N-Hydroxysuccinimide

N-Hydroxysuccinimide

Names
IUPAC name 1-Hydroxy-2,5-pyrrolidinedione
Other names 1-hydroxypyrrolidine-2,5-dione, HOSu
Identifiers
CAS Number	6066-82-6 Y
3D model (Jmol)	Interactive image
ChemSpider	72416 N
ECHA InfoCard	100.025.456
PubChem	80170
UNII	MJE3791M4T N
InChI InChI=1S/C4H5NO3/c6-3-1-2-4(7)5(3)8/h8H,1-2H2 N Key: NQTADLQHYWFPDB-UHFFFAOYSA-N N InChI=1/C4H5NO3/c6-3-1-2-4(7)5(3)8/h8H,1-2H2 Key: NQTADLQHYWFPDB-UHFFFAOYAM
SMILES O=C1N(O)C(=O)CC1
Properties
Chemical formula	C4H5NO3
Molar mass	115.09 g/mol
Appearance	Colourless solid
Melting point	95 °C (203 °F; 368 K)
Related compounds
Related imides	Succinimide N-Bromosuccinimide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

N-Hydroxysuccinimide (NHS) is an organic compound with the formula C₄H₅NO₃. Being slightly acidic, it is an irritant to skin, eyes and mucous membranes.

NHS is commonly found in organic chemistry or biochemistry where it is used as an activating reagent for carboxylic acids. Activated acids (basically esters with a good leaving group) can react with amines to form amides for example, whereas a normal carboxylic acid would just form a salt with an amine.

A common way to synthesize an NHS-activated acid is to mix NHS with the desired carboxylic acid and a small amount of an organic base in an anhydrous solvent. A coupling reagent such as dicyclohexylcarbodiimide (DCC) or ethyl(dimethylaminopropyl) carbodiimide (EDC) is then added to form a highly reactive activated acid intermediate. NHS reacts to form a less labile activated acid. The group itself is usually written as SuO- or -OSu in chemical notation. Such an ester with an acid and NHS, sometimes called succinate ester, is stable enough to be purified and stored at low temperatures in the absence of water and, as such, is commercially available. NHS esters are commonly used for protein modification (e.g. an NHS ester of fluorescein is commercially available, and can be added to a protein to obtain a fluorescently labeled protein in one simple reaction and purification step).

Some alternatives to NHS are the water-soluble analog sulfo-NHS, hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole (HOAt) and pentafluorophenol.