LX 4211, Sotagliflozin, LP-802034 , lex 1287 

UNII-6B4ZBS263Y

Methyl (5S)-5-[4-chloro-3-(4-ethoxybenzyl)phenyl]-1-thio-beta-L-xylopyranoside

β-L-Xylopyranoside, methyl 5-C-[4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl]-1-thio-, (5S)-

 (2S,3R,4R,5S,6R)-2-(4-chloro-3-(4- ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol,

(5S)-Methyl 5-C-[4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl]-1-thio-beta-L-xylopyranoside

1018899-04-1

C21H25ClO5S, 424.94, LP-802034  

LX-4211 is a dual SGLT2/1 inhibitor; Antidiabetic agents.

LX-4211 is a SGLT-2 inhibitor being evaluated in phase II clinical studies at Lexicon Pharmaceuticals for the oral treatment of type 2 diabetes.

More Positive News For Lexicon, But Not The Big Announcement

Apr. 14, 2014 1:54 PM ET  |

Summary

• Co-administration of LX4211 led to a nearly one-third reduction in mealtime insulin for Type 1 diabetics.
• Although there was no reduction in basal insulin use, the LX4211 group saw better glucose control, lower HbA1c, and weight loss.
• Partnering LX4211 is still management’s top priority but independent development in Type 1 diabetes is at least an option.

Lexicon Pharmaceuticals (LXRX) continues to generate data on its SGLT-1/2 inhibitor LX4211 that suggest this is an effective and promising medication for treating not only Type 2 diabetes (the common target for non-insulin medications for diabetes), but also Type 1 as well. Lexicon’s most recent update, a small short-term Phase II study in Type 1 diabetics is certainly a positive update, but it’s not what investors really want to see. Lexicon still needs to find a development partner for LX4211 and the ongoing delays don’t help sentiment or the long-term prospects for the drug.

A Potentially Meaningful Addition To Type 1 Care

On Monday morning, Lexicon released top-line data from a small (33-patient) Phase II study of LX4211 in Type 1 diabetics on insulin. The results support the notion that SGLT inhibition can play a valuable role in improving glucose control for Type 1 diabetics.

This small study enrolled generally well-controlled patients (HbA1c levels ranging from 7 to 9, with an average of 7.9) and the addition of LX4211 led to 32% reduction in bolus (mealtime) insulin versus a 6% reduction in the placebo group. Even with the lower bolus insulin, patients in the LX4211 group showed a 0.55% reduction in HbA1c versus a 0.06% reduction in the placebo group. Patients taking LX4211 demonstrated better glucose control (more time spent in the target range of 70-180 mg/dL) and saw a 1.7kg weight loss versus a 0.5kg weight gain in the placebo group

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 Scheme 1 :

 Scheme 2:

Scheme 3:

3(a) 3(b)

4(a) 4(b)

Scheme 3:

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http://www.google.com/patents/EP2332947A1?cl=en

EXAMPLES

• Aspects of this invention can be understood from the following examples.

6.1. Synthesis of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro [2.3-d][13]dioxol-5-yl)(morpholino)methanone

• To a 12L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and gas bubbler was charged L-(-)-xylose (504.40 g, 3.360 mol), acetone (5L, reagent grade) and anhydrous MgSO₄ powder (811.23g, 6.740 mol / 2.0 equiv). The suspension was set stirring at ambient and then concentrated H₂SO₄ (50 mL, 0.938 mol / 0.28 equiv) was added. A slow mild exotherm was noticed (temperature rose to 24°C over about 1 hr) and the reaction was allowed to stir at ambient overnight. After 16.25 hours, TLC suggested all L-xylose had been consumed, with the major product being the bis-acetonide along with some (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol. The reaction mixture was filtered and the collected solids were washed twice with acetone (500 mL per wash). The stirring yellow filtrate was neutralized with concentrated NH₄OH solution (39 mL) to pH = 8.7. After stirring for 10 min, the suspended solids were removed by filtration. The filtrate was concentrated to afford crude bis-acetonide intermediate as a yellow oil (725.23 g). The yellow oil was suspended in 2.5 L water stirring in a 5L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and gas bubbler. The pH was adjusted from 9 to 2 with 1N aq. HCl (142mL) and stirred at room temperature for 6 h until GC showed sufficient conversion of the bis-acetonide intermediate to (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol. The reaction was neutralized by the addition of 50% w/w aq. K₂HPO₄ until pH=7. The solvent was then evaporated and ethyl acetate (1.25L) was added to give a white suspension which was filtered. The filtrate was concentrated in vacuo to afford an orange oil which was dissolved in 1 L methyl tert-butyl ether. This solution had KF 0.23 wt% water and was concentrated to afford (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol as an orange oil (551.23g, 86% yield, 96.7 area% pure by GC). ¹H NMR (400 MHz, DMSO-d₆)δ1.22 (s, 3 H) 1.37 (s, 3 H) 3.51 (dd, J=11.12, 5.81 Hz, 1 H) 3.61 (dd, J=11.12, 5.05 Hz, 1 H) 3.93 – 4.00 (m, 1 H) 3.96 (s, 1 H) 4.36 (d, J=3.79 Hz, 1 H) 4.86 (br. s., 2 H) 5.79 (d, J=3.54 Hz, 1 H). ¹³C NMR (101MHz, DMSO-d₆) δ26.48, 27.02, 59.30, 73.88, 81.71, 85.48, 104.69, 110.73.
• To a solution of (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol (25.0g, 131 mmol) in acetone (375 mL, 15X) and H₂O (125 mL, 5X) was added NaHC0₃ (33.0g, 3.0 equiv), NaBr (2.8g, 20 mol%) and TEMPO (0.40g, 2 mol%) at 20°C. The mixture was cooled to 0-5°C and solid trichloroisocyanuric acid (TCCA, 30.5 g, 1.0 equiv) was then added in portions. The suspension was stirred at 20°C for 24h. Methanol (20 mL) was added and the mixture was stirred at 20°C for 1h. A white suspension was formed at this point. The mixture was filtered, washed with acetone (50 mL, 2X). The organic solvent was removed under vacuum and the aqueous layer was extracted with EtOAc (300 mL, 12X x3) and the combined organic layers were concentrated to afford an oily mixture with some solid residue. Acetone (125 mL, 5X) was added and the mixture was filtered. The acetone solution was then concentrated to afford the desired acid ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid) as a yellow solid (21.0g, 79%). ¹H NMR (methanol-d₄), δ 6.00 (d, J= 3.2 Hz, 1H), 4.72 d, J= 3.2 Hz, 1H), 4.53 (d, J= 3.2 Hz, 1H), 4.38 (d, J= 3.2 Hz, 1H), 1.44 (s, 3H), 1.32 (s, 3H).
• To a solution of (3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid (5.0g, 24.5 mmol) in THF (100 mL, 20X) was added TBTU (11.8g, 1.5 equiv), N-methylmorpholine (NMM, 4.1 mL, 1.5 equiv) and the mixture was stirred at 20°C for 30 min. Morpholine (3.2 mL, 1.5 equiv) was then added, and the reaction mixture was stirred at 20°C for an additional 6h. The solid was filtered off by filtration and the cake was washed with THF (10 mL, 2X x2). The organic solution was concentrated under vacuum and the residue was purified by silica gel column chromatography (hexanes:EtOAc, from 1:4 to 4:1) to afford 4.3 g of the desired morpholine amide (64%) as a white solid. ¹H NMR (CDCl₃), 8 6.02 (d, J= 3.2 Hz, 1H), 5.11 (br s, 1H), 4.62 (d, J= 3.2 Hz, 1H), 4.58 (d, J= 3.2 Hz, 1H), 3.9-3.5 (m, 8H), 1.51 (s, 3H), 1.35 (s, 3H).

