TEMPO, free radical

• Catalog No.: A12733
• CAS Number: 2564-83-2
• M. F.: C9H18NO
• M. W.: 156.24532
• Purity: 98+%

SYNONYMS

• Title: 2,2,6,6-四甲基哌啶氧化物, 自由基
• IUPAC name: ol
• IUPAC Traditional name: tyrosine(.)
• Synonyms: 2,2,6,6-Tetramethyl-1-piperidinyloxy, free radical

DATABASE IDS

• EC Number: 219-888-8
• Merck Index: 149140
• MDL Number: MFCD00009599
• CAS Number: 2564-83-2
• Beilstein Number: 1422418

PROPERTIES

• Purity: 98+%
• Boiling Point: 193°C dec.
• Flash Point: 67°C(152°F)
• Melting Point: 31-40°C
• GHS Hazard statements: H314-H318
• European Hazard Symbols: Corrosive (C)
• GHS Precautionary statements: P260-P303+P361+P353-P305+P351+P338-P301+P330+P331-P405-P501A
• Risk Statements: 34
• RTECS: TN8991900
• Safety Statements: 26-36/37/39-45-60
• TSCA Listed: 是
• Hazard Class: 8
• UN Number: UN3263
• Packing Group: III

REFERENCES

• For brief features on TEMPO and related reagents, see: Synlett, 563 (2001); 1757 (2003); 657 (2006). For reviews on nitroxide radicals, see: Synthesis, 190, 401 (1971); Chem. Rev., 78, 37 (1978); J. Sci. Ind. Res., 54, 623 (1995).
• In the presence of a catalytic amount of KBr, catalyzes the selective oxidation of primary and secondary alcohols to aldehydes and ketones by buffered NaOCl: J. Org. Chem., 50, 4888 (1985); 52, 2559 (1987); Org. Synth. Coll., 8, 367 (1993). High yields of aldehydes can also be obtained under mild, phase-transfer conditions with Oxone.: Org. Lett., 2, 1173 (2000). In the presence of CuCl, aerobic oxidation of alcohols to aldehydes and ketones has been accomplished in the ionic liquid 1-n-Butyl-3-methylimidazolium hexafluorophosphate, L19086: Org. Lett., 4, 1507 (2002). With NaOCl, ɑ-amino or ɑ-alkoxy alcohols have also been oxidized to the aldehydes: Tetrahedron Lett., 33, 5029 (1992). The use of I₂ as cooxidant is useful for sensitive substrates: Org. Lett., 5, 235 (2003).
• The addition of quaternary salts to the reaction mixture permits further oxidation of aldehydes to acids. Selective oxidation of a primary OH to an aldehyde can be achieved in the presence of a secondary OH: J. Org. Chem., 54, 2970 (1989); Tetrahedron Lett., 31, 2177 (1990). The oxidation can also be performed using NCS under phase-transfer conditions: J. Org. Chem., 61, 7452 (1996), with Iodosobenzene diacetate, B24531: J. Org. Chem., 62, 6974 (1997), or Trichloroisocyanuric acid, B23906: Org. Lett., 3, 3041 (2001).
• For a review of the use of stable nitroxyl radicals for the oxidation of primary and secondary alcohols, see: Synthesis, 1153 (1996).
• Cf also 4-Hydroxy-TEMPO, A12497, and 4-Acetamido-TEMPO, B23456.