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128-08-5 - N-Bromosuccinimide, 99% - NBS - A15922 - Alfa Aesar

A15922 N-Bromosuccinimide, 99%

Codice CAS
128-08-5
Sinonimi
NBS

Dimensioni Prezzo ($) Quantità Disponibilità
250g 37,20
1000g 109,00
5000g 443,00
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N-Bromosuccinimide, 99%

MDL
MFCD00005510
EINECS
204-877-2

Proprietà chimiche

Formula
C4H4BrNO2
Peso formula
177.99
Punto di fusione
175-180° dec.
Densità
2.098
Sensibilità
Light Sensitive
Solubilità
Soluble in acetone, tetrahydrofuran, dimethyl formamide, dimethyl sulfoxide and acetonitrile. Slightly soluble in water and acetic acid. Insoluble in ether, hexane and carbon tetrachloride.

Applicazioni

N-Bromosuccinimide is a chemical reagent used in electrophilic additions and radical substitution reactions in synthetic organic chemistry. In Wohl-Ziegler reaction, it is involved in allylic and benzylic bromination reaction. It is also used in the alfa-bromination of carbonyl derivatives. In the Hofmann rearrangement, it is used in the presence of a strong base, such as 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) reacts with primary amides to produce a carbamate. It oxidizes silyl ethers to aldehydes in the presence of azobisisobutyronitrile. It is also used for the modification of ribosomal sulfhydryl groups.

Note

Moisture and light sensitive. Incompatible with strong oxidizing agents, strong acids, strong bases, iron, iron salts, halogenated hydrocarbons, amines and metals. Store in a cool place.

Letteratura

Source of free-radical or positive bromine. For examples of radical benzylic bromination (Wohl-Ziegler), see: Org. Synth. Coll., 4, 921 (1963); 5, 145, 329, 825 (1973). The use of the ozone depleting solvent CCl4 has been avoided by the use of the ionic liquid 1-n-Butyl-3-methyl­imidazolium hexafluorophosphate, L19086 : Synlett, 702 (2003). Cleavage of carbohydrate benzyl ethers: J. Org. Chem., 55, 378 (1990), and of benzyl esters: Synlett, 219 (1994), occur under mild conditions; the benzyl group is converted to benzaldehyde. For allylic bromination, see e.g.: Org. Synth. Coll., 4, 108 (1963);.9, 112, 191 (1998) review: Chem. Rev., 43, 271 (1948).

For free-radical ɑ-bromination of a Boc glycine ester, see: Org. Synth. Coll., 9, 526 (1998).

Both aliphatic and aromatic aldehydes are converted to acyl bromides under free-radical conditions: Tetrahedron Lett., 3809 (1979); Synlett, 347 (1990); Tetrahedron Lett., 31, 7237 (1990).

In acetonitrile, NBS is a mild and regiospecific nuclear brominating agent for activated aromatics such as methoxybenzenes and naphthalenes: J. Org. Chem., 60, 5328 (1995). Deactivated aromatics, e.g. nitroarenes and benzotrifluorides, can be m-brominated under mild conditions in good yield with NBS in TFA, in the presence of H2SO4: Synlett, 1245 (1999).

In the presence of a phosphine or phosphite, converts alcohols to alkyl bromides with inversion: Tetrahedron Lett., 3937 (1973). For a review of this and related reactions, see: Org. React., 29, 1 (1983).

Alkenes undergo trans-addition reactions with NBS in combination with a nucleophile. For examples, see: Org. Synth. Coll., 6, 184, 560 (1988). With alcohols, bromohydrin ethers are formed. For use in the synthesis of cyclopropenone, see: Org. Synth. Coll., 6, 361 (1988):

In the presence of DBU in MeOH, amides rearrange to amines in good yields, providing a mild and efficient alternative to the classical Hofmann halogen/ caustic alkali conditions: J. Org. Chem., 62, 7495 (1997).

Examples of the use of NBS as a mild, selective oxidizing agent:

Sulfides to sulfoxides: J. Org. Chem., 37, 3976 (1968). Oximes to nitrile oxides: J. Org. Chem., 37, 436 (1968). Secondary alcohol in the presence of primary: Tetrahedron Lett., 2745 (1979). (In DMSO): Alkynes to ɑ-diketones: Can. J. Chem., 49, 1099 (1979).

(Free radical): Aldehydes to acyl bromides or amides: Tetrahedron Lett., 31, 7237 (1990). Benzyl silyl ethers to aldehydes: Synlett, 345 (1990). Aldehydes to esters: Synlett, 347 (1990).

For use as a mild catalyst in acetalization reactions, see Triethyl­ orthoformate, A13587 .

For a brief feature on uses in synthesis, see: Synlett, 498 (2006). See also 1,3-Dibromo-5,5-dimethyl­hydantoin, A15510 .

Guha, S.; Rajeshkumar, V.; Kotha, S. S.; Sekar, G. A Versatile and One-Pot Strategy to Synthesize alpha-Amino Ketones from Benzylic Secondary Alcohols Using N-Bromosuccinimide. Org. Lett. 2015, 17 (3), 406-409.

Wang, W. X.; Zhang, Q. Z.; Zhang, T. Q.; Li, Z. S.; Zhang, W.; Yu, W. N-Bromosuccinimide-Mediated Radical Cyclization of 3-Arylallyl Azides: Synthesis of 3-Substituted Quinolines. Adv. Synth. Catal. 2015, 357 (1), 221-226.

Rischio GHS e dichiarazioni precauzionali

Dichiarazioni di rischio (UE): H302-H314-H318

Harmful if swallowed. Causes severe skin burns and eye damage. Causes serious eye damage.

Dichiarazioni precauzionali: P260u-P303+P361+P353-P305+P351+P338-P301+P330+P331-P405-P501a

IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. IF SWALLOWED: Rinse mouth. Do NOT induce vomiting. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.

Altri riferimenti

Merck
14,1438
Beilstein
113916
Classe di rischio
8
Gruppo di imballaggio
III
Codice tariffe armonizzato
2925.19
TSCA
Yes

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