Die Synthese von 3.5-Bis-dialkylamino-phenolen 2 und 1.3.5-Tris-dialkylamino-benzolen 3 gelingt durch Erhitzen von Phloroglucin (1) mit sek. Aminen im Autoklaven. Die UV-und insbesondere die 1H-NMR-Spektren bestatigen die aus Mesomeriebetrachtungen und einfachen HMO-Berechnungen in der Literatur abgeleiteten besonderen elektronischen Verhaltnisse in diesen Verbindungen.Durch bestimmte Suhstituenten kann eine Annaherung im Reaktionsverhalten olefiniscber und aromatischer Verbindungen erreicht werden. Enolather sind gegenuber einem elektrophilen Angriff durch Sulfonylisocyanate vergleichbar aktiviert wie Benzol durch drei Alkoxybzw. eine Dialkylaminogruppe2,4,5). N.N.N'.N'-Tetramethyl-m-phenylendiamin reagiert mit Isocyanaten ahnlich leicht wie Keten-diLthylacetal6).Aus Mesomeriebetrachtungen und einfachen HMO-Berechnungen7) ergibt sich fur 1.3.5-Triamino-benzole im Vergleich zu anderen Benzolderivaten die kleinste Lokalisierungsenergie, d. h., die Delokalisierung der x-Elektronen ist hier am starksten gestort, wodurch die Annaherung an ein olefinisches Verhalten am ehesten erwartet werden kann.Am Stickstoff nichtsubstituierte aromatische Amine sind zur Untersuchung der elektronischen Einflusse ungeeignet, da Tautomerie-Gleichgewichte vorliegen konnen und das henzoide System dann nicht mehr fixiert ist.Ausgehend von diesen Uberlegungen interessierten wir uns fur das chemische und spektroskopische Verhalten von 1.3.5-Tris-dialkylamino-benzolen. Bisher ist kein Weg zur Darstellung dieser Verbindungsklasse beschrieben. A. Synthese yon 3.5-Bis-dialkylamino-phenolen (2) und 1.3.5-Tris-dialkylaminobenzolen (3)Dialkylamino-benzole werden im allgemeinen durch Alkylierung der Aminoverbindungen erhalteng). Die direkte Kerndialkylaminierung ist fur eine Mehrfachsub-1) Teil der Dissertat. R . Niess, Univ. Stuttgart 1967.
give 148 mg (0.43 mmol) of 1,3,3-triphenylisoÍndole, mp 145°( lit.16 mp 145.5°), identified by comparison with a known sample.15Pyrex-Filtered Irradiation of Benzophenone Azine (1) in Methanol.-The reaction procedure was the same as that described for the Vycor-filtered irradiation of 1 except that a Pyrex filter was used and the reaction time was extended to 72 hr. At the end of this time no reaction had taken place.Vycor-Filtered Irradiation of Benzophenone Azine (1) in Benzene.-The procedure was again the same as the irradiation procedure for 1 in methanol except that the solvent was changed to benzene. The irradiation time was 72 hr. No reaction was observed.Vycor-Filtered Irradiation of 1,1,1', 1'.-Tetraphenylazomethane (7) in Methanol.-The irradiation and isolation procedures were the same as those used in the Vycor-filtered irradiation of 1 except that 1.09 g (3.00 mmol) of 1,1,1', 1 '-tetraphenylazomethane was irradiated and the irradiation time was 45 min.Fractions 7 and 8 afforded 61 mg of a mixture of biphenyl and diphenylmethane. Rechromatography separated this pair into 9 mg (0.06 mmol) of biphenyl and 51 mg (0.30 mmol) of diphenylmethane, both identified by ir and nmr spectroscopy. Fraction 9 yielded 27 mg (0.15 mmol) of cis-stilbene, also identified by ir and nmr spectroscopy. Fractions 14-19 gave 180 mg of l-(2-biphenylyl)-l,2-diphenylethane, mp 75-78°.
Aminobenzenes, XI')Alkylation of 1,3,5-Tripyrrolidinobenzene 1,3,5-Tripyrrolidinoben~ne (1) reacts with alkyl halides through an SN2 reaction to give cyclohexadienylium halides (o-complexes) 2, 7, or 10, which are model substances for electrophilic aromatic substitution in a manner analogous to the Meisenheimer-compounds for nucleophilic aromatic substitution. They can be deprotonated with bases to produce the alkylbenzenes 4,8, or 13. N-Alkylation is observed simultaneously with C-alkylation except for benzyl bromides which show only C-alkylation to2f-kand7a -c,respectively. -Underthereactionconditionsemployed for C-alkylation a preceding N-alkylation can be excluded. The lower homologues (C, and C,) of the o,o'-dibromo-n-alkanes react through an initial C-alkylation and a subsequent intramolecular N-reaction to produce indolinium 9 a and quinolinium bromides 9b, respectively. The higher homologues (C4, C5, and Clo) lead to a coupling of two tripyrrolidinobenzenes 1 by C,C-(lo), C,N-(1 1) and N,N-alkylation (12).
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