Synthesis of 1,4‐Diaryl‐piperazine‐2,5‐diones: New Behavior of N,N‐Dimethylformamide Dimethyl Acetal (DMFDMA)

Reactions of chloroacetamides (5) with N,N‐dimethylformamide dimethyl acetal gave 1,4‐diaryl‐piperazine‐2,5‐diones 11a–e in good yield, rather than 1,5‐diaryl‐3,7‐dimethoxy‐1H,5H‐[1,5]diazocine‐2,6‐diones (9a–e).     

气相色谱-质谱法检测饮用水新生含氮消毒副产物氯代乙酰胺

建立了气相色谱-质谱(GC-MS)法检测饮用水中新生致突变含氮消毒副产物(N-DBPs)二乙酰胺(DCAcAm)和三乙酰胺(TCAcAm)的分析方法.考察了GC/MS和GC/ECD两种检测仪器及不同样品前处理技术对氯代乙酰胺(CAcAms)的检测效果.对比发现,酸催化水解+GC/ECD的分析方法容易受其它消毒副产物(DBPs)的影响,直接液液萃取(LLE)+GC/MS更适合CAcAms的分析;乙酸乙酯(ETAC)的萃取效果优于DBPs分析常用萃取剂甲基叔丁基醚(MTBE).在选定条件下,DAcAm和TAcAm在10～1000 μg/L的范围内线性关系良好,r＞0.9995; 方法回收率在82.0%～111.9%之间;RSD小于10%;检出限(MDL)和测定限(RQL)均低于1 μg/L.     

Synthesis of 2([Methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl]imino)-1,3-thiazolan-4-ones and Their Mannich Bases

Isoxazolyl chloroacetamides (2) were obtained from 4-amino-3-methyl-5-styrylisoxazoles (1) on reaction with chloroacetyl chloride. Cyclocondensation of 2 with NH₄SCN yielded 2([-methyl-5-(E)-2-aryl-1-ethenyl]-4-isoxazolylimino)-1,3-thiazolan-4-ones(3). Mannich reaction of 3 with formaldehyde and secondary amines gave isoxazolyl thiazolidinone Mannich bases (4 and 5).     

Interaction of 5-Aryl-1,3,4-oxadiazoline-2(3H)-thiones wth N-Substituted Chloroacetamides

The reactions of some 5-aryl-1,3,4-oxadiazoline-2(3H)-thiones (aryl = phenyl, 4-bromophenyl, 4-methylphenyl, 2,4-dichlorophenyl) with N-alkyl- and N-arylchloroacetamides has been studied. The nature of the substituents in the molecules of the thiones and the chloroacetamides does not affect the direction of the reaction but does affect the yield of the desired products.     

N-取代-2-氯乙酰胺合成方法的改进及表征

对N-取代-2-氯乙酰胺的合成方法进行了详细研究并提出了改进方法:在Et3N/CH2Cl2体系中,各种胺与氯乙酰氯以物质的量之比为1∶1.2的比例投入,在室温下反应20 min,可定量得到相应的N-取代-2-氯乙酰胺.产物结构经IR、1H NMR和MS表征.     

Synthesis of monothiooxamides of the thiazole series

A convenient method for the synthesis of previously inaccessible monothiooxamides of the thiazole series was developed. The method is based on the reaction of pyridinium salts obtained from 2-(chloroacetylamino)thiazole and pyridine with a solution of elemental sulfur and amines prepared beforehand.     

N-3-Oxoalkylamides and -Thioamides in the Synthesis of Heterocyclic Compounds. 6. The Effect of Structural Factors on the Regiodirection of Cyclization of Pyridinium Derivatives of N-(3-Oxoalkyl)chloroacetamides. Structure of 1-(4-Hydroxy-4,6,6-trimethyl-2-oxo-3-piperidyl)pyridinium Chloride

The structure of 1-(4-hydroxy-4,6,6-trimethyl-2-oxo-3-piperidyl)pyridinium chloride has been established. Reasons have been found influencing the regiodirection of cyclization of pyridinium derivatives of N-(3-oxoalkyl)chloroacetamides.     

Synthesis of monothiooxamides

A convenient method for the synthesis of monothiooxamides by the reaction of chloroacetamides with a solution of elemental sulfur in amines was developed.     

Synthesis and reactivity of monothiooxamides and thiohydrazides of oxamic acids

The review surveys the studies carried out at the Laboratory of Heterocyclic Compounds of the N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, dealing with the chemistry of monothiooxamides and thiohydrazides of oxamic acids. Convenient methods for the synthesis of the title compounds are described and the possibility of converting them into diverse products, including N- and S-containing heterocycles, is demonstrated.