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Concave reagents, 8. Concave pyridines and 1,10‐phenanthrolines with sulfonamide bridgeheads. Increased basicity by 4‐diethylamino substitution of the pyridine unit
Author(s) -
Lüning Ulrich,
Baumstark Roland,
Müller Michael
Publication year - 1991
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.1991199101172
Subject(s) - chemistry , sulfonamide , pyridine , reagent , substitution (logic) , medicinal chemistry , unit (ring theory) , combinatorial chemistry , stereochemistry , organic chemistry , mathematics education , mathematics , computer science , programming language
Bimacrocyclic concave pyridinebissulfonamides 2 and concave 1,10‐phenanthrolinebissulfonamides 4 have been synthesized by bridging macrocyclic pyridinediamines 12 or 1,10‐phenanthrolinediamines 16 with alkylenebis(sulfonyl chloride)s 14 . In contrast to concave pyridine‐ and 1,10‐phenanthrolinebislactams 1 and 3 , the new compounds 2 and 4 exhibit simpler 1 H‐NMR spectra and sharper melting points due to the absence of amide conformers; in comparison to 1 , the basicities of 2 are decreased by a factor of ca. 100. By introduction of donor substituents into the 4‐position of the pyridine ring the basicity loss can be easily compensated. The 4‐diethylamino substituent increases the basicity of the concave pyridines 1 and 2 as expected (ca. + 4 p K units). Since no deviations from the expected basicity and reactivity for the amino‐substituted concave pyridines 1 and 2 have been found, also in these sterically hindered pyridines, the pyridine nitrogen atom is the centre of basicity and reactivity. – The synthesis of new building blocks is described, i.e. 4‐diethylamino‐2,6‐pyridinedicarbaldehyde ( 9c ), the polyether‐based bis(sulfonyl chloride) 14b , the monomacrocyclic diamines 12e–h with a pentaethyleneglycol chain or a 4‐diethylamino substituent.