1,8-Diacetylnaphthalene and its cyclisation to 3-methyl-1H-phenalen-1-one

Abstract

A single isomer of 1,8-diacetyInaphthalene (I) was formed on oxidation of cis-or trans-l,2-dimethylacenaphthene-1,2-diols (11). The dipole moment of diketone (I) (2.37 D) corresponds precisely to that calculated (CND0/2) for the trans-isomer. Cyclisation of (I) to 3-methyl-1 H-phenalen-I -one was achieved in 45 : 55 (v/v) ethanolwater solution on acid or alkali catalysis, or on electrochemical reduction. The rates of these reactions were measured, the cyclisation with alkali proceeding at ca. 50 000 times the rate of the reaction with acid. An explanation for the cyclisation on electrochemical reduction was obtained from calculations (INDO) of electron-densities of the radical anion of (I).

Reactions of carbonyl compounds in basic solutions. Part 26.1 The mechanisms of the base-catalysed cyclisation of 1,2-diacetylbenzene, 1,8-diacetylnaphthalene, 4,5-diacetylphenanthrene and 2,2′-diacetylbiphenyl

“…The activation parameters at 30 ЊC for the base-catalysed cyclisation of 2, 3 and 4 in 5 mol% aqueous DMSO and of 1 in 40 mol% aqueous DMSO are shown in Table 3. The results of a preliminary study 13 of the base-catalysed cyclisation of 2 in aqueous ethanol is in general agreement with the present results. The activation parameters in 40 mol% DMSO for 1 are significantly different from those for 2, 3 and 4 in 5 mol% DMSO, which may well be associated with the switch in the nature of the rate-determining step.…”

“…18 Thus, 2 has been described as having a 'transoid' conformation. 13 This conformation minimises both unfavourable steric 'bulk' and electrostatic interactions in the 1,8-disubstituted naphthalene and 4,5disubstituted phenanthrene systems. The generation of a car-…”

Enhanced carbonyl reactivity and conformational effects in peri-dioxocycloalka[de]naphthalenes

“…6 0 -80 "C) to give cream prisms (3.11 g, 96%), m.p. 12&123 "C (lit.,6 123 "C).1,2-Dihydroacenaphthylene-1 -spirocyclohexan-2-ol(9).-This was prepared in the same way from cyclohexane-2-spiroacenaphthylen-1-one '' (2.85 g) as cream prisms from etherlight petroleum (b.p.…”