{"id":127,"date":"2026-08-27T01:19:02","date_gmt":"2026-08-27T01:19:02","guid":{"rendered":"https:\/\/astinovabiolabs.com\/blog\/?p=127"},"modified":"2026-08-27T01:19:02","modified_gmt":"2026-08-27T01:19:02","slug":"synthesis-of-daraxonrasib-rasonque-drug-intelligence-dossier","status":"publish","type":"post","link":"https:\/\/astinovabiolabs.com\/blog\/synthesis-of-daraxonrasib-rasonque-drug-intelligence-dossier\/","title":{"rendered":"Synthesis of Daraxonrasib (Rasonque) \u2014 Drug Intelligence Dossier"},"content":{"rendered":"\n

Mechanism:<\/strong>\u00a0Daraxonrasib (RMC-6236) is an oral, noncovalent, beyond-Rule-of-5 macrocyclic ‘tri-complex’ (molecular-glue) inhibitor of RAS. It first binds the intracellular chaperone cyclophilin A (CypA); the drug\u2013CypA binary complex then presents a neomorphic composite surface that engages the active, GTP-bound (‘ON’) conformation of RAS at the switch I \/ switch II effector interface, sterically blocking recruitment of downstream effectors (RAF \u2192 MEK \u2192 ERK) and shutting down MAPK signalling. Because it binds a conserved active-state surface via CypA, it is RAS(ON) MULTI-SELECTIVE (pan-RAS): it inhibits KRAS, NRAS and HRAS \u2014 both mutant and wild-type \u2014 spanning G12X (G12D\/V\/R\/C\/A\/S), G13X and Q61X. This contrasts with the approved covalent G12C(OFF)-state inhibitors sotorasib and adagrasib, which trap only the inactive GDP-bound single-cysteine mutant. The genotype-agnostic mechanism is the basis for a PDAC label that requires no RAS mutation test \u2014 apt because PDAC is ~90% KRAS-mutant, dominated by G12D\/G12V\/G12R (G12C is rare). Cellular pERK inhibition EC\u2085\u2080 ~1\u20132.6 nM; potency across mutants spans ~10\u00d7. Tri-complex crystal structures: RCSB PDB 9BG5\/9BG6\/9BGA\/9BGC. Refs: PMID 42223072, PMID 42090791; discovery paper DOI 10.1021\/acs.jmedchem.4c02314.<\/p>\n\n\n\n

Synthesis Route of the Originator<\/h2>\n\n\n\n

Daraxonrasib is a FULLY SYNTHETIC macrocyclic lactone (not a fermentation-derived semi-synthetic natural product, despite the sanglifehrin-inspired cyclophilin-A pharmacophore). The convergent route joins four building blocks \u2014 a \u03b2-(thiazol-4-yl)alanine central residue, (S)-piperazic acid (the CypA motif), the N-ethyl-indole RAS(ON)-binding aromatic core (carrying the gem-dimethyl neopentyl alcohol), and 2-[(1S)-1-methoxyethyl]-5-(4-methylpiperazin-1-yl)pyridine \u2014 via Pd-catalysed biaryl cross-coupling (Suzuki\/Miyaura) and HATU\/T3P amide couplings into an open-chain seco-hydroxy-acid. The (1S,2S)-2-methylcyclopropanecarboxamide is installed by the terminal amide coupling, and the macrocycle is closed by a high-dilution MACROLACTONIZATION (Shiina\/MNBA or Yamaguchi conditions, representative) to give the drug substance (free base). Building-block chemistry disclosed\/implied by the discovery paper (Cregg et al., J Med Chem 2025, 68(6), 6064-6083): asymmetric electrophilic hydrazination for piperazic acid; Buchwald\u2013Hartwig amination for the methylpiperazine-pyridine; ozonolysis for the chiral methylcyclopropane acid. The RevMed scale-up process is captured in patent WO2024216008A1 (Compound A). NOTE: the two intermediate structures shown (seco-amine, seco-acid) were generated by RDKit disconnection from the verified target and are mass-balanced (seco-amine + methylcyclopropanecarboxylic acid \u2212 H\u2082O = seco-acid; seco-acid \u2212 H\u2082O = daraxonrasib); reagents\/conditions are REPRESENTATIVE for the named transformations, not the verbatim proprietary process.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n

a<\/sup>Reagents and conditions: (1) (1S,2S)-2-methylcyclopropane-1-carboxylic acid (1.1 eq), HATU (1.2 eq) or T3P, DIPEA (2\u20133 eq), DMF\/CH\u2082Cl\u2082, 0 \u00b0C \u2192 rt (REPRESENTATIVE for the named amide coupling; the (1S,2S)-methylcyclopropane acid is an ozonolysis-derived chiral building block). Acylates the free \u03b1-amine of the thiazolylalanine residue.; (2) Ring-closing esterification of the piperazic-acid carboxyl onto the neopentyl 1\u00b0 alcohol under high dilution (REPRESENTATIVE conditions for a hindered macrolactonization: e.g. Shiina 2-methyl-6-nitrobenzoic anhydride (MNBA)\/DMAP, or Yamaguchi 2,4,6-trichlorobenzoyl chloride\/Et\u2083N then DMAP; toluene, high dilution). Closes the 11-membered-bridge macrocyclic lactone to give the drug substance (free base). Loss of H\u2082O: 829.1 \u2192 811.1..<\/p>\n\n\n\n

Key intermediates<\/strong><\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n

Crystal Forms, Salts, and Solid-State Profile<\/h2>\n\n\n\n