EP 0 606 046 Al
`
`product containing residual acetic acid. The product is partitioned between ethyl acetate and water (pH =
`7.1), the organic phase is dried (MgSO,), and the solvent is concentrated and then triturated with ether to
`give N-hydroxy-2-[[4-methoxybenzenesulfony!](2-[4-morpholinojethyl)aminoJacetamide, m.p. 108-112°C.
`The starting material is prepared as follows:
`(500 mL),
`Ethyl 2-[[4-methoxybenzenesulfonyllaminolacetate (13.7 g, 50.0 mmol) is dissolved in ethanol
`followed by the addition of sodium spheres (2.5 g, 109.0 mmol). To this solution is added N-(2-chloroethyl)-
`morpholine hydrochloride (10.0 g, 53.7 mmol), the reaction is stirred at room temperature for 2 hours, and
`then refluxed for 1.5 hours. The reaction is partitioned between ethyl acetate and brine. The aqueous phase
`is extracted well with ethyl acetate, the combined organic layers are dried (MgSQ,), and the solvent is
`evaporated to give ethyl 2-[[4-methoxybenzenesulfony|](2-[4-morpholino]ethy|)amino]acetate.
`is ob-
`Example 23: N-Hydroxy-2-[[4-aminobenzenesulfonyl](isobutyl)aminolacetamide, m.p. 50-55°C,
`tained by hydrogenation of N-hydroxy-2-[[4-nitrobenzenesulfonyl](isobutyl)jaminojacetamide (see example
`17x), m.p. 128-130 °, using 10% palladium on carbon.
`The starting material
`is prepared according to example 16 by coupling isobutylamine and 4-nitroben-
`zenesulfonyl chloride in the first step thereof.
`127-
`Example
`24: N-Hydroxy-2-[[4-dimethylaminobenzenesulfonyl]|(isobutylhaminoJacetamide, m.p.
`129°C,
`is obtained by methylation of N-hydroxy-2-[[4-aminobenzenesulfonyl](isobutyl)amino]acetamide
`using the procedure from Synthesis p. 709, 1987.
`Example 25: Ethyl 2-[[4-hexyloxybenzenesulfonyl](isobutyl)aminojacetate (1.22 g, 3.05 mmol) is dis-
`solved in methanol (15 mL). To this solution is added hydroxylamine hydrochloride (0.43 g, 6.11 mmol),
`followed by the addition of sodium methoxide, freshly prepared from sodium (0.35 g, 15.3 mmol) dissolved
`in methanol (5 mL). The reaction is stirred for 36 hours at room temperature. The reaction is worked up by
`partitioning between dilute hydrochloric acid (pH=~3) and ethyl acetate. The aqueous phaseis extracted
`well with ethyl acetate, the combined organic layers are dried (Na2SQ,), and the solvent is evaporated. The
`product
`is crystallized from hexnae/ethyl acetate and collected by filtration to give N-hydroxy-2-[[4-
`hexyloxybenzenesulfonyl](isobutyl)amino]acetamide, m.p. 108-110°C.
`The starting material is prepared as follows:
`A solution of ethanethiol (15 mL) and methylene chloride (15 mL) is cooled to 0°C. Aluminum trichloride
`(9.62 g, 72.2 mmol) is added (the solution turns green), and the reaction is warmed to room temperature.
`Ethyl 2-[[4-methoxybenzenesulfonyl](isobutyl)aminojacetate (4.75 g, 14.44 mmol) is added in methylene
`chloride (5 mL), and the reactiom is stirred for 3.5 hours at room temperature. The reaction is then slowly
`quenched with water, and the crude reaction is partitioned between water and methylene chloride. The
`aqueous layer is extracted well with methylene chloride, the combined organic layers are dried (Na2SOx),
`and the solvent is evaporated. The product is purified by silica gel chromatography (25% to 50% ethyl
`acetate/hexane) to give ethyl 2-[[4-hydroxybenzenesulfony|](isobutyl)amino]acetate.
`Ethyl 2-[[4-hydroxybenzenesulfonyl](isobutyl)aminojacetate (1.0 g, 3.17 mmol) is dissolved in dimethyl-
`formamide (16 mL). Cesium carbonate (1.03 g, 3.17 mmol) is added, followed by 1-iodohexane (0.47 mL,
`3.17 mmol), and the reaction is stirred overnight at room temperature. The reaction is then partitioned
`between water and ethyl acetate,
`the aqueous layer is extracted well with ethyl acetate,
`the combined
`organic layers are dried (NazSO,), and the solvent
`is evaporated. The product is purified by silica gel
`chromatography (10% ethyl acetate/hexane) to give ethyl 2-[[4-hexyloxybenzenesulfonyl](isobutyljamino}-
`acetate.
`
`Example 26: The following compounds are prepared similarly to example 25:
`(a) N-Hydroxy-2-[[4-ethoxybenzenesulfonyl](isobutyl)aminoJacetamide,by using ethyl iodide in the cesium
`carbonate alkylation step, and carrying out the subsequent steps as described in example 25.
