Name | 1,2-BENZISOXAZOLE |
Synonyms | ISOINDOXAZINE 1,2-benzisozole 4,5-Benzisoazole 1-Oxa-2-azaindene 1,2-BENZISOXAZOLE 4,5-Benzisoxazole 1,2-benzoisoxazole 1-Oxa-2-aza-1H-indene |
CAS | 271-95-4 |
EINECS | 205-983-1 |
Molecular Formula | C7H5NO |
Molar Mass | 119.12 |
Density | 1.174 g/mL at 25 °C(lit.) |
Melting Point | 139 °C |
Boling Point | 90-92 °C15 mm Hg(lit.) |
Flash Point | 86°C |
Water Solubility | Soluble in water. 4.1 mg/mL in water at 25°C |
Appearance | Shape Oil, color Colourless |
pKa | -2.03±0.30(Predicted) |
Storage Condition | 2-8°C |
Stability | Light Sensitive |
Refractive Index | n20/D 1.561(lit.) |
MDL | MFCD00005852 |
Use | Application 1, 2-benzoxazole can be widely used in organic synthesis. It can be prepared by 2-hydroxybenzaldehyde as the reaction raw material and the intermediate (E)-2-hydroxybenzaldehyde oxime under the action of hydroxylamine hydrochloride, which is further prepared by reacting with triphenylphosphine/DEAD. |
Risk Codes | 36/37/38 - Irritating to eyes, respiratory system and skin. |
Safety Description | 24/25 - Avoid contact with skin and eyes. |
WGK Germany | 3 |
FLUKA BRAND F CODES | 8 |
Solubility | Chloroform (Slightly), Methanol (Slightly) |
BRN | 2154 |
1)(E)-Synthesis of 2-hydroxybenzaldehyde oxime Triethylamine (190mmol)
Slowly add to a solution of 2-hydroxybenzaldehyde (164mmol) and hydroxylamine hydrochloride (197mmol) in ethanol (200mL), and heat the reaction mixture at 95°C for 5h. The reaction mixture was concentrated and the residue was extracted with ethyl acetate (2 × 150mL) and water (100mL). Wash the combined organic layer with water (3 × 150mL), dry (magnesium sulfate) and concentrate. The residue was purified by rapid chromatography (1/100 ethyl acetate/petroleum ether) to provide (E)-2-hydroxybenzaldehyde oxime in the form of a white solid with a yield of 43%.
2) Synthesis of 1,2-benzoisazole At 0 ℃, within 4 hours, add DEAD(23.0mmol) tetrahydrofuran (150mL) solution to (E)-2-hydroxybenzaldehyde oxime (21.9mmol) and triphenylphosphine (23.0mmol) tetrahydrofuran (300mL) solution, stir the reaction mixture at 0 ℃ for another 60 minutes and concentrate. The residue was purified by rapid chromatography (1/100 ethyl acetate/petroleum ether) to obtain yellow oily 1,2-benzoisazole in 66% yield.