6.2. Alternative synthesis of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahvdrofuro[2.3-d][1,3]dioxol-5-yl)(morpholino)methanone

• A solution of the diol (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol in acetonitrile (5.38 kg, 65% w/w, 3.50 kg active, 18.40 mol), acetonitrile (10.5 L) and TEMPO (28.4 g, 1 mol %) were added to a solution of K₂HPO₄ (0.32 kg, 1.84 mol) and KH₂PO₄ (1.25 kg, 9.20 mol) in water (10.5 L). A solution of NaClO₂ (3.12 kg, 80% w/w, 27.6 mole, 1.50 eq) in water (7.0 L) and a solution of K₂HPO₄ (2.89 kg, 0.90 eq) in water (3.0 L) were prepared with cooling. Bleach (3.0L, approximate 6% household grade) was mixed with the K₂HPO₄ solution. Approximately 20% of the NaClO₂ solution (1.6 L) and bleach/K₂HPO₄ solution (400 mL),∼1 mol %) were added. The remainders of the two solutions were added simultaneously. The reaction mixture turned dark red brown and slow exotherm was observed. The addition rate of the NaClO₂ solution was about 40 mL/min (3-4 h addition) and the addition rate for the bleach/K₂HPO₄ solution was about 10-12 mL/min (10 hr addition) while maintaining the batch at 15-25°C. Additional charges of TEMPO (14.3g, 0.5 mol%) were performed every 5-6 hr until the reaction went to completion (usually two charges are sufficient). Nitrogen sweep of the headspace to a scrubber with aqueous was performed to keep the green-yellowish gas from accumulating in the vessel. The reaction mixture was cooled to < 10°C and quenched with Na₂SO₃ (1.4 kg, 0.6 eq) in three portions over 1 hr. The reaction mixture was then acidified with H₃PO₄ until pH reached 2.0-2.1 (2.5-2.7 L) at 5-15°C. The layers were separated and the aqueous layer was extracted with acetonitrile (10.5 L x 3). The combined organic layer was concentrated under vacuo (∼100-120 torr) at < 35°C (28-32°C vapor, 45-50°C bath) to low volume (- 6-7 L) and then flushed with acetonitrile (40 L) until KF of the solution reached < 1% when diluted to volume of about 12-15Lwith acetonitrile. Morpholine (1.61 L, 18.4 mol, 1.0 eq) was added over 4-6 h and the slurry was aged overnight under nitrogen. The mixture was cooled to 0-5°C and aged for 3 hours then filtered. The filter cake was washed with acetonitrile (10 L). Drying under flowing nitrogen gave 4.13 kg of the morpholine salt of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid as a white solid (92-94% pure based on ¹H NMR with 1,4-dimethoxybenzene as the internal standard), 72-75% yield corrected for purity. ¹H NMR (D₂O) δ5.96 (d, J = 3.6 Hz, 1H), 4.5 8 (d, J = 3.6 Hz, 1H), 4.53 (d, J =3.2Hz,1H), 4.30 (d, J= 3.2 Hz, 1H), 3.84 (m, 2H), 3.18 (m, 2H), 1.40 (s, 1H), 1.25 (s, 1H). ¹³H NMR (D₂O) 8 174.5, 112.5, 104.6, 84.2, 81.7, 75.0, 63.6, 43.1, 25.6, 25. 1.
• The morpholine salt of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid (7.85 kg, 26.9 mol), morpholine (2.40 L, 27.5 mol) and boric acid (340 g, 5.49 mol, 0.2 eq) were added to toluene (31 L). The resulting slurry was degassed and heated at reflux with a Dean-Stark trap under nitrogen for 12 h and then cooled to room temperature. The mixture was filtered to remove insolubles and the filter cake washed with toluene (5 L). The filtrate was concentrated to about 14 L and flushed with toluene (-80 L) to remove excess morpholine. When final volume reached -12 L, heptane (14 L) was added slowly at 60-70°C. The resulting slurry was cooled gradually to room temperature and aged for 3 h. It was then filtered and washed with heptane (12 L) and dry under nitrogen gave a slightly pink solid (6.26 kg, 97% pure, 98% yield). m.p.: 136°C (DSC). ¹H NMR (CDCl₃), δ 6.02 (d, J = 3.2 Hz, 1H), 5.11 (br s, 1H), 4.62 (d, J=3.2 Hz, 1H), 4.58 (d, J=3.2 Hz, 1H), 3.9-3.5 (m, 8H), 1.51 (s, 3H), 1.35 (s, 3H). ¹³C NMR (methanol-d₄) δ 26.84, 27.61, 44.24, 47.45, 68.16, 77.14, 81.14, 86.80, 106.87, 113.68, 169.05.

1-chloro-2-(4-ethoxybenzyl)-4-iodobenzene:

6.3. Synthesis of 1-chloro-2-(4-ethoxybenzyl)-4-iodobenzene

• A 2L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and pressure-equalized addition funnel with gas bubbler was charged with 2-chloro-5-iodobenzoic acid (199.41 g, 0.706 mol), dichloromethane (1.2L, KF = 0.003 wt% water) and the suspension was set stirring at ambient temperature. Then N,N-dimethylformamide (0.6 mL, 1.1 mol %) was added followed by oxalyl chloride (63 mL, 0.722 mol, 1.02 equiv) which was added over 11 min. The reaction was allowed to stir at ambient overnight and became a solution. After 18.75hours, additional oxalyl chloride (6 mL, 0.069 mol, 0.10 equiv) was added to consume unreacted starting material. After 2 hours, the reaction mixture was concentrated in vacuo to afford crude 2-chloro-5-iodobenzoyl chloride as a pale yellow foam which will be carried forward to the next step.
• A jacketed 2L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and pressure-equalized addition funnel with gas bubbler was charged with aluminum chloride (97.68 g, 0.733 mol, 1.04 equiv), dichloromethane (0.65 L, KF = 0.003 wt% water) and the suspension was set stirring under nitrogen and was cooled to about 6°C. Then ethoxybenzene (90 mL, 0.712 mol, 1.01 equiv) was added over 7 minutes keeping internal temperature below 9°C. The resulting orange solution was diluted with dichloromethane (75mL) and was cooled to -7°C. Then a solution of 2-chloro-5-iodobenzoyl chloride (≤ 0.706 mol) in 350 mL dichloromethane was added over 13 minutes keeping the internal temperature below +3°C. The reaction mixture was warmed slightly and held at +5°C for 2 hours. HPLC analysis suggested the reaction was complete and the reaction was quenched into 450mL pre-cooled (∼5°C) 2N aq. HCl with stirring in a jacketed round bottom flask. This quench was done in portions over 10min with internal temperature remaining below 28°C. The quenched biphasic mixture was stirred at 20°C for 45min and the lower organic phase was washed with 1N aq. HCl (200mL), twice with saturated aq sodium bicarbonate (200mL per wash), and with saturated aq sodium chloride (200mL). The washed extract was concentrated on a rotary evaporator to afford crude (2-chloro-5-iodophenyl)(4-ethoxyphenyl)methanone as an off-white solid (268.93g, 99.0 area% by HPLC at 220nm, 1.0 area% regioisomer at 200nm, 98.5 % “as-is” yield).
• A jacketed 1 L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and gas bubbler was charged with crude (2-chloro-5-iodophenyl)(4-ethoxyphenyl)methanone (30.13 g, 77.93 mmol), acetonitrile (300mL, KF = 0.004 wt% water) and the suspension was set stirring under nitrogen and was cooled to about 5°C.Then triethylsilane (28mL, 175.30 mmol, 2.25 equiv) was added followed by boron trifluoride-diethyletherate (24mL, 194.46mmo1,2.50 equiv) which was added over about 30 seconds. The reaction was warmed to ambient over 30min and was stirred for 17 hours. The reaction was diluted with methyl tert-butyl ether (150mL) followed by saturated aq sodium bicarbonate (150mL) which was added over about 1 minutes. Mild gas evolution was noticed and the biphasic solution was stirred at ambient for 45 minutes. The upper organic phase was washed with saturated aq sodium bicarbonate (100 mL), and with saturated aq sodium chloride (50mL). The washed extract was concentrated on a rotary evaporator to about one half of its original volume and was diluted with water (70 mL). Further concentration in vacuo at 45°C was done until white prills formed which were allowed to cool to ambient while stirring. After about 30 minutes at ambient, the suspended solids were isolated by filtration, washed with water (30 mL), and were dried in vacuo at 45°C. After about 2.5 hours, this afforded 1-chloro-2-(4-ethoxybenzyl)-4-iodobenzene as a slightly waxy white granular powder (28.28 g, 98.2 area % by HPLC at 220nm, 97.4 % “as-is” yield).

