Basf Aktiengesellschaft

Michael Acker

Bernhard Albert

Klaus D Schomann

Sibylle Brosius

Harald Kuppelmaier

Peter Neumann

Michael Schmitt

Wolfgang Schrott

Matthias Dust

Gerhard Wagenblast

Helmut Hagen

Udo Bergmann

Helmut Barzynski

Georg Henning

Jacques Dupuis

Karl-Heinz Feuerherd

Peter Hauser

Peter Hammerschmitt

Heidi Benthack-Thoms

Claus Hackmann

Klaus-Dieter Schomann

Siegfried Mensch

Mathias Dust

Kal-Heinz Feuerherd

Preparation of N,N'-dialkylperylene-3,4,9,10-tetracarboxylic acid

Indolizinetrimethine dyes

1-Nitroanthraquinone-2-carboxylic acids of the general formula I ##STR1## where X is hydrogen, chlorine or bromine, are prepared by oxidizing a 1-nitro-2-methylanthraquinone of the general formula II ##STR2## with nitric acid in an organic reaction medium.

Preparation of 1-nitroanthraquinone-2-carboxylic acids

Moving laser beams from useful tracks to alternative positions in devices in which information is stored optically or magneto-optically. This results in higher signal-to-noise ratios.

Repositioning laser beams in information storage media

Polymethine dyes suitable for use in an optical recording medium have the formula ##STR1## where p is 0 or 1,

Heterocyclic polymethine dyes with carbamate or amide groups

An optical recording medium contains novel azulenemethine dyes of the formula ##STR1## where R is unsubstituted or substituted C.sub.1 -C.sub.6 -alkyl, X.sup..crclbar. is an anion, A.sup..sym. is heterocyclic radical, of the formula ##STR2## wherein R.sup.1, R.sup.2, R.sup.3, Y, Z and W are as defined, with the proviso that, when A.sup..sym. is a radical of the formula II f, II g, II i or II k, m is 2, A is 1, 2 or 3 and M is 1 or 2.

Azulenemethine dyes and an optical recording medium containing the novel

Methine dyes of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, X, Y and the rings A and B each have specific meanings, and methine dyes obtainable by reacting an organic mono- or polyisocyanate with such a methine dye of the abovementioned formal where only the radicals R.sup.1 and/and R.sup.4 have a group reacting with an organic mono- or polyisocyanate are useful in optical recording media.

Methine dyes and optical recording medium containing same

Quinoxalinepentamethine dyes of the formula ##STR1## where R.sup.1 is hydrogen, substituted or unsubstituted C.sub.1 -C.sub.22 -alkyl or substituted or unsubstituted C.sub.5 -C.sub.7 -cycloalkyl,

Quinoxalinepentamethine dyes and optical recording medium containing same

Naphtholactamtrimethine dyes useful in optical recording media have the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical or different and each is independently of the others C.sub.1 -C.sub.22 -alkyl, which may be substituted and/or interrupted by one or more oxygen atoms, one or more imino groups or one or more C.sub.1 -C.sub.4 -alkylimino groups, or is substituted or unsubstituted C.sub.5 -C.sub.7 -cycloalkyl or substituted or unsubstituted phenyl, and the rings A, B, C and D may each be substituted and/or benzofused.

Naphtholactamtrimethine dyes and optical recording medium containing same

An optical recording medium comprises a support material and a light-absorbing layer consisting essentially of a soluble mixture of a thermoplastic binder and at least one dye, wherein the thermoplastic binder is a phenol-aldehyde resin having an average molecular weight of greater than 300 which is soluble in an alcohol having a boiling point of less than 200.degree. C.

Optical recording medium

An optical recording medium contains a transparent base, a dye-containing layer which is sensitive to laser light and a reflector layer which contains a silicon-phthalocyanine derivative of the formula ##STR1## where R.sup.1 is hydrogen, alkyl, alkoxy, halogen or trialkylsilyl, n is 1, 2, 3 or 4 and A and B are identical or different and independently of one another are each alkyl, halogen or unsubstituted or substituted alkoxy or trialkylsilyloxy.

Optical recording medium which has a reflector layer containing a

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Heidelberg, Germany

Michael Acker