Patent US3791670A successfully refreshed from Google Patents.
Patent US4916233A successfully refreshed from Google Patents.
US4916233A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for production of 4-methyl-5-(2-aminoethyl)-thiomethyl)-imidazole
Assignee: Nippon Shokubai Co Ltd
•
Filing: 1989-04-25
•
Granted: 1990-04-10
•
Expires: 2009-04-25
Abstract
Abstract 4-Methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole can be effectively produced by causing 4-methylimidazole or a salt thereof to react with at least one member selected from the group consisting of (a) a formaldehyde adduct of cysteamine, (b) 2-aminoethanethiol sulfuric acid and formaldehyde or a formaldehyde oligomer, and (c) thiazolidine or a salt thereof, in the presence of a mineral acid, removing a portion of reaction liquid out of the reaction system while maintaining molar concentration of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole in the reaction system not exceeding 70 mol % based on total mol numbers of 4-methylimidazole and 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole, then separating a liquid containing 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole from the removed portion of reaction liquid, and recycling the remainder into the reaction system.
Inventors
- 👤 Tsunemasa Ueno
- 👤 Koichi Yamamoto
- 👤 Masao Kitano
- 👤 Yutaka Morimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:05
CPC Classifications
C; C07; C07D; C07D233/00; C07D233/54; C07D233/64; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/582
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
113 words
A method for the production of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole comprising causing 4-methylimidazole or a salt thereof to react with at least one member selected from the group consisting of (a) a formaldehyde adduct of cysteamine, (b) 2-aminoethanethiol sulfuric acid and formaldehyde or a formaladehyde oligomer, and (c) thiazolidine or a salt thereof, in the presence of a mineral acid, removing a portion of reaction liquid out of the reaction system while maintaining molar concentration of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole in the reaction system not exceeding 70 mol % based on total mol numbers of 4-methylimidazole and 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole, then separating a liquid containing 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole from the removed portion of reaction liquid, and recycling the remainder into the reaction system.
Claim 2
Independent Claim
113 words
A method for the production of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole comprising causing 4-methylimidazole or a salt thereof to react with at least one member selected from the group consisting of (a) a formaldehyde adduct of cysteamine, (b) 2-aminoethanethiol sulfuric acid and formaldehyde or a formaladehyde oligomer, and (c) thiazolidine or a salt thereof, in the presence of a mineral acid, removing a portion of reaction liquid out of the reaction system while maintaining molar concentration of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole in the reaction system not exceeding 70 mol % based on total mol numbers of 4-methylimidazole and 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole, then separating a liquid containing 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole from the removed portion of reaction liquid, and recycling the remainder into the reaction system.
Claim 3
Dependent Claim
35 words
A method according to claim 1, wherein said mineral acid is used in the form of an aqueous solution containing said mineral acid in a concentration in the range of 10 to 70% by weight.
Claim 4
Dependent Claim
23 words
A method according to claim 1, wherein said reaction is carried out at a temperature in the range of 100° to 180° C.
Claim 5
Dependent Claim
15 words
A method according to claim 1, wherein said separation is effected by an electrodialytic technique.
Claim 6
Dependent Claim
54 words
A method according to claim 1, wherein the molar ratio of 4-methylimidazole or salt thereof to at least one member selected from the group consisting of (a) formaldehyde adduct of cysteamine, (b) 2-aminoethanethiol sulfuric acid and formaldehyde or oligomer thereof, and (c) triazolidine or a salt thereof and is in the range of 1:0.9-1.1.
Claim 7
Dependent Claim
20 words
A method according to claim 1, wherein said concentration is maintained in the range of 40 to 60 mol %.
Claim 8
Independent Claim
86 words
A method for the production of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole comprising causing 4-methylimidazole or a salt thereof to react with a formaldehyde adduct of cysteamine in the presence of a mineral acid, removing a portion of a reaction liquid out of the reaction system while maintaining molar concentration of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole in the reaction system not exceeding 70 mol % based on total mol numbers of 4-methylimidazole and 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole, then separating a liquid containing 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole from the removed portion of reaction liquid, and recycling the remainder into the reaction system.
Claim 9
Independent Claim
86 words
A method for the production of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole comprising causing 4-methylimidazole or a salt thereof to react with a formaldehyde adduct of cysteamine in the presence of a mineral acid, removing a portion of a reaction liquid out of the reaction system while maintaining molar concentration of 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole in the reaction system not exceeding 70 mol % based on total mol numbers of 4-methylimidazole and 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole, then separating a liquid containing 4-methyl-5-[(2-aminoethyl)-thiomethyl]-imidazole from the removed portion of reaction liquid, and recycling the remainder into the reaction system.
Claim 10
Dependent Claim
35 words
A method according to claim 7, wherein said mineral acid is used in the form of an aqueous solution containing said mineral acid in a concentration in the range of 10 to 70% by weight.
Claim 11
Dependent Claim
23 words
A method according to claim 7, wherein said reaction is carried out at a temperature in the range of 100° to 180° C.
Claim 12
Dependent Claim
24 words
A method according to claim 7, wherein the molar ratio of 4-methylimidazole and the formaldehyde adduct of cysteamine is in the range of 1:0.9-1.1.
Claim 13
Dependent Claim
15 words
A method according to claim 7, wherein said separation is effected by an electrodialytic technique.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-09 | 1993-10-09 | 1994-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-09 | 1997-10-09 | 1998-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-09 | 2001-10-09 | 2002-04-10 | $7700.00 | Window Closed / Lapsed |