6.4. Synthesis of (4-chloro-3-(4-ethoxybenzyl)phenyl)((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro [2,3-d][1,3]dioxol-5-yl)methanone

• To a solution of 1-chloro-2-(4-ethoxybenzyl)-4-iodobenzene (500mag, 1.34 mmol) in THF (5.0 mL) was added i-PrMgCl (2.0M in THF, 1.0 mL, 2.00 mmol) at 0-5°C, and the mixture was stirred for 1.5 h at 0-5°C. A solution of (3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)(morpholino)methanone (146.5 mg, 0.536 mmol) in THF (1.0 mL) was added dropwise at 0-5°C and the mixture was kept stirring for 1h, warmed to 20°C and stirred at 20°C for 2 hours. The reaction was quenched with saturated aq NH₄CI, extracted with MTBE, washed with brine. The organic layer was concentrated and the residue was purified by silica gel column chromatography to afford the desired ketone (178 mg, 76%) as a white solid. ¹H NMR (CDCl₃) δ 7. 88 (dd, J= 8.4, 2.0 Hz, 1H), 7.82 (d, J= 2.0 Hz, 1H), 7.50 (d, J= 8.4 Hz, 1H), 7.12 (d, J= 8.4 Hz, 2H), 6.86 (d, J = 8.4 Hz, 2H), 6.07 (d, J = 3.2 Hz, 1H), 5.21 (d, J = 3.2 Hz, 1H), 4.58 (d, J = 3.2 Hz, 1H), 4.56 (d, J = 3.2 Hz, 1H), 4.16 (d, J = 7.2 Hz, 2H), 4.03 (q, J = 7.2 Hz, 2H), 1.54 (s, 3H), 1.42 (t, J= 7.2 Hz, 3H), 1.37 (s, 3H).

6.5. Alternative synthesis of (4-chloro-3-(4-ethoxybenzyl)phenyl)((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)methanone

• To a 20 L reactor equipped with a mechanical stirrer, a temperature controller and a nitrogen inlet was charged with the iodide (3.00 kg, 8.05 mol) and THF (8 L, 4X to the morpholinoamide) at room temperature and cooled to -5°C. To the above solution was added dropwise a solution of i-PrMgCl in THF (Aldrich 2 M, 4.39 L, 8.82 mol) at -5°C over 3 hours. This Grignard solution was used in the ketone formation below.
• [0055]
  To a 50 L reactor equipped with a mechanical stirrer, a temperature controller, and a nitrogen inlet was charged the morpholinoamide (HPLC purity = 97 wt%, 2.01 kg, 7.34 mol) and THF (11 L, 5.5X) at room temperature and stirred for 45 minutes at room temperature and for 15 minutes at 30°C. The homogeneous solution was then cooled to – 25°C. To this solution was added a solution of t-BuMgCl in THF (Aldrich 1 M, 7.32 L, 7.91 mol) at -25°C over 3 hours. Then the above Grignard solution was added to this solution at -20 over 41 minutes. The resulting solution was further stirred at -20°C before quench. The reaction mixture was added to 10 wt% aqueous NH₄Cl (10 L, 5X) at 0°C with vigorous stirring, and stirred for 30 minutes at 0°C. To this mixture was added slowly 6 N HCl (4 L, 2X) at 0°C to obtain a clear solution and stirred for 30 minutes at 10°C. After phase split, the organic layer was washed with 25 wt% aq NaCl (5 L, 2.5X). Then the organic layer was concentrated to a 3X solution under the conditions (200 mbar, bath temp 50°C). EtOAc (24 L, 12X) was added, and evaporated to a 3X solution under the conditions (150 mbar, bath temp 50°C). After removed solids by a polish filtration, EtOAc (4 L, 2X) was added and concentrated to dryness (150 mbar, bath temp 50°C). The wet cake was then transferred to a 50 L reactor equipped with a mechanical stirrer, a temperature controller and a nitrogen inlet. After EtOAc was added, the suspension was heated at 70°C to obtain a 2.5X homogeneous solution. To the resulting homogeneous solution was added slowly heptane (5 L, 2.5X) at the same temperature. A homogeneous solution was seeded and heptane (15 L, 7.5X) was added slowly to a little cloudy solution at 70°C. After stirred for 0.5 h at 70°C, the suspension was slowly cooled to 60°C and stirred for 1 h at 60°C. The suspension was then slowly cool to room temperature and stirred for 14 h at the same temperature. The crystals were collected and washed with heptane (8 L, 4X), dried under vacuum at 45°C to give the desired ketone as fluffy solids (2.57 kg, 100 wt% by HPLC, purity-adjusted yield: 81%).

(2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate:

6.6. Synthesis of (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate

• To a solution of the ketone (4-chloro-3-(4-ethoxybenzyl)phenyl)-((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)methanone (114.7 g, 0.265 mol) in MeOH (2 L, 17X) was added CeCl₃.7H₂O (118.5g, 1.2 equiv) and the mixture was stirred at 20°C until all solids were dissolved. The mixture was then cooled to -78°C and NaBH₄ (12.03g, 1.2 equiv) was added in portions so that the temperature of the reaction did not exceed -70°C. The mixture was stirred at – 78°C for 1 hour, slowly warmed to 0°C and quenched with saturated aq NH₄Cl (550 mL, 5X). The mixture was concentrated under vacuum to remove MeOH and then extracted with EtOAc (1.1L, 10X x2) and washed with brine (550 mL, 5X). The combined organics were concentrated under vacuum to afford the desired alcohol as a colorless oil (crude, 115g). To this colorless oil was added AcOH (650 mL) and H₂O (450 mL) and the mixture was heated to 100°C and stirred for 15 hours. The mixture was then cooled to room temperature (20°C) and concentrated under vacuum to give a yellow oil (crude, ∼118 g). To this crude oil was added pyridine (500 mL) and the mixture was cooled to 0°C. Then, Ac₂O (195 mL, -8.0 equiv) was added and the mixture was warmed to 20°C and stirred at 20°C for 2h. The reaction was quenched with H₂O (500 mL) and diluted with EtOAc (1000 mL). The organic layer was separated and concentrated under vacuum to remove EtOAc and pyridine. The residue was diluted with EtOAc (1000 mL) and washed with aq NaHSO₄ (1N, 500 mL, x2) and brine (300 mL). The organic layer was concentrated to afford the desired tetraacetate intermediate as a yellow foam (-133g).
• To a solution of tetraacetate (133 g, 0.237 mol assuming pure) and thiourea (36.1, 2.0 equiv) in dioxane (530 mL, 4X) was added trimethylsilyl trifluoromethanesulfonate (TMSOTf) (64.5 mL, 1.5 equiv) and the reaction mixture was heated to 80°C for 3.5 hours. The mixture was cooled to 20°C and Mel (37 mL, 2.5 equiv) and N,N-diisopropylethylamine (DiPEA) (207 mL, 5.0 equiv) was added and the mixture was stirred at 20°C for 3h. The mixture was then diluted with methyl tertiary-butyl ether (MTBE) (1.3 L, 10X) and washed with H2O (650 mL, 5X x2). The organic layer was separated and concentrated under vacuum to give a yellow solid. To this yellow solid was added MeOH (650 mL, 5X) and the mixture was reslurried at 60°C for 2h and then cooled to 0°C and stirred at 0°C for 1 hour. The mixture was filtered and the cake was washed with MeOH (0°C, 70 mL, x3). The cake was dried under vacuum at 45°C overnight to afford the desired triacetate (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate (88 g, 60% over 4 steps) as a pale yellow solid. ¹H NMR (CDCl₃) δ 7.37 (d, J= 8.0 Hz, 1H), 7.20 (dd, J= 8.0, 2.0 Hz, 1H), 7.07 (m, 2H), 6.85 (m, 2H), 5.32 (t, J = 9.6 Hz, 1H), 5.20 (t, J = 9.6 Hz, 1H), 5.05 (t, J= 9.6 Hz, 1H), 4.51 (d, J=9.6Hz, 1H), 4.38 (d, J= 9.6Hz, 1h), 4.04 (m, 2H), 2.17 (s, 3H), 2.11 (s, 3H), 2.02 (s, 3H), 1.73 (s, 3H), 1.42 (t, J= 7.2 Hz, 3H).

