Reagents tert-butyl nitrite

Doyle and Bryker (1979) reported high yields of arenediazonium tetrafluoroborates when aromatic amines were reacted with tert-butyl nitrite and trifluoroboro etherate in CH2C12. It is likely that nitrosyl fluoride is formed as nitrosating reagent by fluoride-alkoxy exchange. 

An interesting regioselective deaminative fluorination of a purinc-2.6-diamine derivative 12 has been reported. The nucleoside is selectively fluorinated in the 2-position of the purine moiety by treatment with tert-butyl nitrite in 60% hydrogen fluoride/ pyridine at — 20 C for 10 minutes.149 The hydrogen fluoride concentration of the reagent should not be higher than 65% (suitable 45-65%). 

One-pot diazotization/fluorodediazoniation of aniline derivatives has been reported using potassium fluoride-hydrogen fluoride salts, in various stoichiometric amounts, as reagents together with tert-butyl nitrite (TBN) or sodium nitrite (Table 6).50 The best result is obtained when 6 mmol of potassium hydrogen fluoride (KHF2) and 4 mmol of silicon tetrafluoride are used with 1 mmol of aniline (entry 3). 

The earliest oxidations were effected with nitrous fumes and later with mercuric oxide and isoamyl nitrite.74 Lead tetraacetate in acetic acid is in many cases the reagent of choice, but the removal of by-products can present some difficulties.75 IV-Haloimides and amides in alcoholic solutions have been reported to yield essentially pure tetrazolium salts76 and have been found specially useful in the preparation of heteroaryl-substituted tetrazolium salt.77,78 The novel formazans 49 have been successfully oxidized to 50 using 7V-chloro succinimide (Eq. II).79 tert-Butyl hypo-... 

It was shown that amide formation can be suppressed by the appropriate choice of reaction conditions, such as homogeneous solutions, e.g. in DMF, DMSO, HMPA, high acidity and low temperatures (-30 to -5°C). If the peptide hydrazide contains acid-labile protecting groups, e.g. trityl, 2-(4-biphenyl)propyloxycarbonyl, tert-butyloxycarbonyl, tert-butyl esters and ethers, the temperature has to be kept below -20 °C. Generally, tert-butyl or butyl nitrite is used as the organic nitrite, and for sterically hindered peptides amyl nitrite is employed. The time required for full conversion of the hydrazide into the azide may vary between 5 to 30 min and can be monitored by spray reagents (see experimental procedure below). 

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