- Esterification of free fatty acids (Biodiesel) using nano sulfated-titania as catalyst in solvent-free conditions
-
Nano sulfated titania was tested as catalyst for esterification of free fatty acids, specially methanolic and ethanolic esterification of stearic acid (biodiesels). Factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents on ester conversion. This nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. This prepared sulfated titania showed high catalytic activity in direct esterification of fatty acids as well as benzoic acids with various alcohols and phenols under solvent-free conditions. This method is of great value because of its environmentally benign character, easy handling, high yields, convenient operation, and green. FT-IR studies are shown that the catalyst can be reused for acylation without loss of catalytic activity.
- Hosseini-Sarvari, Mona,Sodagar, Esmat
-
-
Read Online
- Combinatorial synthesis of PEG oligomer libraries
-
A simple chain-extending approach was established for the scale-up of the monoprotected monodisperse PEG diol materials. Reactions of THP-(OCH2CH2)n—OMs (n=4, 8, 12) with a large excess of commercially available H—(OCH2CH2)n—OH (n=1-4) under basic conditions led to THP-(OCH2CH2)n—OH (n=5-15). Similarly, Me-(OCH2CH2)n—OH (n=4-11, 13) were prepared from Me-(OCH2CH2)n—OMs (n=3, 7, 11). For the chain elongation steps, 40-80% yields were achieved through extraction purification. PEG oligomer libraries I and II were generated in 50-95% overall yields by alkylation or acylation of THP-(OCH2CH2)n—OH (n=1-15) followed by deprotection. Alkylation of Me-(OCH2CH2)n—OH (n=1-11, 13) with X—(CH2)m—CO2R (X=Br or OMs) and subsequent hydrolysis led to PEG oligomer library III in 30-60% overall yields. Combinatorial purification techniques were adapted to the larger-scale library synthesis. A total of 498 compounds, each with a weight of 2-5 g and a minimum purity of 90%, were synthesized.
- -
-
Page/Page column 11
(2010/02/15)
-
- Mixtures of drug-oligomer conjugates comprising polyalkylene glycol, uses thereof, and methods of making same
-
A non-polydispersed mixture of conjugates in which each conjugate in the mixture comprises a drug coupled to an oligomer that includes a polyalkylene glycol moiety is disclosed. The mixture may exhibit higher in vivo activity than a polydispersed mixture of similar conjugates. The mixture may be more effective at surviving an in vitro model of intestinal digestion than polydispersed mixtures of similar conjugates. The mixture may result in less inter-subject variability than polydispersed mixtures of similar conjugates.
- -
-
-
- Insulin polypeptide-oligomer conjugates, proinsulin polypeptide-oligomer conjugates and methods of synthesizing same
-
Methods for synthesizing proinsulin polypeptides are described that include contacting a proinsulin polypeptide including an insulin polypeptide coupled to one or more peptides by peptide bond(s) capable of being cleaved to yield the insulin polypeptide with an oligomer under conditions sufficient to couple the oligomer to the insulin polypeptide portion of the proinsulin polypeptide and provide a proinsulin polypeptide-oligomer conjugate, and cleaving the one or more peptides from the proinsulin polypeptide-oligomer conjugate to provide the insulin polypeptide-oligomer conjugate. Methods of synthesizing proinsulin polypeptide-oligomer conjugates are also provided as are proinsulin polypeptide-oligomer conjugates. Methods of synthesizing C-peptide polypeptide-oligomer conjugates and other pro-polypeptide-oligomer conjugates are also provided.
- -
-
-