合成路线1

The condensation of (S)-1-(4-bromophenyl)-1-phenylmethylamine (S)-(I) with phenylboronic acid (II) by means of Pd(OAc)2, PPh3 and Na2CO3 in propanol/water gives the corresponding biphenyl derivative (S)-(III), which is condensed with 3-bromopropanal dimethylacetal (IV) by means of K2CO3 in DMF yielding the secondary amine (S)-(V). The reaction of (S)-(V) with refluxing butyl formate (VI) affords the formamide (S)-(VII), which is cyclized with ammonium acetate in acetic acid to furnish the (S)-enantiomer of the target compound. The corresponding (R)-enantiomer has been obtained by the same reaction sequence but starting from (R)-1-(4-bromophenyl)-1-phenylmethylamine (R)-(I).

合成路线2

The reaction of 2-amino-3-hydroxy benzoic acid methyl ester (I) with 2-benzyloxybenzoyl chloride (II) by means of pyridine in benzene gives the corresponding amide (III), which is cyclized by heating at 230 C yielding 2-(benzyloxyphenyl)benzoxazole-4-carboxylic acid methyl ester (IV). The hydrolysis of (IV) by means of NaOH in THF/water affords the correponding free acid (V), which is condensed with 2-amino-3-hydroxybenzoic acid methyl ester (I) by means of oxalyl chloride to give the expected amide (VI). Finally, this compound is cyclized by means of p-toluenesulfonic acid in refluxing toluene.

合成路线3

The oxidation of N-(benzyloxycarbonyl)-L-phenylalaninol (I) with oxalyl chloride in DMSO gives the corresponding aldehyde (II), which by dimerization with Zn dust in dichloromethane yields (2S,3R,4R,5S)-2,5-bis(benzyloxycarbonylamino)-1,6-diphenylhexane-3,4-diol (III) [along with the (2S,3S,4S,5S)-isomer]. The reaction of (III) with alpha-acetoxyisobutyryl bromide (IV) in hexane/dichloromethane affords (2S,3R,4R,5S)-2,5-bis(benzyloxycarbonylamino)-4-bromo-1,6-diphenylhexan-3-ol acetate ester (V), which is converted into the corresponding epoxide (VI) with NaOH in dioxane/water. The reduction of the epoxide (VI) with NaBH4 in THF affords (2S,3S,5S)-2,5-bis(benzyloxycarbonylamino)-1,6-diphenylhexan-3-ol (VII), which is deprotected with Ba(OH)2 in refluxing dioxane/water yielding the corresponding diamine (VIII). The cyclization of (VIII) with phenylboronic acid (IX) in refluxing toluene gives (4S,6S)-6-[1(S)-amino-2-phenylethyl]-4-benzyl-2-phenyl-1,3,2-oxaazaborinane (X), which is condensed with (5-thiazolylmethyl)(4-nitrophenyl)carbonate (XI) in THF to afford (2S,3S,5S)-5-amino-1,6-diphenyl-2-(5-thiazolylmethoxycarbonylamino) hexan-3-ol (XII). Finally, this compound is condensed with N-[N-(2-isopropylthiazol-4-ylmethyl)-N-methylaminocarbonyl]-L-valine (XIII) by means of 1-hydroxybenzotriazole (HBT) and N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide (DEC) in THF.

合成路线4

6) The reaction of 4-bromothioanisole (XIV) with furan-2(5H)-one (XV) by means of tert-BuLi/CuI in ethyl ether, followed by silylation with trimethylsilyl chloride gives 4-[4-(methylsulfanyl)phenyl]-2-(trimethylsilyloxy)-3,4-dihydrofuran (XVI), which is desilylated with palladium acetate in acetonitrile to afford the furanone (XVII). The iodination of (XVII) with I2 in pyridine yields 3-iodo-4-[4-(methylsulfanyl)phenyl]furan-2(5H)-one (XVIII), which is condensed with phenylboronic acid (XIX) by means of triphenylarsine and a Pd catalyst in refluxing benzene, giving 4-[4-(methylsulfanyl)phenyl]-3-phenylfuran-2(5H)-one (VIII), already described in Scheme 1. Finally, this compound is oxidized with monoperoxyphthalic acid magnesium salt in dichloromethane/methanol.

