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Tag: Benzoxazine ampakine

CX-546

Plain-language summaryIntrigue 42 / 100

CX-546 is a benzoxazine ampakine developed at Cortex as a successor to CX-516 with longer duration. Used in academic research as a higher-potency AMPA potentiator. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNiche research probe

35/100

Second-gen ampakine with real AMPA kinetic advantages but no clinical translation and limited differentiation in a class that moved on

Look, CX-546 is a genuinely interesting pharmacological object from a chapter of neuropharmacology that deserved better. Cortex Pharmaceuticals spent real money on the ampakine program, and CX-546 was a legitimate iterative advance over CX-516: tighter binding kinetics, deeper AMPA potentiation per receptor event, longer-lasting effect. If you are running AMPA receptor biology in vitro or using rodent models to probe synaptic plasticity mechanisms, CX-546 is a functional tool, and thats worth acknowledging upfront.

Here’s the thing though: the compound belongs to a class defined by two recurring problems. First, the dose window between useful potentiation and convulsant territory is uncomfortably narrow across most ampakines, and CX-546 is no exception even if it showed some pharmacokinetic advantage over its predecessor. Second, and more decisively, the whole Cortex program hit a wall. CX-546 never advanced through pivotal human trials in any indication. The respiratory depression angle, which was the most genuinely promising preclinical story, opioid-reversal in rats being an intellectually compelling hypothesis, never became a human signal worth citing in the context of this compound specifically.

On mechanism, we’d give AMPA positive allosteric modulation more credit here if CX-546 specifically had generated better translational data. The mechanism sits in an important space: LTP, synaptic plasticity, cognitive processing, and potentially respiratory drive regulation. But the class has more capable members now. More modern AMPA PAMs from academic groups and later pharma programs have been characterized with better methodology and more rigorous preclinical packages than anything the Cortex series produced.

On differentiation, CX-546 improves on CX-516, but thats a low bar. Compounds like CX-717 went further into development before the program collapsed. Within the ampakine class CX-546 is neither the first word nor the last. It’s a middle entry in a program that ran out of runway.

The bench value is real but bounded. If your research specifically requires an AMPA PAM with CX-546’s kinetic profile and you have a reason to distinguish it from other available tools, it is accessible as a research chemical. Most investigators who need an AMPA PAM, though, have better-characterized options with cleaner sourcing and more published method validation behind them. Vendor quality and purity certification for Cortex-generation ampakines is genuinely inconsistent across the supply chain.

Honest assessment: CX-546 is worth knowing about if you’re digging into the ampakine literature or running AMPA receptor assays where its specific kinetic profile is the variable of interest. For most bench programs it’s a historical artifact of a failed development program. Failed clinical translation, thin and single-source human data, and a class that has moved past it all point toward the lower third of our scale.

Novelty

33

Mechanism promise

52

In-category differentiation

33

Evidence quality

28

Translational signal

20

Research bench value

45

Rationale CX-546 earns modest mechanism and bench-value credit as a functional AMPA PAM probe with improved kinetics over CX-516 and an intellectually interesting respiratory-depression angle, but the Cortex program ended without pivotal human data in any indication, translational signal is essentially zero, and more modern AMPA PAMs have since been characterized with better methodology. The score reflects a compound that is a usable tool in a narrow context but not a priority research target.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Benzoxazine ampakine

A second-generation Cortex Pharmaceuticals ampakine with improved AMPA receptor modulation kinetics and reduced respiratory depression liability.

Abstract

CX-546 (1-(1,4-benzodioxan-6-ylcarbonyl)piperidine; CAS 215923-54-9; molecular formula C14H17NO3; molecular weight 247.29) is a second-generation Cortex Pharmaceuticals ampakine in the benzoxazine subclass. The compound shows improved AMPA receptor modulation kinetics relative to CX-516, with deeper potentiation per binding event and longer-lasting effect. CX-546 was advanced through preclinical development for cognitive impairment and respiratory disorders (the AMPA potentiation can reverse opioid-induced respiratory depression in animal models). The compound did not advance through pivotal human trials in any indication. Pharmacokinetics: short plasma half-life (2 to 3 hours), oral bioavailability moderate. The compound is sold as a research chemical in jurisdictions where it is not scheduled. Research-grade vendor doses are typically 200 to 500 mg per administration in unvalidated human use, scaled from rodent doses.

