118019-72-0Relevant articles and documents
Lewis Base Catalyzed Intramolecular Reduction of Salicylaldehydes by Pinacol-Derived Chlorohydrosilane
Assoah, Benedicta,Vale, Jo?o R.,Kalenius, Elina,Veiros, Luis F.,Candeias, Nuno R.
, p. 2910 - 2917 (2018)
A newly developed stable chlorohydrosilane derived from pinacol is herein described. This was successfully used in the reduction of salicylaldehydes in reasonable to excellent yields (51–97 %). The ability of the hydrosilane to react as a reducing agent is increased upon the in situ formation of a trialkoxyhydrosilane and activation with a Lewis base, as further indicated by density functional theory studies. 1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU) was identified to be a suitable catalyst for this metal-free reduction, promoting the regio- and chemoselective reduction of aldehydes in ortho-position to phenols, despite the presence of vicinal ketones. The performance of pinacol-derived chlorohydrosilane in the reduction of salicylaldehydes was further observed to be superior to that of well-established commercially available chlorohydrosilanes.
Fast, reversible mechanochromism of regioisomeric oxazine mechanophores: Developing in situ responsive force probes for polymeric materials
Qian, Hai,Purwanto, Nathan S.,Ivanoff, Douglas G.,Halmes, Abigail J.,Sottos, Nancy R.,Moore, Jeffrey S.
, p. 1080 - 1091 (2021)
To address hysteretic or irreversible mechanochromism found in most bond-scission-based mechanophores, we developed a new family of mechanophores based on the oxazine (OX) structural motif. Three OX regioisomers differing in their point of attachment to the indole ring show variable mechanochromic mechanoresponsiveness in a polydimethylsiloxane (PDMS) matrix. Constrained DFT simulations correlate the experimental findings to molecular scale events; two of the three regioisomers exhibit a force-activated rearrangement, while the third one is mechanochemically inactive. Most significantly, when compared with the spiropyran (SP) and the naphthopyran (NP), the OX mechanophores exhibit faster and reversible mechanochromism without any sign of fatigue. Such a rapid response to mechanical loads is rationalized by the difference between SP and OX scaffolds, given that the SP ring opening is accompanied by a trans-cis isomerization step. These fast-responsive mechanophores are anticipated to bring deeper understanding to a broad range of soft materials by in situ monitoring the local mechanics.
Tuning the Activation Wavelength of Photochromic Oxazines
Swaminathan, Subramani,Garcia-Amors, Jaume,Thapaliya, Ek Raj,Captain, Burjor,Raymo, Franisco M.,Nonell, Santi
, p. 1852 - 1859 (2016)
The activation wavelength of a photochromic oxazine can be shifted bathochromically with the introduction of a methoxy substituent on the chromophore responsible for initiating the photochemical transformation. This structural modification permits switchi
