Symmetrical dimethylhydrazine

Names
Preferred IUPAC name

1,2-Dimethylhydrazine[2]

Other names

* N,N'-Dimethylhydrazine[1]
* sym-Dimethylhydrazine[1]
* Hydrazomethane[1]

Identifiers

CAS Number

* 540-73-8 Y

3D model (JSmol)

* Interactive image

Abbreviations  | SDMH[1]
ChEBI |

* CHEBI:73755 Y

ChEMBL |

* ChEMBL162921 Y

ChemSpider |

* 1282 Y

KEGG |

* C19176 Y

MeSH | 1,2-Dimethylhydrazine

PubChem CID

* 1322

RTECS number |

* MV2625000

UNII |

* IX068S9745 Y

UN number | 2382

InChI

* InChI=1S/C2H8N2/c1-3-4-2/h3-4H,1-2H3 Y

Key: DIIIISSCIXVANO-UHFFFAOYSA-N Y

SMILES

* CNNC

Properties[3]

Chemical formula

| C2H8N2
Molar mass | 60.100 g·mol−1
Appearance  | Colourless liquid
Odor | Fishy, ammoniacal
Density | 827.4 kg m−3 (at 20 °C)
Melting point |  −9 °C (16 °F; 264 K)
Boiling point |  87 °C; 188 °F; 360 K

Solubility in water

| Miscible
Thermochemistry

Heat capacity (C)

| 171.04 J K−1 mol−1

Std molar
entropy (S ~~o~~ 298)

| 199.15 J K−1 mol−1

Std enthalpy of
combustion (ΔcH⦵298)

| −1987–−1978 kJ mol−1
Hazards
GHS pictograms |
GHS Signal word | Danger

GHS hazard statements

| H301, H311, H331, H350, H411

GHS precautionary statements

| P201, P202, P261, P264, P270, P271, P273, P280, P281, P301+310, P302+352, P304+340, P308+313, P311, P312, P322, P330, P361, P363, P391, P403+233, P405
Related compounds

Related compounds

* Biurea
* Daminozide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is YN ?)
Infobox references

Tracking categories (test):

* SizeSet

Symmetrical dimethylhydrazine (SDMH), or 1,2-dimethylhydrazine, is the organic compound with the formula (CH3NH)2. It is one of the two isomers of dimethylhydrazine. Both isomers are colourless liquids at room temperature, with properties like those of methylamines.[5] Symmetrical dimethylhydrazine is a potent carcinogen that acts as a DNA methylating agent.[6] The compound has no commercial value, in contrast to its isomer unsymmetrical dimethylhydrazine(1,1-dimethylhydrazine, UDMH), which is used as a rocket fuel.[7] SDMH is more toxic than unsymmetrical dimethylhydrazine and is often considered an unwanted impurity in UDMH.[8][9]

It is used to induce colon tumors in experimental animals, particularly mice and feline cell samples.[6]

## Contents

* 1 Synthesis
* 1.1 Reactivity
* 2 Biotransformation
* 3 Adverse effects
* 4 Use and exposure risk
* 5 Molecular mechanism of action
* 6 Toxicology data
* 7 References

## Synthesis

The synthesis of symmetrical dimethylhydrazine is a two-step reaction. First N,N′-bis(ethoxycarbonyl)hydrazide is prepared by elimination of HCl from ethyl chloroformate (2 eq, R1) and hydrazine (1 eq, R1) in the presence of NaOH (2 eq, R1).[10] Then the N,N′-bis(ethoxycarbonyl)hydrazide (1 eq, R2) is reduced by lithium aluminum hydride (6 eq, R2) to form symmetrical dimethylhydrazine.[11]

### Reactivity

The reactive groups of symmetrical dimethyl hydrazine are the NH-groups. Both can accept and donate hydrogen bonds, making it soluble in water. The NH-groups can also act as a nucleophile and as a base.[12]

## Biotransformation

Symmetrical dimethylhydrazine is first oxidized to azomethane which is then oxidized to azoxymethane. This compound is subsequently hydroxylated to methylazoxymethanol (MAM). These processes occur mostly in the liver, and the hydroxylation step is mediated by cytochrome P450 enzymes.[6][13][14]

