US4138547A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing 1,2,4-triazole nucleosides
Assignee: Viratek Inc
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Filing: 1977-12-22
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Granted: 1979-02-06
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Expires: 1997-12-22
Abstract
Abstract 1-β-D-Ribofuranosyl-1,2,4-triazole-3-carboxamide is prepared by a process wherein a suitably substituted formimidic acid hydrazide is condensed with a blocked derivative of D-ribose and the intermediate is ring closed with a reagent which donates one carbon atom to yield a 3-substituted-1-(blocked β-D-ribofuranosyl)-1,2,4-triazole. Treatment of this intermediate with ammonia and/or removal of the blocking group yields the product.
Inventors
- 👤 Leon F. Christensen
- 👤 Joseph T. Witkowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:07
CPC Classifications
C; C07; C07H; C07H9/00; C07H9/02; C07H9/04; C07H19/00; C07H19/02; C07H19/04; C07H19/056
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
84 words
A process for preparing 1-B-D-ribofuranosyl-1,2,4-triazole-3-carboxamide which comprises reacting cyanoformimidic acid hydrazide with ribose which is blocked with a blocking group chosen from the group consisting of isopropylidene, benzylidene, p-methoxybenzylidene, ethoxymethylene or 2,3-cyclic carbonate to from N'-(blocked ribofuranosyl)-cyanoformamidrazone which is ring closed with a one carbon atom donating reagent chosen from the group consisting of triethylorthoformate, aceticformic anhydride, dimethoxymethyl acetate, formic acid-foramide, dimethylforamide dimethyl acetal or dimethylforamide-phosphoryl chloride, to form 3-cyano-1-(blocked-B-D-ribofuranosyl)-1,2,4-triazole which is treated with ammonia to remove the blocking group to yield the product.
Claim 2
Dependent Claim
84 words
A process for preparing 1-B-D-ribofuranosyl-1,2,4-triazole-3-carboxamide which comprises reacting cyanoformimidic acid hydrazide with ribose which is blocked with a blocking group chosen from the group consisting of isopropylidene, benzylidene, p-methoxybenzylidene, ethoxymethylene or 2,3-cyclic carbonate to from N'-(blocked ribofuranosyl)-cyanoformamidrazone which is ring closed with a one carbon atom donating reagent chosen from the group consisting of triethylorthoformate, aceticformic anhydride, dimethoxymethyl acetate, formic acid-foramide, dimethylforamide dimethyl acetal or dimethylforamide-phosphoryl chloride, to form 3-cyano-1-(blocked-B-D-ribofuranosyl)-1,2,4-triazole which is treated with ammonia to remove the blocking group to yield the product.
Claim 3
Dependent Claim
68 words
A process according to claim 1 for preparing 1-B-D-ribofuranosyl-1,2,4-triazole-3-carboxamide which comprises reacting cyanoformimidic acid hydrazide with 2,3-O-isopropylidene-D-ribose to form N'-(2,3-O-isopropylidene-D-ribfuranosyl)-cyanoformamidrazone which is ring closed with a one carbon atom donating reagent chosen from the group consisting of triethylorthoformate, acetic-formic anhydride, dimethoxymethyl acetate, formic acid-foramide, dimethylforamide dimethyl acetal or dimethylforamide-phosphoryl chloride to form 3-cyano-1-(2,3-O-isopropylidene-B-D-ribofuranosyl)-1,2,4-triazole which is treated with aqueous ammonia and the isopropylidene group removed to form the product.
Claim 4
Dependent Claim
19 words
The Process of claim 1 wherein the one carbon atom donating reagent is chosen from triethylorthoformate or acetic-formic anhydride.
Claim 5
Dependent Claim
21 words
The Process of claim 1 wherein the isopropylidene group is removed by treatment with acetic acid, formic acid or trifluoroacetic acid.
References Cited (Backward Citations)
US3798209A
Cited
US4021542A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-05 | 1982-08-07 | 1983-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-05 | 1986-08-07 | 1987-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-05 | 1990-08-07 | 1991-02-06 | $7700.00 | Window Closed / Lapsed |