Bevemipretide

Bevemipretide,

CAS 2356106-71-1 FREE BASE

CAS SBT-272 Trihydrochloride, 2589640-11-7

607.7 g/mol, C₃₁H₄₅N₉O₄ F553HAL9V8

• SBT-272
• (2R)-2-amino-N-[(2S)-1-[[(1S)-5-amino-1-(3-benzyl-1,2,4-oxadiazol-5-yl)pentyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropan-2-yl]-5-(diaminomethylideneamino)pentanamide
• L-Tyrosinamide, D-arginyl-N-[(1S)-5-amino-1-[3-(phenylmethyl)-1,2,4-oxadiazol-5-yl]pentyl]-2,6-dimethyl-
• (2R)-2-amino-N-[(2S)-1-[[(1S)-5-amino-1-(3-benzyl-1,2,4-oxadiazol-5-yl)pentyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropan-2-yl]-5-(diaminomethylideneamino)pentanamide
• L-Tyrosinamide, D-arginyl-N-[(1S)-5-amino-1-[3-(phenylmethyl)-1,2,4-oxadiazol-5-yl]pentyl]-2,6-dimethyl-
• (2R)-2-amino-N-[(1S)-1-{[(1S)-5-amino-1-(3-benzyl-1,2,4-oxadiazol-5-yl)pentyl]carbamoyl}-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]-5-carbamimidamidopentanamide

• Originator Stealth BioTherapeutics
• ClassAntidementias; Antiparkinsonians; Neuroprotectants; Peptidomimetics
• Mechanism of Action Adenosine triphosphatase stimulants; Cardiolipin modulators; Reactive oxygen species inhibitors

• Orphan Drug Status Yes – Amyotrophic lateral sclerosis

Phase IAmyotrophic lateral sclerosis

• Preclinical Dry age-related macular degeneration; Frontotemporal dementia; Parkinson’s disease
• No development reported Multiple system atrophy

18 Sep 2024Pharmacodynamics data from a preclinical trial in dry age related macular degenration released by Stealth BioTherapeutics

• 18 Sep 2024Preclinical trials in Dry age-related macular degeneration in USA (Opthalmic)
• 18 Sep 2024Stealth Biotherapeutics plans clinical trial for Dry age related macular degeneration (Topical)

The present technology relates generally to compounds (i.e. peptidomimetics), compositions (e.g. medicaments) and methods for treating, preventing, inhibiting, amelioration or delaying the onset of ophthalmic diseases, disorders or conditions in a mammalian subject. In some embodiments, the ophthalmic disease, disorder or condition is associated with deterioration of the integrity of the ellipsoid zone of one or more eyes of the mammalian subject. For example, the present technology may relate to administering one or more mitochondrial-targeting peptidomimetics (alone, as formulated and/or in combination with other active pharmaceutical ingredients) in effective amounts to treat, prevent, inhibit, ameliorate or delay the onset of ophthalmic diseases, disorders or conditions (e.g., macular degeneration (including (wet or dry) age-related macular degeneration), dry eye, diabetic retinopathy, diabetic macular edema, cataracts, autosomal dominant optic atrophy (DOA), Leber hereditary optic neuropathy (LHON), pigmentary retinopathy, retinitis pigmentosa, glaucoma, ocular hypertension, uveitis, chronic progressive external ophthalmoplegia (often referred to as CPEO or just PEO, e.g., Kearns-Sayre syndrome), and/or Leber congenital amaurosis (LCA)), in mammalian subjects

[0003] The following introduction is provided to assist the understanding of the reader. None of the information provided, or references cited, is admitted as being prior art to the present technology.

[0004] Diseases, disorders and degenerative conditions of the optic nerve and retina are the leading causes of blindness in the world. Many ophthalmic diseases disorders or conditions result from, or are associated with, mitochondrial dysfunction.

[0005] A significant degenerative condition of the retina is age-related macular degeneration (AMD). AMD is the most common cause of blindness in people over the age of 50 in the United States and its prevalence increases with age. AMD is classified as either wet (neovascular) or dry (non-neovascular). The dry form of the disease is more common.

