IUPAC Name: 3-Hydroxytriazolo[4,5-b]pyridine
Molecular formula: C₅H₄N₄O
Molecular Weight: 136.11 g/mol
storage temp.: Store at RT.
Melting point: 213-216 °C
Flash Point: 181.7 °C
Density: 1.74 g/cm³
Index of Refraction: 1.836 
Molar Refractivity: 34.45 cm³
Molar Volume: 78 cm³
Decomposition: 213-216 °C
Surface Tension: 84.8 dyne/cm
Enthalpy of Vaporization: 64.9 kJ/mol
Boiling Point: 376.8 °C at 760 mmHg
Vapour Pressure: 3.25E-06 mmHg at 25 °C
Appearance: Clear, colorless liquid
Product Categories of 1-Hydroxy-7-azabenzotriazole (CAS NO.39968-33-7): Peptide coupling agents; Heterocycles; PROTECTED AMINO ACID & PEPTIDES; Peptide Coupling Reagents; Heterocyclic Compounds; Peptide;Bases & Related Reagents; Nucleotides

1-Hydroxy-7-azabenzotriazole (CAS NO.39968-33-7) is a triazole used as a peptide coupling reagent. It suppresses the loss of chirality.

Hazard Codes of 1-Hydroxy-7-azabenzotriazole (CAS NO.39968-33-7): T, Xi,Xn, E ,F
 Risk Statements:
R2: Risk of explosion by shock, friction, fire or other sources of ignition
R5:  Heating may cause an explosion 
R11:  Highly Flammable 
R22:  Harmful if swallowed 
R36:  Irritating to the eyes 
R41:  Risk of serious damage to eyes 
R61:  May cause harm to the unborn child 
R20/21:  Harmful by inhalation and in contact with skin 
R37/38:  Irritating to respiratory system and skin 
R36/37/38:  Irritating to eyes, respiratory system and skin 
Safety Statements:
S16:  Keep away from sources of ignition - No smoking 
S26:  In case of contact with eyes, rinse immediately with plenty of water and seek medical advice 
S35:  This material and its container must be disposed of in a safe way 
S36:  Wear suitable protective clothing 
S39:  Wear eye/face protection 
S45:  In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) 
S53:  Avoid exposure - obtain special instruction before use 
RIDADR: UN 1993 3/PG 3
WGK Germany: 1
Hazard Note: Irritant

 1-Hydroxy-7-azabenzotriazole , its cas register number is 39968-33-7. It also can be called Hoat [1-hydroxy-7-azabenzotriazole] ; 1-Hydroxy-7-azabenzotriazole99%puriss ; 3h-1,2,3-Triazolo[4,5-b]pyridine, 3-hydroxy- ; 3h-[1,2,3]-Triazolo[4,5-b]pyridin-3-ol ; 7-aza-1-Hydroxybenzotriazole ; Hoat ; and 1-hydroxy-7-azabenzotriazole solution, 0.5m in dmf .