2H-Isoindole-2-methanesulfonyl chloride, 1,3-dihydro-1,3-dioxo-

2H-Isoindole-2-methanesulfonyl chloride, 1,3-dihydro-1,3-dioxo- (CAS: 61271-03-2) is a highly valuable bifunctional building block widely used in medicinal chemistry, chemical biology, and organic synthesis. Featuring a phthalimide core linked to a reactive methanesulfonyl chloride group, it offers a stable, electron‑withdrawing cyclic imide combined with a highly electrophilic sulfonyl chloride for selective nucleophilic substitution, making it an important tool in modern drug discovery and conjugation chemistry. Its primary applications are outlined below:

1. Organic Synthesis & Pharmaceutical Research

Key Intermediate for Sulfonamide Drug Discovery
The phthalimide scaffold is a privileged structure in medicinal chemistry. This compound serves as a key intermediate for the synthesis of sulfonamide derivatives, which are known to exhibit a wide range of biological activities including antibacterial, anticonvulsant, antidiabetic, and anticancer effects.

Bifunctional Conjugation Linker
The methanesulfonyl chloride group reacts readily with primary and secondary amines, while the phthalimide can be deprotected to reveal a primary amine (via hydrazinolysis). This dual functionality enables the construction of bifunctional molecules such as PROTACs (proteolysis‑targeting chimeras), antibody–drug conjugate (ADC) linkers, and targeted delivery systems.

2. Advanced Intermediate & Functional Compound Development

Construction of PROTAC Linkers
2H-Isoindole-2-methanesulfonyl chloride is widely used as a versatile building block for synthesizing heterobifunctional linkers in targeted protein degradation. The phthalimide end serves as a masked amine for E3 ligase ligand attachment, while the sulfonyl chloride allows efficient coupling to various warheads.

Specialty Chemical & Fine Intermediate Applications
It is employed in the preparation of functionalized sulfonamides, covalent probes, and molecular conjugates for chemical proteomics, enzyme inhibition studies, and high‑value applications in both academic and industrial research settings.

3. Research & Development Applications

Medicinal Chemistry & Covalent Inhibitor Design
Researchers utilize this compound to explore structure–activity relationships of sulfonamide‑based pharmacophores, develop covalent or reversible covalent inhibitors, and optimize linker lengths and compositions in bifunctional molecules.

Process Development & Scale‑Up
Its crystalline, moisture‑sensitive but well‑defined structure makes it suitable for laboratory synthesis, pilot‑scale production, and process optimization. The reactive sulfonyl chloride group enables straightforward derivatization under mild conditions, supporting efficient transition from R&D to commercial manufacturing of specialized conjugates and intermediates.

4. Handling & Storage

Storage Conditions
Store in tightly sealed, moisture‑proof containers under an inert atmosphere (e.g., nitrogen or argon). Keep in a cool, dry place away from strong bases, nucleophiles, and water. The sulfonyl chloride group is highly susceptible to hydrolysis, so minimize atmospheric exposure.

Intended Use
This product is intended for research, development, and industrial synthesis of bifunctional conjugates, sulfonamide drugs, and chemical biology probes. It is not for direct pharmaceutical, food, or human consumption without appropriate regulatory approval.

Summary

The value of 2H-Isoindole-2-methanesulfonyl chloride, 1,3-dihydro-1,3-dioxo- lies in its combination of a robust, deprotectable phthalimide group and an electrophilic methanesulfonyl chloride handle. This structure enables the efficient synthesis of bifunctional molecules, sulfonamide drugs, and covalent probes, supporting innovation in targeted protein degradation (PROTACs), medicinal chemistry, and chemical biology. Its reliable reactivity and well‑defined form make it an indispensable intermediate for modern drug discovery and conjugate development.