New imidazo[1,2-a]pyridines substituted at the 3-position have been synthesized as potential antisecretory and cytoprotective antiulcer agents. The synthetic routes began with cyclization of aminopyridines 5a,b and chloro ketones 6a,b to give imidazo[1,2-a]pyridines 7-9. The side chain at the 3-position was elaborated to give primary amines 12a-c, which were treated with either butoxyaminocyclobutenedione 13 or methoxyaminothiadiazole 1-oxide (15) to give 14a,b and 16a-c, respectively. Thiadiazole 1-oxides 16a-c were converted to thiadiazoles 19a-c in a two-step process which involved extrusion of the sulfoxide in 16a-c to afford diimidamides 17a-c, which were subsequently treated with thiobisphthalimide (18). None of the compounds displayed significant antisecretory activity in the gastric fistula rat model, but several demonstrated good cytoprotective properties in both the EtOH and HCl models. 8-(Benzyloxy)-3-[1-[[2-[(4-amino-1,2,5-thiadiazol-3- yl)amino]ethyl]thio]ethyl]-2-methylimidazo[1,2-a]pyridine (19c) showed comparable cytoprotective activity to SCH-28080 (4).

中文翻译：

---

3-取代的咪唑并[1,2-a]吡啶类化合物的合成及其生物学活性。

已经合成了在3位上取代的新咪唑并[1,2-a]吡啶，作为潜在的抗分泌和细胞保护性抗溃疡药。合成途径开始于氨基吡啶5a，b和氯酮6a，b的环化，得到咪唑并[1,2-a]吡啶7-9。精制3-位的侧链，得到伯胺12a-c，分别用丁氧基氨基环丁二酮13或甲氧基氨基噻二唑1-氧化物（15）处理，分别得到14a，b和16a-c。在两步法中将噻二唑1-氧化物16a-c转化为噻二唑19a-c，该过程包括在16a-c中挤出亚砜，得到二亚胺化物17a-c，随后将其用硫代双邻苯二甲酰亚胺处理（18）。在胃瘘大鼠模型中，没有一种化合物显示出显着的抗分泌活性，但是有几个在EtOH和HCl模型中均显示出良好的细胞保护特性。8-（苄氧基）-3- [1-[[2-[（4-氨基-1,2,5-噻二唑-3-基）氨基]乙基]硫代]乙基] -2-甲基咪唑并[1,2- a]吡啶（19c）具有与SCH-28080（4）相当的细胞保护活性。