Diazald

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
CAS Number	80-11-5 ;
3D model (JSmol)	Interactive image;
ChemSpider	6376;
ECHA InfoCard	100.001.139
EC Number	201-252-6;
MeSH	C418734
PubChem CID	6628;
UNII	K3089966LA ;
CompTox Dashboard (EPA)	DTXSID8058827 ;
	InChI 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;
	SMILES Cc1ccc(cc1)S(=O)(=O)N(C)N=O;
Properties
Chemical formula	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
NFPA 704 (fire 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

^ External MSDS, Sigma Aldrich
^ Diazald in Chemical Synthesis, Sigma Aldrich
^ "Diazomethane". www.orgsyn.org. Retrieved 2018-07-27.
^ 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.

[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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