Addition of Nucleophile Ring Opening

The recyclization of monocyclic pyrylium salts % occurs in accordance with the addition of nucleophile-ring opening-ring closure (ANRORC) mechanism (78ACR462) which starts with the a-addition of the nucleophile2 (Scheme 4). 

ANRORC addition of nucleophile, ring opening and ring closure... 

Another stimulating transformation of benzylamines to benzyl iodides is based on the smooth ANRORC (Addition of Nucleophile, Ring Opening and Ring Closure) reaction of the former with 4,6-diphenylpyran-2-thione followed by quaternization with methyl iodide and thermal decomposition (equation 174)1097. 

The reaction of strongly basic amide anions, R -N-R, with chloro- or bromopyridines, -pyrimidines, and other heterocycles can lead to ring opening and subsequent ring closure to result in substituted amino-N-heterocycles (addition of nucleophile, ring opening, ring closure = ANRORC). 

Purine and its derivatives undergo amination with potassium amide in liquid ammonia. Under these conditions, two different mechanisms may be followed (1) the Chichibabin reaction, and (2) the Sn(ATSIRORC) (Addition of Nucleophile, Ring Opening, Ring Closure) reaction. 

An apparent exception to the relative unreactivity of 3-halo-isoquinolines is provided by the reaction of 3-bromoisoquinoline with sodium amide. Here, a different mechanism, known by the acronym ANRORC (Addition of Nucleophile, Ring Opening and Ring Closure), leads to the product, apparently of direct displacement, but in which a switching of the ring nitrogen to become the substituent nitrogen, has occurred. 

Addition of Nucleophiles, Ring Opening and Ring Closure. 

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