`by using
`(0) N-Hydroxy-2-[[4-butyloxybenzenesulfonyl|(isobutyljaminojacetamide, m.p. 125-127°C,
`iodobutane in the cesium carbonate alkylation step, and carrying out the subsequent steps as described
`in example 25.
`(c) N-Hydroxy-2-[[4-(3-methyl)butyloxybenzenesulfonyl|(isobutyl)aminojacetamide, m.p. 93-96 °C, by us-
`ing 1-iodo-3-methylbutane in the cesium carbonate alkylation step, and carrying out the subsequent
`steps as described in example 25.
`(d) N-Hydroxy-2-[[4-heptyloxybenzenesulfonyl](isobutyl)aminojacetamide, m.p. 120-123°C, by using 1-
`iodoheptane in the cesium carbonate alkylation step, and carrying out the subsequent steps as described
`in example 25.
`(e) N-Hydroxy-2-[[4-(cyclohexylmethoxy)benzenesulfonyl](isobutyljaminolacetamide, m.p. 75-80°C, by
`using cyclohexylmethyl bromide in the cesium carbonate alkylation step, and carrying out the subse-
`quent steps as described in example 25.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`28
`
`AQUESTIVE EXHIBIT 1004 page 0351
`AQUESTIVE EXHIBIT 1004
`page 0351
`
`

`

`EP 0 606 046 Al
`
`(f) N-Hydroxy-2-[[4-isopropyloxybenzenesulfonyl](isobutyljaminoJacetamide, m.p. 65-66°C, by using
`isopropyl bromide in the cesium carbonate alkylation step, and carrying out the subsequent steps as
`described in example 25.
`(g) N-Hydroxy-2-[[4-ethoxyethoxybenzenesulfonyl](isobutyl)aminoJacetamide, m.p. 111-114°C, by using
`2-bromoethyl ethyl ether in the cesium carbonate alkylation step, and carrying out the subsequent steps
`as described in example 25.
`Example 27:
`(a) N-(t-butyloxy)-2-[[4-methoxybenzenesulfonyl](benzyl)amino]-2-[(2-methyl-5-tetrazoly|)-
`methylljacetamide (0.77 g, 1.55 mmol) is dissolved in methylene chloride (2.0 mL) and ethanol (0.1 mL) ina
`glass sealed tube, and the reaction is cooled to 0°C. Hydrochloric acid gas (from a lecture bottle) is
`bubbled through the solution for 20 minutes, and then the tube is sealed at room temperature for 3 days.
`After that time, the solvent is removed, and the reaction is partitioned between ethyl acetate and saturated
`sodium bicarbonate. The organic phase is dried (NazSOx), and the solvent is evaporated. The product is
`purified by silica gel chromatography (2% methanol/methylene chloride) to give N-hydroxy-2-[[4-methox-
`ybenzenesulfonyl](benzyl)amino]-2-[(2-methyl-5-tetrazolyl)methyljacetamide, m.p. 72-75 °C.
`The starting material is prepared as follows:
`D-asparagine (13.2 g, 100.0 mmol) is dissolved in dioxane (75.0 mL) and water (125.0 mL), triethylamine
`(21.0 mL, 150.0 mmol)
`is added, and the solution is cooled to 0°C. To this solution is added 4-
`methoxybenzenesulfonyl chloride (22.7 g, 110.0 mmol) over 10 minutes. The reaction is warmed to room
`temperature and stirred for 3 days. The precipitate is then filtered off, the filtrate is acidified to pH =~4, and
`extracted well with ethyl acetate. A first crop of pure product precipitates from the ethyl acetate and is
`collected byfiltration. A second crop is obtained by evaporating off the ethyl acetate, and rinsing the solid
`obtained with water to remove inorganic salts. The two crops are combined to give N-[4-methoxyben-
`zenesulfonyl]-(D)-asparagine.
`N-[4-methoxybenzenesulfonyl]-(D)-asparagine (10.1 g, 33.3 mmol) is dissolved in dimethylformamide
`(167.0 mL). Cesium carbonate (5.43 g, 16.66 mmol) is added, followed by the addition of methyl iodide
`(2.22 mL, 33.3 mmol), and the reaction is stirred overnight. The reaction is then diluted with saturated
`ammonium chloride (866.0 mL), and extracted well with ethyl acetate. The combined organic extracts are
`washed with brine, dried (Na2SOz), and the solvent is evaporated. The crude productis recrystallized from
`toluene to provide N-[4-methoxybenzenesulfonyl]-(D)-asparagine methyl ester.
`To a suspension of N-[4-methoxybenzenesulfonyl]-(D)-asparagine methyl ester (8.54 g, 27.0 mmol) in
`methylene chloride (47.0 mL) is added pyridine (10.9 mL, 135.0 mmol). Para-toluenesulfony! chloride (10.3
`g, 54.0 mmol) is added, and the reaction mixture is allowed to stand without stirring at room temperature
`overnight. The next day, saturated sodium bicarbonate is added (125.0 mL), and the mixtureis stirred for 1
`hour. The mixture is then diluted with water and extracted well with ethyl acetate. The combined organic
`extracts are washed with brine, dried (NazSQ,), and the solvent
`is evaporated. The crude product
`is
`recrystallized from 20% tetrahydrofuran/methanol
`to provide methyl 2(R)-[[4-methoxybenzenesulfonyl]-
`amino]-4-cyano-propionate.