MAM is chemically unstable and can spontaneously decompose to formaldehyde, water and nitrogen. In this decomposition, the methyldiazonium ion is formed, which can alkylate DNA and increase the risk of mismatched bases.[6][13][14]

## Adverse effects

Chronic exposure of symmetrical dimethylhydrazine led to adverse effects in multiple organs in animals, but its most prominent effect is carcinogenicity. This has been reported in several animal experiments, including rats and mice.[10]

1,2-dimethylhydrazine is classified as a category 2 carcinogen, meaning that there is a significant probability that it can cause cancer in humans as well.[15]

## Use and exposure risk

Symmetrical dimethylhydrazine is mainly used experimentally for its carcinogenic properties, particularly to induce colon cancer in laboratory animals for cancer research.[6] Its isomer, unsymmetrical dimethylhydrazine, is widely used in rocket fuel.[7]

Because symmetrical dimethylhydrazine is not used commercially, it is unlikely to be released into the environment in large volumes. When released into the air, hydrazine compounds are relatively quickly decomposed by reactive compounds in the air. Also, in soil or water hydrazines usually do not persist for longer than a few weeks.[16]

Human exposure is therefore unlikely. Laboratory staff that works with the compound would be most at risk. It might also be possible to come into contact through hazardous waste sites, although unlikely.[16]

## Molecular mechanism of action

Symmetrical dimethylhydrazine is an indirect-acting genotoxin, meaning its carcinogenicity depends on the metabolization to methyldiazonium ions.[13] Methyldiazonium is a strong methylating agent due to its electrophilic nature and can methylate nucleotide bases in DNA.[14][17]

Methylation occurs most frequently at the N7 or O6 sites of guanine[14][18], but it can also methylate at the C8 site of guanine and at the N3 site of adenine, as well as at the O4 site of thymine.[19]

The methylated base may mispair during DNA replication. For example, methylated guanine can pair with thymine, instead of cytosine.[20] This is followed by subsequent replication, which leads to further mispairing and could mutate a GC pair to an AT pair.[6] When mutations occur in certain genes a neoplasm can be initiated.[21]

## Toxicology data

The International Agency for Research on Cancer (IARC) has classified symmetrical dimethyl hydrazine as part of group 2A of the carcinogenesis classification, meaning it is probably carcinogenic to humans.[15] Although the effects of symmetrical dimethyl hydrazine have not been studied on humans in vivo, there is sufficient evidence acquired from animal studies. Similar patterns of DNA damage in humans and a wide range of animals have been observed in vitro, caused by dimethyl hydrazine.[12]

The ILO-WHO International Chemical Safety Cards (ICSCs) warns that symmetrical dimethyl hydrazine can be absorbed into the body by inhalation, ingestion and possibly through the skin contact.[22] Depending on the route of exposure and on the species tested, the LD50 ranged from tens to several hundred mg/kg.[5]

The primary target appears to be the intestines, where morphological and biochemical changes have been observed in the intestinal epithelium after subcutaneous injection.[23]

