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A Novel Synthesis of Tetraaminoethenes by Reduction of Oxalic Amidines and Subsequent Electrophilic Substitution
Author(s) -
Wenzel Matthias,
Beckert Rainer,
Günther Wolfgang,
Görls Helmar
Publication year - 1998
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/(sici)1099-0690(199801)1998:1<183::aid-ejoc183>3.0.co;2-a
Subject(s) - chemistry , electrophile , electrophilic substitution , amidine , medicinal chemistry , steric effects , metalation , dilithium , deoxygenation , substitution reaction , organic chemistry , catalysis , ion , deprotonation
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.