A green and efficient method for regioselective O-acylation of polyphenols has been developed. The acylation can be carried out in potassiumcarbonate/dimethyl sulphoxide system by utilizing the ‘inherent nucleophile’ via an intermolecular cooperative transesterification under mild condition. This method shows particular advantage in regioselective acylation of polyphenols bearing 2′,4′-dihydroxyacetophenone
A compound of formula 1a
1
which is useful for treating reperfusion injury, and salts, prodrugs, and related compounds.
化合物1a1及其盐、前药和相关化合物,可用于治疗再灌注损伤。
Sealant for integrated circuit modules, polyester suitable therefor and preparation of polyester
申请人:International Business Machines
Corporation
公开号:EP0139924A2
公开(公告)日:1985-05-08
Integrated circuit module wherein the cap is sealed to the substrate with a liquid crystalline polyester melt containing about 25 to about 100 mole percent of recurring Units I and about 75 to 0 mole percent of recurring Units II wherein
and
wherein each R and R, is arylene or cycloalkylene or alkylene or alkylidene.
集成电路模块,其中盖用液晶聚酯熔体密封到基板上,该熔体含有约 25 至约 100 摩尔%的重复单元 I 和约 75 至 0 摩尔%的重复单元 II,其中
和
其中每个 R 和 R, 是芳基或环亚烷基或亚烷基。
Liquid-crystalline, completely aromatic copolyesters are disclosed, which are endowed with a heat stability not lower than 350° C, and are constituted by a succession of repeatitive units containing:
wherein A and B, which can be either equal to, or different, from, each other, can be either -O- or -CO- and one of the following moieties:
in which Ar can be 1,4-phenylene, 2-monosubstituted-1,4-phenylene or 4,4′-diphenylene.
Also copolyesters also containing amidic bonding groups are disclosed.
本发明公开了液晶型完全芳香族共聚聚酯,其热稳定性不低于 350°C,由连续的重复单元构成,这些重复单元包含:
其中,A 和 B 可以相互等同或不同,可以是 -O- 或 -CO- 以及下列分子之一:
其中 Ar 可以是 1,4-亚苯基、2-单取代-1,4-亚苯基或 4,4′-二亚苯基。
此外,还公开了同样含有酰胺键基团的共聚多酯。
Thiele; Winter, Justus Liebigs Annalen der Chemie, 1900, vol. 311, p. 355