N-[4-[(3-Chloro-4-fluorophenyl)amino]-7-[[(3S)-tetrahydro-3-furanyl]oxy]-6-quinazolinyl]-4-(dimethylamino)-2-butenamide

Target: This ligand targets EGFR/ERBB-family kinase domains represented by the afatinib-like quinazoline scaffold in biochemical or cellular target-engagement studies.

Mechanism of Action: Used as the target-protein recognition element, this ligand provides the binding interface for EGFR/ERBB-family kinase domains represented by the afatinib-like quinazoline scaffold. In PROTAC design, a derivatizable position on the ligand can be connected through an optimized linker to an E3 ligase ligand, such as a CRBN, VHL, or IAP recruiter, while preserving productive target engagement. The resulting bifunctional molecule brings EGFR/ERBB-family kinase domains represented by the afatinib-like quinazoline scaffold into proximity with the recruited E3 ligase, enabling ternary-complex formation. If the complex has favorable geometry and residence time, target lysine ubiquitination is promoted, leading to proteasome-dependent degradation in experimental systems.

• PROTAC DESIGN FOR DEGRADATION: This ligand can be used as a recruiting or binding module in PROTAC constructs to engage a target protein of interest with high specificity. By linking it to an E3 ligase-binding element through an optimized linker, researchers can promote ubiquitination and subsequent proteasomal degradation rather than simple inhibition.

• OPTIMIZATION OF LINKER ARCHITECTURE: The quinazolinyl and anilide-rich scaffold supports systematic PROTAC engineering, where linker length, rigidity, and attachment points are tuned to maximize ternary complex formation. Iterative synthesis and biochemical ternary-complex assays can guide selection of PROTAC variants that improve degradation potency and reduce off-target ubiquitination.

• CELLULAR TARGET DEGRADATION STUDIES: Incorporate this ligand into PROTACs to evaluate degradation efficacy in relevant cell models using immunoblotting, flow cytometry, or proteomics. Comparing dose–response and time-course profiles helps distinguish degradation from occupancy-driven effects, enabling identification of conditions that sustain target removal.

• MECHANISTIC VALIDATION VIA UBIQUITINATION: Use this ligand-based PROTAC platform to interrogate degradation mechanisms by measuring ubiquitination of the target and assessing dependence on the proteasome. Employing proteasome inhibitors and E3 ligase perturbations can confirm that observed loss of target protein is mediated by the intended ubiquitin–proteasome pathway.

• STRUCTURE-ACTIVITY RELATIONSHIPS: The defined aromatic and heteroatom pattern of this ligand enables structure–activity relationship mapping within PROTAC series. Systematic modifications of functional groups and linker chemistry can reveal how binding affinity, stereochemistry, and spatial orientation influence ternary complex stability and, ultimately, targeted protein degradation efficiency.

Structure: The structure of N-[4-[(3-Chloro-4-fluorophenyl)amino]-7-[[(3S)-tetrahydro-3-furanyl]oxy]-6-quinazolinyl]-4-(dimethylamino)-2-butenamide is characterized by primary or secondary amine/basic nitrogen centers; amide/urea/sulfonamide hydrogen-bonding motifs; halogenated aryl/heteroaryl ring system; heteroaromatic protein-recognition scaffold. These features provide defined hydrogen-bonding, hydrophobic, and steric elements that can support affinity retention while enabling analogue-based linker-vector selection.

Reactivity: The amine/basic nitrogen-containing motif can be evaluated for acylation, sulfonylation, alkylation, or carbamate/urea linker installation when that vector is solvent exposed. For PROTAC construction, the POI ligand can be paired with CRBN ligands such as thalidomide, pomalidomide, or lenalidomide analogues, VHL ligands such as VH032 derivatives, or less common IAP/MDM2/cIAP-recruiting ligands, with alkyl, PEG, piperazine, triazole, or amide linkers screened for ternary-complex formation. In practice, incorporation into PROTACs should begin from derivatives that preserve the reported binding pharmacophore, followed by systematic variation of linker length, polarity, rigidity, and exit-vector geometry to optimize target engagement, E3 recruitment, and cellular degradation readouts.