5,5'-Diamino-3,3,3',3'-tetramethyl-2,2',3,3'-tetrahydro-1,1'-spirobi[indene]-6,6'-diol
[CAS 753437-92-2]

Identification

• Classification: Organic raw materials >> Alcohols, phenols, phenolic compounds and derivatives
• Name: 5,5'-Diamino-3,3,3',3'-tetramethyl-2,2',3,3'-tetrahydro-1,1'-spirobi[indene]-6,6'-diol
• Synonyms: 6,6'-diamino-1,1,1',1'-tetramethyl-3,3'-spirobi[2H-indene]-5,5'-diol
• Molecular Formula: C₂₁H₂₆N₂O₂
• Molecular Weight: 338.44
• CAS Registry Number: 753437-92-2
• SMILES: CC1(CC2(CC(C3=CC(=C(C=C32)O)N)(C)C)C4=CC(=C(C=C41)N)O)C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319
• Safety Statements: P264-P280-P302+P352-P337+P313-P305+P351+P338-P362+P364-P332+P313

Discovery and Applications

5,5'-Diamino-3,3,3',3'-tetramethyl-2,2',3,3'-tetrahydro-1,1'-spirobi[indene]-6,6'-diol is a highly functionalized spirocyclic organic compound built on a spirobi[indene] framework. Molecules of this type have been developed and studied in the context of advanced materials chemistry, particularly for use as rigid monomers in high-performance polymers. The incorporation of multiple amino and hydroxyl groups onto a sterically constrained, three-dimensional scaffold provides a combination of reactivity and structural rigidity that is valuable for constructing thermally stable and mechanically robust materials.

The structure consists of two partially saturated indene units connected through a central spiro carbon at the 1,1' positions. This spiro linkage forces the two ring systems into an orthogonal arrangement, reducing conjugation between them and creating a rigid, non-planar architecture. Four methyl groups at the 3,3,3',3' positions introduce steric bulk, limiting close packing and influencing solubility. The amino groups at the 5 and 5' positions and the hydroxyl groups at the 6 and 6' positions provide four reactive functional sites capable of hydrogen bonding and further chemical transformation. This arrangement allows the molecule to act as a multifunctional building block in step-growth polymerization and crosslinking reactions.

The development of spirobi[indene] derivatives with amino and hydroxyl substituents is associated with efforts to improve the performance of polymeric materials, particularly polyimides and epoxy resins. These compounds are typically synthesized through multistep sequences involving construction of the spiro core followed by nitration and reduction to introduce amino groups, along with controlled oxidation or substitution to install hydroxyl functionalities. Such synthetic strategies have been reported in the literature to yield rigid, well-defined monomers suitable for high-performance applications.

In polymer chemistry, this compound has been used as a diamine or multifunctional monomer for preparing polyimides, polyamides, and thermosetting resins. The amino groups readily react with dianhydrides or diacid derivatives to form polymer backbones, while the hydroxyl groups can participate in additional crosslinking reactions or be modified to adjust polymer properties. The rigid spiro structure reduces chain mobility and increases glass transition temperature, while the bulky substituents can enhance optical transparency and reduce dielectric constant by limiting dense packing. These features are important for applications in electronics, aerospace materials, and advanced coatings.

The combination of amino and hydroxyl groups also enables the compound to serve as a precursor for functional materials with tailored properties. Through derivatization, it can be incorporated into networks that exhibit improved thermal stability, mechanical strength, and chemical resistance. The defined three-dimensional geometry of the spiro center can also influence the formation of ordered structures in polymers and contribute to desirable physical characteristics.

In addition to its role in materials science, the compound is useful as a versatile intermediate in organic synthesis. The amino groups can undergo acylation, alkylation, or condensation, while the hydroxyl groups can be converted into ethers or esters. The sterically hindered environment created by the methyl groups and the spiro framework can lead to selective reactivity, which is advantageous in the synthesis of complex molecules.

Overall, 5,5'-diamino-3,3,3',3'-tetramethyl-2,2',3,3'-tetrahydro-1,1'-spirobi[indene]-6,6'-diol is a rigid, multifunctional compound developed for use in high-performance materials. Its spirocyclic structure, combined with multiple reactive sites, makes it an important building block for advanced polymers and functional materials requiring stability, strength, and controlled physical properties.

References

2000. A new class of HIV-1 integrase inhibitors: the 3,3,3', 3'-tetramethyl-1,1'-spirobi(indan)-5,5',6,6'-tetrol family. Journal of Medicinal Chemistry.
DOI: 10.1021/jm990600c