`is added
`To a suspension of sodium hydride (0.93 g, 23.2 mmol) in dimethylformamide (95.0 mL),
`methyl 2(R)-[[4-methoxybenzenesulfonyllamino]-4-cyano-propionate (6.92 g, 23.2 mmol)
`in dimethylfor-
`mamide (10.0 mL). After stirring at room temperature for 20 minutes, benzyl bromide (3.1 mL, 25.5 mmol) is
`added, and the reaction is stirred overnight at room temperature. The reaction is then partitioned between
`ethyl acetate and acidic water (epH=~5), the organic layer is dried (NazSO,), and the solvent is evaporated.
`The product is purified by silica gel chromatography (40% ethyl acetate/hexane) to give methyl 2(R)-[[4-
`methoxybenzenesulfonyl](benzyl)amino]-4-cyano-propionate.
`To a solution of methyl 2(R)-[[4-methoxybenzenesulfonyl](benzyl)amino]-4-cyano-propionate (1.34 g,
`3.47 mmol) in dimethylformamide (5.4 mL) is added triethylamine hydrochloride (0.95 g. 6.93 mmol) and
`sodium azide (0.45 g, 6.93 mmol). The reaction is stirred at 110°C overnight. The next day, the solventis
`evaporated,
`the residue is acidified with 1N hydrochloric acid (16.0 mL), and extracted well with ethy!
`acetate. The combined organic extracts are washed with brine, dried (Na2SQ.), and the solvent
`is
`evaporated to yield methyl 2(R)-[[4-methoxybenzenesulfonyl](benzy|)amino]-2-[(5-tetrazolyl)methylJacetate.
`This crude tetrazole is dissolved in dimethylformamide (17.4 mL). Cesium carbonate (0.56 g, 1.73
`mmol) is added, followed by the addition of methyl iodide (0.23 mL, 3.47 mmol), and the reaction is stirred
`overnight. The reaction is then diluted with brine and extracted well with ethyl acetate. The combined
`organic extracts are washed with brine, dried (Na2SO.), and the solvent
`is evaporated. The product
`is
`purified by silica gel chromatography (40% ethyl acetate/hexane) to give separately the two regioisomers:
`methyl 2(R)-[[4-methoxybenzenesulfonyl](benzyl)amino]-2-[(1-methyl-5-tetrazolyl)methyllacetate
`(0.50 gg):
`and methyl 2(R)-[[4-methoxybenzenesulfonyl](benzyl)amino]-2-[(2-methy|-5-tetrazolyl)methylacetate.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`30
`
`AQUESTIVE EXHIBIT 1004 page 0352
`AQUESTIVE EXHIBIT 1004
`page 0352
`
`

`

`EP 0 606 046 Al
`
`Methy! 2(R)-[[4-methoxybenzenesulfonyl](benzyl)amino]-2-[(2-methyl-5 -tetrazolyl)methyllacetate (1.0 g,
`2.27 mmol) is dissolved in tetrahydrofuran (11.3 mL) and water (11.3 mL). To this solution is added lithium
`hydroxide hydrate (0.095 g, 2.27 mmol), and the reaction is stirred at room temperature for 2 hours. The
`reaction is then acidified to pH=~3 using 1N hydrochloric acid, and extracted well with ethyl acetate. The
`combined organic extracts are washed with brine, dried (Na2SO.), and the solvent is evaporated to provide
`2(R)-[[4-methoxybenzenesulfonyl](benzyl)amino]-2-[(2-methyl-5-tetrazolyl)methyllacetic acid (0.96 g).
`g,
`2(R)-[[4-methoxybenzenesulfonyl](benzyl)amino]-2-[(2-methyl-5-tetrazolyl)methyllacetic
`acid
`(0.96
`2.24 mmol), 1-hydroxybenzotriazole (0.30 g, 2.24 mmol), 4-methylmorpholine (0.86 mL, 7.89 mmol), and O-
`t-butylhydroxylamine hydrochloride (0.30 g, 2.24 mmol) are dissolved in methylene chloride (75.0 mL). N-
`[dimethylaminopropyl]-N’-ethylcarbodiimide hydrochloride (0.86 g, 4.48 mmol) is added, and the reaction is
`stirred overnight. The reaction is then diluted with water and extracted with methylene chloride. The
`combined organic extracts are washed with brine, dried (NazSQx.), and the solvent is evaporated. The crude
`product is purified by silica gel chromatography (50% ethyl acetate/hexane) to give N-(t-butyloxy)-2-[[4-
`methoxybenzenesulfonyl |(benzyl)amino]-2-[(2-methyl-5-tetrazolyl)methyllacetamide.
