急需开发的医药中间体--2-氰基吡嗪

2-氰基吡嗪是生产治疗结核病药物吡嗪酰胺的重要原料.目前仅日本实现了2-氰基吡嗪的工业化生产,主要生产商是日本的KOEI公司.全球2-氰基吡嗪的年需求量约为2600t,年产量约为1600t,市场缺口达1000t/a.我国生产吡嗪酰胺年需求2-氰基吡嗪600t/a,而其设计能力仅为300t/a,年进口量为480t.国内近几年对2-氰基吡嗪的合成研究较多.文章还对我国2-氰基吡嗪的发展提出了建议.     

HPLC测定吡嗪酰胺片的含量

目的 为吡嗪酰胺片含量测定建立新的质量控制方法.方法 采用高效液相色谱法(HPLC)测定吡嗪酰胺片中吡嗪酰胺的含量.色谱柱:Agilent C18(250 mm×4.6 mm,5μm),流动相:甲醇-水(10∶90),检测波长269 nm,流速1.0mL/min,柱温30℃,理论板数按吡嗪酰胺峰计算应不低于3000.结果 在2.024～20.24 μg/mL浓度范围内,吡嗪酰胺进样量与峰面积呈良好的线性关系,r=0.9999,平均回收率为99.8％(n=6),RSD=0.8％.结论 本法简便、准确,重现性及灵敏度高,可用于吡嗪酰胺片中吡嗪酰胺的含量测定.     

益生菌补充改善吡嗪酰胺致大鼠肝损伤及肠道菌群紊乱的效果

目的：吡嗪酰胺作为抗结核药物治疗结核病可引起患者肝损伤及肠道菌群紊乱,本研究拟探讨益生菌 （干酪乳杆菌（Lactobacillus casei,LcS））补充对吡嗪酰胺致大鼠肝损伤及肠道菌群紊乱的影响。方法：将40 只 成年雄性SD大鼠随机分为4 组,即正常对照组（NC组）、吡嗪酰胺组（L0组）、低剂量LcS组（L1组）、高剂 量LcS组（L2组）。L0组、L1组和L2组均给予吡嗪酰胺处理,以建立肝损伤模型;L0为阳性（药物肝损伤）组; L1组和L2组大鼠每天分别给予10、20 mL/（kg·d）LcS（108 CFU/mL）灌胃,持续10 周。苏木精-伊红染色观察 各组大鼠肝脏组织病理学变化;速率法检测各组大鼠血清丙氨酸氨基转移酶（alanine aminotransferase,ALT）和 天冬氨酸氨基转移酶（aspartate aminotransferase,AST）水平;实时荧光定量聚合酶链式反应技术对大鼠粪便中 的双歧杆菌、乳酸杆菌及大肠杆菌16S rDNA V3可变区进行定量分析。结果：经吡嗪酰胺处理10 周后,L0组大鼠 苏木精-伊红染色切片显示肝细胞中度水肿,出现明显的气球样变,肝索结构消失并伴有炎性细胞浸润,病理学 评分达到3.20 分,血清ALT及AST水平分别升高到95.90 U/L和188.60 U/L,显著高于正常对照组的73.90 U/L和 139.20 U/L,说明肝损伤造模成功。经过不同剂量的LcS干预10 周后,大鼠肝小叶结构均较L0组得到明显改善,病 理学评分、血清ALT和AST水平均降低到正常对照组水平。实验菌株定量分析结果显示,大鼠经过不同分组及干预 时间的延长,3 种代表菌株在组间及组内均具有统计学差异。从分组来看,高剂量LcS组大鼠在干预第6周末及干预 第10周末,双歧杆菌和乳酸杆菌的量均较L0组明显升高,大肠杆菌的量明显降低（P＜0.05）;从干预时间来看, 高剂量LcS组大鼠在干预第10周末,双歧杆菌和乳酸杆菌的量均较干预前显著增加,分别达到干预前的1.18 倍和 1.03 倍。结论：LcS对吡嗪酰胺诱导的肝损伤及肠道菌群紊乱具有一定的改善作用,且随着时间的延长及剂量的增 加,效果更明显。其作用机制可能与LcS维持肠道内环境稳态、调节肠道菌群有关。     

N-(甲酰基吡嗪)-α-氨基酸甲酯的合成

以2,3-吡嗪二羧酸和α-氨基酸(甘氨酸、缬氨酸、亮氨酸)为原料,在氯化亚砜的作用下,采取分步法和一步法,得到不同的吡嗪酰胺类衍生物,其结构经1HNMR、13CNMR、IR和HR-MS等方法确定。探讨了不同反应条件对吡嗪酰胺类衍生物合成的影响。结果表明,在氯化亚砜的作用下,采用分步法和一步法,分别得到N-(2-羧基-3-甲酰基吡嗪)-α-氨基酸甲酯和N-(2,3-二甲酰基吡嗪)-α-氨基酸甲酯。其最优反应条件为:在分步法和一步法中,α-氨基酸甲酯盐酸盐与Et3N的摩尔比约为1∶2.1时,氨基释放完全,目标产物的收率最高;分步法2,3-吡嗪二甲酰氯盐酸盐的制备采用直接抽滤为最优方法,收率达75%以上;一步法N-(2,3-二甲酰基吡嗪)-α-氨基酸甲酯的制备中,氯化亚砜的量为6 mL时,收率最高。从整体来看,分步法的收率较高,均50%以上。     

