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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]
ECHA InfoCard 100.010.618
EC Number 211-678-4
MeSH Methylnitrosourea
Molar mass 103.08 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

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. 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. ^ a b c 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.