`(o) Similarly prepared is
`the other tetrazole regioisomer, N-hydroxy-2-[[4-methoxybenzenesulfonyl]}-
`(benzyl)amino]-2-[(1-methy!-5-tetrazolyl)methyljacetamide, m.p. 92-96 °C, by completing the synthesis as
`described above.
`
`(c) Similarly prepared is N-hydroxy-2-[[4-methoxybenzenesulfonyl](benzyl)amino]-2-[(5-tetrazolyl)methyl]-
`acetamide, m.p. 91-94°C, by completing the synthesis as described above, excepttrityl chloride is used
`to protect the tetrazole ring in place of methyl iodide.
`(d)
`Similarly
`prepared
`is N-hydroxy-2-[[4-methoxybenzenesulfonyl](4-phenylbenzyl)amino]-2-[(5-
`tetrazolyl)methyljacetamide, m.p. 184°C, by completing the synthesis as described above, except 4-
`chloromethylbiphenyl is used in place of benzyl bromide in the alkylation step.
`Example 28: Oxalyl chloride (106 mL, 1.22 mol) is added over 1 hour to dimethylformamide (92 mL) in
`methylene chloride (1250 mL) at 0°C. To this is added a solution of 2(R)-[[4-methoxybenzenesulfonyl](3-
`picolyl)amino]-3-methylbutanoic acid hydrochloride (248 g, 0.6 mol) in dimethylformamide (450 mL) over 1
`hour, maintaining the temperature at 0°C. This solution is stirred an additional 2 hours at room temperature,
`and then added dropwise to a mixture of hydroxylamine (460 g of a 50% aqueous solution, 6.62 mol) in
`tetrahydrofuran (2400 mL). The reaction is stirred an additional 3 hours at 5°C, and then at
`room
`temperature overnight. The reaction mixture is filtered, the organic layer is collected, and the solvent is
`evaporated. The crude product is re-dissolved in methylene chloride (2 L), washed with water (2 X 1 L),
`saturated sodium bicarbonate (4 X 1 L), brine (1 L), dried (NazSO.), and the solvent is evaporated. The
`productis dissolved in ethyl acetate (700 mL) and diluted with ether (1400 mL) to induce precipitation. The
`pure product
`is collected by filtration to provide N-hydroxy-2(R)-[[4-methoxybenzenesulfony!](3-picoly])-
`amino}|-3-methyloutanamide. After conversion to the hydrochloride salt, a white solid is obtained, m.p. 169-
`170°C (dec).
`The starting material is prepared as follows:
`To a solution of D-valine (2000 g, 17.09 mol) in water (16.9 L) and acetone (9.5 L), cooled to 5°C, is added
`triethylamine (4769 mL, 34.22 mol), and the reaction is stirred for 30 minutes. Then a solution of 4-
`methoxybenzenesulfonyl chloride (3524 g, 18.48 mol) in acetone (7.4 L) is added over 30 minutes, and the
`reaction is stirred at room temperature overnight. Most of the acetone is evaporated off, and the pH is
`adjusted to pH = 8.25 with 6N sodium hydroxide. The crude product is washed with toluene (2 X 10 L), and
`then the pH is re-adjusted to pH=2.2 with 6N hydrochloric acid. The mixture is then extracted with
`methylene chloride (3 X 12 L), the combined organic layers are washed with 2N hydrochloric acid, water,
`dried (NazSO,), and the solvent is evaporated to provide N-[4-methoxybenzenesulfony|]-(D)-valine.
`To a solution of N-[4-methoxybenzenesulfonyl]-(D)-valine (8369 g, 29.13 mol) in methanol (30 L) at 5°C
`is added thionyl chloride (2176 mL, 29.7 mol) over 2.5 hours. After stirring for 3 hours at 5°C, the reaction
`is stirred for 36 hours at room temperature. Most of the solvent is evaporated, and the crude product is
`dissolved in toluene (80 L). The toluene layer
`is then washed with water
`(20 L), saturated sodium
`bicarbonate (20 L), water again (20 L), 2N hydrochloric acid (20 L), brine (20 L), dried (NazSO,), and the
`solvent is evaporated. The solid obtained is dissolved in ethyl acetate (8 L) and heptane (16 L) is added to
`induce crystallization. The precipitated product is collected by filtration to provide methyl 2(R)-[[4-methox-
`ybenzenesulfonylJamino]-3-methylbutanoate.
