Invalidity dossier
US 4479951
1.4;3.6-Dianhydrohexitol nitrates substituted by purine bases, processes for their preparation and pharmaceutical compositions
Current assignee: Dr Willmar Schwabe GmbH and Co KG
Added 9/21/2026, 10:22:29 AM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US4479951A
Title: "1.4;3.6-Dianhydrohexitol nitrates substituted by purine bases, processes for their preparation and pharmaceutical compositions"
Assignee: Dr. Willmar Schwabe GmbH & Co. KG (Dr. Willmar Schwabe initially).
Inventors: Klaus Klessing and Shyam S. Chatterjee.
Key dates: Priority 1980-07-25; filed 1981-07-20; granted/published 1984-10-30; anticipated expiration 2001-10-30. Status: Expired – Fee Related.
Purpose: The invention addresses the need for improved nitrate-based cardiovascular agents. Known isosorbide nitrates (e.g., isosorbide dinitrate, per U.S. Pat. No. 3,886,186) are effective vasodilators but cause side effects (notably headaches), are poorly resorbed as mononitrates, and can be explosive to prepare and handle. The new compounds are described as non-explosive, with good oral absorption, long action, a good therapeutic range, and coronary flow-increasing, spasmolytic, and blood-pressure-lowering effects.
Plain-language scope: The compounds are 1.4;3.6-dianhydrohexitol mononitrates bearing purine groups, specifically adenyldesoxy derivatives (formula Ia) and theophyllinyldesoxy derivatives (formula Ib). They are made from L-isoidide, D-isosorbide, or D-isomannide. One route converts the hexitol with a sulphonic acid chloride (e.g., methanesulphonic or toluenesulphonic acid chloride) to a mono-O-acyl intermediate, then reacts it with an alkali-metal salt of a purine (adenine, 6-N-substituted adenine, theophylline, 6-methyl-mercaptopurine, or 6-chloropurine) in a dipolar aprotic solvent at elevated temperature, followed by nitration of the free hydroxyl group. Substituted adenines are derived by reacting the 6-methylmercapto- or 6-chloropurine derivatives with amines. Pharmaceutical compositions with conventional carriers and physiologically acceptable acid-addition salts are also claimed.
Not established by this excerpt: The complete claims, exact claim scope, working examples, and quantitative pharmacological data are not included. No litigation, ownership transfers, validity analysis, or prior-art assessment is addressed.
Source: https://patents.google.com/patent/[US4479951](/patent/US4479951)/en
Generated 10/1/2026, 10:01:40 PM
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Assignment history
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Prior art
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Obviousness
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Extensions
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