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3,3,3-trifluoro-2-hydroxy-N-(4-nitro-3-(trifluoromethyl)phenyl)-2-(((2-(trifluoromethyl)phenyl)thio)methyl)propanamide

Cas 1929605-82-2

Dr Marcella Bassetto

Post Doctoral Research Associate

bassettom@cardiff.ac.uk

https://www.researchgate.net/profile/Marcella_Bassetto

http://marcellabassetto.blogspot.in/

SYNTHESIS

3-Bromo-1,1,1-trifluoroacetone (48) was coupled with thiophenol 47 to afford 49, which was then converted into cyano derivative 50 using potassium cyanide and 25% sulfuric acid [16]. Intermediate 51 was obtained after refluxing 50 in concentrated HCl and glacial acetic acid. Coupling of 51 with commercially available 4-nitro-3-(trifluoromethyl)aniline 8yielded the desired amide 52.

 Synthesis of 1,1,1-rifluoro-3-((2-(trifluoromethyl)phenyl)thio)propan-2-one (49)

To a mixture of NaH (10.47 mmol) in 10 mL anhydrous THF was added a solution of 2-(trifluoromethyl)benzenethiol (10.47 mmol) in 2mL anhydrous THF at 0 °C. This mixture was stirred for 20 min. 3-Bromo-1,1,1-trifluoropropan-2-one was then added dropwise to the mixture at 0 °C, the reaction was warmed to r.t. and stirred for 12 h. The mixture was filtered trough celite, the filtered pad was washed with THF, and the filtrate was evaporated to dryness. The residue was purified by flash column chromatography eluting with n-hexane/EtOAc 100:0 v/v increasing to n-hexane/EtOAc 85:15 v/v to give a pale yellow oil in 93% yield. ¹H-NMR (CDCl₃): d 7.76-7.69 (m, 2H), 7.60-7.53 (m, 1H), 7.42-7.38 (m, 1H), 3.44 (s, 2H). ¹⁹F-NMR (CDCl₃): d -59.91 (s, 3F), -85.26 (s, 3F). ¹³C-NMR (CDCl₃): d 189.6, 137.7, 135.9, 134.5, 133.2, 130.6, 129.6 (q, J= 26.3 Hz), 127.0 (q, J= 3.8 Hz), 124.3 (q, J= 4.1 Hz), 124.0 (q, J= 3.7 Hz), 94.4 (q, J= 30.4 Hz), 40.4.

Synthesis of    3,3,3-trifluoro-2-hydroxy-2-(((2-(trifluoromethyl)phenyl)thio)methyl)propanenitrile (50)

A 20% aqueous solution of H₂SO₄ (3.4 mL) was added dropwise to a mixture of 49 (11.03 mmol) and KCN (13.24 mmol) in 5 mL H₂O at 0 °C. The reaction mixture was warmed to r.t. and stirred for 20 h. The mixture was then diluted with water (50 mL) and extracted with Et₂O (3 x 150 mL). The organic extracts were washed with sat. aq. NaHCO₃ and brine, dried over Na₂SO₄ and concentrated in vacuo. The residue was purified by flash column chromatography eluting with n-hexane/EtOAc 100:0 v/v increasing to n-hexane/EtOAc 95:5 v/v to give a pale yellow oil in 86% yield. ¹H-NMR (CDCl₃): d 7.80 (d, J= 7.8 Hz, 1H), 7.77-7.76 (m, 1H), 7.72-7.59 (m, 1H), 7.52-7.49 (m, 1H), 4.36 (bs, 1H), 3.58 (d, J= 14.6 Hz, 1H), 3.44 (d, J= 14.6 Hz, 1H). ¹⁹F-NMR (CDCl₃): d -57.08 (s, 3F), -79.51 (s, 3F). ¹³C-NMR (CDCl₃): d 135.4, 132.8, 132.5 (q, J= 30.1 Hz), 129.1, 128.7 (q, J= 5.5 Hz), 126.7, 124.9, 124.6, 122.6, 122.4, 120.4, 114.0, 71.4 (q, J= 32.9), 40.75.

