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Skeletal formula of N-nitroso-N-methylurea
Ball and stick model of N-nitroso-N-methylurea
Spacefill model of N-nitroso-N-methylurea
Preferred IUPAC name
Other names
3D model (JSmol)
Abbreviations NMU[citation needed]
EC Number
  • 211-678-4
MeSH Methylnitrosourea
Molar mass 103.081 g·mol−1
log P −0.302
Acidity (pKa) 12.365
Basicity (pKb) 1.632
Related compounds
Related ureas
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
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N-Nitroso-N-methylurea (NMU) is a highly reliable carcinogen, mutagen, and teratogen. NMU is an alkylating agent, and exhibits its toxicity by transferring its methyl group to nucleobases in nucleic acids, which can lead to AT:GC transition mutations.

NMU is the traditional precursor in the synthesis of diazomethane. It has the potentially advantageous property that the stoichiometric byproducts formed are water, carbon dioxide, and ammonia, which are innocuous or easily removed. However, because it is unstable at temperatures beyond 20 °C and somewhat shock-sensitive, it has become obsolete for this purpose and replaced by other N-nitroso compounds: (N-methyl)nitrosamides and nitrosamines. Most chemical supply houses have stopped carrying it.

Acute exposure to NMU in humans can result in skin and eye irritation, headache, nausea, and vomiting.[2] NMU is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals (IARC 1972, 1978, 1987).[3] Various cancers induced in animal models include: squamous cell carcinomas of the forestomach, sarcomas and gliomas of the brain, adenocarcinomas of the pancreas, mammary carcinomas, leukemia, and lymphomas.[3] However, the actual potential for human exposure is quite limited, as the chemical is not produced or used in large quantities [3]

NMU is teratogenic and embryotoxic, resulting in craniofacial (cleft palate) and skeletal defects, fetal growth retardation, and increased fetal resorption.[4][5][6] Exposure to NMU during pre-implantation, post-implantation, organogenesis, or by paternal exposure can result in these effects.


  1. Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 663. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. 
  2. Hazardous Substance Fact Sheet for NMU New Jersey Department of Health and Senior Services
  3. 3.0 3.1 3.2 NMU Substance Profile NTP, Report on Carcinogens, Eleventh Edition
  4. Wada, A., et al. (1994). Induction of Congenital Malformations in Mice by Paternal Methylnitrosourea Treatment. Congenital Anomalies 34:65-70.
  5. Nagao, T., et al. (1991). Induction of Fetal Malformations After Treatment of Mouse Embryos with Methylnitrosourea at the Preimplantation Stages. Teratogenesis, Carcinogenesis, and Mutagenesis 11:1-10.
  6. Faustman, E., et al. (1989). In Vitro Developmental Toxicity of Five Direct-Acting Alkylating Agents in Rodent Embryos: Structure-Activity Patterns. Teratology 40:199-210.

External links