合成路线5

The reaction of 3-phenacyl-4,5,6,7-tetrahydro-3H-imidazo[4,5-c]pyridine-6(S)-carboxylic acid methyl ester (I) with 2,2-diphenylacetic acid (II) gives 5-(2,2-diphenylacetyl)-3-phenacyl-4,5,6,7-tetrahydro-3H-imidazo[4,5-c]pyridine-6(S)-carboxylic acid methyl ester (III), which is condensed with 3,5-dibromobenzyl bromide (IV) in acetic acid yielding the corresponding 1-(3,5-dibromobenzyl) derivative (V). The hydrolysis of the ester group of (V) with NaOH affords the expected free acid (VI), which is condensed with L-proline tert-butyl ester (VII) giving the corresponding N-substituted L-proline ester (VIII). Finall this compound is coupled with phenylboronic acid (IX), catalized with palladium tetrakis(triphenylphosphine) complex.

合成路线6

The acylation of 4-benzyloxyaniline (I) with trifluoroacetyl chloride and triethylamine in dichloromethane gives the corresponding amide (II), which is treated with resin-supported triphenylphosphine and CCl4 to yield the iminochloride (III). The cyclization of (III) with sodium azide in hot acetic acid affords the tetrazole (IV), which is debenzylated with H2 over Pd/C in ethanol/THF, giving the phenol (V). The reaction of (V) with hexamethylenetetramine (HMT) in hot trifluoroacetic acid yields the benzaldehyde (VI), which by methylation with methyl iodide/K2CO3 in acetone affords 2-methoxy-5-[5-(trifluoromethyl)tetrazol-1-yl]benzaldehyde (VII). Finally, this compound is reductocondensed with (2S,3S)-2-phenylpiperidin-3-amine (VIII) by means of sodium triacetoxyborohydride/acetic acid in dichloromethane. The chiral (2S,3S)-2-phenylpiperidin-3-amine (VIII) has been obtained as follows: The condensation of 2-chloro-3-nitropyridine (IX) with phenylboronic acid (X) by means of palladium tetrakis(triphenylphosphine) and Na2CO3 in dimethoxyethane gives 3-nitro-2-phenylpyridine (XI), which is hydrogenated with H2 over Pd/C in ethanol/HCl, yielding (?-cis-2-phenylpiperidin-3-amine (XII). Finally, this compound is submitted to optical resolution by means of di-p-toluoyl-L-tartaric acid in ethanol/water.

合成路线7

The 2-phenylpyridine-3-amine (V), an intermediate in the synthesis of 235944, has been obtained with better yields by three related ways: 1. The acylation of 2-chloropyridine-3-amine (I) with Ac2O and TEA in dichloromethane gives the corresponding acetamide (II), which is condensed with phenylboronic acid (III) by means of Pd(PPh3)4 and Na2CO3 in ethanol/toluene, yielding N-(2-phenylpyridin-3-yl)acetamide (IV). Finally, this compound is hydrolyzed with HCl in methanol to afford the target 2-phenylpyridine-3-amine (V) intermediate. 2. The condensation of 2-chloropyridine-3-amine (I) with benzaldehyde (VI) in refluxing toluene gives the corresponding imine (VII), which is condensed with phenylboronic acid (III) as before to yield the 2-phenylpyridine derivative (VIII). Finally, the imino group of (VIII) is hydrolyzed with aqueous HCl to afford the target intermediate (V). 3. The one-pot condensation of 2-chloropyridine-3-amine (I), boronic acid (III) and benzaldehyde (VI) by means of Pd(PPh3)2Cl2 and Na2CO3 in hot toluene gives the already reported 2-phenylpyridine derivative (VIII), which is hydrolyzed as before to afford the target intermediate (V).

