70637-00-2Relevant articles and documents
Divergent Synthesis of Monosubstituted and Unsymmetrical 3,6-Disubstituted Tetrazines from Carboxylic Ester Precursors
Fang, Yinzhi,Fox, Joseph M.,Huang, Zhen,Tallon, Amanda M.,Xie, Yixin,am Ende, Christopher W.
supporting information, p. 16967 - 16973 (2020/08/10)
Since tetrazines are important tools to the field of bioorthogonal chemistry, there is a need for new approaches to synthesize unsymmetrical and 3-monosubstituted tetrazines. Described here is a general, one-pot method for converting (3-methyloxetan-3-yl)methyl carboxylic esters into 3-thiomethyltetrazines. These versatile intermediates were applied to the synthesis of unsymmetrical tetrazines through Pd-catalyzed cross-coupling and in the first catalytic thioether reduction to access monosubstituted tetrazines. This method enables the development of new tetrazine compounds possessing a favorable combination of kinetics, small size, and hydrophilicity. It was applied to a broad range of aliphatic and aromatic ester precursors and to the synthesis of heterocycles including BODIPY fluorophores and biotin. In addition, a series of tetrazine probes for monoacylglycerol lipase (MAGL) were synthesized and the most reactive one was applied to the labeling of endogenous MAGL in live cells.
Isomerization of cyclic ethers having a carbonyl functional group: New entries into different heterocyclic compounds
Kanoh, Shigeyoshi,Naka, Masashi,Nishimura, Tomonari,Motoi, Masatoshi
, p. 7049 - 7064 (2007/10/03)
Oxiranes (epoxides) and oxetanes having a carbonyl functional group are chemoselectively isomerized to different heterocyclic compounds via Lewis acid-promoted 1,6- and 1,7-intramolecular nucleophilic attacks of the carbonyl oxygen on the electron-deficient carbon neighboring the oxonium oxygen: for example, cyclic imides to bicyclic acetals, esters to bicyclic orthoesters, sec-amides to 4,5-dihydrooxazole or 5,6-dihydro-4H-1,3-oxazines, and tert-amides to bicyclic acetals or azetidines. The intramolecular attack of a 1,5-positioned carbonyl oxygen predominantly results in a propagating-end isomerization polymerization. On the other hand, cyclic ethers having a 1,8- or farther positioned carbonyl group undergo conventional ring-opening polymerization. A tetrahydrofuran (oxolane) ring does not open, even with a 1,6-positioned carbonyl group.
Nature of the Slow Step in the Hydrolysis of Cyclic and Bicyclic Ortho Esters Containing 1,3-Dioxane Rings
McClelland, Robert A.,Gedge, Sherrin,Bohonek, Jon
, p. 886 - 891 (2007/10/02)
A kinetic investigation is reported of the hydrolysis of a series of ortho esters containing 1,3-dioxane rings.Included are monocyclic 2-aryl-2-methoxy-1,3-dioxanes and bicyclic 1-aryl-4-methyl-2,6,7-trioxabicyclooctanes.Both types of compounds exh