A new heterocyclic structure. The Benzopyrano[6,5,4‐def] Benzopyran. (1,6‐dioxapyrene)

Abstract

1,6‐Dioxapyrene, the first unsubstituted dioxa‐analogue of pyrene was synthesized in good yield from 2‐carbomethoxy‐6‐methoxynaphtho[1,8‐bc]pyran in a four‐step reaction involving a peri‐heterocyclisation. Its 1H nmr spectral characteristics were compared with those of native pyrene.

Photochemistry of Pyrene on Unactivated and Activated Silica Surfaces

“…The GC/MS analysis of F4 revealed presence of two isomers with m / z equal to 208. Although 1,6- and 1,8-dioxapyrenes ( , ) have a molecular formula of C 14 H 8 O 2 and a mass of 208, the observed MS fragmentation pattern and absorption spectrum for F4 do not allow its assignment as either of the two species. Fraction F5 shows an absorption spectrum resembling substituted phenanthrene and a MS fragmentation pattern indicating loss of −COH and −CO 2 H. Although its molecular weight suggests a molecular formula of C 15 H 12 O 3 , based on the available data we cannot assign a definitive structure to this fraction.…”

A new donor for charge-transfer systems: synthesis and properties of 2,4,7,9-tetramethyl-1,6-dithiapyrene (TMDTP) and structure of (TMDTP)3(PF6)2·2THF and TMDTP–TCNQ

“…30,31 This led to the question if it would be possible to use the pyrene p-frame as a test tube for investigating the effect of the heteroatom on the conducting materials properties. Since it is not possible to synthesize 1,6-dioxapyrenes by the same methodology 32 (Scheme 1), different methodologies have been developed based either on 2,6-dialkyl-1,5-naphthalenediols as starting materials 33,34 or on using 1,4,5,8-tetrasubstituted naphthalenes as intermediates [35][36][37][38] but both strategies have their limitations.…”

The chemistry of 1,6‐dioxapyrenes part 3 : Scope and limitations of an acid catalyzed ring‐closing reaction

“…Two different strategies for solving this problem have been devised. Strategy 1 relies on the intermediacy of 1,4,5,8-tetrasubstituted napththalenes, which are generally difficult to synthesise due to the peri-strain [2,11], where strategy 2 takes advantage of the use of alkyl substitution in the 2 and 6-positions of the naphthalene ring to prevent ring closure to the furane (Scheme 1) [1]. We wanted to investigate the scope and limitations of this last approach.…”