Macular degeneration occurs when the central retina has become distorted and thinned. This change is usually associated with age but also characterized by intra-ocular inflammation and angiogenesis (wet AMD only) and/or intra-ocular infection. The subsequent generation of free radicals, resulting in oxidative tissue damage, local inflammation and production of growth factors (such as VEGF and FGF) and inflammatory mediators, can lead to inappropriate neovascularization in common with the wet form of AMD. Mitochondrial dysfunction is believed to play a role in age-related disorders such as AMD. (Liu et al., Appl. Sci. (2021) 11: 7385). Pieramici & Ehlers have reported that: “RPE mitochondria in AMD eyes undergo more pronounced degenerative changes, with lower mitochondrial density, organelle area and cristae number.” (Pieramici & Ehlers, Presentation at 54^th Annual Retina Society Meeting, Sept.30, 2021, slide 3).

[0006] Retinopathy is a leading cause of blindness in type I diabetes and is also common in type II diabetes. The degree of retinopathy depends on the duration of diabetes, and generally begins to occur ten or more years after onset of diabetes. Diabetic retinopathy may be classified as non-proliferative, where the retinopathy is characterized by increased capillary permeability, edema and exudates, or proliferative, where the retinopathy is characterized by neovascularization extending from the retina to the vitreous, scarring, deposit of fibrous tissue and the potential for retinal detachment. Diabetic retinopathy is believed to be caused by the development of glycosylated proteins due to high blood glucose and leads to damage in small blood vessels in the eye. Diabetic retinopathy (often if left untreated) can progress to diabetic macular edema. Diabetic macular edema involves damage to the blood vessels in the retina that progress to a point where they leak fluid into the macula thereby causing the macula to swell and this results in blurred vision. Mitochondrial dysfunction has been linked to the pathogenesis of diabetic retinopathy. (Wu et al. Hindawi Oxidative Medicine and Cellular Longevity, Volume 2018, Article 3420187)

[0007] Glaucoma is made up of a collection of eye diseases that cause vision loss by damage to the optic nerve and retinal ganglion cells (RGCs). An intraocular pressure (IOP) of over 21 mmHg without optic nerve damage is known as ocular hypertension. Elevated IOP due to inadequate ocular drainage is the primary cause of glaucoma. Lowering IOP reduces the risk of progressive RGC loss in glaucoma; however, no currently available treatments directly prevent RGC damage. Glaucoma often develops as the eye ages, or it can occur as the result of an eye injury, inflammation, tumor or in advanced cases of cataract or diabetes. It can also be caused by the increase in IOP caused by treatment with steroids. Drug therapies that are proven to be effective in glaucoma reduce IOP either by decreasing vitreous humor production or by facilitating ocular draining. Such agents are often vasodilators and as such act on the sympathetic nervous system and include adrenergic antagonists. It has been stated that: “… mitochondrial dysfunction plays an important role in the pathogenesis of neurodegenerative diseases…” and “… mitochondrial damage may provide potential strategies for the treatment of glaucoma….” (Liu et al., Appl. Sci. (2021) 11: 7385).

[0008] Autosomal dominant optic atrophy (DOA) is a genetic X-linked neuro-ophthalmic condition characterized by bilateral degeneration of optic nerves. It affects approximately 1 in 10,000 (Denmark) to 1 in 30,000 (worldwide) persons. The nerve damage causes visual loss. It generally begins to manifest itself during the first decade of life and progresses thereafter. The disease itself affects primarily the retinal ganglion nerves. Mutations in the genes known as OPA1 and OPA3, which encode inner mitochondrial membrane proteins (resulting in mitochondrial dysfunction), are generally associated with DOA.

[0009] Leber Hereditary Optic Neuropathy (LHON) is a genetically-based inherited disease that generally starts to manifest itself between the ages of 15 and 35. In LHON, mitochondrial mutations affect complex I subunit genes in the respiratory chain leading to selective degeneration of retinal ganglion cells (RGCs) and optic atrophy generally within a year of disease onset. LHON is caused by mutations in the MT-NDI1, MT-ND4, MT-ND4L and MT-ND6 genes; all of which are associated with mitochondrial genome coding. LHOH affects approximately 1 in 50,000 people worldwide. It generally starts in one eye and progresses quickly to the other eye. Subjects with LHON may eventually become legally or totally blind, often before they turn 50. LHON affects vision needed for tasks such as reading, driving and recognizing others.

