- Phase solubility studies of poorly soluble drug molecules by using O -phosphorylated calixarenes as drug-solubilizing agents
-
This study is the first report on the solubilizing effect of O-phosphorylated calix[n]arenes that form complexes with neutral molecules such as nifedipine, niclosamide, and furosemide by host-guest complexation. These complexation studies were carried out by using the phase solubility technique. From the obtained results, it was observed that the solubility of guest molecules such as nifedipine, niclosamide, and furosemide was significantly increased in the presence of host molecules tetrakis-O-(diethoxyphosphoryl)-p- tert-butylcalix[4]arene (1), tetrakis-O-(diethoxyphosphoryl)-calix[4]arene (2), bis-O-(diethoxyphosphoryl)-p-tert-butylcalix[4]arene (3), bis-O- (diethoxyphosphoryl)-calix[4]arene (4), and octakis-O-(diethoxyphosphoryl)-p- tert-butylcalix[8]arene (5). The increase in solubility of drugs by the calixarene host 1 to 5 was most probably due to inclusion complexation between drug molecules and cavities of the calixarene skeleton similar to drug-cyclodextrin complexes.
- Bayrakc, Mevluet,Ertul, Seref,Yilmaz, Mustafa
-
p. 233 - 239
(2013/01/15)
-
- Titanacalixarenes in homogeneous catalysis: Synthesis, conformation and catalytic activity in ethylene polymerisation
-
Variously substituted titanacalixarenes were synthesised and tested for their performance as catalysts in ethylene polymerisation: p-tert-butylcalix[4] arene was derivatised to afford distal diether p-tert-butylcalix[4]arenes L1-L4, distal dihydroxy-depleted L5, proximal dihydroxy-depleted L6, proximal diether p-tert-butylcalix[4]arene L7, proximal intra-bridged disiloxane L8 and proximal monoether L9. (Dichlorotitana)-p-tert-butylcalix[4]arenes 1-8 and (monochlorotitana)-p-tertbutylcalix[4]arene 9 have been successfully synthesised by reacting L1-L4 with TiCl4·2THF or L5-L9 with TiCl 4. The structural conformation of complexes 1-9 in solution were determined by 1H NMR, 13C NMR, NOESY and COSY spectroscopic studies. Compounds 2, 3 and 4 have been structurally characterised by single-crystal X-ray diffraction. Upon activation with methylaluminoxane, compounds 1-8 revealed low to moderate activities for the production of high-density polyethylene (HDPE) to ultra-high-molecular-weight polyethylene (UHMWPE). 6/MAO gave the best activity at 770 kgPE(molTi) -1h-1.
- Espinas, Jeff,Darbost, Ulrich,Pelletier, Jeremie,Jeanneau, Erwan,Duchamp, Christian,Bayard, Francois,Boyron, Olivier,Broyer, Jean-Pierre,Thivolle-Cazat, Jean,Basset, Jean-Marie,Taoufik, Mostafa,Bonnamour, Isabelle
-
experimental part
p. 1349 - 1359
(2010/07/16)
-
- Partially OH Depleted Calixarenes
-
The partially OH depleted dihydroxy- and trihydroxycalixarenes 2 and 3 were synthesized in order to assess the relative importance of the cyclic hydrogen bond on the conformation of p-tert-butylcalixarene.Both compounds were prepared from the same diethyl diphosphate ester precursor under different reductive cleavage conditions.The ring inversion barriers of 2 and 3 are -1, respectively.The completely OH depleted calixarene 5 and the MeOH solvate of dihydroxycalixarene 2 exist in the crystal in a 1,2-alternate conformation.Trihydroxycalixarene 3 crystallizes as a 1:2 pyridine solvate in which 3 adopts a cone conformation.One pyridine molecule is hydrogen bonded to one OH group of 3, while simultaneously being included into the cavity of another molecule of 3.It is concluded that three phenolic units are sufficient to stabilize the cone conformation.
- Grynszpan, Flavio,Goren, Zafrir,Biali, Silvio E.
-
p. 532 - 536
(2007/10/02)
-
- Multiple Reductive Cleavage of Calixarene Diethyl Phosphate Esters: a Route to n>metacyclophanes
-
The OH groups of p-t-butylcalixarene (n = 4 and 8) were converted into diethyl phosphate esters and reductively cleaved by treatment with K/NH3 to yield tetra-p-t-butyl4>- and octa-p-t-butyl8>metacyclophanes (4) and (7).
- Goren, Zafrir,Biali, Silvio E.
-
p. 1484 - 1487
(2007/10/02)
-
- Selectively Dehydroxylated Calixarenes and 1,3-Dithiocalixarenes; Novel Classes of Calixarenes
-
Selective modification of calixarenes either by selective dehydroxylation via the reductive removal of phosphate(s), or via the Newman-Kwart rearrangement of 1,3-bis(dimethylthiocarbamoyl)calixarenes yields calixarenes 3 and 1,3-dithiocalixarenes 6, respectively.
- Ting, Yuhua,Verboom, Willem,Groenen, Leo C.,Loon, Jan-Dirk van,Reinhoudt, David N.
-
p. 1432 - 1433
(2007/10/02)
-