- Preparation of Sterically Crowded t-Butylfurans by Direct t-Butylation and Cyclisation of t-Butyl Substituted 1,4-Diketones. Selective Dehydrodimerisation of Neopentyl Ketones by Lead Dioxide
-
o-Di-t-butylfurans can be obtained in high yields via Friedel-Crafts alkylation and via cyclisation of 1,4-diketones, but minor differences in the substitution pattern of the starting materials prevent o-di-t-butylation, or govern escape reactions to relieve the steric strain.
- Wynberg, Hans,Wiersum, Ulfert E.
-
-
Read Online
- ALKYLATION OF FURAN CATALYZED BY ARENETRICARBONYLMOLYBDENUM
-
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.
- Milner, David J.
-
-
Read Online
- An Electron Spin Resonance Study of the Radical Cations of Pyrroles, Furans, and Thiophenes in Liquid Solution
-
Photolysis of alkylpyrroles in trifluoroacetic acid containing mercury(II) trifluoroacetate, alkylfurans in trifluoroacetic acid, or alkylthiophenes in sulphuric acid, induces oxidation to the corresponding radical cations.The e.s.r. spectra show that the electronic configuration is similar in all three species, the unpaired electron occupying the φA MO in which the heteroatom lies in a nodal plane.Photolysis of 2,6-dimethyl- and 2,6-diethyl-thiophene in trifluoroacetic acid containing mercury(II) trifluoroacetate, on the other hand, gave rise to spectra with a high g value (2.0062), showing hyperfine coupling to two non-equivalent pairs of alkyl groups in an unsymmetrical dimer.
- Davies, Alwyn G.,Julia, Luis,Yazdi, Safieh N.
-
p. 239 - 244
(2007/10/02)
-
- TERTIARY BUTYLATION OF FIVE MEMBERED HETEROCYCLES. A UPS STUDY
-
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.
- Nyulaszi, L.,Gyuricza, A.,Veszpremi, T.
-
p. 5955 - 5960
(2007/10/02)
-
- Silica Gel as an Effective Catalyst for the Alkylation of Phenols and Some Heterocyclic Compounds
-
In the presence of silica gel, the reaction of phenol with t-BuBr was examined under a variety of conditions and it was found that silica gel is an effective catalyst for the alkylation.As a result of this work 2-tert-butyl-, 2,6-di-tert-butyl-, and 2,4,6-tri-tert-butylphenols, all of which are hard to obtain directly by the Friedel-Crafts process, could be prepared easily by this one-step reaction.Several other alkyl halides were also used in this reaction.The alkylations of some heterocyclic aromatic compounds which cannot be alkylated by the conventional Friedel-Crafts method were also succesfully performed by this reaction.
- Kamitori, Yasuhiro,Hojo, Masaru,Masuda, Ryoichi,Izumi, Tatsuo,Tsukamoto, Shuichi
-
p. 4161 - 4165
(2007/10/02)
-
- Process for the preparation of alkyl furans
-
A process for the preparation of alkyl furans which comprises reacting furan with an alkyl halide in the presence of iron (III) oxide and an iron (II) halide or iron (III) halide as catalyst.
- -
-
-