Diazald
Names
Preferred IUPAC name
N,4-Dimethyl-N-nitrosobenzene-1-sulfonamide
Other names
N-Methyl-N-nitroso-4-methylbenzenesulfonamide; N-Methyl-N-nitroso-p-toluenesulphonamide; N-Methyl-N-nitroso-4-methylbenzenesulphonamide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.001.139
EC Number
  • 201-252-6
MeSH C418734
UNII
  • InChI=1S/C8H10N2O3S/c1-7-3-5-8(6-4-7)14(12,13)10(2)9-11/h3-6H,1-2H3
    Key: FFKZOUIEAHOBHW-UHFFFAOYSA-N
  • InChI=1/C8H10N2O3S/c1-7-3-5-8(6-4-7)14(12,13)10(2)9-11/h3-6H,1-2H3
    Key: FFKZOUIEAHOBHW-UHFFFAOYAJ
  • Cc1ccc(cc1)S(=O)(=O)N(C)N=O
Properties
C8H10N2O3S
Molar mass 214.24 g·mol−1
Appearance Light yellow solid
Melting point 61–62 °C (142–144 °F; 334–335 K)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Skin sensitiser, irritant, explosive[1]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
2
0
3
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Diazald (N-methyl-N-nitroso-p-toluenesulfonamide) is used as a relatively safe and easily handled precursor to diazomethane, which is toxic and unstable.[2] Diazald has become the favored commercially available precursor for the synthesis of diazomethane, compared to reagents like N-methyl-N-nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine, which are less thermally stable and more toxic and mutagenic, respectively.

Upon the addition of a base such as sodium hydroxide or potassium hydroxide and mild heating (65–70 °C) in a mixture of water, diethyl ether, and a high boiling polar cosolvent (e.g., diethylene glycol monomethyl ether[3]), the N-nitrososulfonamide undergoes successive elimination reactions to produce diazomethane (which is codistilled as an ethereal solution) as well as a p-toluenesulfonate salt as a byproduct, according to the following mechanism:

Like other nitroso compounds, it is thermally sensitive, as a result of its weak N–NO bond whose bond dissociation energy was measured to be 33.4 kcal/mol.[4]

References

  1. ↑ External MSDS, Sigma Aldrich
  2. ↑ Diazald in Chemical Synthesis, Sigma Aldrich
  3. ↑ "Diazomethane". www.orgsyn.org. Retrieved 2018-07-27.
  4. ↑ Zhu, Xiao-Qing; Hao, Wei-Fang; Tang, Hui; Wang, Chun-Hua; Cheng, Jin-Pei (March 2005). "Determination of N−NO Bond Dissociation Energies ofN-Methyl-N-nitrosobenzenesulfonamides in Acetonitrile and Application in the Mechanism Analyses on NO Transfer". Journal of the American Chemical Society. 127 (8): 2696–2708. doi:10.1021/ja0443676. ISSN 0002-7863. PMID 15725027.
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