Solvent-Controlled C2/C5-Regiodivergent Alkenylation of Pyrroles
作者:Youla Su、Shang Gao、Yue Huang、Aijun Lin、Hequan Yao
DOI:10.1002/chem.201502418
日期:2015.10.26
A solvent‐controlled C2/C5‐selective alkenylation of 3,4‐disubstituted pyrroles has been developed. The C3 substituent of pyrroles proved crucial to the regioselectivity. Substrates bearing directing groups at the C3 position exhibited excellent C2‐selectivities in chelation‐assisted CH activation in toluene or 1,4‐dioxane. However, a DMSO/DMF solvent system could override the chelation effect of
Synthesis of Pyrrole-Annulated Heterocycles through Copper-Catalyzed Site-Selective Dehydrogenative Cross-Coupling
作者:Krishna N. Tripathi、Devalina Ray、Ravi P. Singh
DOI:10.1002/ejoc.201700929
日期:2017.10.17
A method for the Cu-catalyzed, intramolecular dehydrogenative cross-coupling of 3-substituted and 3,4-disubstituted pyrrole–azole systems was developed. The C–H bond in the C2 position was site-selectively activated over the C–H bond in the C5 position of unsymmetrically substituted pyrroles, and the six- and seven-membered annulated pyrrole products were directly accessed in moderate to good yields
An Efficient Synthesis of Substituted 3(4)-Nitropyrroles from Nitroalkenes and Tosylmethyl Isocyanides
作者:Ronald ten Have、Frederik R. Leusink、Albert M. van Leusen
DOI:10.1055/s-1996-4306
日期:1996.7
A series of 3(4)-nitropyrroles with alkenyl substituents in the 2- and 3-positions (or 3-position only) is synthesized efficiently in one operation by a base-induced addition of tosylmethyl isocyanide (TosMIC), or unsaturated homologs of TosMIC, to nitroalkenes.
Synthesis and characterization of β-substituted 5,10,15,20-tetraphenyl-21,23-dithiaporphyrins are reported. The absorption and emission spectra exhibited large bathochromic shifts due to nonplanarity of porphyrin ring which is induced on β-substitution.
Synthesis of β-pyrrole and β-thiophene substituted 21,23-dithia and 21-monothiaporphyrins
作者:Neeraj Agarwal、Mangalampalli Ravikanth
DOI:10.1016/j.tet.2004.03.047
日期:2004.5
A series of beta-pyrrole and beta-thiophene substituted porphyrins with N2S2 and N3S porphyrin cores were synthesized and characterized. The introduction of substituents at beta-pyrrole and beta-thiophene carbons resulted in significant shifts in H-1 NMR, absorption and fluorescence maxima. These effects were attributed to alteration of the porphyrin ring current caused by substituents at beta-positions. (C) 2004 Elsevier Ltd. All rights reserved.