`To a solution of methyl 2(R)-[[4-methoxybenzenesulfonyl]jamino]-3-methylbutanoate (1662 g, 5.52 mol)
`in dimethylformamide (10.9 L)
`is added 3-picolyl chloride hydrochloride (947.3 g, 5.77 mol) followed by
`powdered potassium carbonate (2409.9 g, 17.36 mol). The reaction mixture is stirred at room temperature
`for 2 days. At
`that time, additional quantities of 3-picolyl chloride hydrochloride (95 g) and powdered
`potassium carbonate (241 g) are added, and the reaction is stirred for 3 more days. The solids are then
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`3
`
`AQUESTIVE EXHIBIT 1004 page 0353
`AQUESTIVE EXHIBIT 1004
`page 0353
`
`

`

`EP 0 606 046 Al
`
`is poured into water (22 L), and the pH is adjusted to pH=8 with 6N
`the crude product
`filtered away,
`sodium hydroxide. This solution is extracted well with toluene (4 X 10 L), the combined organic layers are
`washed with water (2 X 12 L), and then with 6N hydrochloric acid (3 X 1600 mL). This aqueous layer is then
`re-adjusted to pH=8 with 6N sodium hydroxide, extracted with toluene (4 X 10 L), dried (Na2SQOxz), and the
`solvent is evaporated. The oil obtained is re-dissolved in ethyl acetate (12 L), cooled to 5°C, and to this is
`added methanolic HCl (834 mL). After stirring for 2 hours, the precipitated product is collected byfiltration
`to give methyl 2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)amino]-3-methyloutanoate hydrochloride.
`Methyl 2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)amino]-3-methylbutanoate hydrochloride (7164 g,
`16.7 mol) is added to a solution of water (27 L) and concentrated hydrochloric acid (9 L), and heated to
`120°C for 3 days. After cooling down to room temperature, charcoal (350 g) is added, stirring is continued
`for 45 minutes, the reaction is filtered, and the solvent is evaporated. The crude solid is re-dissolved in
`methanol
`(7.1 L) and ethyl acetate (73 L), and cooled to 3°C for 2 hours. The precipitated product
`is
`collected byfiltration to give 2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)amino]-3-methyloutanoic acid hy-
`drochloride.
`
`Example 29: N-Benzyloxy-2(R)-[[4-methoxybenzenesulfonyl](3-picolyljamino]-3-methyloutanamide (see
`example 29a) is reacted with hydrogen in the presence of 10% palladium on charcoal catalyst at room
`temperature and atmospheric pressure to yield N-hydroxy-2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)-
`amino]-3-methyloutanamide. After conversion to the hydrochloride salt, a white solid is obtained, m.p. 169-
`170°C (dec).
`(a) The N-(benzyloxy) substituted prodrug derivative of the above compound is prepared as follows:
`2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)amino]-3-methylbutanoic acid hydrochloride is reacted with
`O-benzylhydroxylamine hydrochloride under conditions described for
`reaction with O-t-butylhydrox-
`ylamine hydrochloride to yield N-(benzyloxy)-2(R)-[[4-methoxybenzenesulfony!](3-picolyl)amino]-3-meth-
`yl-butanamide, m.p. 74.5-76° C.
`(b) The corresponding N-(4-methoxybenzyloxy) substituted prodrug derivative, N-(4-methoxybenzyloxy)-
`2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)amino]-3-methyl-butanamide, is prepared as follows:
`g, 5.82
`2(R)-[[4-methoxybenzenesulfony!](3-picolyl)amino}-3-methylbutanoic acid hydrochloride (2.41
`mmol), 1-hydroxybenzotriazole (0.786 g, 5.82 mmol), 4-methyl-morpholine (1.9 mL, 17.46 mmol), and O-
`(4-methoxybenzyl)hydroxylamine (1.78 g, 11.63 mmol) (prepared according to Pol. J. Chem. 55, 1163-
`1167 (1981)) are dissolved in methylene chloride (55 mL). N-[dimethylaminopropyl]-N'-ethylcarbodiimide
`hydrochloride (1.45 g, 7.57 mmol) is added, and the reaction is stirred overnight. The reaction is then
`diluted with water and extracted with methylene chloride. The combined organic extracts are washed
`with brine, dried (NazSO.), and the solvent is evaporated. The crude product is purified by silica gel
`chromatography (ethyl acetate followed by 5% methanol/ethyl acetate) to give N-(4-methoxybenzyloxy)-
`2(R)-[[4-methoxybenzenesulfonyl](3-picoly|)amino]-3-methylbutanamide, m.p. 45-53 °C.
`Similarly prepared are:
`(c) the N-(2,4-dimethoxybenzyloxy)-substituted prodrug derivative, N-(2,4-
`dimethoxybenzyloxy)-2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)amino]-3-methyl-butanamide, m.p. 45-
`60°C;
`(d) the N-(2-methoxybenzyloxy)-substituted prodrug derivative, N-(2-methoxybenzyloxy)-2(R)-[[4-methox-
`ybenzenesulfonyl](3-picolyl)amino]-3-methyl-butanamide m.p. 46-56 °C.
`Example
`30:
`N-(t-Butyloxy)-2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)jamino]-3(R)-(3-picolyloxy)-
`butanamide (1.3 g, 2.4 mmol) is dissolved in methylene chloride (50 mL) containing ethanol (0.14 mL, 2.4
`mmol) in a round bottom flask, and the reaction is cooled to -10°C. Hydrochloric acid gas (from a lecture
`bottle)
`is bubbled through for 20 minutes. The reaction is sealed, allowed to slowly warm to room
`temperature, and stirred for two days. The solvent is reduced to 1/3 the volume by evaporation and the
`residue is triturated with ether. The mixture is filtered,
`the fiter cake is removed and dried in vacuo to
`provide
`N-hydroxy-2(R)-[[4-methoxybenzenesulfonyl](3-picolyl)amino]-3(R)-(3-picolyloxy)-butanamide
`dihydrochloride as a white solid; [a]Jp® = +35.26° (c=5.58, DMSO).
