Roxadustat

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ROXADUSTAT

ASP1517; ASP 1517; ASP-1517; FG-4592; FG 4592; FG4592; Roxadustat.

CAS 808118-40-3
Chemical Formula: C19H16N2O5
Exact Mass: 352.10592

THERAPEUTIC CLAIM
Treatment of anemia

Roxadustat nonproprietary drug name

CHEMICAL NAMES

(4-hydroxy-1-methyl-7-phenoxyisoquinoline-3-carbonyl)glycine

1. Glycine, N-[(4-hydroxy-1-methyl-7-phenoxy-3-isoquinolinyl)carbonyl]-

2. N-[(4-hydroxy-1-methyl-7-phenoxyisoquinolin-3-yl)carbonyl]glycine

MOLECULAR FORMULA C19H16N2O5
MOLECULAR WEIGHT  352.3
SPONSOR FibroGen
CODE DESIGNATIONS FG-4592; ASP1517
CAS REGISTRY NUMBER 808118-40-3
WHO NUMBER 9717

Roxadustat, also known as ASP1517 and FG-4592, is an HIF α prolyl hydroxylase inhibitor in a cell-free assay. It stabilizes HIF-2 and induces EPO production and stimulates erythropoiesis. Roxadustat transiently and moderately increased endogenous erythropoietin and reduced hepcidin

• Originator FibroGen
• Developer Astellas Pharma; AstraZeneca; FibroGen
• Class Amides; Antianaemics; Carboxylic acids; Isoquinolines; Small molecules
• Mechanism of Action Basic helix loop helix transcription factor modulators; Hypoxia-inducible factor-proline dioxygenase inhibitors

• Phase III Anaemia
• Discontinued Sickle cell anaemia

Most Recent Events

• 09 Jun 2016 Phase-III clinical trials in Anaemia in Japan (PO)
• 20 May 2016 In collaboration with FibroGen, Astellas Pharma plans a phase III trial for Anaemia (In chronic kidney disease patients undergoing peritoneal dialysis) in Japan (PO) (NCT02780726)
• 19 May 2016 In collaboration with FibroGen, Astellas Pharma plans a phase III trial for Anaemia (In erythropoiesis stimulating agent-naive, chronic kidney disease patients undergoing haemodialysis) in Japan (PO) (NCT02780141)

Roxadustat (FG-4592) is a novel new-generation oral hypoxia-induciblefactor (HIF) prolyl hydroxylase inhibitor (PHI) for the treatment of ane-mia in patients with chronic kidney disease (CKD). HIF is a cytosolic tran-scription factor that induces the natural physiological response to lowoxygen conditions, by stimulating erythropoiesis and other protectivepathways. Roxadustat has been shown to stabilize HIF and induce ery-thropoiesis. Consequently, it corrects anemia and maintains hemoglo-bin levels without the need for intravenous iron supplementation in CKDpatients not yet receiving dialysis and in end-stage renal disease pa-tients receiving dialysis. There are many concerns about the use of ery-thropoiesis-stimulating agents (ESA) to treat anemia as they causesupra-physiologic circulating erythropoietin (EPO) levels and are asso-ciated with adverse cardiovascular effects and mortality. Available clin-ical data show that modest and transient increases of endogenous EPOinduced by HIF-PHI (10- to 40-fold lower than ESA levels) are sufficientto mediate erythropoiesis in CKD patients. Evidence suggests that rox-adustat is well tolerated and, to date, no increased risk of cardiovascu-lar events has been found. This suggests that roxadustat provides adistinct pharmacological and clinical profile that may provide a saferand more convenient treatment of CKD anemia

FG-4592 is a new-generation hypoxia-inducible factor prolyl hydroxylase inhibitor in early clinical trials at FibroGen for the oral treatment of iron deficiency anemia and renal failure anemia. Preclinical studies are ongoing for the treatment of sickle cell anemia.

The investigational therapy is designed to restore balance to the body’s natural process of erythropoiesis through mechanisms including: natural EPO production, suppression of the effects of inflammation, downregulation of the iron sequestration hormone hepcidin, and an upregulation of other iron genes, ensuring efficient mobilization and utilization of the body’s own iron stores. In April 2006, FG-4592 was licensed to Astellas Pharma by originator FibroGen in Asia, Europe and South Africa for the treatment of anemia. FibroGen retains rights in the rest of the world. In 2007, the FDA put the trial on clinical hold due to one case of death by fulminant hepatitis during a phase II clinical trial for patients with anemia associated with chronic kidney disease and not requiring dialysis. However, in 2008, the FDA informed the company that clinical trials could be resumed. Phase II/III clinical trials for this indication resumed in 2012. In 2013, the compound was licensed to AstraZeneca by FibroGen for development and marketing in US, CN and all major markets excluding JP, Europe, the Commonwealth of Independent States, the Middle East and South Africa, for the treatment of anemia associated with chronic kidney disease (CKD) and end-stage renal disease (ESRD).
PATENTS
WO 2004108681
WO 2008042800
WO 2009058403
WO 2009075822
WO 2009075824
WO 2012037212
WO 2013013609
WO 2013070908
SYNTHESIS……..http://zliming2004.lofter.com/post/1cc9dc55_79ad5d8

