69009-33-2Relevant academic research and scientific papers
Synthesis and antitumor activity of novel 3,4-diaryl squaric acid analogs
Liu, Zong-Ying,Wang, Yue-Ming,Han, Yan-Xing,Liu, Ling,Jin, Jie,Yi, Hong,Li, Zhuo-Rong,Jiang, Jian-Dong,Boykin, David W.
, p. 187 - 194 (2013/10/01)
A series of novel 3,4-diaryl squaric acid analogs 4a-r related to combretastatin A-4 (CA4) using squaric acid as the cis-restricted linker were prepared and studied for their anticancer activity against selected human cancer cell lines. New compounds 4g,
Selective cross-couplings. Sequential Stille-Liebeskind/Srogl reactions of 3-chloro-4-arylthiocyclobutene-1,2-dione
Aguilar-Aguilar, Angelica,Pena-Cabrera, Eduardo
, p. 4163 - 4166 (2008/02/12)
The synthesis and initial reactivity studies of 2 are described. It was found that it participates in Stille couplings exclusively at the C-Cl site with a number of organostannanes (58-71% yield) in the absence of Cu(I). Then, these new derivatives were f
Synthesis of the substituted 3-cyclobutene-1,2-diones
Ivanovsky, Sergey A.,Dorogov, Mikhail V.,Kravchenko, Dmitry V.,Ivachtchenko, Alexandre V.
, p. 2527 - 2542 (2008/02/10)
A convenient synthesis of the novel squaric acid derivatives is reported. Unsymmetrically substituted 3,4-diamino-3-cyclobutene-1,2-diones and 3-amino-4-hydroxy-3-cyclobutene-1,2-diones were prepared by interaction of diethyl squarate with different nucle
Squaric Acids: A New Motif for Designing Inhibitors of Protein Tyrosine Phosphatases
Xie, Jian,Comeau, Anthony B.,Seto, Christopher T.
, p. 83 - 86 (2007/10/03)
(Equation presented) Protein tyrosine phosphatases (PTPases) are important targets in medicinal chemistry. These enzymes play a role in a number of human diseases, including type II diabetes and infection by Yersinia pestis, the causative agent of bubonic
Selective 1,4-addition of arenes to 3-chloro-3-cyclobutene-1,2-dione under friedel-crafts conditions. Synthesis and reactivity of 4-aryl-3-chloro-2- hydroxy-2-cyclobuten-1-ones
Schmidt, Arthur H.,Kircher, Gunnar,Maus, Stephan,Bach, Heinz
, p. 2085 - 2094 (2007/10/03)
The reaction of semisquaric chloride (7) with arenes 2 has been investigated. In the presence of 1.1 equiv of AlCl3 and in the temperature range of -15° C to rt the arenes 2a-q afford the 4-aryl-3-chloro-2-hydroxy-2-cyclobuten-1-ones (chloroenols) 8a-q in good yield. By contrast, 7 reacts with 1,4-dimethoxybenzene (2l) in boiling CH 2Cl2 to give a mixture of (2,5-dimethoxyphenyl) cyclobutenedione (9a) (27% yield) and bis(2,5-dimethoxyphenyl)cyclobutenedione (10a) (8% yield). With 1,2,4-trimethoxybenzene (2r) in the presence of trifluoroacetic acid is generated (2,4,5-trimethoxyphenyl)-cyclobutenedione (9b) in 21% yield. The chloroenols 8 allow a series of valuable transformation reactions: with diazomethane the chloroenol methyl ethers 11 are generated, with chlorine the 3-aryl-4-chlorocyclobutenediones 12, and with bromine in MeOH the 3-aryl-4-methoxycyclobutenediones 13. In DMSO or in acetone/H2O the chloroenols 8 eliminate HCl, furnishing the arylcyclobutenediones 14. In a mixture of acetone-d6/D2O/DCl are obtained 4-aryl-cyclobutenediones-3-d 15. For the latter two processes the corresponding 3-aryl-4-chlorocyclobutane-1,2-diones 16 are postulated as intermediates. Thermolysis of the chloroenols 8 and the chloroenol methyl ethers 11 in refluxing m-xylene afforded the 3-chloro-1,2-dihydroxynaphthalenes 17 and the 3-chloro-1-hydroxy-2-methoxynaphthalenes 18, respectively.
