Oblon, Spivak, McClelland, Maier & Neustadt
Azulenesquaric acid dyes that contain urethane groups
 Azulenesquaric acid dyes of the formula ##STR1## where L is substituted or unsubstituted C.sub.1 -C.sub.12 -alkylene, PA0 R.sup.1 is C.sub.1 -C.sub.20 -alkyl, C.sub.5 -C.sub.7 -cycloalkyl or substituted or unsubstituted phenyl and PA0 R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each independently of the others hydrogen or substituted or unsubstituted C.sub.1 -C.sub.12 -alkyl, with the proviso that when R.sup.5 is hydrogen the positions of the substituents CH.sub.2 --L--O--CO--NHR.sup.1 and R.sup.4 on an azulene ring may also be interchanged within a ring in either or both of the azulene rings, derived from azulene intermediates that contain urethane groups, are suitable for use in an optical recording medium. 
BASF Aktiengesellschaft
C C C C C C
C07C C07C C07C C07C C09B C07C
additional additional inventional inventional inventional additional
Sibylle Klaus D. Michael Harald Wolfgang Peter
Brosius Schomann Schmitt Kuppelhamier Schrott Neumann