ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Quinoxaline and 2(1H)-quinoxalones react with organomagnesium salts differently from the corresponding phthalazines and quinazolines. 3-Dimethylaminopropyl-magnesiumchloride alkylates quinoxaline easily by addition to the 2 and 3 position forming a tetrahydroquinoxaline 2, which can be dehydrogenated to the corresponding dialkylated quinoxaline 3. The monosubstituted dihydroquinoxaline 5 is obtained only with difficulty. It can equally be dehydrogenated, yielding 6.Quinoxalones react with CH3MgI, C6H5MgBr, (CH3)2N—(CH2)3—MgCl by addition to the 3,4-C=N bond (not at the CO-group), yielding 11-13. These dihydroquinoxalones are dehydrogenated to the 3-substituted 2(1H)-quinoxalones 14-16. Only 3-phenyl-quinoxalone adds a Grignard reagent at the CO group, forming a 2-substituted 3-phenylquinoxaline (26). 3-Methyl-quinoxalone exhibits an abnormal behaviour: It is deprotonated by the mentioned reagents at the CH3 group, and the 3-methylenequinoxalone-anion so formed attacks another molecule of methylquinoxalone, finally yielding 32 and 33.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19710540814