6.7. Alternative synthesis of (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate

• To a 50 L reactor under nitrogen atmosphere, 40 L MeOH was charged, followed with the ketone (2.50 kg, 5.78 mol) and CeCl₃.7H₂O (2.16 kg, 1.0 equiv). Methanol (7.5 L) was added as rinse (totally 47.5 L, 19X). A freshly prepared solution of NaBH₄ (87.5 g, 0.4 equiv) in aqueous 1 N NaOH (250 mL) was added slowly (35 min) at 15-25°C. The mixture was then stirred for 15 min. HPLC analysis of the reaction mixture showed approximately 90:10 diastereomeric ratio. The reaction was quenched with 10 wt% aq NH₄Cl (2.5 L, 1X) and the mixture was concentrated under vacuum to 5X, diluted with water (10 L, 4X) and MTBE (12.5L, 5X). The mixture was cooled to 10°C and 6 N aq HCl was added until the pH of the mixture reached 2.0. Stirring was continued for 10 minutes and the layers were separated. The organic layer was washed with H₂O (5L, 2X). The combined aqueous layer was extracted with MTBE (12.5 L, 5X). The combined organic layers were washed with brine (2.5 L, 1X) and concentrated under vacuum to 3X. MeCN (15 L, 6X) was added. The mixture was concentrated again to 10 L (4X) and any solid residue was removed by a polish filtration. The cake was washed with minimal amount of MeCN.
• The organic filtrate was transferred to 50 L reactor, and a pre-prepared 20 mol% aqueous H₂SO₄ solution (61.8 mL 98% concentrated H₂SO₄ and 5 L H₂O) was added. The mixture was heated to 80°C for 2 hours and then cooled to 20°C. The reaction was quenched with a solution of saturated aqueous K₂CO₃ (5 L, 2X) and diluted with MTBE (15 L, 6X). The organic layer was separated, washed with brine (5 L, 2X) and concentrated under vacuum to 5 L (2X). MeCN (12.5 L, 5X) was added and the mixture was concentrated to 7.5 L (3X).
• The above MeCN solution of (3S,4R,SR,6S)-6-(4-chloro-3-(4-ethoxybenzyl)phenyl)tetrahydro-2H-pyran-2,3,4,5-tetraol was cooled to 10°C, added with dimethylaminopyridine (17.53 g, 2.5 mol%), followed by slow addition of acetic anhydride (3.23 L, 6.0 equiv) and triethylamine (5 L, 2X, 6.0 equiv) so that the temperature of the mixture was kept below 20°C. The reaction was then warmed to 20°C and stirred for 1 hour and diluted with MTBE (15 L, 6X). The mixture was slowly quenched with water (7.5 L, 3X). The organic layer was separated and washed with saturated aqueous KHCO₃ (5L, 2X), 1 N NaHSO₄ (5 L, 2X), and brine (5 L, 2X) in sequence.
• The organic layer was then concentrated under vacuum to 5 L (2X). MeCN (12.5 L, 5X) was added and the solution was concentrated to 7.5 L (3X) (KF = 0.08%). Dioxane (12.5 L, 5X) was added and the solution was concentrated to 7.50 L (3X) (KF = 0.02%). Any residual solid was removed by a polish filtration and the cake was washed with minimal amount of dioxane (500 mL).
• To the above filtrate was added thiourea (880 g, 2.0 equiv) and TMSOTf (1.57 L, 1.5 equiv). The reaction mixture was heated to 80°C for 3 hours (>97% conversion). The mixture was cooled to 20°C and methyl iodide (541 mL, 1.5 equiv) and diethylisopropylamine (3.02 L, 3.0 equiv) were added and the mixture was stirred at 20°C for 18 hours. An extra methyl iodide charge (90 mL, 0.25 equiv) was added and the mixture was stirred at 20°C for 1 hours. The mixture was then diluted with MTBE (25 L, 10X) and washed with water (12.5 L, 5X x2). The organic layer was separated and concentrated under vacuum to -5 L (2X). MeOH (12.5 L, 5X) was added and the mixture was concentrated to 5X to afford a slurry. The mixture was then heated at 60°C for 1 hour and cooled to 0°C and stirred at 0°C for 1 hour. The mixture was filtered and the cake was washed with MeOH (0°C, 2.5 L, 1X x2, 1.0 L, 0.4X). The cake was dried under vacuum at 45°C overnight to afford the desired triacetate (1.49 kg, 47% over 4 steps) as a pale yellow/off-white solid.

6.8. Synthesis of (2S,3R,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol

• To a slurry of (2S,3S,4R,SS,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate (90.0 g, 0.164mo1) in MeOH (900 mL, 10X) was added NaOMe in MeOH (25 wt%, 18 mL, 0.2X) at 20°C and the mixture was stirred at 20°C for 2 hours until all solids disappeared. The mixture was then concentrated to 300 mL, added to H2O (1L) and stirred for 1 hour. The solid was filtered and washed with H2O (100 mL, x3) and the cake was dried under vacuum at 45°C overnight to afford the desired methyl thiolate (67.0g, 95%). 1H NMR (CDCl3) δ 7.38 (d, J = 8.4 Hz, 1H), 7.22 (m, 2H), 7.11 (d, J = 8.8 Hz, 2H), 6.83 (d, J = 8.8 Hz, 2H), 4.35 (d, J = 9.6 Hz, 1H), 4.15 (d, J = 9.6 Hz, 1H), 4.10-3.95 (m, 3H), 3.64 (t, J = 8.8 Hz, 1H), 3.50 (m, 2H), 3.42 (br s, 1H), 2.95 (br s, 1H), 2.57 (br s, 1H), 2.17 (s, 3H), 1.40 (t, J = 7.2 Hz, 3H).

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http://www.google.com/patents/WO2010009197A1?cl=en

(2S,3R,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H- pyran-3,4,5-triol:

LEX-1287 The compound is an inhibitor of the sodium glucose co-transporter 2, and may be useful in the treatment of diabetes and a variety of other diseases and conditions. See U.S. patent application no. 11/862,690, filed September 28, 2007.

