New imidazo[1,2-a]pyrazine derivatives with bronchodilatory and cyclic nucleotide phosphodiesterase inhibitory activities
摘要:
lNew imidazo[1,2-a]pyrazine derivatives have been synthesized either by direct cyclization from pyrazines or by electrophilic substitutions: The presence nf electron donating groups On position 8 greatly enhances the reactivity of the heterocycle towards such reactions on position 3 of the heterocycle. The activities of these derivatives in trachealis muscle relaxation and in inhihiting cyclic nucleotide phosphodiesterase(PDE) isoenzyme types III and IV have been assessed All compounds demonstrated higher relaxant potency than theophylline. All the derivatives were moderately potent in inhibiting the type IV isoenzyme of PDE but only those with a cyano group on position 2 were potent in inhibiting the type III isoenzyme. (C) 1999 Elsevier Science Ltd. All rights reserved.
Synthesis and antibronchospastic activity of 8-alkoxy- and 8-(alkylamino)imidazo[1,2-a]pyrazines
摘要:
Theophylline still occupies a dominant place in asthma therapy. Unfortunatly its adverse central nervous system (CNS) stimulant effects can dramatically limit its use, and adjustments in the dosage are often needed. We have synthesized a new series of imidazo[1,2-a]pyrazine derivatives which are much more potent bronchodilators than theophylline in vivo and do not exhibit the CNS stimulatory profile. In vitro studies on isolated rat uterus and guinea pig trachea confirm the high potentialities of these derivatives. 6-Bromo-8-(methylamino)imidazo[1,2-a]pyrazine-3-carbonitrile (23) is identified as the most potent compound of the series. As in the case of theophylline, phosphodiesterase inhibition appears unlikely to be the unique mechanism of action of this series of heterocycles.
Aza-indolizine with bridgehead nitrogen. Metalation, halogen-metal exchange and directed ortho-lithiation in the imidazo[1,2-a]pyrazine series
作者:Olivier Vitse、Jacques Bompart、Guy Subra、Henri Viols、Roger Escale、Jean P. Chapat、Pierre A. Bonnet
DOI:10.1016/s0040-4020(98)00287-7
日期:1998.6
The n-BuLi and lithium 2,2,6,6-tetramethylpiperidine (LTMP) metalation of imidazo[1,2-a]pyrazine heterocycles and subsequent quenching with electrophiles is described. Bromine atoms exhibit different behaviours towards lithiation depending on their positions (3 or 6) on the imidazo[1,2-a]pyrazine heterocycle. Halogen-metal exchange occurs readily with the bromine on position 3. On the contrary, bromine
描述了咪唑并[1,2- a ]吡嗪杂环的n -BuLi和2,2,6,6-四甲基哌啶锂(LTMP)金属化以及随后用亲电试剂的猝灭。溴原子根据其在咪唑并[1,2- a ]吡嗪杂环上的位置(3或6)表现出不同的锂化行为。位置3上的溴很容易发生卤素金属交换。相反,位置6上的溴仅导致C-5取代的衍生物进一步产生邻位导向作用。