1.1.1        Synthesis         of         3,3,3-trifluoro-2-hydroxy-2-(((2-(trifluoromethyl)phenyl)thio)methyl)propanoic acid (51)

A mixture of 51 (6.89 mmol), concentrated HCl (23.4 mL) and AcOH (4.1 mL) was refluxed o.n. with vigorous stirring. The mixture was then diluted with water (100 mL) and extracted with Et₂O (4 x 100 mL), which was in turn washed with sat. aq. NaHCO₃ (4 x 100 mL). The water solution was acidified with concentrated HCl to pH 1 and extracted with Et₂O (4x 150 mL). The Et₂O extracts were dried over Na₂SO₄, filtered and concentrated to dryness to give a pale yellow waxy solid in 41% yield. ¹H-NMR (CDCl₃): d 9.57 (bs, 1H), 7.70 (d, J= 7.7 Hz, 1H), 7.67 (d, J= 7.7 Hz, 1H), 7.54-7.51 (m, 1H), 7.39-7.36 (m, 1H), 3.60 (s, 2H). ¹⁹F-NMR (CDCl₃): d -60.10 (s, 3F), -77.7 (s, 3F). ¹³C-NMR (CDCl₃): d 172.0, 134.1, 134.0, 131.2 (q, J= 30.1 Hz), 127.5, 126.7 (q, J= 5.6 Hz), 124.2 (q, J= 121.9 Hz), 121.9 (q, J= 126.7 Hz), 78.2 (q, J= 28.7 Hz), 37.7.

Synthesis of 3,3,3-trifluoro-2-hydroxy-N-(4-nitro-3-(trifluoromethyl)phenyl)-2-(((2-(trifluoromethyl)phenyl)thio)methyl)propanamide (52)

Thionyl chloride (1.16 mmol) was added dropwise to a stirring solution of 51 in anhydrous DMA at -10 °C under Ar atmosphere. The reaction mixture was stirred for 1 h, then a solution of 8 in 2 mL anhydrous DMA was added dropwise. The reaction mixture was warmed to r.t. and stirred for 72 h. The mixture was then diluted with sat. aq. NaHCO₃ (40 mL) and extracted with Et₂O (3 x 40 mL). The organic extracts were filtered trough celite, dried over Na₂SO₄ and evaporated to dryness. The residue was purified by flash column chromatography eluting with n-hexane/EtOAc 100:0 v/v increasing to n-hexane/EtOAc 80:20 v/v to give a pale yellow solid in 13% yield.

¹H-NMR (CDCl₃): d 8.93 (bs, 1H), 7.94 (d, J= 8.8 Hz, 1H), 7.87 (d, J= 2.2 Hz, 1H), 7.72 (d, J= 8.1 Hz, 1H), 7.69 (dd, J= 8.8 Hz, 2.2 Hz, 1H), 7.50-7.47 (m, 2H), 7.26-7.23 (m, 1H), 4.41 (s, 1H), 4.19 (d, 14.7 Hz, 1H), 3.45 (d, J= 14.7 Hz, 1H).

¹⁹F-NMR (CDCl₃): d -59.7 (s, 3F), -60.12 (s, 3F), -77.4 (s, 3F).

¹³C-NMR (CDCl₃): d 164.6, 143.8, 140.0, 134.7, 132.6, 131.1 (q, J= 29.8 Hz), 130.5, 128.3, 126.8 (q, J= 5.5 Hz), 126.7, 125.2 (q, J= 36.3 Hz), 124.5, 123.9, 122.6, 122.4, 122.2, 121.7, 120.4, 118.2 (q, J= 5.8 Hz), 76.3 (q, J= 27.8 Hz), 38.5.

MS [ESI, m/z]: 523.0 [M+H]⁺.

EI-HMRS (M-H)^– found 521.0215, calculated for C₁₈H₀N₂O₄F₉S 521.0218.

