93626-99-4Relevant academic research and scientific papers
Δ3-DIHYDROPYRANS AND TETRAHYDROPYRANS BY REDUCTION OF PYRYLIUM SALTS WITH SODIUM BOROHYDRIDE IN ACETIC ACID
Balaban, Teodor-Silviu,Balaban, Alexandru, T.
, p. 1341 - 1344 (2007/10/02)
The major reduction products with triacetoxyborohydride (NaBH4 in AcOH) of 2,4,6-trisubstituted pyrylium salts bearing alkyl substituents in the 2- and/or 6-position are the Δ3-dihydropyrans with cis 2- and 6-substituents and all-cis-2,4,6-trisubstituted tetrahydropyrans. Δ3-dihydropyrans are shown to be formed via 2H-pyrans by a 1,4 reduction while tetrahydropyrans result from 4H-pyrans by reduction of both enol-ether double bonds.
Formation of Di-iron Hexacarbonyl Complexes of 3H-1,2-Diazepines and the Effects of Complexation on Ring Inversion and the Rate of Sigmatropic Hydrogen Migration
Argo, Carl B.,Sharp, John T.
, p. 1581 - 1587 (2007/10/02)
A number of 3H-1,2-diazepines have been synthesised by the reactions of 6,7-dihydro-1-tosyl-1,2-diazepines with base.These diazepines are in dynamic equilibrium at room temperature via sigmatropic hydrogen migrations but in some cases could be separated by h.p.l.c. at 0 deg C.The reactions of 1H-2,3-benzodiazepines, 3H-1,2-benzodiazepines and the monocyclic 3H-1,2-diazepines (9)/(10) with di-iron noncarbonyl gave the dinuclear iron hexacarbonyl complexes (12), (14), and (15)/(16), respectively, in moderate yield.The complexes were found undergo ring inversion more easily than their precursors, and activation energies were determined.The complexation of the azo group also stopped the easy sigmatropic hydrogen shift observed for (9)/(10) and this is discussed in terms of changes in electronic effect and in the structural geometry of the diazepine ring.
