US4973706A
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Process for the preparation of indigo compounds
Assignee: Mitsui Chemicals Inc
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Filing: 1989-04-25
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Granted: 1990-11-27
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Expires: 2009-04-25
Abstract
Abstract Disclosed is a process for preparing an indigo compound in improved yield by reacting indole or other indole compound having no substituent at the 2- and 3-positions with an organic hydroperoxide in the presence of an additive selected from the group consisting of (1) a carboxyl compound and (2) a boric acid ester compound. The yield of the indigo compound can further be increased by using a metallic compound catalyst capable of oxidizing carbon atom at the 3-position of the indole compound, such as a compound of a metal of group 4A, 5A or 6A of the periodic table.
Inventors
- 👤 Yoshihiro Yamamoto
- 👤 Usaji Takaki
- 👤 Shinobu Aoki
- 👤 Isao Hara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 03:19
CPC Classifications
C; C09; C09B; C09B7/00; C07; C07D; C07D209/00; C07D209/02; C07D209/04; C07D209/30; C07D209/32; C07D209/36; C09B7/02
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
68 words
In a method for the preparation of an indigo compound wherein an indole compound is oxidized, the improvement wherein the starting indole lacks a substituent at the 2- and 3- positions and is oxidized in one step to the indigo compound with an organic hydroperoxide in the presence of an additive selected from the group consisting of (1) a carboxyl compound and (2) a boric acid ester compound.
Claim 2
Dependent Claim
68 words
In a method for the preparation of an indigo compound wherein an indole compound is oxidized, the improvement wherein the starting indole lacks a substituent at the 2- and 3- positions and is oxidized in one step to the indigo compound with an organic hydroperoxide in the presence of an additive selected from the group consisting of (1) a carboxyl compound and (2) a boric acid ester compound.
Claim 3
Dependent Claim
21 words
A process as claimed in claim 1 wherein the indole compound having no substituent at the 2- and 3-positions is indole.
Claim 4
Dependent Claim
25 words
A process as claimed in claim 1 wherein the organic hydroperoxide is a compound selected from the group consisting of secondary and tertiary alkyl hydroperoxides.
Claim 5
Dependent Claim
19 words
A process as claimed in claim 1 wherein the organic hydroperoxide is tert-butyl hydroperoxide, 1-phenylethyl hydroperoxide or 1-methyl-1-phenylethyl hydroperoxide.
Claim 6
Dependent Claim
27 words
A process as claimed in claim 1 wherein the organic hydroperoxide is used in an amount of 0.01 to 100 moles per mole of the indole compound.
Claim 7
Dependent Claim
26 words
A process as claimed in claim 1 wherein the carboxyl compound is a compound selected from the group consisting of carboxylic acids and carboxylic acid anhydrides.
Claim 8
Dependent Claim
29 words
A process as claimed in claim 1 wherein the boric acid ester compound is a compound selected from the group consisting of orthoboric acid esters and metaboric acid esters.
Claim 9
Dependent Claim
42 words
A process as claimed in claim 1 wherein the additive selected from the group consisting of a carboxyl compound and a boric acid ester compound is used in an amount of not greater than 50 moles per mole of the indole compound.
Claim 10
Dependent Claim
48 words
A process as claimed in claim 1 wherein the indole compound having no substituent at the 2- and 3- positions is indole, wherein the organic hydroperoxide is tert-butyl hydroperoxide, 1-phenylethyl hydroperoxide or 1-methyl-1-phenylethyl hydroperoxide, and wherein the reaction temperature is in the range of -10° to 200° C.
Claim 11
Dependent Claim
48 words
A process as claimed in claim 1 wherein the reaction is carried out in the presence of at least one solvent selected from the group consisting of water, aliphatic and alicyclic hydrocarbons, aromatic hydrocarbons, aliphatic and aromatic halogen compounds, ethers, alcohols, ketones, esters, carbonates and aromatic nitro compounds.
Claim 12
Dependent Claim
26 words
A process as claimed in claim 1 wherein the formed indigo compound is recovered in the form of a solid according to a solid-liquid separation technique.
Claim 13
Dependent Claim
34 words
A process as claimed in claim 1 wherein the reaction is carried out in the presence of a metallic compound catalyst capable of oxidizing the carbon atom at the 3-position of the indole compound.
Claim 14
Dependent Claim
33 words
A process as claimed in claim 12 wherein the metallic compound catalyst is a compound of a metal selected from the group consisting of groups 4A, 5A and 6A of the periodic table.
Claim 15
Dependent Claim
28 words
A process as claimed in claim 12 wherein the metallic compound catalyst is a compound selected from the group consisting of compounds of titanium, vanadium, molybdenum and tungsten.
Claim 16
Dependent Claim
17 words
A process as claimed in claim 12 wherein the metallic compound catalyst is a compound of molybdenum.
Claim 17
Dependent Claim
29 words
A process as claimed in claim 12 wherein the metallic compound catalyst is used in an amount of not greater than 0.5 mole per mole of the indole compound.
Claim 18
Dependent Claim
21 words
A process as claimed in claim 12 wherein the indole compound having no substituent at the 2- and 3-positions is indole.
Claim 19
Dependent Claim
25 words
A process as claimed in claim 12 wherein the organic hydroperoxide is a compound selected from the group consisting of secondary and tertiary alkyl hydroperoxides.
Claim 20
Dependent Claim
19 words
A process as claimed in claim 12 wherein the organic hydroperoxide is tert-butyl hydroperoxide, 1-phenylethyl hydroperoxide or 1-methyl-1-phenylethyl hydroperoxide.
Claim 21
Dependent Claim
27 words
A process as claimed in claim 12 wherein the organic hydroperoxide is used in an amount of 0.01 to 100 moles per mole of the indole compound.
Claim 22
Dependent Claim
26 words
A process as claimed in claim 12 wherein the carboxyl compound is a compound selected from the group consisting of carboxylic acids and carboxylic acid anhydrides.
Claim 23
Dependent Claim
29 words
A process as claimed in claim 12 wherein the boric acid ester compound is a compound selected from the group consisting of orthoboric acid esters and metaboric acid esters.
Claim 24
Dependent Claim
42 words
A process as claimed in claim 12 wherein the additive selected from the group consisting of a carboxyl compound and a boric acid ester compound is used in an amount of not greater than 50 moles per mole of the indole compound.
Claim 25
Dependent Claim
47 words
A process as claimed in claim 12 wherein the indole compound having no substituent at the 2- and 3-positions is indole, wherein the organic hydroperoxide is tert-butyl hydroperoxide, 1-phenylethyl hydroperoxide or 1-methyl-1-phenylethyl hydroperoxide, and wherein the reaction temperature is in the range of -10° to 200° C.
Claim 26
Dependent Claim
48 words
A process as claimed in claim 12 wherein the reaction is carried out in the presence of at least one solvent selected from the group consisting of water, aliphatic and alicyclic hydrocarbons, aromatic hydrocarbons, aliphatic and aromatic halogen compounds, ethers, alcohols, ketones, esters, carbonates and aromatic nitro compounds.
Claim 27
Dependent Claim
26 words
A process as claimed in claim 12 wherein the formed indigo compound is recovered in the form of a solid according to a solid-liquid separation technique.
References Cited (Backward Citations)
US4151170A
Cited
JPS54124027A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-11-26 | 1994-05-28 | 1994-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-26 | 1998-05-28 | 1998-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-26 | 2002-05-28 | 2002-11-27 | $7700.00 | Window Closed / Lapsed |