2,3,6,7,10,11‐Hexamethoxytribenzotriquinacene: Synthesis, Solid‐State Structure, and Functionalization of a Rigid Analogue of Cyclotriveratrylene

Abstract

The syntheses of several tribenzotriquinacenes bearing six methoxy groups at the outer peripheral positions of the aromatic rings are reported. The centro‐methyl derivative is accessible in surprisingly good yield through two‐fold cyclodehydration in the final step of a synthesis route which requires special care in the preparation of some electron‐rich key intermediates, such as 5,6‐dimethoxy‐2‐methylindane‐1,3‐dione and bis(3,4‐dimethoxyphenyl)methanol. X‐ray single‐crystal structure analysis of the centro‐methyl derivative confirms its C3v‐symmetrical molecular structure but, at variance from the parent centro‐methyltribenzotriquinacene and the similarly shaped cyclotriveratrylene, the hexamethoxytribenzotriquinacene analog does not form columnar stacks in the solid state. Functionalization of the three benzhydrylic bridgehead positions leads to the tetramethyl analog and the bridgehead triol in good yields. In contrast, attempts to functionalize the ortho positions by nitration or bromination mainly give rise to ring cleavage through electrophilic ipso attack, which parallels the behavior of cyclotribenzylenes and cyclotriveratrylenes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Synthesis and carbonic anhydrase isoenzymes I and II inhibitory effects of novel benzylamine derivatives

“…Table 2. hCA I and II isoenzymes inhibition data with some synthesized benzylamine derivatives (22)(23)(24)(25)(26)(27)(28) by an esterase assay with 4-NPA as substrate. …”

“…Human erythrocyte CA I isoenzyme was purified, 312.2-fold with a specific activity of 626 EU/mg and overall yield of 60.7%; CA II isoenzyme was purified, 296-fold with a specific activity of 594 EU/mg and an overall yield of 44.1%. We report here the first study on the inhibitory effects of novel benzylamine derivatives (22)(23)(24)(25)(26)(27)(28) on the esterase activity of hCA I and II. The inhibitor concentrations that caused 50% inhibition (IC 50 ) were determined from activity versus (%)-[benzylamines] plots and the K i values were calculated from the Lineweaver-Burk plots ( Table 2).…”

“…The inhibitor concentrations that caused 50% inhibition (IC 50 ) were determined from activity versus (%)-[benzylamines] plots and the K i values were calculated from the Lineweaver-Burk plots ( Table 2). The data of Table 2 show the following inhibition of hCA I and II with novel benzylamine derivatives (22)(23)(24)(25)(26)(27)(28), by an esterase assay, with 4-NPA as substrate:…”

“…CA isoenzymes inhibition effects CA isoenzymes (hCA I and hCA II) inhibitory effects of the novel benzylamine derivatives (22)(23)(24)(25)(26)(27)(28) were tested under in vitro conditions and K i values were calculated and given in Table 2.…”

The First Centrohexaindane Bearing Twelve Functional Groups at Its Outer Molecular Periphery and Related Lower Veratrole‐Derived Centropolyindanes

“…[6] In view of the lively interest in building blocks with rigid, well-defined 3D-geometry of the framework and the pendant functionalities, [7][8][9][10][11][12][13][14][15][16][17][18] access to derivatives of 1 that bear functional groups at the twelve arene positions of the outer periphery of this C 41 H 24 hydrocarbon is a promising goal. In this report, we disclose the synthesis of the first twelve-fold functionalized derivative of 1, namely 2, 3,6,7,10,11,14,15,20,21,26,27-dodecamethoxycentrohexaindane (2), bearing this particular, still T d -symmetrical pattern of peripheral substituents. In this context, the syntheses of two lower congeners of 2, which also belong to the centropolyindane family, [19] viz.…”