[0010] Retinitis pigmentosa (RP) is a group of hereditary retinal degenerative disorders characterized by progressive vision loss. RP is a leading cause of inherited blindness in the developed world. Clinically, RP is manifested by night vision difficulties due to the death of rod photoreceptors followed by the progressive loss of peripheral vision eventually leading to central vision impairment from the secondary loss of cone photoreceptors. RP is caused by mutations of at least 87 genes. The pathogenesis of RP is not well understood. However, mitochondrial dysfunction and oxidative damage are believed to play a key role in the pathogenesis of photoreceptor cell death in RP. (Gopalakrishnan et al., Scientific Reports (2020) 10: 20382)

[0011] Pigmentary retinopathy (PR) is a frequent feature of retinitis pigmentosa.

Pigmentary retinopathy is a non-specific finding that may be found in several mitochondrial diseases, such as Neurogenic weakness, Ataxia, and Retinitis Pigmentosa (NARP). PR is an inherited degenerative disorder of the retina, characterized by progressive photoreceptor damage. The damage leads to atrophy and cell death of the photoreceptors. Patients with PR can follow an autosomal-dominate, autosomal recessive or X-linked recessive pattern. The prevalence is about one in about three to four thousand individuals. Symptoms of the disease include nyctalopia (night blindness), peripheral visual field constriction, and sometimes loss of the central visual acuity or visual field.

[0012] Uveitis is array of intraocular inflammatory diseases of the eye that often results in irreversible visual loss. Uveitis is responsible for an estimated 30,000 new cases of legal blindness annually in the USA. It is believed that this disease is at least in part due to retinal tissue damage caused excessive mitochondrial oxidative stress that triggers a damaging immune response.

[0013] Chronic progressive external ophthalmoplegia (CPEO) is a condition characterized mainly by a loss of the muscle functions including in eye and eyelid movement. The condition typically appears in adults between ages 18 and 40 and slowly worsens over time. CPEO can be caused by genetic changes in any of several genes, which may be located in mitochondrial DNA or nuclear DNA. CPEO can occur as part of other underlying conditions, such as ataxia neuropathy spectrum and Kearns-Sayre syndrome. These conditions may not only involve CPEO, but various additional features that are not shared by most individuals with CPEO.

[0014] Kearns-Sayre syndrome is a condition that affects many parts of the body, especially the eyes. The features of Kearns-Sayre syndrome usually appear before age 20, and the condition is diagnosed by a few characteristic signs and symptoms. People with Kearns-Sayre syndrome have progressive external ophthalmoplegia. Affected individuals also have an eye condition called pigmentary retinopathy, which results from breakdown (degeneration) of the retina that gives it a speckled and streaked appearance.

[0015] Leber congenital amaurosis (LCA) is a rare genetic eye disorder that affects infants. The infants are often blind at birth. LCA can be associated with mitochondrial dysfunction. (Castro-Gago et al., J. Child Neurol. (1996) 11(2):108-11) Children born with LCA have light-gathering cells (rods and cones) of the retina that do not function properly. LCA has been estimated to be 1-2/100,000 births. This disorder affects males and females in equal numbers.

[0016] Drusen are small yellow or white spots between the retinal pigment epithelium and Bruch’s membrane in the retina that can be detected by an ophthalmologist during a dilated eye exam or with retinal photography. Drusen can also be imaged and monitored by optical coherence tomography (OCT). Drusen are made up of lipids and proteins. Drusen are a defining feature of macular degeneration. Drusen can be hard or soft. Larger numbers of drusen, as well as drusen of larger size, indicate higher risk for some vision loss in the future. “Hard” drusen are small and indicate lower risk of future vision loss than “soft” drusen. “Soft” drusen are larger, cluster together, and have edges that are not as clearly defined. Soft drusen are more likely to lead to vision loss.