6.8. Synthesis of (2S,3R,4R,5S,6R)-2-(4-chloro-3-(4- ethoxybenzyl)phenyl)-6-fmethylthio)tetrahydro-2H-pyran-3,4,5-triol To a slurry of (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-

(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate (90.0 g, 0.164mol) in MeOH (900 mL, 10X) was added NaOMe in MeOH (25 wt%, 18 mL, 0.2X) at 20⁰C and the mixture was stirred at 20⁰C for 2 hours until all solids disappeared. The mixture was then

18

LEX-1287 concentrated to 300 mL, added to H2O (IL) and stirred for 1 hour. The solid was filtered and washed with H2O (100 mL, x3) and the cake was dried under vacuum at 45°C overnight to afford the desired methyl thiolate (67.Og, 95%). IH NMR (CDC13) δ 7.38 (d, J = 8.4 Hz, IH), 7.22 (m, 2H), 7.11 (d, J = 8.8 Hz, 2H), 6.83 (d, J = 8.8 Hz, 2H), 4.35 (d, J = 9.6 Hz, IH), 4.15 (d, J = 9.6 Hz, IH), 4.10-3.95 (m, 3H), 3.64 (t, J = 8.8 Hz, IH), 3.50 (m, 2H), 3.42 (br s, IH), 2.95 (br s, IH), 2.57 (br s, IH), 2.17 (s, 3H), 1.40 (t, J = 7.2 Hz, 3H).

6.9. Preparation of Crystalline Anhydrous (2S,3R,4R,5S,6R)-2-(4-chloro-

3-f4-ethoxybenzyl)phenyl)-6-fmethylthio)tetrahydro-2H-pyran- 3,4,5-triol Form 1

Under slightly positive nitrogen pressure, to a 50 L reactor was charged MeOH (12 L) and the triacetate (1.70 Kg, 3.09 mol). Methanol (5L) was added as a rinse. The slurry was then added NaOMe in MeOH (25 wt%, 340 mL, 0.2X) in 15 minutes at 20⁰C and the mixture was stirred at 20⁰C for 2 hours until all solids disappeared. To the mixture was added slowly water (25.5 L, 15X) in 45 minutes with 5 g seeding (DSC123°C). Solids crashed out and the mixture was stirred at 20⁰C for 1 hour, cooled to 0⁰C and stirred for 30 minutes. The solid was filtered and washed with water (1.7 L, IX, x2) and the cake was dried under vacuum at 45°C overnight to afford the title compound (m.p. ~ 123 ⁰C by DSC peak; 1.28 Kg, 97.7% yield).

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http://www.google.com/patents/US20090030198

 EXAMPLES

Aspects of this invention can be understood from the following examples, which do not limit its scope.

6.1. Synthesis of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)(morpholino)methanone

To a 12 L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and gas bubbler was charged L-(−)-xylose (504.40 g, 3.360 mol), acetone (5 L, reagent grade) and anhydrous MgSO₄ powder (811.23 g, 6.740 mol/2.0 equiv). The suspension was set stirring at ambient and then concentrated H₂SO₄ (50 mL, 0.938 mol/0.28 equiv) was added. A slow mild exotherm was noticed (temperature rose to 24° C. over about 1 hr) and the reaction was allowed to stir at ambient overnight. After 16.25 hours, TLC suggested all L-xylose had been consumed, with the major product being the bis-acetonide along with some (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol. The reaction mixture was filtered and the collected solids were washed twice with acetone (500 mL per wash). The stirring yellow filtrate was neutralized with concentrated NH₄OH solution (39 mL) to pH =8.7. After stirring for 10 min, the suspended solids were removed by filtration. The filtrate was concentrated to afford crude bis-acetonide intermediate as a yellow oil (725.23 g). The yellow oil was suspended in 2.5 L water stirring in a 5 L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and gas bubbler. The pH was adjusted from 9 to 2 with 1N aq. HCl (142 mL) and stirred at room temperature for 6 h until GC showed sufficient conversion of the bis-acetonide intermediate to (3aS,5 S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol. The reaction was neutralized by the addition of 50% w/w aq. K₂HPO₄ until pH=7. The solvent was then evaporated and ethyl acetate (1.25 L) was added to give a white suspension which was filtered. The filtrate was concentrated in vacuo to afford an orange oil which was dissolved in 1 L methyl tert-butyl ether. This solution had KF 0.23 wt % water and was concentrated to afford (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol as an orange oil (551.23 g, 86% yield, 96.7 area % pure by GC). ¹H NMR (400 MHz, DMSO-d₆) δ 1.22 (s, 3 H) 1.37 (s, 3 H) 3.51 (dd, J=11.12, 5.81 Hz, 1 H) 3.61 (dd, J=11.12, 5.05 Hz, 1 H) 3.93-4.00 (m, 1 H) 3.96 (s, 1 H) 4.36 (d, J=3.79 Hz, 1 H) 4.86 (br. s., 2 H) 5.79 (d, J=3.54 Hz, 1 H). ³C NMR (101 MHz, DMSO-d₆) δ 26.48, 27.02, 59.30, 73.88, 81.71, 85.48, 104.69, 110.73. To a solution of (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol (25.0 g, 131 mmol) in acetone (375 mL, 15×) and H₂O (125 mL, 5×) was added NaHCO₃ (33.0 g, 3.0 equiv), NaBr (2.8 g, 20 mol %) and TEMPO (0.40 g, 2 mol %) at 20° C. The mixture was cooled to 0-5° C. and solid trichloroisocyanuric acid (TCCA, 30.5 g, 1.0 equiv) was then added in portions. The suspension was stirred at 20° C. for 24h. Methanol (20 mL) was added and the mixture was stirred at 20° C. for 1 h. A white suspension was formed at this point. The mixture was filtered, washed with acetone (50 mL, 2×). The organic solvent was removed under vacuum and the aqueous layer was extracted with EtOAc (300 mL, 12× ×3) and the combined organic layers were concentrated to afford an oily mixture with some solid residue. Acetone (125 mL, 5×) was added and the mixture was filtered. The acetone solution was then concentrated to afford the desired acid ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid) as a yellow solid (21.0 g, 79%).¹H NMR (methanol-d₄), δ 6.00 (d, J=3.2 Hz, 1H), 4.72 d, J=3.2 Hz, 1H), 4.53 (d, J=3.2 Hz, 1H), 4.38 (d, J=3.2 Hz, 1H), 1.44 (s, 3H), 1.32 (s, 3H). To a solution of (3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid (5.0 g, 24.5 mmol) in THF (100 ML, 20×) was added TBTU (11.8 g, 1.5 equiv), N-methylmorpholine (NMM, 4.1 mL, 1.5 equiv) and the mixture was stirred at 20° C. for 30 min. Morpholine (3.2 mL, 1.5 equiv) was then added, and the reaction mixture was stirred at 20° C. for an additional 6h. The solid was filtered off by filtration and the cake was washed with THF (10 mL, 2× ×2). The organic solution was concentrated under vacuum and the residue was purified by silica gel column chromatography (hexanes:EtOAc, from 1:4 to 4: 1) to afford 4.3 g of the desired morpholine amide (64%) as a white solid. ¹H NMR (CDCl₃), δ 6.02 (d, J=3.2 Hz, 1H), 5.11 (br s, 1H), 4.62 (d, J=3.2 Hz, 1H), 4.58 (d, J=3.2 Hz, 1H), 3.9-3.5 (m, 8H), 1.51 (s, 3H), 1.35 (s, 3H).

