The synthesis of quinoline derivatives by cyclocondensation of anilines with 1,2‐ethanediol, 1,2‐propanediol, and 1,2‐butanediol in the presence of iron‐containing catalysts was performed for the first time.
8-Hydroxyquinolines are synthesized from O-2,4-dinitrophenyloximes of m-hydroxyphenethyl ketones by the treatment with sodium hydride, and then with 2,3-dichloro-4,5-dicyano-p-benzoquinone (DDQ).
Regioselective Synthesis of Quinolin-8-ols and 1,2,3,4-Tetrahydroquinolin-8-ols by the Cyclization of 2-(3-Hydroxyphenyl)ethyl Ketone<i>O</i>-2,4-Dinitrophenyloximes
Cyclization of 2-(3-hydroxyphenyl)ethylketone O-2,4-dinitrophenyloximes proceeds on the oxime nitrogen atom by the treatment with NaH and then with 2,3-dichloro-5,6-dicyano-p-benzoquinone and acetic acid to yield quinolin-8-ols regioselectively. The reaction in the presence of Na[BH3(CN)] affords 1,2,3,4-tetrahydroquinolin-8-ols. The present cyclization proceeds via alkylideneaminyl radical intermediates
2-(3-羟基苯基)乙基酮 O-2,4-二硝基苯基肟的环化反应在肟氮原子上进行,先用 NaH 处理,然后用 2,3-二氯-5,6-二氰基-对苯醌和乙酸处理区域选择性地产生喹啉-8-醇。在 Na[BH3(CN)] 存在下反应得到 1,2,3,4-四氢喹啉-8-醇。本环化通过亚烷基亚胺基自由基中间体进行,该中间体由 3-羟基苯基和 2,4-二硝基苯基部分之间的单电子转移产生。
PhI(OAc)<sub>2</sub>/Pd(OAc)<sub>2</sub> promoted the formation of 8-hydroxyquinoline derivatives from benzoxazoles and alcohols
A PhI(OAc)2/Pd(OAc)2 system that synergistically promotes the formation of 8-hydroxyquinoline derivatives from benzoxazoles and alcohols has been developed. The reaction proceeded smoothly with a range of benzoxazoles and alcohols to give the corresponding 8-hydroxyquinoline derivatives in moderate yields.
Polyester/Urethane base coating composition and curing agent therefor
申请人:NISSHINBO INDUSTRIES, INC.
公开号:EP0767188A1
公开(公告)日:1997-04-09
A curing agent in the form of an isocyanate compound whose isocyanate group is blocked with a carbodiimide group is provided. When used in a urethane base coating composition, the carbodiimide-blocked isocyanate compound cancels its isocyanate blockage upon baking and heating, allowing the isocyanate group to exert curing action on the coating composition. When used in a polyester/urethane base coating composition, the curing agent is effective for improving the hydrolysis resistance of a coating. Particularly when a blocked isocyanate compound whose isocyanate group is blocked with an intramolecular carbodiimide group is used, the problem of generating harmful VOC and disgusting odor upon heating is eliminated. The polyester/urethane base coating composition using the curing agent cures into a tough aesthetic coating having chemical resistance, weather resistance and durability.