Patenting Chemical Inventions with Compound Claims
Compound Claims for New Molecules
A compound claim is the strongest way to claim a chemical invention. It defines the inventor’s new molecule by structural formula. A claim to a compound covers the compound in any context— including all uses of the compound. Below is an example of a compound claim, claiming vitamin C by it’s structural formula. (Notably this claim is not patentable because vitamin C is not a new molecule).
Example Claim to Specific Molecule — Vitamin C
A compound having the following structural formula:
When inventors create new molecules, they can claim those molecules per se. This extensive claim scope rewards the inventors’ exceptional contribution. By creating a new molecule, the inventor made possible all uses of the molecule. Only the person who creates the molecule can claim it as a compound. After that, the molecule itself is no longer new. And only new things can be patented.
Compound Claims Cover All Uses of the Molecule
A compound claim covers all uses of the molecule. In the example above (vitamin C), the claim would cover making, using, or selling the molecule (vitamin C) in any way. For example, the claim would cover selling
any form of vitamin C, any mixture having vitamin C, any process for making vitamin C, and any method of using vitamin C.
Compound claims are valuable because they cover a molecule in any context. They are extremely broad claims. By contrast, method of use claims would only cover one use of the molecule; Composition claims would be limited to a particular mixture or formulation having the molecule.
Generalizing Compounds with Variable Groups
Notably, inventors can claim far more compounds than they actually make. An inventor can use variable groups to broaden the scope of the invention. For historical reasons, the patent community refers to variable groups as “Markush groups.”
In place of a specific atom, an inventor may use a variable group to explain that the atom could be chosen from a list of options. Using variable groups broadens the claim scope substantially. For example, instead of claiming only vitamin C (above), that claim could be drafted to include all variants having “R” groups on the alcohol positions (below).
Example Claim to Genus of Molecules Based on Vitamin C
A compound have the following structural formula:
wherein each R group is independently is chosen from an alkyl group, a substituted alkyl group, hydrogen, an ester, or a carboxylic acid.
By using variable groups, the scope of compounds claimed expands exponentially. Rather than limiting these positions to hydrogen atoms, each position may be selected from a list of possibilities. The terms “alkyl,” “ester,” etc. could also be defined broadly, covering a variety of different carbon groups. For example saturated and unsaturated alkyl chains, cyclic alkyls, aromatic groups, etc.