β-substituted pyrroles via electrophilic substitution of n-triisopropylsilylpyrrole.
作者:Joseph M Muchowski、Dennis R Solas
DOI:10.1016/s0040-4039(00)86011-6
日期:1983.1
N-Triisopropylsilylpyrrole undergoes predominant or exclusive kinetic electrophilic substiution at C-3, and the compounds obtained thereby, upon desilylation with tetra--butylammonium fluoride, give 3-substituted pyrroles in good overall yields.
Efficient synthesis of <i>N</i>-methyltetranitropyrrole: A stable, insensitive and high energy melt-castable material
作者:Vikranth Thaltiri、Kurumurthy Chavva、B. Sathish Kumar、Pradeepta K. Panda
DOI:10.1039/c9nj01227c
日期:——
1-Methyl-2,3,4,5-tetranitropyrrole, a potential high energy density material, first reported in 1979 in only 0.28% overall yield, has been synthesized efficiently (in more than 5% overall yield) by following two alternate routes from 1-(triisopropylsilyl)pyrrole and 1-methylpyrrole. Detailed characterization shows that it is stable up to 196 °C and possesses a density of 1.93 g cm−3. The corresponding
1-甲基-2,3,4,5-四硝基吡咯是一种潜在的高能量密度材料,于1979年首次报道,其总收率仅为0.28%,它是通过以下两种替代方法有效合成的(总收率超过5%)由1-(三异丙基甲硅烷基)吡咯和1-甲基吡咯制得。详细的表征表明,它在高达196°C的温度下稳定,密度为1.93 g cm -3。相应的爆震速度和爆震压力分别为8950 ms -1和36.9 GPa。这些值比RDX略好一些,而其对冲击和摩擦的敏感度则比RDX低得多。此外,其熔点为100°C,进一步彰显了其在高能配方中作为可熔融浇铸材料的潜力。
Alkylatlon orientation rules in conjugate addition of grignard reagents to nitropyrrole and nitrothiophene systems
Conjugate addition of various Grignardreagents to 1-alkyl-2-nitropyrroles and to 2-nitrothiophene has been investigated. 1-Alkyl-2-nitropyrroles undergo alkylation at 3 and 5 positions with prevalence of the latter isomer. On the contrary, in 2-nitrothiophene system, formation of the 3-isomer prevails. In both systems, a bulkier Grignardreagent favours the 5-isomer formation. This trend can be reversed
N-(Triisopropylsilyl)pyrrole. A progenitor "par excellence" of 3-substituted pyrroles
作者:Brian L. Bray、Peter H. Mathies、Reto Naef、Dennis R. Solas、Thomas T. Tidwell、Dean R. Artis、Joseph M. Muchowski
DOI:10.1021/jo00313a019
日期:1990.12
A very effective strategy has been devised for the synthesis of 3-substituted pyrroles based on the use of the triisopropylsilyl (TIPS) moiety as a sterically demanding nitrogen substituent to obstruct the attack of electrophilic reagents at the alpha-positions. 1-(Triisopropylsilyl)pyrrole (1) undergoes highly preferential kinetic electrophilic substitution at the beta-position with a variety of electrophiles (Br+, I+, NO2+, RCO+, etc.) and fluoride ion induced desilylation of the products provides the corresponding 3-substituted pyrroles in good overall yields. Competitive trifluoroacetylation experiments demonstrate that substitution of TIPS-pyrrole at the alpha-positions is decelerated by a factor of > 10(4), vs pyrrole at the same sites, without affecting reactivity at the beta-positions. 1-(Triisopropylsilyl)-3-bromopyrrole (2) is readily converted into the 3-lithio compound 44 by bromine-lithium interchange with alkyllithium reagents. This previously unavailable, formal equivalent of 3-lithiopyrrole is itself an excellent source of a wide range of beta-substituted pyrroles, many of which would not be directly preparable from 1. TIPS-pyrrole can be 3,4-dihalogenated and these compounds undergo sequential halogen-metal interchange trapping reactions. This process is exemplified by an efficient, three-step synthesis of the antibiotic verrucarin E (63) from the dibromo compound 5.
BRAY, BRIAN L.;MATHIES, PETER H.;NAEF, RETO;SOLAS, DENNIS R.;TIDWELL, THO+, J. ORG. CHEM., 55,(1990) N6, C. 6317-6328
作者:BRAY, BRIAN L.、MATHIES, PETER H.、NAEF, RETO、SOLAS, DENNIS R.、TIDWELL, THO+