Read the full monograph

The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

May 9, 2026
CX-614

Plain-language summaryIntrigue 40 / 100

CX-614 is another benzoxazine ampakine in the Cortex series. Investigated in early clinical trials for cognitive impairment. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundNiche research probe

42/100

Potent AMPA probe with real bench utility but no translational path and a stalled class

CX-614 is a benzoxazine ampakine out of the Cortex Pharmaceuticals program that ran through the late 1990s and 2000s alongside CX-516 and CX-546. The compound is legitimately interesting as a probe: its roughly 100-fold potency advantage over CX-516 in AMPA receptor potentiation assays isn’t marketing noise, it shows up consistently in comparative cellular work. If you’re running BDNF induction studies and want pharmacological control over AMPA throughput without saturating concentrations, CX-614 is a real tool.

The BDNF upregulation story is the most compelling part of the science here. Chronic ampakine treatment drives hippocampal BDNF expression through transcriptional mechanisms downstream of AMPA potentiation. This is a legitimate model for studying neurotrophin-mediated synaptic plasticity and it’s been used by multiple independent groups, not just the originating program. That matters. Replication outside Cortex gives the bench utility real credibility and separates CX-614 from single-lab-only probe compounds.

Here’s the thing though: the ampakine class as a therapeutic direction has largely stalled. CX-516 had a small clinical footprint and the results were underwhelming. Seizure risk and excitotoxicity concerns have shadowed every high-potency member of the class. CX-614’s potency, which is an asset on the bench, is a liability from a translational standpoint. That 100-fold number doesnt come with a 100-fold therapeutic window, and there’s no sponsor currently pushing a benzoxazine ampakine through a pipeline.

We dont see a strong path to clinical relevance for CX-614 specifically. The novel angle, AMPA-driven BDNF induction as a tractable route to synaptic plasticity enhancement, remains interesting theoretically, but the pharmacological levers available today include BDNF mimetics, TrkB agonists, and ketamine’s downstream BDNF release mechanism, all of which generate stronger translational signals with more current evidence behind them. The class simply hasn’t rehabilitated itself with more recent data, and CX-614 inherits that problem.

What CX-614 does well is narrow but real: it’s a high-potency probe for dissecting AMPA receptor contributions to BDNF signaling in controlled in vitro and rodent systems. If thats the question you’re asking, honestly, it earns a spot in the toolkit. If you’re looking for a compound that carries a compelling story toward clinical translation or opens a genuinely new mechanistic frontier, there are better candidates right now. The score reflects a compound that occupies a legitimate but limited niche: not junk, not boring, but not the compound you build a program around in 2026.

Novelty

38

Mechanism promise

48

In-category differentiation

45

Evidence quality

42

Translational signal

22

Research bench value

62

Rationale CX-614 earns its place as a legitimate preclinical probe for AMPA-mediated BDNF induction, with multi-lab use validating the bench utility score; however, the ampakine class has largely failed to translate and CX-614 itself has never entered human trials, keeping translational and novelty scores low and pulling the overall to the low 40s.

Editorial commentary from Kodiac biolabs. Not a recommendation, not clinical advice. Research use only.

Benzoxazine ampakine

A potent benzoxazine ampakine with research applications in BDNF upregulation and synaptic plasticity studies.

Abstract

CX-614 (2H,3H,6aH-pyrrolidino-[2,1-3′,2′]1,3-oxazino-[6′,5′-5,4]benzo[e]1,4-dioxan-10-one; CAS 215923-55-0; molecular formula C16H17NO4; molecular weight 287.32) is a potent benzoxazine-class ampakine developed at Cortex Pharmaceuticals as part of the same program that produced CX-516 and CX-546. CX-614 shows substantially higher AMPA potentiation potency than CX-516 in cellular assays (approximately 100-fold greater per molecule). The compound has been used extensively as a research probe for BDNF upregulation studies; chronic ampakine treatment elevates hippocampal BDNF expression through transcriptional mechanisms downstream of AMPA potentiation, providing a pharmacological model for neurotrophin-mediated synaptic plasticity. CX-614 has not been advanced to human clinical trials. The compound is sold as a research chemical with limited availability.

Read the full monograph

The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

KDC-MN-056Open in new tab →

Download PDF →

FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

May 9, 2026

Bench-grade research compounds. Cited research. Verified COAs.

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