合成路线8

The condensation of 2-bromo-4-nitrotoluene (I) with phenylboronic acid (II) by means of Pd(OAc)2 in aqueous acetone gives the biphenyl (III), which is oxidized with KMnO4 in aqueous pyridine yielding the biphenyl-2-carboxylic acid (IV). The condensation of (IV) with L-methionine methyl ester (V) by means of EDC and HOBT affords the amide (VI), which is reduced with SnCl2 to give the 5-aminobiphenyl derivative (VII). The reductocondensation of (VII) with N-(tert-butoxycarbonyl)-S-trityl-L-cysteinal (VIII) by means of NaBH3CN affords the secondary amine (IX), which is finally deprotected with HgCl2 and H2S in methanol to furnish the target ester.

合成路线9

The condensation of 6-methoxy-1-tetralone (I) with 1-[2-(4-bromophenoxy)ethyl]pyrrolidine (II) by means of CeCl3 and butyllithium in THF gives 1-[2-[4-(6-methoxy-3,4-dihydronaphthalen-1-yl)phenoxy]ethyl]pyrrolidine (III), which is brominated with pyridinium bromide perbromide in THF yielding the bromo derivative (IV). The condensation of (IV) with phenylboronic acid (V) by means of tetrakis(triphenylphosphonium) palladium/Na2CO3 in THF affords 1-[2-[4-(6-methoxy-2-phenyl-3,4-dihydronaphthalen-1-yl)phenoxy]ethyl]pyrrolidine (nafoxidene) (VI). Nadoxifene is reduced with H2 over Pd/C in ethanol/methanol giving (±)-cis-1-[2-[4-(6-methoxy-2-phenyl-1,2,3,4-tetrahydronaphthalen-1-yl)phenoxy]ethyl]-pyrrolidine (VII). The demethylation of (VII) with boron tribromide in dichloromethane or 48% HBr in hot acetic acid yields (±)-cis-6-phenyl-5-[4-[2-(1-pyrrolidinyl)ethoxy]-phenyl]-5,6,7,8-tetrahydronaphthalen-2-ol (VIII), which is submitted to optical resolution by chromatography over a Chiralcell OD column in 99.95% (ethanol/heptane 5:95)/0.05% diethylamine, by crystallization with (­)-(R)-1,1'- binaphthyl-2,2'-diyl hydrogenphosphate (R-binaph) or by crystallization with D-tartaric acid.

合成路线10

Ethoxycarbonylpiperidone (I) was converted into enol triflate (II), and this was coupled with either phenylboronic acid or phenyl trimethylstannane using Pd catalysts to give 4-phenyltetrahydro-pyridine (III). Subsequent double bond hydrogenation produced a racemic mixture of cis piperidines (IV) and (V), from which several routes were used to synthesize the chiral title compounds. Removal of BOC protecting groups with HCl in EtOAc gave racemic (VI), which was alkylated with bromide (VII) in the presence of diisopropylethylamine to afford racemic (VIII). The enantiomers of (VIII) were separated utilizing chiral HPLC on a Chiralcel OD column, yielding the (-)(S,S) compound (XV, 247751) and the (+)(R,R) compound (XIV, 247752). Alternatively, racemic piperidine (VI) could be separated using a Chiralcel OD column into enantiomers (-)(S,S) (IX) and (+)(R,R) (X), which were separately alkylated with bromide (VII) to furnish (XV) and (XIV), respectively. Resolution of the racemic mixture (IV) and (V) was also achieved by hydrolysis to the racemic acids (XI) with LiOH under controlled conditions, followed by treatment with (S)-a-methylbenzylamine (XII) and crystallization of the resulting salt (XIII), whose absolute configuration was determined by X-ray diffraction. Liberation of the (S,S) acid, followed by BOC removal and esterification with an ethanolic solution of HCl then provided ester (IX), which could be alkylated with bromide (VII) to afford (XV).