[0017] Geometric Atrophy (GA) is generally considered part of the later stage of age-related macular degeneration (AMD) and refers to progression of the disease to a point where in regions of the retina, cells begin to waste away and die (i.e. atrophy).

[0018] Best corrected visual acuity (BCVA) is a measure of the best possible vision an eye can achieve with the use of glasses or corrective lenses. It is typically measured using Snellen lines on an eye chart. Repeated testing of the BCVA over time can be used to determine if a subject’s vision is stable, improving or deteriorating.

[0019] Low luminance visual acuity (LLVA) involves standard visual acuity testing under low-light conditions. This is often achieved by adding a neutral density filter in front of the testing eye. It is a useful visual function marker in those with geographic atrophy (GA) and neovascular age-related macular degeneration. Repeated testing of the LLVA over time can be used to determine if a subject’s vision, under low light conditions, is stable, improving or deteriorating.

[0020] Optical coherence tomography (OCT) is a non-invasive imaging method used to generate a picture of the back of the eye (i.e. the retina). OCT uses a low-powered laser to create pictures of the layers of the retina and optic nerve. The cross-sectional images are three-dimensional and color-coded. OCT can measure the thickness of the retina and optic nerve. OCT can be used to diagnose and manage Glaucoma, AMD, diabetes-related retinopathy, cystoid macular edema, macula pucker and macular hole.

[0021] Spectral domain optical coherence tomography (SDOCT) is an interferometric technique that provides depth-resolved tissue structure information encoded in the magnitude and delay of the back-scattered light by spectral analysis of the interference fringe pattern. SDOCT increases axial resolution 2- to 3-fold and scan speed 60- to 110-fold vs conventional (TD) OCT.

[0022] The ellipsoid zone can be mapped using SCOCT and the integrity of (or changes in) the ellipsoid zone can be determined from such mapping/scanning activity. (Itoh et al., Br J Ophthalmol. (2016) 100(3): 295-299). The technology is capable of evaluating the structures of the external limiting membrane (ELM), ellipsoid zone (EZ), interdigitation zone (IZ) and the retinal pigment epithelium (RPE). Id. Use of this technology is capable of accessing EZ integrity and EZ-RPE alterations. Id. The EZ and ELM, in particular, have been linked to visual outcomes and prognosis in numerous macular conditions, such as age-related macular degeneration (AMD) Id. Itoh et al. suggest that the utility of SDOCT as an assessment tool for EZ integrity for clinical trials and disease prognostication/management may prove particularly useful.

[0023] Swept source OCT (SS-OCT) and OCT angiography (OCTA) are relatively new techniques that are capable of better resolution of the retinal pigment epithelium (RPE), Bruch’s membrane (BM) and choriocapillaris (CC) structures. (Zhou et al. Biomedical Optics Express (2020) 11(4): 1834-1850) Using this technology it is possible to generate relative distance and thickness maps of the RPE-BM-CC complex. Id. Use of these techniques may provide a better understanding of the CC in three dimensions, and further

investigate potential functional relationships between RPE, BM and CC, and their involvement in age-related ocular diseases. Id.

[0024] The ellipsoid zone (EZ) of the eye is a mitochondrial rich tissue (Ball et al., Sci. Adv.8, eabn2070 (2022)). The ellipsoid zone can be imaged using optical coherence tomography (Fujita et al., Scientific Reports (2019) 9:12433). The integrity of the EZ can be quantified. (Fugita et al.). There is a clear relationship between the integrity of the ellipsoid zone and visual function. (Fugita et al., Figure.3). Ball et al. suggest that tightly packed mitochondria in the ellipsoid “focus” light for entry into the outer segment and that healthy mitochondria structure (including cristae structure) might be important for producing a Stiles-Crawford effect (SCE) and maintaining visual resolution in mammals. Pieramici & Ehlers describe mapping the ellipsoid zone to thereby observe the ellipsoid zone and possibly monitor changes in the integrity of the ellipsoid zone. (Pieramici & Ehlers, Presentation at 54^th Annual Retina Society Meeting, Sept.30, 2021). Pieramici & Ehlers further described the use of Sub-RPE compartment maps as a means to find and monitor drusen formation and RPE atrophy in a subject. In the study being described (which described results from a P2 clinical trial involving treatments with elamipretide), Pieramici & Ehlers concluded, inter alia, that: (i) “Average BCVA and LLVA in NCGA and HRD patients improved significantly at 24 weeks [of treatment with elamipretide]” and (ii) “Baseline higher order OCT parameters, such as EZ integrity, correlated with improved LLVA in Elamipretide-treated eyes” (Pieramici & Ehlers at slide 15).

