Photochromic naphthopyrans

US6342459B1 · kind B1 · utility

Assignee

• Optische Werke G. Rodenstock · DE

Inventors

• Manfred Melzig · Weßling, DE
• Claudia Mann · Munich, DE
• Udo Weigand · Munich, DE

Key dates

• Filing date: May 18, 2000
• Grant date: Jan 29, 2002
• Expiry date: May 18, 2020

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B5/23
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to photochromic 2H-naphtho[1,2-b]pyrans as well as their use in synthetic resins of all types, especially for ophthalmic purposes. In particular, the present invention relates to photochromic naphthopyran compounds, for which a further ring system is bonded to the f side of the naphthopyran. The inventive photochromic dyes generally have the general formula (I) wherein n, R1, R2, R3, X, B and B′ are defined as in claim 1. The inventive compounds are distinguished by good darkening and decolorizing properties and a very good service life.