6.2. Alternative synthesis of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)(morpholino)methanone

A solution of the diol (3aS,5S,6R,6aS)-5-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-ol in acetonitrile (5.38 kg, 65% w/w, 3.50 kg active, 18.40 mol), acetonitrile (10.5 L) and TEMPO (28.4 g, 1 mol %) were added to a solution of K₂HPO₄ (0.32 kg, 1.84 mol) and KH₂PO₄ (1.25 kg, 9.20 mol) in water (10.5 L). A solution of NaClO₂ (3.12 kg, 80% w/w, 27.6 mole, 1.50 eq) in water (7.0 L) and a solution of K₂HPO₄ (2.89 kg, 0.90 eq) in water (3.0 L) were prepared with cooling. Bleach (3.0 L, approximate 6% household grade) was mixed with the K₂HPO₄ solution. Approximately 20% of the NaClO₂solution (1.6 L) and bleach/K₂HPO₄ solution (400 mL, 1 mol %) were added. The remainders of the two solutions were added simultaneously. The reaction mixture turned dark red brown and slow exotherm was observed. The addition rate of the NaClO₂ solution was about 40 mL/min (3-4 h addition) and the addition rate for the bleach/K₂HPO₄ solution was about 10-12 mL/min (10 hr addition) while maintaining the batch at 15-25° C. Additional charges of TEMPO (14.3 g, 0.5 mol %) were performed every 5-6 hr until the reaction went to completion (usually two charges are sufficient). Nitrogen sweep of the headspace to a scrubber with aqueous was performed to keep the green-yellowish gas from accumulating in the vessel. The reaction mixture was cooled to <10° C. and quenched with Na₂SO₃ (1.4 kg, 0.6 eq) in three portions over 1 hr. The reaction mixture was then acidified with H₃PO₄ until pH reached 2.0-2.1 (2.5-2.7 L) at 5-15° C. The layers were separated and the aqueous layer was extracted with acetonitrile (10.5 L ×3). The combined organic layer was concentrated under vacuo (˜100-120 torr) at <35° C. (28-32° C. vapor, 45-50° C. bath) to low volume (˜6-7 L) and then flushed with acetonitrile (40 L) until KF of the solution reached <1% when diluted to volume of about 12-15Lwith acetonitrile. Morpholine (1.61 L, 18.4 mol, 1.0 eq) was added over 4-6 h and the slurry was aged overnight under nitrogen. The mixture was cooled to 0-5° C. and aged for 3 hours then filtered. The filter cake was washed with acetonitrile (10 L). Drying under flowing nitrogen gave 4.13 kg of the morpholine salt of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid as a white solid (92-94% pure based on ¹H NMR with 1,4-dimethoxybenzene as the internal standard), 72-75% yield corrected for purity. ¹H NMR (D₂O) δ 5.96 (d, J=3.6 Hz, 1H), 4.58 (d, J=3.6 Hz, 1H), 4.53 (d, J=3.2 Hz, 1H), 4.30 (d, J=3.2 Hz, 1H), 3.84 (m, 2H), 3.18 (m, 2H), 1.40 (s, 1H), 1.25 (s, 1H). ¹³H NMR (D₂O) δ 174.5, 112.5, 104.6, 84.2, 81.7, 75.0, 63.6, 43.1, 25.6, 25.1. The morpholine salt of ((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carboxylic acid (7.85 kg, 26.9 mol), morpholine (2.40 L, 27.5 mol) and boric acid (340 g, 5.49 mol, 0.2 eq) were added to toluene (31 L). The resulting slurry was degassed and heated at reflux with a Dean-Stark trap under nitrogen for 12 h and then cooled to room temperature. The mixture was filtered to remove insolubles and the filter cake washed with toluene (5 L). The filtrate was concentrated to about 14 L and flushed with toluene (˜80 L) to remove excess morpholine. When final volume reached 12 L, heptane (14 L) was added slowly at 60-70° C. The resulting slurry was cooled gradually to room temperature and aged for 3 h. It was then filtered and washed with heptane (12 L) and dry under nitrogen gave a slightly pink solid (6.26 kg, 97% pure, 98% yield). m.p.: 136° C. (DSC). ¹H NMR (CDCl₃), δ 6.02 (d, J=3.2 Hz, 1H), 5.11 (br s, 1H), 4.62 (d, J=3.2 Hz, 1H), 4.58 (d, J=3.2 Hz, 1H), 3.9-3.5 (m, 8H), 1.51 (s, 3H), 1.35 (s, 3H). ¹³C NMR (methanol-d₄) δ 26.84, 27.61, 44.24, 47.45, 68.16, 77.14, 81.14, 86.80, 106.87, 113.68, 169.05.

6.3. Synthesis of 1-chloro-2-(4-ethoxybenzyl)-4-iodobenzene

A 2 L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and pressure-equalized addition funnel with gas bubbler was charged with 2-chloro-5-iodobenzoic acid (199.41 g, 0.706 mol), dichloromethane (1.2L, KF=0.003 wt % water) and the suspension was set stirring at ambient temperature. Then N,N-dimethylformamide (0.6 mL, 1.1 mol %) was added followed by oxalyl chloride (63 mL, 0.722 mol, 1.02 equiv) which was added over 11 min. The reaction was allowed to stir at ambient overnight and became a solution. After 18.75hours, additional oxalyl chloride (6 mL, 0.069 mol, 0.10 equiv) was added to consume unreacted starting material. After 2 hours, the reaction mixture was concentrated in vacuo to afford crude 2-chloro-5-iodobenzoyl chloride as a pale yellow foam which will be carried forward to the next step. A jacketed 2 L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and pressure-equalized addition funnel with gas bubbler was charged with aluminum chloride (97.68 g, 0.733 mol, 1.04 equiv), dichloromethane (0.65 L, KF=0.003 wt % water) and the suspension was set stirring under nitrogen and was cooled to about 6° C. Then ethoxybenzene (90 mL, 0.712 mol, 1.01 equiv) was added over 7 minutes keeping internal temperature below 9° C. The resulting orange solution was diluted with dichloromethane (75 mL) and was cooled to −7° C. Then a solution of 2-chloro-5-iodobenzoyl chloride (<0.706 mol) in 350 mL dichloromethane was added over 13 minutes keeping the internal temperature below +3° C. The reaction mixture was warmed slightly and held at +5° C. for 2 hours. HPLC analysis suggested the reaction was complete and the reaction was quenched into 450 mL pre-cooled (˜5° C.) 2N aq. HCl with stirring in a jacketed round bottom flask. This quench was done in portions over 10 min with internal temperature remaining below 28° C. The quenched biphasic mixture was stirred at 20° C. for 45 min and the lower organic phase was washed with 1N aq. HCl (200 mL), twice with saturated aq. sodium bicarbonate (200 mL per wash), and with saturated aq. sodium chloride (200 mL). The washed extract was concentrated on a rotary evaporator to afford crude (2-chloro-5-iodophenyl)(4-ethoxyphenyl)methanone as an off-white solid (268.93 g, 99.0 area % by HPLC at 220 nm, 1.0 area % regioisomer at 200 nm, 98.5 % “as-is” yield). A jacketed 1 L three-necked round bottom flask with mechanical stirrer, rubber septum with temperature probe and gas bubbler was charged with crude (2-chloro-5-iodophenyl)(4-ethoxyphenyl)methanone (30.13 g, 77.93 mmol), acetonitrile (300 mL, KF=0.004 wt % water) and the suspension was set stirring under nitrogen and was cooled to about 5° C. Then triethylsilane (28 mL, 175.30 mmol, 2.25 equiv) was added followed by boron trifluoride-diethyletherate (24 mL, 194.46 mmol, 2.50 equiv) which was added over about 30 seconds. The reaction was warmed to ambient over 30 min and was stirred for 17 hours. The reaction was diluted with methyl tert-butyl ether (150 mL) followed by saturated aq sodium bicarbonate (150 mL) which was added over about 1 minutes. Mild gas evolution was noticed and the biphasic solution was stirred at ambient for 45 minutes. The upper organic phase was washed with saturated aq. sodium bicarbonate (100 mL), and with saturated aq. sodium chloride (50 mL). The washed extract was concentrated on a rotary evaporator to about one half of its original volume and was diluted with water (70 mL). Further concentration in vacuo at 45° C. was done until white prills formed which were allowed to cool to ambient while stirring. After about 30 minutes at ambient, the suspended solids were isolated by filtration, washed with water (30 mL), and were dried in vacuo at 45° C. After about 2.5 hours, this afforded 1-chloro-2-(4-ethoxybenzyl)-4-iodobenzene as a slightly waxy white granular powder (28.28 g, 98.2 area % by HPLC at 220 nm, 97.4 % “as-is” yield).