## References

1. ↑ 1.0 1.1 1.2 1.3 74-79-3 1,2-Dimethylhydrazine
2. ↑ 1,2-Dimethylhydrazine from PubChem
3. ↑ Record of 1,2-Dimethylhydrazin in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on 21 March 2008.
4. ↑ "1,2-Dimethylhydrazine" (in en). https://pubchem.ncbi.nlm.nih.gov/compound/1322#section=Safety-and-Hazards.
5. ↑ 5.0 5.1 PubChem. "1,2-Dimethylhydrazine" (in en). https://pubchem.ncbi.nlm.nih.gov/compound/1322.
6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Venkatachalam, Karthikkumar; Vinayagam, Ramachandran; Arokia Vijaya Anand, Mariadoss; Isa, Nurulfiza Mat; Ponnaiyan, Rajasekar (2020-04-24). "Biochemical and molecular aspects of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis: a review" (in en). Toxicology Research 9 (1): 2–18. doi:10.1093/toxres/tfaa004. ISSN 2045-4538. PMID 32440334. PMC 7233314. https://academic.oup.com/toxres/article/9/1/2/5813023.
7. ↑ 7.0 7.1 Elizaveta, Ivanova; Margarita, Osipova; Tatyana, Vasilieva; Alexey, Eremkin; Svetlana, Markova; Ekaterina, Zazhivihina; Svetlana, Smirnova; Yurii, Mitrasov et al. (2023). "The Recycling of Substandard Rocket Fuel N,N-Dimethylhydrazine via the Involvement of Its Hydrazones Derived from Glyoxal, Acrolein, Metacrolein, Crotonaldehyde, and Formaldehyde in Organic Synthesis" (in en). International Journal of Molecular Sciences 24 (24). doi:10.3390/ijm. ISSN 1422-0067. https://www.mdpi.com/1422-0067/24/24/17196.
8. ↑ Schmidt, Eckart W. (2022-12-31) (in en), Dimethylhydrazines Part 1, De Gruyter, pp. 1333–1499, doi:10.1515/9783110750287-016, ISBN 978-3-11-075028-7, https://www.degruyterbrill.com/document/doi/10.1515/9783110750287-016/html, retrieved 2026-03-14
9. ↑ Cruse, J. P.; Lewin, M. R.; Ferulano, G. P.; Clark, C. G. (1978). "Co-carcinogenic effects of dietary cholesterol in experimental colon cancer" (in en). Nature 276 (5690): 822–825. doi:10.1038/276822a0. ISSN 1476-4687. PMID 723955. https://www.nature.com/articles/276822a0.
10. ↑ 10.0 10.1 Waki, Kunio; Zhao, Jincai; Horikoshi, Satoshi; Watanabe, Natsuko; Hidaka, Hisao (2000-08-01). "Photooxidation mechanism of nitrogen-containing compounds at TiO2/H2O interfaces: an experimental and theoretical examination of hydrazine derivatives". Chemosphere 41 (3): 337–343. doi:10.1016/S0045-6535(99)00500-7. ISSN 0045-6535. PMID 11057595. https://www.sciencedirect.com/science/article/pii/S0045653599005007.
11. ↑ Hinman, Richard L. (1956). "The Synthesis of Alkylhydrazines. I. The Reaction of Lithium Aluminum Hydride with Mono- and Diacylhydrazines1". Journal of the American Chemical Society 78 (8): 1645–1649. doi:10.1021/ja01589a040. https://pubs.acs.org/action/cookieAbsent. Retrieved 2026-03-14.
12. ↑ 12.0 12.1 PubChem. "Hazardous Substances Data Bank (HSDB) : 4039" (in en). https://pubchem.ncbi.nlm.nih.gov/source/hsdb/4039.
13. ↑ 13.0 13.1 13.2 Fiala, ES (November 1977). <2436::AID-CNCR2820400908>3.0.CO;2-U "Investigations into the metabolism and mode of action of the colon carcinogens 1,2-dimethylhydrazine and azoxymethane". doi:10.1002/1097-0142(197711)40:5. https://doi.org/10.1002/1097-0142(197711)40:5+<2436::AID-CNCR2820400908>3.0.CO;2-U.
14. ↑ 14.0 14.1 14.2 14.3 Hartwig, A (2021). "1,2-Dimethylhydrazine". The Mak Collection for Occupational Health and Safety 9 (4). doi:10.34865/mb54073e9_4ad. https://doi.org/10.34865/mb54073e9_4ad.
15. ↑ 15.0 15.1 "List of Classifications" (in en-US). https://monographs.iarc.who.int/list-of-classifications.
16. ↑ 16.0 16.1 TOXICOLOGICAL PROFILE FOR HYDRAZINES. U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES. September 1997.
17. ↑ Pozharisski, K. M.; Shaposhnikov, J. D.; Petrov, A. S.; Likhachev, A. J. (1976-01-01). "Distribution and carcinogenic action of 1,2-dimethylhydrazine (SDMH) in rats" (in en). Zeitschrift für Krebsforschung und Klinische Onkologie 87 (1): 67–80. doi:10.1007/BF00285075. ISSN 1432-1335. PMID 136114. https://doi.org/10.1007/BF00285075.
18. ↑ Autrup, Herman; Schwartz, Rochelle D.; Essigmann, John M.; Smith, Lee; Harris, Curtis C.; Trump, Benjamin F. (1981). "Metabolism of aflatoxin B1, benzo[apyrene, and 1,2-dimethylhydrazine by cultured rat and human colon"] (in en). Teratogenesis, Carcinogenesis, and Mutagenesis 1 (1): 3–13. doi:10.1002/tcm.1770010103. ISSN 1520-6866. PMID 6119799. https://onlinelibrary.wiley.com/doi/abs/10.1002/tcm.1770010103.
19. ↑ Likhachev AL, Petrov AS, P’rvanova LG, Pozharisski KM. Mechanism of methylation of DNA bases by symmetrical dimethylhydrazine.
20. ↑ Lawley PD. Carcinogenesis by alkylating agents. In: Chemical Carcinogens. Washington (DC): American Chemical Society; 1984.
21. ↑ Pegg, A. E. (1990), Cooper, Colin S.; Grover, Philip L., eds., "DNA Repair and Carcinogenesis by Alkylating Agents" (in en), Chemical Carcinogenesis and Mutagenesis II, Handbook of Experimental Pharmacology (Berlin, Heidelberg: Springer) 94 / 2: pp. 103–131, doi:10.1007/978-3-642-74778-6_5, ISBN 978-3-642-74778-6, https://doi.org/10.1007/978-3-642-74778-6_5, retrieved 2026-03-14
22. ↑ "ICSC 1662 - 1,2-DIMETHYLHYDRAZINE". https://chemicalsafety.ilo.org/dyn/icsc/showcard.display?p_card_id=1662.
23. ↑ Record  in the GESTIS Substance Database of the Institute for Occupational Safety and Health

