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US 4,710,570 AGranted
Azine redox dyes and leuco azine dyes
AssigneeMinnesota Mining and Manufacturing Company
InventorTran V. Thien
Life of this patent
Estimating the term…
Abstract
Azine redox dyes and their corresponding dyes of the formula: ##STR1## in which: X is O, S, NR.sup.2, Z completes a fused aromatic of heterocyclic ring system, n is 0 or 1 to allow one R.sup.1 ring substituent, Q represents CR.sup.4 R.sup.5 in which at least one of R.sup.4 and R.sup.5 is an electronegative group or R.sup.4 and R.sup.5 may complete a ring, or when X is S Q may represent NR.sup.3 in which R.sup.3 is an aromatic or heterocyclic group. The leuco dyes are useful as dye generators in pressure sensitive, thermographic or photothermographic imaging systems.
Claims12
A compound of the general formula:
- ##STR67## in which:
- X represents O or S;
- Z represents the necessary atoms to complete a fused aromatic or heterocyclic ring system, which may be polynuclear, of up to 16 skeletal atoms selected from carbon and nitrogen;
- n is 0 or 1;
- R.sup.1 represents an alkyl or aromatic sulphonyl group, containing up to 15 skeletal atoms selected from carbon, nitrogen, oxygen, and sulphur;
- Q represents CR.sup.4 R.sup.5
- in which
- R.sup.4 and R.sup.5 each contain up to 20 skeletal atoms selected from carbon, nitrogen, oxygen and sulphur, at least one of R.sup.4 and R.sup.5 is selected from the group consisting of electronegative groups selected from the group consisting of carbonyl, cyano and sulphonyl groups, and substituted aryl groups, and the other of R.sup.4 and R.sup.5 may additionally be selected from aryl, alkoxy, thioalkoxy, alkylamino and arylamino, or R.sup.4 and R.sup.5 together comprise the necessary atoms to form a 5-membered .alpha.-oxoheterocyclic ring, and when X represents O, R.sup.4 and R.sup.5 together may additionally comprise the necessary atoms to form a 6-membered .alpha.-oxoheterocyclic ring.
5 more elements
Dependencies are inferred from the claim text.