`The starting material is prepared as follows:
`(50 mL) and dioxane (50 mL) containing
`in water
`To a solution of D-threonine (5.0 g, 0.042 mol)
`triethylamine(8.9 mL, 0.063 mol) at room temperature is added 4-methoxybenzenesulfonyl chloride (9.54 g,
`0.046 mol). The reaction mixture is stirred overnight at room temperature. Most of the dioxane is evaporated
`off, and the pH is adjusted to pH=2 with 1N HCl. The mixture is then extracted with ethyl acetate. The
`combined organic extracts are washed with brine, dried (Na2SO«), and concentrated in vacuo to provide N-
`[4-methoxybenzenesulfonyl]-(D)-threonine.
`N-[4-methoxybenzenesulfonyl]-(D)-threonine (4.0 g, 13.84 mmol), 1-hydroxybenzotriazole (1.87 g, 13.84
`mmol), 4-methylmorpholine (7.9 mL, 69.2 mmol), and O-t-butylhydroxylamine hydrochloride (5.22 g, 41.52
`mmol) are dissolved in methylene chloride (100 mL). To this solution is added N-[dimethylaminopropyl]-N'-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`32
`
`AQUESTIVE EXHIBIT 1004 page 0354
`AQUESTIVE EXHIBIT 1004
`page 0354
`
`

`

`EP 0 606 046 Al
`
`ethylcarbodiimide hydrochloride (3.45 g, 17.99 mmol), and the reaction is stirred overnight. The mixture is
`then diluted with water and extracted with methylene chloride. The combined organic extracts are washed
`with brine, dried (NazSO.), and concentrated in vacuo. The crude product
`is purified by silica gel
`chromatography (ethyl acetate) to give N-(t-butyloxy)-2(R)-[[4-methoxybenzenesulfonyl]-amino]-3(R)-hydrox-
`ybutanamide.
`To a solution of N-(t-butyloxy)-2(R)-[[4-methoxybenzenesulfonyljamino]-3(R)-hydroxybutanamide (3.04
`g, 8.44 mmol) in dimethylformamide (150 mL) is added 3-picolyl chloride hydrochloride (1.45 g, 8.87 mmol)
`followed by potassium carbonate (11.65 g, 84.4 mmol). The reaction mixture is stirred at room temperature
`overnight, then heated to 45°C for 5 hours. An additional amount of 3-picolyl chloride hydrochloride (692.0
`mg, 4.23 mmol) is added at this point. The reaction mixture is stirred at 45°C for 10 hours. The reaction
`mixture is diluted with water and extracted with ethyl acetate. The combined organic extracts were washed
`with brine, dried (NazSO.), and concentrated in vacuo. The crude product
`is purified by silica gel
`chromatography (ethyl acetate,
`then 5% methanol/methylene chloride)
`to give N-(t-butyloxy)-2(R)-[[4-
`methoxybenzenesulfonyl](3-picolyljamino]-3(R)-(3-picolyloxy)butanamide.
`Example 31:
`(a) N-(t-Butyloxy)-2(R)-[[4-methoxybenzenesulfonyl](4-picolyljamino]cyclohexylacetamide
`(1.9 g, 3.9 mmol) is dissolved in dichloroethane (50 mL) containing ethanol (0.21 mi, 3.9 mmol) in a round
`bottom flask, and the reaction is cooled to -10°C. Hydrochloric acid gas (from a lecture bottle) is bubbled
`through for 30 minutes. The reaction is sealed, allowed to slowly warm to room temperature, and stirred for
`4 days. The solvent
`is reduced to 1/3 volume by evaporation and triturated with ether. Tne mixture is
`filtered, filter cake removed, and dried in vacuo to provide N-hydroxy-2(R)-[[4-methoxybenzenesulfonyl](4-
`picolyl)amino]-2-cyclohexylacetamide hydrochloride as a white solid, m.p. 154.5-156 °C.
`The starting material is prepared as follows:
`To a solution of D-cyclohexyiglycine hydrochloride (10.4 g, 53.7 mmol) in 1:1 dioxane/water (200 mL)
`containing triethylamine (37.0 g, 366.0 mmol) at room temperature is added 4-methoxybenzenesulfonyl
`chloride (15.0 g, 73.0 mmol), and the reaction mixture is stirred at room temperature overnight. The mixture
`is then diluted with methylene chloride, washed with 1N aqueous hydrochloric acid and water. The organic
`layer
`is washed again with brine, dried (NazSOQ.), and the solvent
`is evaporated to provide N-[4-
`methoxybenzenesulfonyl]-(D)-cyclohexylglycine as a crude product. A solution of this crude product
`in
`toluene (200 mL) containing N,N-dimethylformamide di-t-butyl acetal (48.5 mL, 200.0 mmol) is heated to
`95°C for 3 hours. The solvent is then evaporated. The crude product is purified by silica gel chromatog-
`raphy (30% ethyl acetate/hexanes) to provide N-[4-methoxybenzenesulfonyl](D)-cyclohexylglycine t-butyl
`ester.
