Steven Michael Partington

Synthesis and photochromic properties of some fluorine-containing naphthopyrans

A series of novel naphthopyrans containing fluorine substituents has been prepared and their behaviour following irradiation with UV light has been investigated. The colourless naphthopyrans exhibit photochromism through electrocyclic opening of the pyran ring. The spectral properties of the resulting coloured naphthalene-based dienones are discussed.

Synthesis and Photochromic Properties of Methoxy Substituted 2,2-Diaryl-2H-naphtho[1,2-b]pyrans

A series of methoxy-substituted 2,2-di(4-methoxyphenyl)-2H-naphtho[1,2-b]pyrans has been synthesised from 3-alkoxycarbonyl-1-naphthols and 1,1-di(4-methoxyphenyl)prop-2-yn-1-ol. The influence of the methoxy group on the wavelength of maximum absorption and the stability of the ring-opened naphthopyrans is discussed.

Synthesis and spectroscopic properties of some merocyanine dyes

The reaction between some 1,1-diarylprop-2-yn-1-ols 3 and cyclohexane-1,3-diones affords merocyanine dyes 7, the valence tautomers of the tetrahydro-2H-[1]benzopyrans. The spectroscopic properties of these dyes are discussed. The isomeric merocyanine dyes 14 and 15 derived from the reaction of 1,1-bis(4-dimethyl-aminophenyl)prop-2-yn-1-ol and 2-tetralone are dehydrogenated to the photochromic 3H-naphtho[2,1-b]pyran 12. This protocol constitutes a new route to the photochromic naphthopyran unit.

Photochromism of some thienobenzopyrans

Some novel thienobenzopyrans have been synthesised and their photochromic properties are discussed.

Synthesis and Photochromic Properties of 2H,9H-Indeno[1,2-f]- and 3H,7H-Indeno[2,1-i]- naphtho[2,1-b]pyrans

ABSTRACT Expedient syntheses of the 3-hydroxy- and 6-hydroxy- derivatives of 11H-benzo[a]fluoren-11-one, obtained via Suzuki-Miyaura couplings are described. Reactions of these phenols with 1,1-diarylprop-2-yn-1-ols give indeno[2,1-i]- and indeno[1,2-f]- naphtho[2,1-b]pyranones respectively. The photochromic properties of these and the reduced derivatives are reported. A rationale for the pronounced hypsochromic shift in λmax of the photomerocyanine from a 2H,9H-indeno[1,2-f]naphtho[2,1-b]pyran is presented.

Photochromism of Some Heterobenzopyrans

Abstract Some novel heterobenzopyrans have been synthesised and their photochromic properties are discussed.

Protolysis of Spironaphtho(aza)pyranoindoles

Abstract Some novel amino-substituted spiroindolinonaphthopyrans have been synthesised. Whilst these compounds exhibit no observable photochromic properties at ambient temperature, protonation results in ring opening to give stable, intensely coloured dyes. Recyclisation and decolouration result on basification.

Photochromic Naphthopyrans Containing a Latent Carbene Unit

ABSTRACT 3-(Hydroxyalkyl)-1-naphthols 12 have been accessed in two steps from an isoquinolinium salt. The naphthopyrans 15, derived from 12, were readily diazoacylated with ethyl diazomalonyl chloride. The carbenoid generated from 16 failed to undergo any cycloaddition and was instead intercepted by water to afford 18.