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Substance Name: Metoprine [USAN]
RN: 7761-45-7


  • Histamine methyltransferase antagonist.
  • Histamine methyltransferase antagonist.

    NCI: A diaminopyrimidine folate antagonist with potential antineoplastic activity. Metoprine inhibits dihydrofolate reductase, resulting in decreased cellular folate metabolism and cell growth; it also inhibits histamine-N-methyltransferase, resulting in decreased histamine catabolism. Lipid-soluble metoprine is capable of crossing the blood-brain barrier. (NCI Thesaurus)

Molecular Formula

  • C11-H10-Cl2-N4

Molecular Weight

  • 269.134

Classification Codes

  • Antineoplastic
  • Antineoplastic Agents
  • Enzyme Inhibitors
  • Folic Acid Antagonists
  • Mutation Data
  • Reproductive Effect
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Names and Synonyms

Name of Substance

  • Metoprine
  • Metoprine [USAN]


  • 2,4-Diamino-5-(3',4'-dichlorophenyl)-6-methyl pyrimidine
  • 2,4-Diamino-5-(3,4-dichlorophenyl)-6-methylpyrimidine
  • 5-(3,4-Dichlorophenyl)-6-methyl-2,4-pyrimidinediamine
  • 5-(3,4-Dichlorphenyl)-6-methyl-2,4-pyrimidindiamin
  • 5-25-12-00253 (Beilstein Handbook Reference)
  • AI3-26402
  • BRN 0223622
  • BW 50-197
  • BW-197U
  • DDMP
  • Methodichlorophen
  • Metoprine
  • NSC 19494
  • NSC 7364
  • NSC-19494
  • SK 5265
  • U 197
  • U-197
  • UNII-2L9RKX796Q

Systematic Names

  • 2,4-Pyrimidinediamine, 5-(3,4-dichlorophenyl)-6-methyl-
  • Pyrimidine, 2,4-diamino-5-(3,4-dichlorophenyl)-6-methyl-

Registry Numbers

CAS Registry Number

  • 7761-45-7


  • 2L9RKX796Q

System Generated Number

  • 0007761457

Structure Descriptors








Organism Test Type Route Reported Dose (Normalized Dose) Effect Source
mouse LD50 subcutaneous 50mg/kg (50mg/kg) BEHAVIORAL: CONVULSIONS OR EFFECT ON SEIZURE THRESHOLD Cancer Treatment Reports. Vol. 60, Pg. 547, 1976.
rat LD50 intraperitoneal 7mg/kg (7mg/kg)   "International Congress of Chemotherapy, Proceedings of the 3rd Congress, 1963," Kuemmerle, H.P., and Prezios, P., Stuttgart, Fed. Rep. Ger., Georg Thieme Verlag, 1964Vol. -, Pg. 367, 1964.

Physical Properties

Physical Property Value Units Temp (deg C) Source
pKa Dissociation Constant 7.15 (none) 20 EXP
log P (octanol-water) 2.82 (none)   EXP
Water Solubility 72.2 mg/L 25 EST
Vapor Pressure 3.82E-08 mm Hg 25 EST
Henry's Law Constant 6.02E-11 atm-m3/mole 25 EST
Atmospheric OH Rate Constant 2.00E-10 cm3/molecule-sec 25 EST

Physical property data is provided to ChemIDplus by SRC, Inc.