[0025] In brief, there are many ophthalmic diseases for which there remains a need for treatments/therapies or improved treatments/therapies. For example, there remains a need for treatments/therapies, or improved treatments/therapies, to address ophthalmic diseases, disorders or conditions such as macular degeneration (including (wet or dry) age-related macular degeneration), dry eye, diabetic retinopathy, diabetic macular edema, cataracts, autosomal dominant optic atrophy (DOA), Leber hereditary optic neuropathy (LHON), pigmentary retinopathy, retinitis pigmentosa, glaucoma, ocular hypertension, uveitis, chronic progressive external ophthalmoplegia (e.g., Kearns-Sayre syndrome), and/or Leber congenital amaurosis (LCA). This forgoing discussion addresses these needs.

SCHEME

MAIN

PATENT

WO2023069255

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2023069255&_cid=P22-M93M8P-34013-1

Synthesis of (R)-2-amino-N-((S)-1-(((S)-5-amino-1-(3-benzyl-1,2,4-oxadiazol-5- yl)pentyl)amino)-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropan-2-yl)-5- guanidinopentanamide (D-Arg-DMT-NH((S)-5-amino-1-(3-benzyl-1,2,4-oxadiazol-5- yl)pent-1-yl), 7a (a.k.a. ((Formula IIa)):

[0134] In some embodiments, Compound 7a (a.k.a. Formula IIa) may be synthesized as illustrated in Scheme 5, below (Also see WO2019/118878, incorporated herein by reference), wherein compound 12a can be prepared as illustrated in Scheme 6, below

[0135] Step a: Synthesis of benzyl (S)-2-((R)-2-((tert-butoxycarbonyl)amino)-5- guanidinopentanamido)-3-(4-hydroxy-2,6-dimethylphenyl)propanoate (3a). To a suspension of 2,6-Dmt-OBn^.HCl (2a, 45.0 g, 134 mmol) in ACN (800 mL), NMM (32.7 mL, 298 mmol) was added at 0⁰C. The reaction mixture was stirred until the reaction mixture became transparent. Then Boc-D-Arg-OH^.HCl (1a, 46.3 g, 149 mmol) and HOBt^.H₂O (9.11 g, 59.5 mmol) were added to reaction mixture and stirred for 15 min. Finally, EDC^.HCl (38.5 g, 201 mmol) was added and mixture was stirred at 0⁰C for 4 h. Then EtOAc (450 mL), 1N HCl in brine (300 mL) were added. The combined organic extracts were washed with 1N HCl in brine (7×150 mL), NaHCO₃/brine (300 mL and until pH of aqueous layer is about pH=6 to 7), dried over Na₂SO₄, filtered and concentrated to afford 86.0 g (97%) of Boc-D-Arg-DMT- OBn (3a) that was used without further purification.¹H-NMR (400 MHz, Methanol-d₄) δ 7.33 – 7.18 (m, 5H), 6.43 (s, 2H), 5.06 (s, 2H) 4.71 (t, J=7.8Hz, 1H), 4.07 (t, J=6.7Hz,1H), 3.19 – 3.09 (m, 3H), 3.03-2.97 (m, 1H), 2.23 (s, 6H), 1.72 – 1.65 (m, 1H), 1.54 – 1.43 (m, 3H), 1.45 (s, 9H).

