Orthoesters

Orthoesters

Polymeric Biomaterials in Tissue Engineering

Published in Chander Prakash, Sunpreet Singh, J. Paulo Davim, Functional and Smart Materials, 2020

Poly(ortho-esters) (POEs) are the polymers of ortho-ester groups along with the main chain. An ortho-ester is a functional group containing three alkoxy groups linked with single carbon atom [54]. POEs are derived by the transesterification of ortho-esters and by polyaddition between a diol and a diketene acetal [55]. (See Figure 2.8) POEs are divided into four types [56]: Poly-ortho-ester (POE I).Poly-ortho-ester (POE II).Poly-ortho-ester (POE III).Poly-ortho-ester (POE IV).

Reactions of thiocarbonyl compounds with electrophilic and nucleophilic carbenes as well as with their metal complexes

View Article

Journal Information

Published in Journal of Sulfur Chemistry, 2020

Grzegorz Mlostoń, Heinz Heimgartner

Methyl dithiobenzoate (133a) reacts with DMC yielding two different products, i.e. a mixture of the expected 2-methylthio-2-phenylacetate 134 (22% yield) and dimethyl phenylmalonate (135) (28%). On the other hand, the reaction of DMC with methyl monothiobenzoate (133b) led to the ester 135 exclusively, obtained in 84% yield [54] (Scheme 34). These different reaction pathways were explained by an easy migration of the MeS and MeO group, respectively, in the intermediates 136 to give thioketones 137, addition of a second carbene 115a yielding thiiranes 138, elimination of sulfur, and subsequent hydrolysis of the labile orthoester formed thereby. In the case of 136a, competitive ring closure leads to the corresponding thiirane, followed by elimination of sulfur and hydrolysis. The intermediate 138b, formed in the reaction with monothiobenzoate 133b, could be detected by NMR spectroscopy.

Explore chapters and articles related to this topic

Polymeric Biomaterials in Tissue Engineering

Reactions of thiocarbonyl compounds with electrophilic and nucleophilic carbenes as well as with their metal complexes