ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Heterocyclizations, X. Synthesis of Pyrimido[3.4-α]indolesThe 2.3.3-trimethylindolenines 1 add iso(thio)cyanates with two electrophilic centers (3) at the cyclic nitrogen to give 1-carbamoyl-2-methyleneindolines 4; these readily undergo isomerization to the 2-(carbamoylmethylene)-indolines 5. In the presence of basic catalysts the adducts 5 cyclize to pyrimido[3.4-α]indoles (6,7) with a bridge head nitrogen. A chlorine substituent in the 7-position of 1 inhibits the cyclization.
Notes:
2.3.3-Trimethyl-indolenine (1) addieren Iso(thio)cyanate mit zwei elektrophilen Zentren (3) zuerst am Ring-N zu den 1-Carbamoyl-2-methylen-indolinen 4; diese lagern sich schnell in die isomeren 2-Carbamoylmethylen-indoline 5 um. In Gegenwart von basischen Katalysatoren cyclisieren die Addukte 5 zu Pyrimido[3.4-α]indolen (6,7) mit Brückenkopfstickstoff. Ein 7-ständiger Chlorsubstituent in 1 verhindert die Cyclisierung.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19721050815
