18667-21-5Relevant articles and documents
Process for the preparation of pyridinium intermediates
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, (2008/06/13)
A process for the preparation of halobenzoic acids, comprising the step of reacting a halonitrobenzene with a pyridinium salt to form an intermediate of the formula STR1 wherein R is selected from the group consisting of hydrogen, alkyl, aryl, alkenyl, alkynyl, --CN, --COOR' and --COR' where R' is alkyl or aryl; X is chloro or fluoro; Y is hydrogen, chloro or fluoro; and Z is chloro, bromo or iodo.
Stereoselective Cycloaddition of Pyridinium or Isoquinolinium Methylides with Olefinic Dipolarophiles and Subsequent Cycloadditions of the Cycloadducts with Nitrile Oxides
Tsuge, Otohiko,Kanemasa, Shuji,Takenaka, Shigeori
, p. 3631 - 3636 (2007/10/02)
Pyridinium or isoquinolinium methylides undergo highly stereo- and regioselective cycloadditions with olefinic dipolarophiles to form unstable tetrahydroindolizine derivatives.One of the two double bonds existing in the dihydro heteroaromatic ring of the cycloadducts reacts with nitrile oxides, in the same flask, in stereo-, regio-, and periselective fashions to lead to stable isoxazole-fused tetrahydroindolizines in good yields.
Preparation of Tetrahydroindolizines from Pyridinuim and Isoquinolinium Ylides
Katritzky, Alan R.,Grzeskowiak, Nicholas E.,Alvarez-Builla, Julio
, p. 1180 - 1185 (2007/10/02)
Carbonyl- and nitrile-stabilised pyridinium and cyclic azonium methylides condense with chalcones to form tetrahydroindolizines and analogous fused pyrrolidines.The stereochemistry is illuminated by 13C and 1H n.m.r. spectroscopy.Several incorrect literature structures are rectified.