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The First 1,10‐Diaza[2.2]metacyclophanes – Strained Medium Membered Heterocycles ☆
Author(s) -
Habel Mathias,
Niederalt Christoph,
Grimme Stefan,
Nieger Martin,
Vögtle Fritz
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(199807)1998:7<1471::aid-ejoc1471>3.0.co;2-e
Subject(s) - chemistry , diamine , hydrolysis , dilution , alkaline hydrolysis , proton nmr , medicinal chemistry , quantum chemical , computational chemistry , stereochemistry , polymer chemistry , organic chemistry , molecule , physics , thermodynamics
The N ‐protected 1,10‐diaza[2.2]metacyclo‐ and 1,10‐diaza‐[2]metacyclo[2](2,6)‐pyridinophanes 4 and 5 have been synthesized for the first time using high dilution conditions. The free secondary diamine 7 was obtained from 4 by alkaline hydrolysis. – Quantum chemical calculations support the hypothesis that 7 is one of the most strained anti ‐hetera[2.2]metacyclophanes known. This is also evident from the 1 H‐NMR spectrum of 7 , which shows one of the strongest high field shifts for the intraannular protons in comparison to other anti ‐[2.2]metacyclophanes.