[0136] Step b: Synthesis of (S)-2-((R)-2-((tert-butoxycarbonyl)amino)-5-guanidinopentanamido)-3-(4-hydroxy-2,6-dimethylphenyl)propanoic acid (4a). To a solution of Boc-D-Arg-DM-Tyr-OBn (3a, 84.0 g, 142 mmol) in MeOH (1000 mL) Pd/C (10% w/w, 14.0 g) was added. The hydrogen was purged in reaction mixture at room temperature for 4h. Then reaction mixture was filtrated through filter paper and washed with MeOH (150 mL). The solvent was removed by evaporation. White foam product 4a was obtained (74.0 g, 93%) and used without further purification.¹H-NMR (400 MHz, Methanol-d₄) δ 6.44 (s, 2H), 4.68 (t, J = 7.2 Hz, 1H), 4.04 (t, J = 6.8 Hz, 1H), 3.15 – 3.09 (m, 3H), 3.02 – 2.94 (m, 1H), 2.29 (s, 6H), 1.74 – 1.59 (m, 1H), 1.54 – 1.43 (m, 1H), 1.45 (s, 9H).

[0137] Step c: Synthesis of tert-butyl ((6R,9S,12S)-1-amino-12-(3-benzyl-1,2,4-oxadiazol-5-yl)-9-(4-hydroxy-2,6-dimethylbenzyl)-1-imino-20,20-dimethyl-7,10,18-trioxo-19-oxa-2,8,11,17-tetraazahenicosan-6-yl)carbamate (6a). DMF (200 mL) was added to 4a (11.17 g, 24 mmol) and stirred at r.t. for 15 min. To the resulting suspension, 12a (10.65 g, 20 mmol) was added and stirred at r.t. for 20 min. After addition of HOBt (612 mg, 4.00 mmol), the suspension was cooled in ice bath. EDC ^. HCl (5.38 g, 28 mmol) was added in one portion, and the reaction mixture was stirred while cooled in ice bath for 2.5 h and then, for 4.5 h at r.t. The nearly homogeneous reaction mixture was quenched with EtOAc (1500 mL) and the resulting solution was washed for 10 times with brine/aq.0.5 M HCl (1:1; 400 mL). During the 6th and 9th washings, gel in the aqueous phase was formed. After addition of iPrOH (40 mL in each case) and repeated shaking the layers went clear again. Afterwards, the organic phase was washed for 6 times with brine/sat. aq. NaHCO₃ (9:1; 400 mL). During the 4th washing, gel in the aqueous phase was formed. After addition of iPrOH (40 mL) and repeated shaking the layers were separated easily. The organic phase was washed with brine (200 mL) and water (100 mL) and the solvent was removed under reduced pressure. No vigorous shaking was performed upon washing with water to avoid difficulties in phase separation. As a result, 16.8 g of the crude product were obtained (6a, 97.0 % purity by HPLC, white amorphous solid).¹H-NMR (300 MHz, Methanol-d₄) ppm: δ = 7.33–7.16 (m, 5H), 6.38 (s, 2H), 5.18-5.07 (m, 1H), 4.64-4.55 (m, 1H), 4.10 – 3.92 (m, 3H), 3.18-2.77 (m, 6H), 2.20 (s, 6H), 1.97-1.76 (m, 2H), 1.75-1.14 (m, 8H), 1.43 (s, 9H), 1.41 (s, 9H).