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Hydrazines

* 4-PTSC
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* ADH
* Adjudin
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* Benmoxin
* Cadralazine
* Carbazide
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* Carbohydrazide
* Daminozide
* Dihydralazine
* DNPH
* Endralazine
* Gyromitrin
* HBT
* Hydralazine
* Hydrazide
* Hydrazine
* Hydrazone
* Iproclozide
* Iproniazid
* Isocarboxazid
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* Mebanazine
* Metfendrazine
* MMH
* Nialamide
* Octamoxin
* PEH
* Phenelzine
* Pheniprazine
* Phenoxypropazine
* Phenylhydrazine
* Pildralazine
* Pimagedine
* Pivalylbenzhydrazine
* Procarbazine
* Safrazine
* Semicarbazide
* Semicarbazone
* SDMH
* Tetrafluorohydrazine
* UDMH

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Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Symmetrical_dimethylhydrazine&oldid=4310153"
*[CID]: Compound ID
*[H301]: Toxic if swallowed
*[H311]: Toxic in contact with skin
*[H331]: Toxic if inhaled
*[H350]: May cause cancer
*[H411]: Toxic to aquatic life with long lasting effects
*[P201]: Obtain special instructions before use
*[P202]: Do not handle until all safety precautions have been read and understood
*[P261]: Avoid breathing dust/fume/gas/mist/vapours/spray
*[P264]: Wash … thoroughly after handling
*[P270]: Do not eat, drink or smoke when using this product
*[P271]: Use only outdoors or in a well-ventilated area
*[P273]: Avoid release to the environment
*[P280]: Wear protective gloves/protective clothing/eye protection/face protection
*[P281]: Use personal protective equipment as required
*[P301+310]: IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician
*[P302+352]: IF ON SKIN: Wash with soap and water
*[P304+340]: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing
*[P308+313]: IF exposed or concerned: Get medical advice/attention
*[P311]: Call a POISON CENTER or doctor/physician
*[P312]: Call a POISON CENTER or doctor/physician if you feel unwell
*[P322]: Specific measures (see … on this label)
*[P330]: Rinse mouth
*[P361]: Remove/Take off immediately all contaminated clothing
*[P363]: Wash contaminated clothing before reuse
*[P391]: Collect spillage
*[P403+233]: Store in a well ventilated place. Keep container tightly closed
*[P405]: Store locked up
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