Patent · US Expired

Benzopyran derivatives

US4958021A · kind A · utility

1Cited by

9References

1Claims

0Family size

Assignee

BASF SE

Inventors

Andreas Guentner · Bischofswerda, DE
Udo Mayer · Bischofswerda, DE
Andreas Oberlinner · Ludwigshafen, DE

Key dates

Filing date	Jul 19, 1988
Grant date	Sep 18, 1990
Priority date	—
Expiry date	Jul 19, 2008

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07D311/58
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

Benzopyran derivatives of the formula ##STR1## where X is the radical ##STR2## and R.sup.1, R.sup.2, R.sup.3, R.sup.4 and also the ring A have defined meanings are used in pressure- or heat-sensitive layers.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.