Synthesis and antiserotonin activity of pyrrolo[1,2-a]imidazole derivatives

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

“…The reaction of α-haloketones with N -heterocyclic compounds shown in Scheme 19 is completely different and leads to quarternization in most cases [ 141 , 142 ]. This reaction has been used in the Chichibabin quaternization followed by cycloaddition of the obtained ylides with alkenes or alkynes to give the corresponding fused pyrrole derivat-ives starting from pyridines [ 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 ], pyridazines [ 152 ], pyrimid-ines [ 153 , 154 ], pyrazines [ 155 , 156 , 157 ], imidazoles [ 158 , 159 , 160 , 161 ], thia-zoles [ 162 , 163 ], and triazoles [ 164 , 165 , 166 , 167 , 168 ]. This general synthetic route to pyrroles a-fused to a heterocyclic ring may be represented by the preparation of 68 starting from 66 ( Scheme 19 ).…”

The Chemistry of α‐Haloketones and Their Utility in Heterocyclic Synthesis

“…The reaction of α-haloketones with N-heterocyclic compounds shown in Scheme 19 is completely different and leads to quarternization in most cases [141,142]. This reaction has been used in the Chichibabin quaternization followed by cycloaddition of the obtained ylides with alkenes or alkynes to give the corresponding fused pyrrole derivatives starting from pyridines [143][144][145][146][147][148][149][150][151], pyridazines [152], pyrimidines [153,154], pyrazines [155][156][157], imidazoles [158][159][160][161], thiazoles [162,163], and triazoles [164][165][166][167][168]. This general synthetic route to pyrroles a-fused to a heterocyclic ring may be represented by the preparation of 68 starting from 66 (Scheme 19).…”