合成路线11

Nitration of 5-bromoisoquinoline (I) using KNO3 in H2SO4 gave 5-bromo-8-nitroisoquinoline (II), which upon methylation with dimethyl sulfate was converted to the isoquinolinium salt (III). Subsequent reduction of (III) with NaBH4 in AcOH provided tetrahydroisoquinoline (IV). This was coupled with phenylboronic acid (V) in the presence of Pd(PPh3)4 and NaHCO3 to yield the 5-phenylisoquinoline (VI). Further reduction of the nitro group of (VI) by catalytic hydrogenation over Pd/C afforded amine (VII). The pyrroloisoquinoline (VIII) was then formed by condensation of (VII) with chloral and hydroxylamine in boiling water, followed by cyclization of the intermediate (oxymino)acetamide in methanesulfonic acid at 120 C. After chlorosulfonation of (VIII), the sulfonyl chloride (IX) was condensed with dimethylamine in THF to afford sulfonamide (X). Hydroxylamine derivative (XIV) was prepared by O-alkylation of N-hydroxyphthalimide (XI) with alpha-bromo-gamma-butyrolactone (XII), followed by hydrolysis of the phthalimide (XIII) in boiling 1 M HCl. Hydroxylamine derivative (XIV) was then condensed with sulfonamide (X) to furnish oxime (XV). Finally, hydrolysis of the butyrolactone group of (XV) with aqueous NaOH gave the title compound.

合成路线12

The cyclization of 2-amino-5-bromobenzoic acid (I) with 3-phenylpropionyl chloride (II) by means of DMAP and Et3N in DMF gives the benzoxazinone (III), which by heating with glycine methyl ester (IV) yields the quinazolinone (V). The hydrolysis if (V) with NaOH in THF/water affords 2-[6-bromo-4-oxo-2-(2-phenylethyl)-3,4-dihydroquinazolin-3-yl]acetic acid (VI), which is condensed with the monoprotected hexane-1,6-diamine (VII), by means of HOBt, EDC and NMM to provide the amide (VIII). The condensation of (VIII) with phenylboronic acid (IX) by means of palladium tetrakis(triphenylphosphoine) gives the 6-phenyl substituted quinazolinone (X), which is finally deprotected with HCl.

合成路线13

Treatment of triethyl phosphoacetate (I) with NaH and 4-bromobenzyl bromide (II) in DMF provides the 2-substituted triethyl phosphoacetate (III), which then undergoes reaction with formaldehyde and K2CO3 to afford acrylate derivative (IV). Michael condensation of (IV) with phosphinic acid (V) in N,O-bistrimethylsilylacetamide (BSA) yields intermediate (VI), which then undergoes Suzuki condensation in toluene with phenylboronic acid (VII) and NaHCO3 in MeOH catalyzed by Pd(PPh3)4 to give (VIII). Hydrolysis of ethyl ester (VIII) by means of NaOH in EtOH furnishes carboxylic acid (IX), which is then coupled to L-alanine (X) by means of BOP and DIEA or Et3N in DMF to yield methyl ester (XI). Compound (XI) is then hydrolyzed by treatment with NaOH or LiOH in EtOH and, finally, the Z-protecting group is removed with BBr3 in dichloromethane.

合成路线14

The condensation of 2-bromo-4-nitrotoluene (I) with phenylboronic acid (II) by means of Pd(OAc)2 in aqueous acetone gives the biphenyl (III), which is oxidized with KMnO4 in aqueous pyridine yielding the biphenyl-2-carboxylic acid (IV). The condensation of (IV) with L-methionine methyl ester (V) by means of EDC and HOBT affords the amide (VI), which is reduced with SnCl2 to give the 5-aminobiphenyl derivative (VII). The reductocondensation of (VII) with N-(tert-butoxycarbonyl)-S-trityl-L-cysteinal (VIII) by means of NaBH3CN affords the secondary amine (IX), which is finally deprotected and hydrolyzed first with LiOH and THF and then with TFA and Et3SiH in dichloromethane to furnish the target free acid.