6.4. Synthesis of (4-chloro-3-(4-ethoxybenzyl)phenyl)((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro [2,3-d][1,3]dioxol-5-yl)methanone

To a solution of 1-chloro-2-(4-ethoxybenzyl)-4-iodobenzene (500 mg, 1.34 mmol) in THF (5.0 mL) was added i-PrMgCl (2.0M in THF, 1.0 mL, 2.00 mmol) at 0-5° C., and the mixture was stirred for 1.5 h at 0-5° C. A solution of (3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)(morpholino)methanone (146.5 mg, 0.536 mmol) in THF (1.0 mL) was added dropwise at 0-5° C. and the mixture was kept stirring for 1 h, warmed to 20° C. and stirred at 20° C. for 2 hours. The reaction was quenched with saturated aq NH₄Cl, extracted with MTBE, washed with brine. The organic layer was concentrated and the residue was purified by silica gel column chromatography to afford the desired ketone (178 mg, 76%) as a white solid. ¹H NMR (CDCl₃) δ 7.88 (dd, J=8.4, 2.0 Hz, 1H), 7.82 (d, J=2.0 Hz, 1H), 7.50 (d, J=8.4 Hz, 1H), 7.12 (d, J=8.4 Hz, 2H), 6.86 (d, J=8.4 Hz, 2H), 6.07 (d, J=3.2 Hz, 1H), 5.21 (d, J=3.2 Hz, 1H), 4.58 (d, J=3.2 Hz, 1H), 4.56 (d, J=3.2 Hz, 1H), 4.16 (d, J=7.2 Hz, 2H), 4.03 (q, J=7.2 Hz, 2H), 1.54 (s, 3H), 1.42 (t, J=7.2 Hz, 3H), 1.37 (s, 3H).

6.5. Alternative synthesis of (4-chloro-3-(4-ethoxybenzyl)phenyl)((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d]1,3]dioxol-5-yl)methanone

To a 20 L reactor equipped with a mechanical stirrer, a temperature controller and a nitrogen inlet was charged with the iodide (3.00 kg, 8.05 mol) and THF (8 L, 4× to the morpholinoamide) at room temperature and cooled to −5° C. To the above solution was added dropwise a solution of i-PrMgCl in THF (Aldrich 2 M, 4.39 L, 8.82 mol) at −5° C. over 3 hours. This Grignard solution was used in the ketone formation below. To a 50 L reactor equipped with a mechanical stirrer, a temperature controller, and a nitrogen inlet was charged the morpholinoamide (HPLC purity=97 wt %, 2.01 kg, 7.34 mol) and THF (11 L, 5.5×) at room temperature and stirred for 45 minutes at room temperature and for 15 minutes at 30° C. The homogeneous solution was then cooled to −25° C. To this solution was added a solution of t-BuMgCl in THF (Aldrich 1 M, 7.32 L, 7.91 mol) at −25° C. over 3 hours. Then the above Grignard solution was added to this solution at −20 over 41 minutes. The resulting solution was further stirred at −20° C. before quench. The reaction mixture was added to 10 wt % aqueous NH₄Cl (10 L, 5×) at 0° C. with vigorous stirring, and stirred for 30 minutes at 0° C. To this mixture was added slowly 6 N HCl (4 L, 2×) at 0° C. to obtain a clear solution and stirred for 30 minutes at 10° C. After phase split, the organic layer was washed with 25 wt % aq NaCl (5 L, 2.5×). Then the organic layer was concentrated to a 3× solution under the conditions (200 mbar, bath temp 50° C.). EtOAc (24 L, 12×) was added, and evaporated to a 3× solution under the conditions (150 mbar, bath temp 50° C.). After removed solids by a polish filtration, EtOAc (4 L, 2×) was added and concentrated to dryness (150 mbar, bath temp 50° C.). The wet cake was then transferred to a 50 L reactor equipped with a mechanical stirrer, a temperature controller and a nitrogen inlet. After EtOAc was added, the suspension was heated at 70° C. to obtain a 2.5× homogeneous solution. To the resulting homogeneous solution was added slowly heptane (5 L, 2.5×) at the same temperature. A homogeneous solution was seeded and heptane (15 L, 7.5×) was added slowly to a little cloudy solution at 70° C. After stirred for 0.5 h at 70° C., the suspension was slowly cooled to 60° C. and stirred for 1 h at 60° C. The suspension was then slowly cool to room temperature and stirred for 14 h at the same temperature. The crystals were collected and washed with heptane (8 L, 4×), dried under vacuum at 45° C. to give the desired ketone as fluffy solids (2.57 kg, 100 wt % by HPLC, purity-adjusted yield: 81%).

6.6. Synthesis of (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate

To a solution of the ketone (4-chloro-3-(4-ethoxybenzyl)phenyl)((3aS,5R,6S,6aS)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)methanone (114.7 g, 0.265 mol) in MeOH (2 L, 17×) was added CeCl₃.7H₂O (118.5 g, 1.2 equiv) and the mixture was stirred at 20° C. until all solids were dissolved. The mixture was then cooled to −78° C. and NaBH₄ (12.03 g, 1.2 equiv) was added in portions so that the temperature of the reaction did not exceed −70° C. The mixture was stirred at −78° C. for 1 hour, slowly warmed to 0° C. and quenched with saturated aq NH₄Cl (550 mL, 5×). The mixture was concentrated under vacuum to remove MeOH and then extracted with EtOAc (1.1 L, 10× ×2) and washed with brine (550 mL, 5×). The combined organics were concentrated under vacuum to afford the desired alcohol as a colorless oil (crude, 115 g). To this colorless oil was added AcOH (650 mL) and H₂O (450 mL) and the mixture was heated to 100° C. and stirred for 15 hours. The mixture was then cooled to room temperature (20° C.) and concentrated under vacuum to give a yellow oil (crude, 118 g). To this crude oil was added pyridine (500 mL) and the mixture was cooled to 0° C. Then, Ac₂O (195 mL, ˜8.0 equiv) was added and the mixture was warmed to 20° C. and stirred at 20° C. for 2 h. The reaction was quenched with H₂O (500 mL) and diluted with EtOAc (1000 mL). The organic layer was separated and concentrated under vacuum to remove EtOAc and pyridine. The residue was diluted with EtOAc (1000 mL) and washed with aq NaHSO₄ (1N, 500 mL, ×2) and brine (300 mL). The organic layer was concentrated to afford the desired tetraacetate intermediate as a yellow foam (˜133 g). To a solution of tetraacetate (133 g, 0.237 mol assuming pure) and thiourea (36.1, 2.0 equiv) in dioxane (530 mL, 4×) was added trimethylsilyl trifluoromethanesulfonate (TMSOTf) (64.5 mL, 1.5 equiv) and the reaction mixture was heated to 80° C. for 3.5 hours. The mixture was cooled to 20° C. and MeI (37 mL, 2.5 equiv) and N,N-diisopropylethylamine (DiPEA) (207 mL, 5.0 equiv) was added and the mixture was stirred at 20° C. for 3 h. The mixture was then diluted with methyl tertiary-butyl ether (MTBE) (1. 3 L, 10×) and washed with H₂O (650 mL, 5× ×2). The organic layer was separated and concentrated under vacuum to give a yellow solid. To this yellow solid was added MeOH (650 mL, 5×) and the mixture was reslurried at 60° C. for 2 h and then cooled to 0C and stirred at 0° C. for 1 hour. The mixture was filtered and the cake was washed with MeOH (0° C., 70 mL, ×3). The cake was dried under vacuum at 45° C. overnight to afford the desired triacetate (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate (88 g, 60% over 4 steps) as a pale yellow solid. ¹H NMR (CDCl₃) 6 7.37 (d, J=8.0 Hz, 1H), 7.20 (dd, J=8.0, 2.0 Hz, 1H), 7.07 (m, 2H), 6.85 (m, 2H), 5.32 (t, J=9.6 Hz, 1H), 5.20 (t, J=9.6 Hz, 1H), 5.05 (t, J =9.6 Hz, 1H), 4.51 (d, J =9.6 Hz, 1H), 4.38 (d, J=9.6 Hz, 1h), 4.04 (m, 2H), 2.17 (s, 3H), 2. 11 (s, 3H), 2.02 (s, 3H), 1.73 (s, 3H), 1.42 (t, J=7.2 Hz, 3H).

