7040-43-9Relevant articles and documents
TERTIARY BUTYLATION OF FIVE MEMBERED HETEROCYCLES. A UPS STUDY
Nyulaszi, L.,Gyuricza, A.,Veszpremi, T.
, p. 5955 - 5960 (2007/10/02)
The reaction of 2-chloromercuryfuran and t-butylbromide was studied by UV photoelectron spectroscopy.During the reaction the formation of t-butylfuran, 2,5-di-t-butylfuran, t-butylchloride, isobutylene and furan were found.In accordance with the experimental observations a novel reaction mechanism has been proposed.The first fast and the second slow step of the reaction has been interpreted.The corresponding thiophene derivative gave similar results.
Gas-phase Heteroaromatic Substitution. Part 4. Electrophilic Attack of t-Butyl Cation on Pyrrole, N-Methylpyrrole, Furan, and Thiophene
Margonelli, Andrea,Speranza, Maurizio
, p. 1491 - 1498 (2007/10/02)
t-Butyl cation, obtained in the gas state from the γ-radiolysis of neopentane has been allowed to react with pyrrole (1), N-methylpyrrole (2), furan (3), and thiophene (4).Experiments have been carried out in the pressure range 50-760 Torr and in the presence of variable concentrations of a gaseous base (NMe3).The reactivity of simple heteroaromatic compounds relative to toluene in competition experiments is found to depend markedly upon the composition of the gaseous reaction environment.The apparent kS/kT ratios decrease slightly with increasing pressure.At atmospheric pressure, these ratios increase with the NMe3 concentration levelling off to a value of 1.0 (1), 2.2 (2), 2.6 (3), and 0.6 (4), at the highest base concentration (PNMe3=10 Torr).Under the same conditions, predominant β substitution occurs in the pyrroles , whereas α-attack is favoured in the case of furan (β:α=9:91) and thiophene (β:α=20:80).The gaseous elecrophile appears rather unselective between the n- and the ?-type centres of furan (O:ring=50:50) and thiophene (S:ring=40:60), while it displays no or very limited substitution on the heteroatom of pyrroles.A mechanism based upon reversible addition of the t-butyl cation to the heteroaromatic nucleus, involving premilinary formation of an electrostatic adduct, is used to account for the formation of the t-butylated products and their isomeric composition.It is concluded that the gas-phase t-butyl alkylation of simple five-membered heteroaromatic compounds is regulated by electrostatic interactions established within the encounter pair.A close correspondence exists between this rationalization of the present gas-phase results and recent theoretical and experimental evidence concerning related alkylation processes.
ALKYLATION OF FURAN CATALYZED BY ARENETRICARBONYLMOLYBDENUM
Milner, David J.
, p. 199 - 203 (2007/10/02)
Furan reacted with t-butyl chloride at 130 deg C in the presence of ArMo(CO)3 to yield 2-t-butylfuran and 2,5-di-t-butylfuran.The catalyst was largely deactivated after 12 h.Up to 150 alkylation events occurred per Mo atom.At low conversions (10percent), using a furan/Mo ratio of 1000/1, the yields of 2-t-butylfuran were high (typically 65-80percent).Yields fell sharply with increasing catalyst concentration.Butylation of 2-t-butylfuran occurred more readily than that of furan, and 2,5-di-t-butylfuran was formed in high yield at 30percent conversion.Both furan and 2-t-butylfuran reacted with t-butyl chloride more than 50 times as fast as toluene.Evidence is given that the catalytic species do not contain chloride.