[0138] Step d: Synthesis of (R)-2-amino-N-((S)-1-(((S)-5-amino-1-(3-benzyl-1,2,4-oxadiazol-5-yl)pentyl)amino)-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropan-2-yl)-5-guanidinopentanamide (7a, but also referred to as (IIa – the tri-hydrochloride salt of Compound I) herein). After 6a (16.8 g) was dissolved in DCM (100 mL) and cooled to 0°C, TFA (20 mL) was added dropwise and the solution was allowed to stir at 0 °C for 10 min, and then at r.t. for 3 h (LC/MS shows no starting material). Then reaction mixture was evaporated (at 0–5 °C) and additionally re-evaporated from DCM (100 mL, at 0–5 °C). The purification by flash chromatography on reverse phase (cartridge C-18, 120G) was performed on crude material divided in 4 parts. Then all solvents were evaporated at reduced pressure at <40^oC. White foam was dissolved in isopropanol (100 mL) and 5 mL of HCl in isopropanol (5-6M) was added at 0 ^oC and evaporated under reduced pressure. This step was repeated 3 times. Additionally, 100 mL of ACN was added and suspension was evaporated one more time. As a result, white powder of 7a was obtained as the tri-hydrochloride salt.¹H-NMR (300 MHz, Methanol-d₄) δ 7.36 – 7.14 (m, 5H), 6.40 (s, 2H), 5.15 (dd, J = 8.5, 6.3 Hz, 1H), 4.68 (dd, J = 8.7, 7.5 Hz, 1H), 4.07 (s, 2H), 3.97 (t, J = 6.3 Hz, 1H), 3.18 (t, J = 6.9 Hz, 2H), 3.11 (dd, J = 14.2, 8.8 Hz, 1H), 2.95 – 2.84 (m, 3H), 2.22 (s, 6H), 2.02 – 1.59 (m, 6H), 1.57 – 1.28 (m, 4H). MS: EI-MS: m/z 608.4 [M+1].

Synthesis of (S)-1-(3-Benzyl-1,2,4-oxadiazol-5-yl)-5-((tert-Butoxycarbonyl)amino)pentan-1-Aminium 4-Methylbenzenesulfonate (12a)

step a: NH₂OH; step b: T₃P, NaHCO₃; step c: TEA; step d: PTSA

[0139] Step a: Synthesis of N-hydroxy-2-phenylacetimidamide (9a). To a solution of nitrile 8a (1.0 mol) in EtOH (1.2 L) was added NH₂OH (50% aqueous solution, 130 g, 2.0 mol).

The solution was heated to reflux and stirred for 12 hours (hrs.). After completion, the reaction mixture was concentrated under reduced pressure. The resulting residue was re-dissolved in EtOH (350 mL) and concentrated under reduced pressure again (this procedure was repeated three times). The resulting solid was triturated in hexane (350 mL), filtered, washed with hexane (100 mL), and then dried to give the desired product 9a as white solid. (10.5 kg; KF = 1295) with good results (purity by HPLC, > 98.9 A%; Assay = 22.2 w%, yield = 91%).¹H NMR (300 MHz, DMSO-d₆): δ 8.90 (s, 1H), 7.28-7.18 (m, 5H), 5.40 (s, 2H), 3.25 (s, 2H) ppm. MS: (M+H)⁺: m/z = 151.1

[0140] Step b: Synthesis of (9H-Fluoren-9-yl)methyl tert-Butyl (1-(3-Benzyl-1,2,4-oxadiazol-5-yl)pentane-1,5-diyl) (S)-Dicarbamate (11a). To a solution of protected enantiomerically pure N2-(((9H-fluoren-9-yl)methoxy)carbonyl)-N6-(tert-butoxycarbonyl)-L-lysine (10a, 4.31 kg, 9.2 mol) and hydroxyimidamide 9a (1.1 equivalents “equiv.” or “eq.”) in ethyl acetate was added NaHCO₃ (3.0 equiv.). The mixture was stirred at 25 ^oC for 20 minutes (min.). Then, propane phosphonic acid anhydride (T₃P, 50% solution in ethyl acetate, 3.0 equivalents (equiv.)) was added and the reaction mixture was heated to 80 ^oC and stirred for 4 hrs. (about 60% conversion of compound 10a based on HPLC). Then compound 9a (1.1 equiv.) was added and the reaction mixture was stirred at 80^oC for another 20 hr. (about 10% compound 10a remained). The reaction mixture was cooled to room temperature, saturated aqueous NaHCO₃ (2.0 L) was added, the mixture was then extracted with ethyl acetate (3x 1.0 L). The combined organic layers were then washed with brine (1 L)_, dried over anhydrous Na2SO4, filtered and concentrated to give a crude residue, which was generally purified by silica gel column chromatography (Petroleum ether (PE):EtOAc = 5: 1) to give crude product, (9H-fluoren-9-yl)methyl tert-butyl (1-(3-benzyl-1,2,4-oxadiazol-5-yl)pentane-1,5-diyl) (S)-dicarbamate (11a), solution in ACN (19.7 kg, assay = 20%, chiral HPLC purity = 99.12 A%，yield = 73%).¹H-NMR (300 MHz, CDCl₃): δ 7.78 (d, J = 7.5 Hz, 2H), 7.61 (d, J = 6.3 Hz, 2H), 7.42 (t, J = 7.5 Hz, 2H), 7.35-7.30 (m, 7H), 5.52 (br, 1H), 5.09-5.05 (m, 1H), 4.56-4.37 (m, 3H), 4.22 (t, J = 6.6 Hz, 1H), 4.08 (s, 2H), 1.95-1.86 (m, 2H), 1.48-1.42 (m, 11H) ppm. MS: (M-100+H)⁺: m/z = 483.2.

