5426-58-4Relevant academic research and scientific papers
RECYCLABLE POLYMERS BASED ON RING-FUSED GAMMA-BUTYROLACTONES
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Page/Page column 34; 41; 42, (2020/02/23)
The invention discloses a class of new polymers, trans-ring-fused poly(4-hydroxybutyrate)s (RF-P4HB) that exhibit a unique set of properties, including robust thermal stability and mechanical strength, quantitative recyclability to the building block monomers via thermolysis and/or chemical catalysis, and convenient production from the chemical ring-opening polymerization under ambient temperature and pressure. Another unique property is the formation of crystalline stereocomplexed polymers with high melting temperature upon mixing the two enantiomeric RF-P4HB chains via stereocomplexing co-crystallization. This invention also provides the corresponding ring-fused lactone monomer structures that enable the synthesis of the RF-P4HB polymers, through trans-fusing of rings to the parent γ-butyrolactone ring. Furthermore, a polymerization or copolymerization process for the synthesis of RF-P4HB polymers and copolymers is disclosed.
Nucleophilic Additions to Fused Bicyclic Five-Membered Ring Oxocarbenium Ions: Evidence for Preferential Attack on the Inside Face
Smith, Deborah M.,Tran, Michelle B.,Woerpel
, p. 14149 - 14152 (2007/10/03)
Evidence is provided that nucleophilic attack on five-membered ring oxocarbenium ions occurs from the inside face of the envelope. An eight-five fused-bicyclic system in which two substituents are constrained to pseudoequatorial positions underwent nucleophilic addition with selectivity that was comparable to an unconstrained monocyclic system. On the other hand, a bicyclic six-five analogue underwent reaction with low selectivity. This observation indicates that minimization of eclipsing interactions by attacking inside the envelope is not enough to control selectivity, but that the changes in the overall three-dimensional structure of the ring must be favorable as well. In the bicyclic six-five series, the six-membered ring is accommodated in the cation, but it destabilizes the transition state structure leading to the first-formed product of inside attack.
Synthesis and evaluation of cardiotonic activity of simple butenolides
Feliciano, A. San,Medarde, M.,Caballero, E.,Hebrero, MB.,Tome, F.,et al.
, p. 413 - 417 (2007/10/02)
Simple butenolide derivatives have been synthesized and their properties have been tested as inotropic agents.Although these compounds maintain the butenolide and the 14-hydroxyl group as compared with natural cardenolides, they lack inotropic activity.
THE ASSYMETRIC MICHAEL REACTION OF (2R,3S)-3,4-DIMETHYL-2-PHENYLPERHYDRO-1,4-OXAZEPINE-5,7-DIONE WITH 1-NITROCYCLOHEXENE
Takeda, Takeshi,Hoshihiko, Tomonori,Mukaiyama, Teruaki
, p. 797 - 800 (2007/10/02)
Optically active (2-nitrocyclohexyl)acetic acid(III) was obtained by the Michael reaction of (2R,3S)-3,4-dimethyl-2-phenylperhydro-1,4-oxazepine-5,7-dione(I) with 1-nitrocyclohexene in the presence of potassium t-butoxide (or cesium fluoride) and crown et