HPLC (method 1): retention time = 23.84 min.

clips

Prostate cancer (PC) is a leading cause of male death worldwide and it is the most frequently diagnosed cancer among men aged 65–74 [1]. The prognosis varies greatly, being highly dependent on a number of factors such as stage of diagnosis, race and age. Currently, PC treatment includes androgen deprivation, surgery, radiation, endocrine therapy and radical prostatectomy.

PC cell growth is strongly dependent on androgens, therefore blocking their effect can be beneficial to the patient’s health. Such outcomes can be achieved by antagonism of the androgen receptor (AR) using anti-androgen drugs, which have been extensively explored either alone or in combination with castration [2]. Flutamide (Eulexin^®) (1) (in its active form as hydroxyflutamide (2)), bicalutamide (Casodex^®) (3), nilutamide (Niladron^®) (4) and enzalutamide (previously called MDV3100) (Xtandi^®) (5) are all non-steroidal androgen receptor antagonists approved for the treatment of PC (Fig. 1). In many cases, after extended treatment over several years, these anti-androgens become ineffective and the disease may progress to a more aggressive and lethal form, known as castration resistant prostate cancer (CRPC). The major cause of this progressive disease is the emergence of different mutations on the AR, which cause the anti-androgen compounds to function as agonists, making them tumour-stimulating agents[3].

Among the drugs used for the treatment of PC, bicalutamide and enzalutamide selectively block the action of androgens while presenting fewer side effects in comparison with other AR antagonists [4], [5] and [6]. The structure of these molecules is characterised by the presence of a trifluoromethyl substituted anilide, which appears to be critical for biological activity (Fig. 1). As a means to improve the anti-proliferative activity of these compounds, and in order to exploit the well established potential of the fluorine atom in enhancing the pharmacological properties and drug-like physicochemical characteristics of candidate compounds [7], [8] and [9], a wide array of diverse new structures has been rationally designed and synthesised, through the introduction of fluoro-, trifluoromethyl- and trifluoromethoxy groups in diverse positions of both aromatic rings of the parent scaffolds. Our modifications resulted in a marked improvement of in vitro anti-proliferative activities on a range of human PC cell lines (VCap, LNCaP, DU-145 and 22RV1). In addition, we probed full versus partial AR antagonism for our new compounds.

Paper

European Journal of Medicinal Chemistry

Volume 118, 8 August 2016, Pages 230–243

http://www.sciencedirect.com/science/article/pii/S0223523416303452

Top cancer scientist dies of the disease he spent his life trying to cure

Professor Chris McGuigan, 57, of Cardiff University, was trying to invent new drugs to use in the fight against the disease

A top cancer scientist has died from the disease – after a lifetime of research looking for a cure.

Professor Chris McGuigan, 57, was trying to invent new drugs to use in the fight against the disease.

But the tragic scientist, who was head of medicinal chemistry at Cardiff University’s School of Pharmacy and Pharmaceutical Sciences, died after his own fight with cancer.

A spokesman for Cardiff University said: “Professor McGuigan had been at the heart of scientific research for more than 30 years. He was an exceptionally gifted inventor and chemist.

“His loss will be felt cross the university and the wider scientific community.

South Wales Echo

“He had a strong drive to use his scientific ideas for social good, working tirelessly to address medical needs where they were unmet.

“Our thoughts are with his family, friends and close colleagues at this very sad time.”

Prof McGuigan’s research led him to try and develop new drugs for cancer, HIV, hepatitis B and C, shingles, measles, influenza and central nervous system (CNS) disease.

He also invented four new experimental drugs that were used in human clinical trials.

Prof McGuigan, who lived in Cardiff, is survived by wife Maria, 50, and his two young daughters Phoebe and Grace.

References

///////////1929605-82-2, bicalutamide and enzalutamide derivatives, antiproliferative agents,  treatment of prostate cancer,  School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edward VII Avenue, CF10 3NB, Cardiff, Wales, UK

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