P(HEMA)-SO3H catalyst: preparation, characterization and its catalytic activity in Ritter reaction

Facile preparation of N-tert-butyl amides under heat-, metal- and acid-free conditions by using tert-butyl nitrite (TBN) as a practical carbon source

“…Note the lack of effectiveness of many reported methods for the synthesis of N-( tert -butyl)acetamide ( 2b ) and N -( tert -butyl)trideuteroacetamide ( 2c ) from acetonitrile or trideuteroacetonitrile. 12–19 The reactions involving several benzylic nitriles and aryl nitriles were then investigated. Under the optimal conditions with a slightly extended reaction time of 24 h, both benzylic nitriles and aryl nitriles bearing electron-donating groups at the para - or meta -position reacted favourably and produced the anticipated N-tert -butyl amides ( 2i–2l and 2n–2u ) in good to excellent yields (Table 2).…”

“…A plausible reaction mechanism was derived considering the control experiments and previous literature reports (Scheme 4). 12–19…”

“…Note that the reported protocols (Scheme 1c) for the conversion of nitriles to N-tert-butyl amides (2) generally utilize tert-butyl alcohol, tert-butyl-hydrogen peroxide, tert-butyl acetate, tert-butyl bromide, di-tert-butyl dicarbonate or methylpropene as a source of the tert-butyl unit, along with a stoichiometric amount of a mineral acid, Lewis acid or metal ion as a promoter at elevated temperatures. [12][13][14][15][16][17][18] Many of these reported procedures, however, are not applicable for scaled-up synthesis of N-tert-butyl amides (2) due to the rapid decomposition of tert-butyl sources into isobutylene gas under the reaction conditions. 14,19 We present herein an unprecedented function of TBN as a carbon (tert-butyl group, Scheme 1d) source for the synthesis of N-tert-butyl amides (2) from nitriles (1) and water under very mild reaction conditions (Scheme 1d).…”

“…14,19 We present herein an unprecedented function of TBN as a carbon (tert-butyl group, Scheme 1d) source for the synthesis of N-tert-butyl amides (2) from nitriles (1) and water under very mild reaction conditions (Scheme 1d). Based on the control experiments and literature reports, [12][13][14][15][16][17][18][19] a feasible reaction mechanism has also been derived (vide infra).…”

“…Note the lack of effectiveness of many reported methods for the synthesis of N-(tert-butyl)acetamide (2b) and N-(tert-butyl)trideuteroacetamide (2c) from acetonitrile or trideuteroacetonitrile. [12][13][14][15][16][17][18][19] The reactions involving several benzylic nitriles and ) as a model precursor, TBN (d = 0.867 g ml À1 ) as a tert-butyl source and water (d = 1.0 g ml À1 ) as a nucleophile at room temperature.…”