`
`To a solution of N-[4-methoxybenzenesulfonyl]-(D)-cyclohexylglycine t-butyl ester (2.0 g, 4.1 mmol) in
`dimethylformamide (100 mL)
`is added 4-picolyl chloride hydrochloride (0.74 g, 4.5 mmol) followed by
`potassium carbonate (5.61 g, 40.7 mmol). The reaction mixture is stirred at room temperature for 4 days.
`The mixture is then diluted with water and extracted with ethyl acetate. The combined organic extracts are
`washed with brine, dried (NazSO,), and the solvent is evaporated. The crude product is purified by silica
`gel chromatography (ethyl acetate)
`to give t-butyl 2(R)-[[4-methoxybenzenesulfonyl](4-picolyljamino]-2-
`cyclohexylacetate.
`t-Butyl 2(R)-[[4-methoxybenzenesulfonyl](4-picolyl)amino]-cyclohexyla cetate (2.0 g, 4.2 mmol) is dis-
`solved in methylene chloride (80 mL) and cooled to -10°C. Hydrochloric acid gas is bubbled into the
`solution for 10 minuntes. The reaction mixture is then sealed, warmed to room temperature and stirred
`overnight. The solvent is then evaporated to provide 2(R)-[[4-methoxybenzenesulfonyl](4-picolyljamino]}-2-
`cyclohexylacetic acid hydrochloride.
`4.2
`(1.8g,
`hydrochloride
`acid
`2(R)-[[4-Methoxybenzenesulfonyl](4-picolyl)amino}]-cyclohexylacetic
`mmol), 1-hydroxybenzotriazole (0.65 g, 4.81 mmol), 4-methyl-morpholine (2.4 mL, 24.04 mmol), and O-t-
`butylhydroxylamine hydrochloride (1.81 g, 14.4 mmol) are dissolved in methylene chloride (100 mL). N-
`[dimethylaminopropyl]-N’-ethylcarbodiimide hydrochloride (1.2 g, 6.25 mmol) is added, and the reaction is
`stirred overnight. The reaction is then diluted with water and extracted with methylene chloride. The
`combined organic extracts are washed with brine, dried (Na2SO,), and the solvent is evaporated. The crude
`product is purified by silica gel chromatography (65% methanol/methylene chloride) to give N-(t-butyloxy)-2-
`(R)-[[4-methoxybenzenesulfonyl](4-picolyl)jamino]-2-cyclohexylacetamide.
`(6)
`Similarly
`prepared
`is N-hydroxy-2(R)-[[4-methoxybenzenesulfonyl](2-(2-pyridyl)ethyljamino}]-2-
`cyclohexylacetamide, m.p. 131.5-134.0°C.
`The first
`two steps are carried out as described above. A Mitsunobu step is substituted for the
`alkylation step as described below.
`To a stirring solution of N-[4-methoxybenzenesulfonyl]-(D)-cyclohexylglycine-t-butyl ester (2.0 g, 5.25
`mmol) in tetrahydrofuran (50 mL) is added triphenylphosphine (4.13 g, 15.75 mmol) and 2-(2-hydrox-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`33
`
`AQUESTIVE EXHIBIT 1004 page 0355
`AQUESTIVE EXHIBIT 1004
`page 0355
`
`

`

`EP 0 606 046 Al
`
`yethyl)-pyridine (646.0 mg, 5.25 mmol) followed by diethyl azodicarboxylate (2.28 g, 13.1 mmol). The
`reaction mixture is stirred at room temperature for 48 hours. The mixture is concentrated directly in
`vacuo. The crude mixture is applied to a column of silica gel (80% ethylacetate/hexane) to provide t-
`butyl 2(R)-[N-[4-methoxybenzenesulfonyl](2-(2-pyridyljethyl)amino]- 2-cyclohexylacetate.
`All of the subsequent steps are carried out as described under (a).
`Similarly
`prepared
`is N-hydroxy-2(R)-[[4-methoxybenzenesulfonyl](3-(3-pyridyl)propyl)amino]-2-
`(c)
`cyclohexylacetamide, m.p. 136.0-138°C, by using 3-pyridinepropanol
`in the Mitsunobu step, and
`carrying out the subsequent steps as described above.
`(d) Similarly prepared is N-hydroxy-2(R)-[[4-methoxybenzenesulfonyl](2-methylpyrid-5-ylmethyl)amino]-2-
`cyclohexylacetamide, m.p. 156.5-157.0°C, by using 6-methyl-3-pyridinemethanol (prepared as in J. Org.
`Chem. 53 3513 (1988)) in the Mitsunobu step, and carrying out the subsequent steps as described
`above.
