A Convenient Synthesis of 4-Chloro- and 4-Bromocinnolines from o-Aminophenylacetylenes
作者:S. F. Vasilevsky、E. V. Tretyakov、H. D. Verkruijsse
DOI:10.1080/00397919408010177
日期:1994.6
Abstract 4-Chlorocinnolines and 4-bromocinnolines have been obtained in fair to good yields by diazotation of o-aminophenylacetylenes with sodiumnitrite and concentrated hydrochloric acid or hydrobromicacid at temperatures between 25 and 30°C.
Brønsted Acid-Promoted Sequential Hydroarylation- Hydroamidation of Arene-Tethered 1-(2-Alkynylphenyl)ureas: Direct Access to 4,4-Spiro-3,4-dihydro-2-(1H)-quinazolinones
A Brønstedacid-promoted approach to 4,4-sipro-3,4-dihydro-2-(1H)-quinazolinones from arene-tethered1-(2-alkynylphenyl)ureas has been developed. The reaction is initiated by intramolecular hydroarylation followed by hydroamidation, assisted by intramolecular proton transfer from the protonated urea moiety. A variety of tethering atoms, including carbon, oxygen, sulfur, and protected nitrogen are compatible