A convenient one-pot protocol for the synthesis of N,N′-disubstituted and N,N,N′-trisubstituted amidines is reported. In the presence of the Ph3P–I2/Et3N system, a variety of secondary amides were smoothly reacted with primary or secondary amines to afford the corresponding amidines in good to excellent yields under mild conditions.
报道了一种方便的一锅法合成N,N'-二取代的N,N,N,N'-三取代的am。在Ph 3 P–I 2 / Et 3 N体系存在下,多种仲酰胺与伯胺或仲胺平稳反应,在温和条件下以良好或极佳的收率得到相应的am。
Isolation and Reactions of Imidoyl Fluorides Generated from Oxime Using the Diethylaminosulfur Trifluoride/Tetrahydrofuran (DAST–THF) System
mild diethylaminosulfur trifluoride/tetrahydrofuran (DAST–THF) system affords imidoyl fluorides. These compounds were isolated, and their structures were confirmed by X-ray single-crystal structure analysis. Reaction of imidoyl fluorides with various nucleophiles efficiently afforded amides, amidines, thioamides, and amine derivatives in high yields. Furthermore, one-pot reaction of in situ generated
用相对温和的二乙氨基三氟化硫/四氢呋喃 (DAST–THF) 系统氟化肟,得到亚氨基氟化物。这些化合物被分离出来,并通过 X 射线单晶结构分析确定了它们的结构。亚氨基氟化物与各种亲核试剂的反应有效地以高产率提供酰胺、脒、硫代酰胺和胺衍生物。此外,由肟原位生成亚氨基氟化物的一锅法反应也适用于这些产品的高效合成。肟立体化学和酸不稳定保护基在该系统中保持完整。
305. Amidines. Part IX. Preparation of substituted amidines from ketoxime sulphonates and ammonia or amines
作者:P. Oxley、W. F. Short
DOI:10.1039/jr9480001514
日期:——
Efficient Microwave Access to Polysubstituted Amidines from Imidoylbenzotriazoles
作者:Alan R. Katritzky、Chunming Cai、Sandeep K. Singh
DOI:10.1021/jo052443x
日期:2006.4.1
Microwave reactions of primary and secondary amines with imidoylbenzotriazoles 6a-w gave diversely substituted amidines 7a-Aa in 76-94% yields. Convenient preparations of a variety of amides 5a-Ab (87-96%) and imidoylbenzotriazoles 6a-w (56-95%) have also been developed using microwave irradiation under mild conditions and short reaction times. These results demonstrate further the advantages of microwave synthesis and introduce a new application of imidoylbenzotriazoles in the preparation of polysubstituted amidines.
Specialization of work in England, 1100-1300
作者:R.H Britnell
DOI:10.1111/1468-0289.00181
日期:2001.2
The twelfth and thirteenth centuries were to some extent a period of increasing occupational specialization. As towns grew, and money circulated more frequently, some groups of workers became more specialized, and as they did so their productivity is likely to have risen. However, this argument has limited value as evidence for rising aggregate levels of welfare. This article queries the extent of productivity gains attributable specifically to occupational specialization between 1100 and 1300, first by proposing that increasing specialization characterized only a small proportion of the workforce and secondly by arguing that there were offsetting trends elsewhere in the economy.