`
`(e) Similarly prepared is N-hydroxy-2(R)-[[4-methoxybenzenesulfonyl](4-tetrahydropyranmethyl)amino]-2-
`cyclohexylacetamide, m.p. 75.0-87.0°C, by using 4-(hydroxymethyl)tetrahydropyran (prepared as in
`Okrytiya. Izobret. 82 (1985)) in the Mitsunoba step, and carrying out the subsequent steps as described
`above.
`
`Example 32: N-(t-Butyloxy)-2(R)-[(4-methoxybenzenesulfonyl)(benzyl)amino]-2-(4-N-methylpiperidiny|)-
`acetamide (733.0 mg, 1.46 mmol) is dissolved in methylene chloride (60 mL) containing ethanol (67.0 mg,
`146 mmol), and the reaction is cooled to -10°C. Hydrochloric acid gas (from a lecture bottle) is bubbled
`through for 15 minutes. The reaction is sealed, allowed to slowly warm to room temperature, and stirred for
`6 days. The solvent
`is reduced to 1/3 volume by evaporation and triturated with ether. The mixture is
`filtered, filter cake removed, and dried in vacuo to provide N-hydroxy-2(R)-[(4-methoxybenzenesulfonyl)-
`(benzyl)amino]-2-(4-N-methylpiperidinyl)acetamide hydrochloride as a light tan solid, m.p. >160°C (dec).
`The starting material is prepared as follows:
`To a solution of ethyl 4-pyridylacetate (11.17 g, 67.62 mmol) in 2N hydrochloric acid (100 mL) is added
`platinum (IV) oxide (275 mg). The mixture is shaken in a Parr hydrogenation apparatus for 60 hours under a
`hydrogen pressure of 50 psi (= 3.45 bar). The reaction mixture is basified to pH 8-9 with saturated aqueous
`sodium carbonate and then washed with methylene chloride. The aqueous layer is concentrated in vacuo
`providing sodium 4-piperidyl acetate as a white solid. To a solution of the crude product (5.0 g, 30.3 mmol)
`in 3:1 water/dioxane (200 mL) at 0°C is added a solution of di-tert-butyldicarbonate (6.38 g, 29.3 mmol) in
`dioxane (25 mL) in one portion. The cloudy reaction mixture is warmed to room temperature and stirred
`overnight. The mixture is then filtered, cooled to 0°C and acidified with cold 6N hydrochloric acid (pH = 2-
`3).This solution is extracted with ethy! acetate. The combined organic layers are dried (NazSOx), and the
`solvent is evaporated to provide N-t-BOC-piperidine-4-acetic acid as a white crystalline solid.
`To a solution of N-t-BOC-piperidine-4-acetic acid (4.67 g, 19.22 mmol) in tetrahydrofuran at -78°C is
`added triethylamine (2.53 g, 24.99 mmol) followed by pivaloyl chloride (2.55 g, 21.14 mmol). The resulting
`white slurry is stirred at -78°C for 15 minutes, warmed to 0°C for 45 minutes, then recooled to -78°C. Ina
`separate flask, (R)-(+)-4-benzyl-2-oxazolidinone (4.09 g, 23.1 mmol) is dissolved in tetrahydrofuran (50 mL)
`and 1M n-butyl
`lithium in hexanes (14.4 mL, 23.06 mmol) is added dropwise at -78°C. The solution is
`added via cannula to the aforementioned white slurry at -78°C. The reaction mixture is stirred at -78°C for
`15 minutes, then warmed to room temperature over 2.5 hours. The mixture is quenched with saturated
`aqueous sodium carbonate and the tetrahydrofuran is evaporated in vacuo. The remaining aqueous layeris
`diluted with water and extracted with ethyl acetate. The combined organic extracts are washed with brine,
`dried (NazSO,), and the solvent
`is evaporated under vacuum. The product
`is purified by silica gel
`chromatography (75% to 50% hexane/ethyl acetate) to give 3-[2-(N-t-BOC-4-piperidinyl)-1-oxoethyl]-4(R)-
`(benzyl)-2-oxazolidinone.
`To a solution of 3-[2-(N-t-BOC-4-piperidinyl)-1-oxoethyl]-4(R)-(benzyl)-2-oxazolidinone (7.54 g, 18.76
`mmol) in tetrahydrofuran (175 mL) at -78°C is added a 0.5 M solution of potassium bis (trimethylsilylamide
`in toluene (37.5 mL, 18.76 mmol) dropwise. After stirring for 20 minutes at -78°C, a pre-cooled solution of
`trisylazide (7.25 g, 23.4 mmol) in tetrahydrofuran (565 mL) is added via cannula at -78°C. The mixture is
`stirred for 15 minutes at -78°C, then acetic acid 3.38 g, 56.28 mmol) is added followed by immediate
`warming to room temperature through immersion in a water bath. The reaction mixture is stirred for 1.5
`hours at room temperature. The tetrahydrofuran is removed under vacuum and the resulting residue is
`partitioned