Organolanthanide Compounds Containing Methanesulfonate and Pyrazinamide Ligand in Styrene Polymerization

The synthesis of organolanthanide compounds identified as LnCp*(MS)2PzA, Ln=Sm, Tb, Yb (MS=methanesulfonate, Cp*=pentamethylcyclopentadienyl, and PzA=pyrazinamide), by the reaction of coordination compounds Ln(MS)3(PzA)4 with NaCp in THF was reported. The complexes were formulated according to elemental analyses, complexometric titration with EDTA (%Ln), and 1H NMR. IR spectroscopy revealed that PzA coordinates with lanthanide(Ⅲ) ions and methanesulfonate coordinates via oxygen atoms in a non-equivalent manner. In preliminary catalytic studies, these compounds were active in styrene polymerization that used MAO as a cocatalyst with an activity of 12.3 kg PS mol Sm-1h-1. Differential scanning calorimetry (DSC) of polystyrene showed that the polymer was mainly atactic.     

Niosomal encapsulation of the antitubercular drug,pyrazinamide

It is estimated that more than one-third of the world population is infected with Mycobacterium tuberculosis. Pyrazinamide (PZA) plays a unique role in shortening therapy because it kills a population of semilatent tubercle bacilli residing in an acidic environment. Niosomes are vesicles made up of non-ionic surfactant and exhibit behavior similar to liposomes in vivo. Preparation of PZA niosomes took place using different molar ratios of Span 60 and Span 85, with cholesterol (CH) i.e. Span: CH (1:1) and (4:2). Dicetyl phosphate and stearyl amine were used in preparation of negative and positively charged niosomes, respectively. Free PZA was separated by cooling centrifugation and estimated spectrophotometrically at 268.4?nm. Niosomes were characterized by electron microscopy and differential scanning calorimetry. The highest percentage PZA entrapped was obtained using Span 60 and the molar ratio (4:2:1) negatively charged niosomes. This was followed by the neutral PZA neutral (4:2) Span 60 niosomes. Biological evaluation of selected PZA niosomal formulations took place on guinea pigs infected with M. tuberculosis. The present work is an attempt to target maximum concentration of PZA to the affected site (lungs) and to exclude undesirable side effects and decrease toxicity. Macrophage targeting and overcoming drug resistance is our final goal.     

Studies of the Binding of Modest Modulators of the Human Enzyme,Sirtuin 6, by STD NMR

Pyrazinamide (PZA), an essential constituent of short‐course tuberculosis chemotherapy, binds weakly but selectively to Sirtuin 6 (SIRT6). Despite the structural similarities between nicotinamide (NAM), PZA, and pyrazinoic acid (POA), these inhibitors modulate SIRT6 by different mechanisms and through different binding sites, as suggested by saturation transfer difference (STD) NMR. Available experimental evidence, such as that derived from crystal structures and kinetic experiments, has been of only limited utility in elucidation of the mechanistic details of sirtuin inhibition by NAM or other inhibitors. For instance, crystallographic structural analysis of sirtuin binding sites does not help us understand important differences in binding affinities among sirtuins or capture details of such dynamic process. Hence, STD NMR was utilized throughout this study. Our results not only agreed with the binding kinetics experiments but also gave a qualitative insight into the binding process. The data presented herein suggested some details about the geometry of the binding epitopes of the ligands in solution with the apo‐ and holoenzyme. Recognition that SIRT6 is affected selectively by PZA, an established clinical agent, suggests that the rational development of more potent and selective NAM surrogates might be possible. These derivatives might be accessible by employing the malleability of this scaffold to assist in the identification by STD NMR of the motifs that interact with the apo‐ and holoenzymes in solution.     

用近红外光谱-PLS法非破坏性分析吡嗪酰胺片

应用偏最小二乘法结合近红外光谱法(NIRS-PLS)对吡嗪酰胺片中吡嗪酰胺的含量进行了非破坏性定量分析。采用近红外一阶导数800~1200 nm光谱区间建立了吡嗪酰胺片中吡嗪酰胺的含量定量分析模型,校正集预测值与真实值的相关系数(R)达到0.9989,预测均方根误差(RMSEP)为0.563,表明所建模型准确可靠,预测准确度高,NIRS-PLS方便快捷,可作为药品分析的一种常规方法。