38003-70-2Relevant articles and documents
Prilezhaev dihydroxylation of olefins in a continuous flow process
Van Den Broek, Bas A. M. W.,Becker, René,K?ssl, Florian,Delville, Mari?lle M. E.,Nieuwland, Pieter J.,Koch, Kaspar,Rutjes, Floris P. J. T.
, p. 289 - 292 (2012)
Epoxidation of both terminal and non-terminal olefins with peroxy acids is a well-established and powerful tool in a wide variety of chemical processes. In an additional step, the epoxide can be readily converted into the corresponding trans-diol. Batch-wise scale-up, however, is often troublesome because of the thermal instability and explosive character of the peroxy acids involved. This article describes the design and semi-automated optimization of a continuous flow process and subsequent scale-up to preparative production volumes in an intrinsically safe manner. Olefins go with the flow: Prilezhaev dihydroxylation can be performed on a large scale in continuous flow microreactor systems in the oxidation of terminal and internal olefins. Major drivers for a continuous flow process include better control, improved safety, and a faster overall process, leading to a significantly higher throughput. Copyright
Insights into gold-catalyzed synthesis of azelaic acid
Kulik, Anna,Martin, Andreas,Pohl, Marga-Martina,Fischer, Christine,Koeckritz, Angela
supporting information, p. 1799 - 1806 (2014/04/17)
A novel green route for the synthesis of azelaic and pelargonic acid via aerobic gold-catalyzed cleavage of 9,10-dihydroxystearic acid (DSA) was investigated recently. In this study, the examination of the reaction mechanism is described. The results of the application of 18O-labeled molecular oxygen and sodium hydroxide as well as of diastereomeric pure erythro- and threo-DSA were discussed. Assumed reaction intermediates were synthesized and subjected to the same reaction conditions as with DSA. As a conclusion from the obtained data, an oxidative dehydrogenation mechanism was postulated. Additionally, the aging of the gold catalyst used under different storage conditions was explored. the Partner Organisations 2014.
Cork suberin molecular structure: Stereochemistry of the C18 epoxy and vic-diol ω-hydroxyacids and α,ω-diacids analyzed by nmr
Santos, Sara,Cabral, Vanessa,Graca, Jose
, p. 7038 - 7047 (2013/08/23)
Suberin is the biopolyester that protects the secondary tissues of plants against environmental variability and aggressions. Cork suberin is composed mostly of C18 ω-hydroxyacids and α,ω-diacids, 9,10-substituted with an unsaturation, an epoxide ring, or a vic-diol group. Although determinant for suberin macromolecular structure, the stereochemistry of these monomers is poorly studied, sometimes with contradictory results. An NMR technique was used here to assign the configuration of the 9,10-epoxy and 9,10-diol groups in C18 suberin acids, comparing the chemical shifts of diagnostic 1H and 13C signals with the ones of model compounds, before and after conversion of the vic-diol group into benzylidene acetal derivatives. The relative configuration was proved to be cis in the C18 9,10-epoxy and threo in the C18 9,10-diol suberin acids. These monomers were present in suberin probably as racemic mixtures, as shown by polarimetry. The revealed stereochemistry allows the suberin macromolecule to be built as an ordered array of midchain kinked C18 acids, reinforced by intramolecular hydrogen bonding.
