zopyran‐1‐ones), 4‐substituted 3,4‐dihydro‐3‐methoxyisocoumarins 2, can be obtained by a one‐pot process from α‐substituted 2‐bromo‐β‐methoxystyrenes 1. Thus, lithium 2‐(1‐aryl(or methyl)‐2‐methoxyethenyl)benzoates are conveniently generated via the Br/Li exchange between 1 and BuLi, followed by the action of CO2 on the resulting α‐substituted 2‐lithio‐β‐methoxystyrenes. Upon treating with concentrated
可以通过一锅获得一种新型的异香豆素(= 1 H-异色n-1-酮= 1 H -2-苯并吡喃-1-酮),4-取代的3,4-二氢-3-甲氧基异香豆素2。由α-取代的2-溴-β-甲氧基苯乙烯制备1。因此,通过1和BuLi之间的Br / Li交换可方便地生成2-(1-芳基(或甲基)-2-甲氧基乙烯基)苯甲酸锂,然后通过CO 2对生成的α-取代的2-lithio-苯甲酸作用β-甲氧基苯乙烯。在室温下用浓盐酸处理后,这些苯甲酸锂会发生内酯化反应,从而以相对较高的收率提供所需的3,4-二氢异香豆素2。
Synthesis of 1-Iminoisothiochroman Derivatives Based on Reactions of 2-Lithio-β-methoxystyrene Derivatives with Isothiocyanates Followed by Acid-Mediated Cyclization
The reaction of 2-lithio-beta-methoxystyrene derivatives with isothiocyanates yields the corresponding 2-(2-methoxyvinyl)thiobenzamide derivatives. Treatment of these thiobenzamides with concentrated hydriodic acid affords 1-imino-3-methoxyisothiochroman (1-imino-3-methoxy-3,4-dihydro-1H-2-benzothiopyran) derivatives.
Synthesis of 2,4-Disubstituted Isoquinolin-1(2H)-ones Based on Reactions of a-Substituted 2-Lithio-b-methoxystyrenes with Isocyanates
An efficient method for the preparation of 2,4-disubstituted isoquinolin-1(2H)-ones is described. The reaction of alpha-substituted 2-lithio-beta-methoxystyrenes, generated by treating alpha-substituted 2-bromo-beta-methoxystyrenes with butyllithium, with isocyanates yields the corresponding a-substituted 2-(2-methoxyvinyl)benzamide derivatives, which in turn are transformed into 2,4-disubstituted isoquinolin-1(2H)-ones on treatment with a catalytic amount of concentrated hydriodic acid.