Synthetic Antimicrobials. II. Synthesis of Pyrazolo [1, 5-a] pyridine Derivatives. (1)
作者:SEIGO SUZUE、MASAAKI HIROBE、TOSHIHIKO OKAMOTO
DOI:10.1248/cpb.21.2146
日期:——
2-Alkyl-3-acyloxypyrazolo [1, 5-a] pyridines (III) were prepared by refluxing 1-amino-2-hydroxymethylpyrioinium chloride (Ia) in excess acyl anhydride in the presence of a base. III were converted into 2-alkyl-3-hydroxy derivatives (IVa-f) by acid hydrolysis. Ia was refluxed with ethyl orthoformate in acetic acid containing sodium acetate to give 3-hydroxy derivative (IVg). Reaction of Ia with benzoyl chloride in H2O-K2CO3 gave mainly O, N-dibenzoyl ylide (VIIa) and 2-phenyl-3-benzoyloxypyrazolo [1, 5-a] pyridine (IXa). Pyrolysis of VIIa gave 2-phenyl-3-hydroxy derivative (VIIIa), which was also obtained from 1-ben-zimido-2-hydroxymethylpyridine (VIa) by treatment with H2SO4, followed by alkali treatment. Further the compound (VIIIa) was prepared by the reaction of 1-benzimido-2-picoline (XVIIa) with I2 in pyridine. Analogously various 2-substituted-3-hydroxy derivatives (VIIIb-1 and IVa) were obtained. 1-Anilinothiocarbonylimino-2-hydroxymethylpyridine (XIXa) was converted into cyclic pyridinium salt (XXa) by treating with H2SO4, and XXa was treated with K2CO3 to give 2, 2'-dianilinopyrazolo [1, 5-a] pyridine-3, 3'-disulfide (XXIIa). XXIIa was converted into 2-anilino derivative (XXIIIa) by Raney Ni reduction. Analogously 2-benzamido derivative (XXIIIb) was obtained from 1-benzamidothiocarbonylimino-2-hydroxymethylpyridine (XIXa) by the same procedure. 2-Acetamido derivative (XXIX) was obtained by heating pyridine-2-acetamidoxime (XXVII) with acetic anhydride. The compounds (XXIIIa and XXIX) were also converted into the corresponding 3-thiocyano and 3-nitro derivatives (XXIV, XXV, XXXIb and XXXIc). The tuberculostatic activities of the pyrazolo [1, 5-a] pyridine derivatives were also indicated.
2- 烷基-3-乙酰氧基吡唑并[1,5-a]吡啶(III)是在碱存在下,用过量的酰基酸酐回流 1-氨基-2-羟甲基吡啶氯化物(Ia)而制备的。通过酸水解将 III 转化为 2-烷基-3-羟基衍生物(IVa-f)。Ia 与含醋酸钠的醋酸中的原甲酸乙酯回流,得到 3-羟基衍生物(IVg)。Ia 与苯甲酰氯在 H2O-K2CO3 中反应,主要得到 O,N-二苯甲酰氯(VIIa)和 2-苯基-3-苯甲酰基氧基吡唑并[1,5-a]吡啶(IXa)。热解 VIIa 得到 2-苯基-3-羟基衍生物 (VIIIa),该衍生物也是由 1-苄基-2-羟甲基吡啶 (VIa) 通过 H2SO4 处理,然后碱处理得到的。此外,化合物 (VIIIa) 是由 1-苯亚甲基-2-吡啶 (XVIIa) 与 I2 在吡啶中反应制备的。类似地得到了各种 2-取代-3-羟基衍生物(VIIIb-1 和 IVa)。1-Anilinothiocarbonylimino-2-hydroxymethylpyridine (XIXa) 经 H2SO4 处理转化为环状吡啶鎓盐 (XXa),XXa 经 K2CO3 处理得到 2,2'-dianilinopyrazolo [1,5-a] pyridine-3,3'-disulfide (XXIIa)。通过 Raney Ni 还原,XXIIa 被转化为 2-苯胺基衍生物 (XXIIIa)。类似地,通过相同的步骤,从 1-苯甲酰胺硫代羰基亚氨基-2-羟甲基吡啶 (XIXa) 中得到 2-苯甲酰胺衍生物 (XXIIIb)。用乙酸酐加热吡啶-2-乙酰胺肟(XXVII)得到 2-乙酰胺基衍生物(XXIX)。化合物(XXIIIa 和 XXIX)还转化成了相应的 3-硫氰基和 3-硝基衍生物(XXIV、XXV、XXXIb 和 XXXIc)。吡唑 [1, 5-a] 吡啶衍生物的抗结核活性也得到了证实。