ISSN:
1434-193X
Keywords:
Oxalic amidines
;
Lithium diamides
;
Tetraaminoethenes
;
Nitrogen heterocycles
;
Reduction
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reduction of the 1,4-diaza-1,3-butadiene substructure of hexasubstituted amidines 1 with lithium metal yields the dilithium diamides 2. Subsequent reactions of these with various electrophiles give the title substances 3, 4 and 5. The quenching reaction of 2 with organosilicon derivatives leads to open-chain 3b as well as to cyclic tetraaminoethenes 4a,b. Treatment of 2 with methanol gives 3a which in the presence of oxygen is reoxidized to the starting amidine 1. Using alkyl halides as electrophiles, compounds 3c-e and 4c,d could be obtained in moderate to good yields. X-ray structural analyses of derivatives 3e and 4c reveal sterically overloaded central C-C double bonds. Whereas phosgene and its thio derivative give the imidazolines 4e,f, methyl benzoate allows a stepwise substitution leading to tetraaminoethenes bearing different residues at the nitrogen atoms.
Type of Medium:
Electronic Resource