[0141] Step c: Synthesis of tert-Butyl (S)-(5-Amino-5-(3-Benzyl-1,2,4-oxadiazol-5-yl)pentyl)-carbamate (5a). To a solution of compound (9H-fluoren-9-yl)methyl tert-butyl (1-(3-benzyl-1,2,4-oxadiazol-5-yl)pentane-1,5-diyl) (S)-dicarbamate (11a) was added TEA (2.5 eq.). The mixture was kept stirring with mechanical stirrer at 20~ 25 °C for 15 h. The reaction mixture was diluted by tap water and MTBE. Separated, aqueous layer was extracted by MTBE for one time. Both MTBE layers were combined, and then washed by NH₄Cl. Then anhydrous Na₂SO₄ was added and that solution stirred for least 2 h, then filtered and washed with MTBE to afford tert-butyl (S)-(5-amino-5-(3-benzyl-1,2,4-oxadiazol-5-yl)pentyl)-carbamate (5a) solution in MTBE (32.9 kg, assay = 6.5%, yield = 88%).¹H-NMR (300 MHz, DMSO-d₆): δ 7.33-7.25 (m, 5H), 6.78 (br, 1H), 5.09-5.05 (m, 1H), 4.56-4.37 (m, 3H), 4.06 (s, 2H), 3.98 (t, J = 6.6 Hz, 1H), 2.87-2.84 (m, 2H), 2.10 (s, 2H), 1.38-1.34 (m, 2H), 1.24 (s, 9H), 1.20-1.15 (m, 2H) ppm. MS: (M+H)⁺: m/z = 361.1.

[0142] Step d: Synthesis of (S)-1-(3-Benzyl-1,2,4-oxadiazol-5-yl)-5-((tert-Butoxycarbonyl)-amino)pentan-1-Aminium 4-Methylbenzenesulfonate (12a). p-toluenesulfonic acid (PTSA) was added to solution of crude tert-butyl (S)-(5-amino-5-(3-benzyl-1,2,4-oxadiazol-5-yl)pentyl)-carbamate (5a) in MTBE to afford (S)-1-(3-benzyl-1,2,4-oxadiazol-5-yl)-5-((tert-butoxycarbonyl)amino)pentan-1-aminium 4-methylbenzenesulfonate (12a) (2.7 kg, yield = 85 %, HPLC purity > 99%, ee > 99%) as white solid.¹H-NMR (400 MHz, DMSO-d₆): δ 8.74 (br, 3H), 7.48 (d, J = 8.0 Hz, 2H), 7.37-7.26 (m, 5H), 7.11 (d, J = 8.0 Hz, 2H), 6.77 (t, J = 5.2 Hz, 1H), 4.82 (t, J = 6.8 Hz, 1H), 4,17 (s, 2H), 2.90-2.86 (m, 2H), 2.29 (s, 3H), 1.39-1.36 (m, 11H), 1.35-1.28 (m, 2H) ppm. MS: (M-172+H)⁺: m/z = 361.1.

PATENT WO2021016462

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2021016462&_cid=P22-M93MJV-41323-1

WO2019118878

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2019118878&_cid=P22-M93MNH-43976-1

/////////Bevemipretide, SBT-272 Trihydrochloride, SBT 272, ORHAN DRUG, Stealth BioTherapeutics