed inventories in data/raw/. View the record.