Condensation of 5-bromophthalide (I) with phenol (II) in the presence of K2CO3, CuBr and acetylacetone in DMF gives 5-phenoxyphthalide (III), which upon lactone ring opening using SOCl2, Ph3PCl2, B(OMe)3 and K2CO3 in refluxing toluene yields 2-chloromethyl-4-phenoxybenzoyl chloride (IV). Esterification of acid chloride (IV) with MeOH at 50 °C furnishes the methyl ester (V), which is then condensed with methyl N-tosylglycinate (VI) in the presence of K2CO3 and NaI in DMF at 50 °C to afford N-substituted aminoester (VII). Cyclization of the intermediate diester (VII) using NaOMe in MeOH leads to methyl 4-hydroxy-7-phenoxyisoquinoline-3-carboxylate (VIII), which is submitted to Mannich reaction with bis-dimethylaminomethane (IX) in the presence of AcOH at 57 °C to provide the dimethylaminomethyl compound (X). Treatment of amine (X) with Ac2O at 103 °C, followed by selective hydrolysis of the phenolic acetate with morpholine leads to methyl 1-acetoxymethyl-4-hydroxy-7-phenoxyisoquinoline-3-carboxylate (XI). Hydrogenolysis of the benzylic acetate (XII) in the presence of Pd/C and Na2CO3 in EtOAc yields methyl 4-hydroxy-1-methyl-7-phenoxyisoquinoline-3-carboylate (XII), which finally couples with glycine (XIII) in the presence of NaOMe in MeOH at 110 °C to afford the target roxadustat (1-3).

Cyclization of 4-phenoxyphthalic acid (I) with glycine (II) at 215 °C gives the phthalimide (III), which upon esterification with MeOH and H2SO4 at reflux yields methyl ester (IV). Subsequent rearrangement of phthalimidoacetate (IV) by means of Na in BuOH at 97 °C, followed by flash chromatography provides the isoquinoline-2-carboxylate (V). Bromination of intermediate (V) using POBr3 and NaHCO3 in acetonitrile leads to butyl 8-bromo-3-hydroxy-6-phenoxy-isoquinoline-2-carboxylate (VI), which upon hydrolysis with NaOH in refluxing H2O/EtOH furnishes carboxylic acid (VII). Substitution of bromine in intermediate (VII) using MeI and BuLi in THF at -78 °C, followed by alkylation with PhCH2Br in the presence of K2CO3 in refluxing acetone affords the 2-methyl isoquinoline (VIII). Ester hydrolysis in intermediate (VIII) using KOH in MeOH gives the corresponding carboxylic acid (IX), which is then activated with i-BuOCOCl and Et3N in CH2Cl2, followed by coupling with benzyl glycinate hydrochloride (X) to yield benzylated roxadustat (XI). Finally, debenzylation of intermediate (XI) with H2 over Pd/C in EtOAc/MeOH provides the title compound (1).

Condensation of 4-nitro-ortho-phthalonitrile (I) with phenol (II) in the presence of K2CO3 in DMSO gives 4-phenoxy-ortho-phthalonitrile (III) (1), which upon hydrolysis with NaOH (1) or KOH (2) in refluxing MeOH yields 4-phenoxyphthalic acid (IV) (1,2). Dehydration of dicarboxylic acid (IV) using Ac2O and AcOH at reflux furnishes the phthalic anhydride (V), which is then condensed with methyl 2-isocyanoacetate (VI) using DBU in THF to provide oxazole derivative (VII). Rearrangement of intermediate (VII) with HCl in MeOH at 60 °C leads to isoquinoline derivative (VIII), which is partially chlorinated by means of POCl3 at 70 °C to afford 1-chloro-isoquinoline derivative (IX). Substitution of chlorine in intermediate (IX) using Me3B, Pd(PPh3)4 and K2CO3 in refluxing dioxane gives methyl 4-hydroxy-1-methyl-7-phenoxy-3-carboxylate (X), which is then hydrolyzed with aqueous NaOH in refluxing EtOH to yield the carboxylic acid (XI). Coupling of carboxylic acid (XI) with methyl glycinate hydrochloride (XII) by means of PyBOP, (i-Pr)2NH and Et3N in CH2Cl2 yields roxadustat methyl ester (XII), which is finally hydrolyzed with aqueous NaOH in THF to afford the target roxadustat (1).

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