合成路线15

The reaction of tropanone (I) with N,N-bis(trifluoromethylsulfonyl)aniline and sodium hexamethyldisilylazide in THF gives the enol triflate (II), which is condensed with 4-methylphenylboronic acid (III) by means of palladium tetrakis(triphenylphosphine) yielding the p-tolyltropane (IV). The hydrolysis of the methyl ester of (IV) with KOH affords the carboxylic acid (V), which is treated with diphenoxyphosphoryl azide in hot toluene to give the isocyanate (VI). The hydrolysis of (VI) in refluxing ethanol yields the tropanone (VII). By reaction of the tropanone (VII) with N,N-bis(trifluoromethylsulfonyl)aniline to give the corresponding enol triflate (IX), which is then condensed with phenylboronic acid (X) by means of Pd(Ph3)4 to give (XI), which by reaction with phenyl chloroformate in dichloromethane yields the N-carboxylate (XII). The reduction of (XII) with H2 over Pd/C in methanol affords a mixture of the (exo, exo) (XIII) and (endo, endo) (XIV) compounds, which is reduced with LiAlH4 in ethyl ether providing a mixture of the target compound and its (endo, endo) isomer (XV) that is separated by chromatography.

合成路线16

Bromination of N-phthaloyl tryptamine (I) with pyridinium tribromide provided the 2-bromo indole (II). Suzuki coupling of bromide (II) with phenylboronic acid (III) gave the 2-phenyl indole (IV). The phthaloyl group of (IV) was then removed by treatment with dimethylamine to furnish 2-phenyltryptamine (V). Then condensation of amine (V) with 3-methyl-2-oxovaleric acid (VI) using EDC and HOBt yielded the corresponding amide.

合成路线17

Coupling of N-Boc-L-tert-leucine (I) with (R)-1-phenylethylamine (II) using EDC and HOBt gave amide (III) which, after acid cleavage of the N-Boc group, provided amino amide (IV). Acylation of amine (IV) with (R)-2-allylsuccinic acid 4-tert-butyl ester (V) afforded the diamide (VI). Biphenylyl bromide (IX) was prepared by the Suzuki coupling between 5-bromo-2-iodotoluene (VII) and phenylboronic acid (VIII). The biaryl group was then introduced via Heck reaction of biphenylyl bromide (IX) with olefin (VI), yielding adduct (X). Subsequent hydrogenation of the olefin double bond of (X) over Pd/C afforded (XI). Carboxylic acid (XII) was then obtained by trifluoroacetic acid-promoted cleavage of the tert-butyl ester group of (XI). Conversion of (XII) to the title hydroxamic acid was then achieved by coupling of carboxylic acid (XII) with O-allylhydroxylamine (XIII), followed by O-allyl group cleavage in the presence of ammonium formate and palladium catalyst.

合成路线18

The cyclization of 4-bromobenzaldehyde (I) with butanedione monooxime (II) by means of HCl in acetic acid gives 2-(4-bromophenyl)-4,5-dimethyloxazole N-oxide (III), which is chlorinated with POCl3 in refluxing chloroform to yield the chloromethyl derivative (IV). The reaction of (IV) with KCN and KI in hot DMF affords the cyanomethyl compound (V), which is hydrolyzed with KOH in water/2-methoxyethanol to provide the acetic acid derivative (VI). The reduction of (VI) with BH3/THF in THF gives the ethanol intermediate (VII), which is condensed with phenylboronic acid (VIII) by means of PPh3 and Pd(OAc)2 in propanol to yield the biphenyl derivative (IX). The reaction of the OH group of (IX) with tosyl anhydride in dichloromethane affords the tosylate (X), which is condensed with 2-(4-hydroxyphenoxy)-2-methylpropionic aid ethyl ester (XI) by means of Cs2CO3 in hot DMF to provide the ethyl ester precursor (XII). Finally, this compound is hydrolyzed with NaOH in methanol/water to obtain the target propionic acid.

