4-Amino-1-azabutadienes(3-amino-2-alkenimines) react with Schiff bases to afford N,N-disubstituted 4-amino-1-azabutadienes. Both the starting and the product 4-amino-1-azabutadienes can be reductively cleaved with lithium aluminum hydride followed by hydrolysis to afford 2-aminoalkyl ketones whereas the reduction with sodium/isopropanol gives 1,3-alkanediamines.
Reactivity of the Nitrogen-Silicon Bond. Pyridines and Furo[2,3-<i>b</i>][1,4]diazepines from 4-Amino-1-azabutadienes via 1,2-Dihydro-1,3,2-diazasilines
作者:José Barluenga、Miguel Tomás、Alfredo Ballesteros、Jian-She Kong
DOI:10.1055/s-1992-34176
日期:——
1,2-Dihydro-1,3,2-diazasilines 2 are prepared from 4-amino-1-azadienes 1 and react with dialkyl acetylenedicarboxylates to produce six- and seven-membered heterocycles depending on the substitution pattern of 1. Highly functionalized pyridine-2-carboxylates 5 and 8,8a-dihydro-2H-furo [2,3-b][1,4]diazepin-2-ones 11 are formed starting from azadienes 1 with R3 = H and R2 = R3 = H, respectively. On heating diazepines 11 undergo ring-contraction to alkyl 4-hydroxy-5-(iminomethyl) pyridine-2-carboxylates 13 which can be hydrolyzed to the corresponding 5-formyl-4-hydroxypyridine-2-carboxylates 14.
Formation of a novel N–N bond through SO extrusion. Regioselective synthesis of 1,2,6-thiadiazine S-oxides and pyrazoles
作者:José Barluenga、J. Francisco López-Ortiz、Vicente Gotor
DOI:10.1039/c39790000891
日期:——
The preparation of the 1,2,6-thiadiazineS-oxides (3) and their conversion into the pyrazoles (4) is described; the formation of (4) results from N–Nbondformation following the extrusion of SO.
Reaction of 4-Amino-1-azabutadiene Derivatives with Phosphorus(III) Halides: Synthesis of 1,2-Dihydro-1,3,2-<i>P</i>
<sup>III</sup>-diazaphosphorine Derivatives