US5256799A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of 6-hydroxyindolines and their use for preparation of novel laser dyes
Assignee: United States Department of Energy
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Filing: 1992-07-14
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Granted: 1993-10-26
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Expires: 2012-07-14
Abstract
Abstract A novel method for the synthesis of 6-hydroxyindolines and new fluorescent dyes produced therefrom, which dyes are ring-constrained indoline-based rhodamine class dyes. These dyes have absorption and emission spectra which make them particularly useful in certain dye laser applications.
Inventors
- 👤 George F. Field
- 👤 Peter R. Hammond
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:59
CPC Classifications
C; C07; C07D; C07D491/00; C07D491/12; C07D491/14; C07D209/00; C07D209/02; C07D209/04; C07D209/08
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
73 words
A method of preparing 6-hydroxyindolines of the formula: ##STR5## where R 1 is hydrogen or lower alkyl, comprising the steps of: (a) treating phenethyl acetate with a nitrating agent to form an intermediate of 2-(2,4-dinitrophenyl)-acetate; (b) converting said intermediate to 2-(2,4-dinitrophenyl)-ethanol; (c) reducing said 2-(2,4-dinitrophenyl)-ethanol to form 2-(2,4-diaminophenyl)-ethanol; and (d) reacting said 2-(2,4-diaminophenyl)-ethanol with a strong aqueous acid and at a temperature of from about 140° C. to 180° C. to form 6-hydroxyindoline.
Claim 2
Independent Claim
73 words
A method of preparing 6-hydroxyindolines of the formula: ##STR5## where R 1 is hydrogen or lower alkyl, comprising the steps of: (a) treating phenethyl acetate with a nitrating agent to form an intermediate of 2-(2,4-dinitrophenyl)-acetate; (b) converting said intermediate to 2-(2,4-dinitrophenyl)-ethanol; (c) reducing said 2-(2,4-dinitrophenyl)-ethanol to form 2-(2,4-diaminophenyl)-ethanol; and (d) reacting said 2-(2,4-diaminophenyl)-ethanol with a strong aqueous acid and at a temperature of from about 140° C. to 180° C. to form 6-hydroxyindoline.
Claim 3
Dependent Claim
25 words
A method as in claim 1 wherein said strong aqueous acid is selected from the group consisting of phosphoric, sulfuric, methanesulfonic, trifluoromethanesulfonic and hydrobromic acids.
Claim 4
Dependent Claim
24 words
A method as in claim 1 wherein said strong aqueous acid is 70% w/w phosphoric acid, and step (d) occurs under constant volume conditions.
Claim 5
Dependent Claim
23 words
A method as in claim 1 wherein said strong aqueous acid is 85% w/w phosphoric acid, and step (d) occurs at atmospheric pressure.
Claim 6
Dependent Claim
35 words
A method as in claim 1, further comprising the step of: (e) reacting said 6-hydroxyindoline, wherein R 1 is H, with a C 1 -C 4 alkylating agent to form N-[C 1 -C 4 ]-6-hydroxyindoline.
Claim 7
Dependent Claim
14 words
A method as in claim 5 wherein said alkylating agent is a methylating agent.
Claim 8
Dependent Claim
13 words
A method as in claim 6, wherein said methylating agent is trimethyl phosphate.
Claim 9
Dependent Claim
18 words
A method as in claim 1, wherein the reaction of step (d) occurs at less than 170° C.
Claim 10
Dependent Claim
19 words
A method as in claim 1, wherein the reduction of step (c) is with hydrazine catalyzed by Raney metal.
Claim 11
Independent Claim
76 words
A method of preparing 6-hydroxyindolines of the formula: ##STR6## where R 1 is hydrogen or lower alkyl, comprising the steps of: (a) treating phenethyl acetate with a nitrating agent to form an intermediate of 2-(2,4-dinitrophenyl)-acetate; (b) converting said intermediate to 2-(2,4-dinitrophenyl)-ethanol; (c) reducing said 2-(2,4-dinitrophenyl)-ethanol to form 2-(2,4-diaminophenyl)-ethanol; (d) reacting said 2-(2,4-diaminophenyl)-ethanol with hydrobromic acid to form 6-aminoindoline; and (e) reacting said 6-aminoindoline with phosphoric acid at a temperature of about 170° C. to form 6-hydroxyindoline.
Claim 12
Independent Claim
76 words
A method of preparing 6-hydroxyindolines of the formula: ##STR6## where R 1 is hydrogen or lower alkyl, comprising the steps of: (a) treating phenethyl acetate with a nitrating agent to form an intermediate of 2-(2,4-dinitrophenyl)-acetate; (b) converting said intermediate to 2-(2,4-dinitrophenyl)-ethanol; (c) reducing said 2-(2,4-dinitrophenyl)-ethanol to form 2-(2,4-diaminophenyl)-ethanol; (d) reacting said 2-(2,4-diaminophenyl)-ethanol with hydrobromic acid to form 6-aminoindoline; and (e) reacting said 6-aminoindoline with phosphoric acid at a temperature of about 170° C. to form 6-hydroxyindoline.
Claim 13
Independent Claim
72 words
A method of preparing 6-hydroxyindolines of the formula: ##STR7## where R 1 is a lower alkyl, comprising the steps of: (a) treating phenethyl acetate with a nitrating agent to form an intermediate of 2-(2,4-dinitrophenyl)-acetate; (b) converting said intermediate to 2-(2,4-dinitrophenyl)-ethanol; (c) reducing said 2-(2,4-dinitrophenyl)-ethanol to form 2-(2,4diaminophenyl)-ethanol; and (d) reacting said 2(2,4-diaminophenyl)-ethanol with a strong aqueous acid and at a temperature of from about 140° C. to 180° C. to form 6-hydroxyindoline.
Claim 14
Independent Claim
72 words
A method of preparing 6-hydroxyindolines of the formula: ##STR7## where R 1 is a lower alkyl, comprising the steps of: (a) treating phenethyl acetate with a nitrating agent to form an intermediate of 2-(2,4-dinitrophenyl)-acetate; (b) converting said intermediate to 2-(2,4-dinitrophenyl)-ethanol; (c) reducing said 2-(2,4-dinitrophenyl)-ethanol to form 2-(2,4diaminophenyl)-ethanol; and (d) reacting said 2(2,4-diaminophenyl)-ethanol with a strong aqueous acid and at a temperature of from about 140° C. to 180° C. to form 6-hydroxyindoline.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1996-10-25 | 1997-04-26 | 1997-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-25 | 2001-04-26 | 2001-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-25 | 2005-04-26 | 2005-10-26 | $7700.00 | Window Closed / Lapsed |