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Benzisoxazole

Names
Preferred IUPAC name 1,2-Benzoxazole
Other names Benzoisoxazole; Indoxazine
Identifiers
CAS Number	271-95-4
3D model (JSmol)	Interactive image
Beilstein Reference	2154
ChEBI	CHEBI:51554
ChEMBL	ChEMBL314871
ChemSpider	64227
ECHA InfoCard	100.005.440
EC Number	205-983-1
PubChem CID	71073
UNII	D879RKM5NQ
CompTox Dashboard (EPA)	DTXSID20181567
InChI InChI=1S/C7H5NO/c1-2-4-7-6(3-1)5-8-9-7/h1-5HKey: KTZQTRPPVKQPFO-UHFFFAOYSA-N InChI=1/C7H5NO/c1-2-4-7-6(3-1)5-8-9-7/h1-5HKey: KTZQTRPPVKQPFO-UHFFFAOYAI
SMILES n2oc1ccccc1c2
Properties
Chemical formula	C7H5NO
Molar mass	119.123 g·mol
Appearance	Colorless liquid
Density	1.18 g/cm
Boiling point	35 to 38 °C (95 to 100 °F; 308 to 311 K) (at 2.67 hPa) 101-102 °C (at 2 kPa)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Flash point	58 °C (136 °F; 331 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). N verify (what is  ?) Infobox references

1,2-Benzisoxazole is an aromatic organic compound with a molecular formula C₇H₅NO containing a benzene-fused isoxazole ring structure. The compound itself has no common applications; however, functionalized benzisoxazoles and benzisoxazoyls have a variety of uses, including pharmaceutical drugs such as some antipsychotics (including risperidone, paliperidone, ocaperidone, and iloperidone) and the anticonvulsant zonisamide.

Its aromaticity makes it relatively stable; however, it is only weakly basic.

Synthesis

Benzisoxazole may be prepared from inexpensive salicylaldehyde, via a base catalyzed room temperature reaction with hydroxylamine-O-sulfonic acid.

Reactions

Kemp elimination

First reported by Daniel S. Kemp, the relatively weak N-O bond can be cleaved by a strong base to yield a 2-hydroxybenzonitrile species.

See also

Structural isomers

• Benzoxazole
• Anthranil

References

1. Katritzky, A. R.; Pozharskii, A. F. (2000). Handbook of Heterocyclic Chemistry (2nd ed.). Academic Press. ISBN 0080429882.
2. Clayden, J.; Greeves, N.; Warren, S.; Wothers, P. (2001). Organic Chemistry. Oxford, Oxfordshire: Oxford University Press. ISBN 0-19-850346-6.
3. Domene, Carmen; Jenneskens, Leonardus W.; Fowler, Patrick W. (2005). "Aromaticity of anthranil and its isomers, 1,2-benzisoxazole and benzoxazole". Tetrahedron Letters. 46 (23): 4077–4080. doi:10.1016/j.tetlet.2005.04.014. hdl:1874/14837. ISSN 0040-4039.
4. Kemp, D.S.; Woodward, R.B. (1965). "The N-ethylbenzisoxazolium cation—I". Tetrahedron. 21 (11): 3019–3035. doi:10.1016/S0040-4020(01)96921-2. ISSN 0040-4020.
5. Casey, Martha L.; Kemp, D. S.; Paul, Kenneth G.; Cox, Daniel D. (June 1973). "Physical organic chemistry of benzisoxazoles. I. Mechanism of the base-catalyzed decomposition of benzisoxazoles". The Journal of Organic Chemistry. 38 (13): 2294–2301. doi:10.1021/jo00953a006.
6. Kemp, D. S.; Cox, Daniel D.; Paul, Kenneth G. (December 1975). "Physical organic chemistry of benzisoxazoles. IV. Origins and catalytic nature of the solvent rate acceleration for the decarboxylation of 3-carboxybenzisoxazoles". Journal of the American Chemical Society. 97 (25): 7312–7318. doi:10.1021/ja00858a018.
7. Kemp, Daniel S. (April 1970). "Decarboxylation of benzisoxazole-3-carboxylic acids. Catalysis by extraction of possible relevance to the problem of enzymic mechanism". Journal of the American Chemical Society. 92 (8): 2553–2554. doi:10.1021/ja00711a061.

• Aromatic bases
• Benzisoxazoles
• Simple aromatic rings