57728-69-5Relevant articles and documents
Microwave-Assisted Synthesis of 2-Substituted 2-Thiazolines and 5,6-Dihydro-4 H -1,3-thiazines
Bisceglia, Juan A.,Kilimciler, Natalia B.,Mancinelli, Michele,Mollo, María C.,Orelli, Liliana R.
, p. 1666 - 1679 (2020/06/01)
An efficient and general method for the synthesis of 2-substituted thiazolines and 5,6-dihydro-4 H -1,3-thiazines is developed via microwave-assisted ring closure of ω-thioamidoalcohols promoted by ethyl polyphosphate (PPE). The cyclization reaction involves an S N 2-type mechanism and features the advantages of very short reaction times, high yields and a predictable stereochemical outcome. The acyclic precursors are prepared in high overall yields by an improved diacylation-thionation-saponification sequence from commercially available ω-amino alcohols. The whole process is metal-free and operationally simple.
Development and Applications of Transesterification Reactions Catalyzed by N-Heterocyclic Olefins
Blümel, Marcus,Noy, Janina-Miriam,Enders, Dieter,Stenzel, Martina H.,Nguyen, Thanh V.
supporting information, p. 2208 - 2211 (2016/06/01)
A novel method to utilize N-heterocyclic olefins (NHOs), the alkylidene derivatives of N-heterocycic carbenes, as organocatalysts to promote transesterification reactions has been developed. Because of their strong Br?nsted/Lewis basicity, NHOs can enhance the nucleophilicity of alcohols for their acylation reactions with carboxylic esters. This transformation can be employed in industrially relevant processes such as the production of biodiesel, the depolymerization of polyethylene terephthalate (PET) from plastic bottles for recycling purposes, and the ring-opening polymerization of cyclic esters to form biodegradable polymers such as polylactide (PLA) and polycaprolactone (PCL).
Microwave-Assisted Synthesis of 2-Aryl-2-oxazolines, 5,6-Dihydro-4H-1,3-oxazines, and 4,5,6,7-Tetrahydro-1,3-oxazepines
Mollo, María C.,Orelli, Liliana R.
supporting information, p. 6116 - 6119 (2016/12/09)
The first general procedure for the synthesis of 5- to 7-membered cyclic iminoethers by microwave-assisted cyclization of ω-amido alcohols promoted by polyphosphoric acid (PPA) esters is presented. 2-Aryl-2-oxazolines and 5,6-dihydro-4H-1,3-oxazines were efficiently prepared using ethyl polyphosphate/CHCl3. Trimethylsilyl polyphosphate in solvent-free conditions allowed for the synthesis of hitherto-unreported 4,5,6,7-tetrahydro-1,3-oxazepines. The method involves good to excellent yields and short reaction times.The reaction mechanism and the role of PPA esters were investigated in a chiral substrate.