6.7. Alternative synthesis of (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate

To a 50 L reactor under nitrogen atmosphere, 40 L MeOH was charged, followed with the ketone (2.50 kg, 5.78 mol) and CeCl₃.7H₂O (2.16 kg, 1.0 equiv). Methanol (7.5 L) was added as rinse (totally 47.5 L, 19×). A freshly prepared solution of NaBH₄ (87.5 g, 0.4 equiv) in aqueous 1 N NaOH (250 mL) was added slowly (35 min) at 15-25° C. The mixture was then stirred for 15 min. HPLC analysis of the reaction mixture showed approximately 90:10 diastereomeric ratio. The reaction was quenched with 10 wt % aq NH₄Cl (2.5 L, 1×) and the mixture was concentrated under vacuum to 5×, diluted with water (10 L, 4×) and MTBE (12.5 L, 5×). The mixture was cooled to 10° C. and 6 N aq HCl was added until the pH of the mixture reached 2.0. Stirring was continued for 10 minutes and the layers were separated. The organic layer was washed with H₂O (5L, 2×). The combined aqueous layer was extracted with MTBE (12.5 L, 5×). The combined organic layers were washed with brine (2.5 L, 1×) and concentrated under vacuum to 3×. MeCN (15 L, 6×) was added. The mixture was concentrated again to 10 L (4×) and any solid residue was removed by a polish filtration. The cake was washed with minimal amount of MeCN. The organic filtrate was transferred to 50 L reactor, and a pre-prepared 20 mol % aqueous H₂SO₄ solution (61.8 mL 98% concentrated H₂SO₄ and 5 L H₂O) was added. The mixture was heated to 80° C. for 2 hours and then cooled to 20° C. The reaction was quenched with a solution of saturated aqueous K₂CO₃ (5 L, 2×) and diluted with MTBE (15 L, 6×). The organic layer was separated, washed with brine (5 L, 2×) and concentrated under vacuum to 5 L (2×). MeCN (12.5 L, 5×) was added and the mixture was concentrated to 7.5 L (3×). The above MeCN solution of (3S,4R,5R,6S)-6-(4-chloro-3-(4-ethoxybenzyl)phenyl)tetrahydro-2H-pyran-2,3,4,5-tetraol was cooled to 10° C., added with dimethylaminopyridine (17.53 g, 2.5 mol %), followed by slow addition of acetic anhydride (3.23 L, 6.0 equiv) and triethylamine (5 L, 2×, 6.0 equiv) so that the temperature of the mixture was kept below 20° C. The reaction was then warmed to 20° C. and stirred for 1 hour and diluted with MTBE (15 L, 6×). The mixture was slowly quenched with water (7.5 L, 3×). The organic layer was separated and washed with saturated aqueous KHCO₃ (5L, 2×), 1 N NaHSO₄ (5 L, 2×), and brine (5 L, 2×) in sequence. The organic layer was then concentrated under vacuum to 5 L (2×). MeCN (12.5 L, 5×) was added and the solution was concentrated to 7.5 L (3×) (KF=0.08%). Dioxane (12.5 L, 5×) was added and the solution was concentrated to 7.50 L (3×) (KF=0.02%). Any residual solid was removed by a polish filtration and the cake was washed with minimal amount of dioxane (500 mL). To the above filtrate was added thiourea (880 g, 2.0 equiv) and TMSOTf (1.57 L, 1.5 equiv). The reaction mixture was heated to 80° C. for 3 hours (>97% conversion). The mixture was cooled to 20° C. and methyl iodide (541 mL, 1.5 equiv) and diethylisopropylamine (3.02 L, 3.0 equiv) were added and the mixture was stirred at 20° C. for 18 hours. An extra methyl iodide charge (90 mL, 0.25 equiv) was added and the mixture was stirred at 20° C. for 1 hours. The mixture was then diluted with MTBE (25 L, 10×) and washed with water (12.5 L, 5× ×2). The organic layer was separated and concentrated under vacuum to ˜5 L (2×). MeOH (12.5 L, 5×) was added and the mixture was concentrated to 5× to afford a slurry. The mixture was then heated at 60° C. for 1 hour and cooled to 0° C. and stirred at 0° C. for 1 hour. The mixture was filtered and the cake was washed with MeOH (0° C., 2.5 L, 1× ×2, 1.0 L, 0.4×). The cake was dried under vacuum at 45° C. overnight to afford the desired triacetate (1.49 kg, 47% over 4 steps) as a pale yellow/off-white solid.

6.8. Synthesis of (2S,3R,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol

To a slurry of (2S,3S,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triyl triacetate (90.0 g, 0. 164 mol) in MeOH (900 mL, 10×) was added NaOMe in MeOH (25 wt %, 18 mL, 0.2×) at 20° C. and the mixture was stirred at 20° C. for 2 hours until all solids disappeared. The mixture was then concentrated to 300 mL, added to H₂O (1 L) and stirred for 1 hour. The solid was filtered and washed with H₂O (100 mL, ×3) and the cake was dried under vacuum at 45° C. overnight to afford the desired methyl thiolate (67.0 g, 95%). ¹H NMR (CDCl₃) 6 7.38 (d, J=8.4 Hz, 1H), 7.22 (m, 2H), 7.11 (d, J=8.8 Hz, 2H), 6.83 (d, J=8.8 Hz, 2H), 4.35 (d, J=9.6 Hz, 1H), 4.15 (d, J=9.6 Hz, 1H), 4.10-3.95 (m, 3H), 3.64 (t, J=8.8 Hz, 1H), 3.50 (m, 2H), 2.73 (br s, 3H), 2.17 (s, 3H), 1.40 (t, J=7.2 Hz, 3H).

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SGLT inhibitors: a novel target for diabetes.

On the importance of synthetic organic chemistry in drug discovery: reflections on the discovery of antidiabetic agent ertugliflozin. Vincent Mascitti, Benjamin A. Thuma, Aaron C. Smith, Ralph P. Robinson, Thomas Brandt, Amit S. Kalgutkar, Tristan S. Maurer, Brian Samas, Raman Sharma, Med. Chem. Commun., 2013, 4, 101