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Synthesis and Reactivity of 3′,5′‐Dichloro‐1 H ‐spiro(quinazoline‐2,4′‐[1,2,6]thiadiazin)‐4(3 H )‐ones
Author(s) -
Kalogirou Andreas S.,
Kourtellaris Andreas,
Koutentis Panayiotis A.
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201900576
Subject(s) - chemistry , stille reaction , quinazoline , stereochemistry , chloride , methoxide , crystal structure , reactivity (psychology) , medicinal chemistry , ferrocene , methanol , organic chemistry , polymer , medicine , alternative medicine , electrode , pathology , electrochemistry
A three‐step synthesis of 3′,5′‐dichloro‐1 H ‐spiro(quinazo‐line‐2,4′‐[1,2,6]thiadiazin)‐4(3 H )‐ones starting from 3,4,4,5‐tetra‐chloro‐4 H ‐1,2,6‐thiadiazine is presented. The latter reacts with 2‐aminobenzonitriles to give 2‐[(3,5‐dichloro‐4 H ‐1,2,6‐thiadiazin‐4‐ylid‐ene)amino]benzonitriles, which affords, after hydration, the respective benzamides. Upon heating at reflux in EtOH or HFIP, the benzamides intramolecularly cyclize onto the thiadiazine C4 position to give 3′,5′‐dichloro‐1 H ‐spiro(quinazoline‐2,4′‐[1,2,6]thiadiazin)‐4(3 H )‐ones. Single crystal X‐ray crystallography supports the structure of two analogues. The chloride displacement of these new spiroquinazolinones was demonstrated by Stille coupling, and by reaction with methoxide to afford both the mono and bis‐methoxy derivatives.