合成路线19

The Horner-Emmons condensation of 4,4'-dibromobenzophenone (I) with triethyl phosphonoacetate leads to the 3,3-diarylpropenoate (II). Ester (II) is subsequently reduced to the allylic alcohol (III) employing DIBAL in cold THF. Suzuki coupling of aryl bromide (III) with phenylboronic acid (IV) furnishes 3,3-bis-(biphenyl-4-yl)-2-propen-1-ol (V). Coupling of allylic alcohol (V) with (S) ethyl 2-ethoxy-3-(4-hydroxyphenyl)propionate (VI) by means of 1,1'-(azodicarbonyl)dipiperidine (ADDP) and tributylphosphine under Mitsunobu conditions gives rise to the ether adduct (VII). Finally, saponification of the ethyl ester group of (VII) provides the target carboxylic acid.

合成路线20

合成路线21

Selective bromide displacement in 2,5-dibromopyridine (I) with NaOMe in refluxing MeOH affords 5-bromo-2-methoxypyridine (II) (1), which alternatively can be obtained by bromination of 2-methoxypyridine (III) with elemental bromine in the presence of NaOAc in EtOAc at 50 °C (2). Metalation of 5-bromo-2-methoxypyridine (II) with BuLi in THF at –75 °C followed by addition of trimethyl borate and aqueous acidic hydrolysis leads to (6-methoxy-3-pyridyl)boronic acid (IV). Subsequent Suzuki coupling of boronic acid (IV) with 2-bromopyridine (V) in the presence of Pd(OAc)2, PPh3 and K2CO3 in DME/H2O at reflux provides 6-methoxy-3,2’-bipyridine (VI) (1). In an alternative method, bipyridine (VI) can be obtained by metalation of 5-bromo-2-methoxypyridine (II) with BuLi in THF at –75 °C followed by condensation with 2-(phenylsulfonyl)pyridine (VII) . Hydrolysis of 6-methoxy-3,2’-bipyridine (VI) by means of aqueous HCl at reflux yields 5-(2-pyridyl)-2-pyridone (VIII) . In a related method, Stille coupling of 5-bromo-2-methoxypyridine (II) with (2-pyridyl)tributyltin (IX) in the presence of Pd(Ph3)4 in DMF at 120 °C followed by methoxy group hydrolysis with concentrated HBr at 110 °C leads to 5-(2-pyridyl)-2-pyridinone (VIII) . N-Arylation of pyridone (VIII) with either phenylboronic acid (X) or its trimeric anhydride 2,4,6-triphenylboroxine (XI) in the presence of Cu(OAc)2 in pyridine/DMF under air blowing conditions gives 1-phenyl-5-(2-pyridyl)-2-pyridinone (XII), which is brominated using NBS in DMF or EtOAc to yield the 3-bromopyridone derivative (XIII). Finally, this compound is subjected to Suzuki coupling with 2-(2-cyanophenyl)-1,3,2-dioxaborinane (XIV) by means of Pd(OAc)2, PPh3, CuI and K2CO3 in DME .
In a different synthetic strategy, Suzuki coupling of 5-bromo-6-methoxy-3,2’-bipyridine (XV) with 2-(2-cyanophenyl)-1,3,2-dioxaborinane (XIV) using Pd(PPh3)4 and Cs2CO3 in DMF at 140 °C gives 3-(2-cyanophenyl)-5-(2-pyridyl)-2-methoxypyridine (XVI), which undergoes methoxy group hydrolysis by means of ClSiMe3 and NaI in acetonitrile to produce the pyridone derivative (XVII). Finally, subsequent N-arylation of pyridone (XVII) with phenylboronic acid (X) in the presence of Cu(OAc)2 and Et3N in CH2Cl2 furnishes perampanel