合成路线1

The condensation of 4-fluorobenzaldehyde (I) with ethyl acetoacetate (II) by means of piperidine, followed by a treatment with hot NaOH and esterification with methanol in acid medium, gives 3-(4-fluorophenyl)glutaric acid dimethyl ester (III), which is stereoselectively hydrolyzed with liver esterase in aqueous acetone, yielding the monoester (IV) with a 95% ee. The selective reduction of the ester group of (IV) with LiH and LiBH4 in THF affords the chiral 5-hydroxypentanoic acid (V), which is esterified with dimethyl sulfate in methanol to the corresponding methyl ester (VI). The reaction of (VI) with MsCl and TEA in toluene gives the mesylate (VII), which is cyclized with benzylamine (VIII) and TEA in toluene, affording the chiral piperidone (IX).The reaction of (IX) with dimethyl carbonate (X) and NaH in hot toluene yields the chiral carboxylate (XI), which is reduced at the carboxylate and ketonic groups with LiAlH4 or BH3 in DMSO, providing the chiral piperidine methanol derivative (XII). The reaction of (XII) with MsCl and TEA in toluene yields the mesylate (XIII), which is condensed with the phenol derivative (XIV) by means of NaH in hot DMF, affording the adduct (XV). Finally, this compound is debenzylated by hydrogenation with H2 over Pd/C.

合成路线2

The condensation of 4-fluorocinnamic acid ethyl ester (I) with cyanacetic acid ethyl ester (II) by means of NaOEt in ethanol gives 2-cyano-3-(4-fluorophenyl)glutaric acid diethyl ester (III). Alternatively, glutarate (III) can also be obtained by condensation of 4-fluorobenzaldehyde (V) with cyanacetic ester (II) and acetic acid ethyl ester (VI). The reduction of the cyano group of (III) with H2 over PtO2 in ethanol, followed by cyclization in refluxing toluene, yields 4-(4-fluorophenyl)-6-oxopiperidine-3-carboxylic acid ethyl ester (IV) as a mixture of the cis- and trans-isomers. The reaction of the mixture (IV) with EtONa in refluxing toluene causes isomerization of the cis-isomer, affording (rac)-trans-4-(4-fluorophenyl)-6-oxopiperidine-3-carboxylic acid ethyl ester (VII), which is reduced with LiAlH4 or borane (NaBH4/BF3) to provide the (rac)-(trans)-hydroxymethylpiperidine (VIII). Finally, this compound is reductively methylated by treatment with formaldehyde and H2 over Pd/C in ethanol to furnish (rac)-(trans)-4-(4-fluorophenyl)-3-(hydroxymethyl)-1-methylpiperidine (IX), the desired intermediate. Alternatively, the cis/trans mixture 4-(4-fluorophenyl)-6-oxopiperidine-3-carboxylic acid ethyl ester (IV) can be methylated first with formaldehyde as before to give 4-(4-fluorophenyl)-1-methyl-6-oxopiperidine-3-carboxylic acid ethyl ester (X), also as a cis/trans mixture. This mixture is treated with EtONa in refluxing toluene to yield (rac)-(trans)-4-(4-fluorophenyl)-1-methyl-6-oxopiperidine-3-carboxylic acid ethyl ester (XI). Finally, this compound is reduced with LiAlH4 in THF/toluene to afford the previously described target intermediate (IX).

合成路线3

The synthesis of the optical enantiomers of mosapride has been described: The reductocondensation of 4-fluorobenzaldehyde (I) with ethanolamine (II) by means of NaBH4 and NaHCO3 in refluxing methanol gives 2-(4-fluorobenzylamino)ethanol (III), which is condensed with epichlorohydrin (IV) to yield the diol (V). Compound (V), without isolation, is cyclized with conc. H2SO4 to afford 2-(chloromethyl)-4-(4-fluorobenzyl)morpholine (VI), which is treated with refluxing water-formamide to afford the corresponding methanol derivative (VII). Tosylation of (VII) with tosyl chloride and triethylamine/4-(dimethylamino)pyridine in dichloromethane gives the tosylate (VIII) as a racemic mixture. The optical resolution of (VIII) with N-(p-toluenesulfonyl)-L-glutamic acid in methanol affords the (S)-tosylate [(S)-IX] and the (R)-tosylate [(R)-IX]. The reaction of both [(S)-IX] and [(R)-IX] with sodium azide followed by reduction with bis(2-methoxyethoxy)aluminum hydride (vitride) gives the chiral amines [(S)-X] and [(R)-X], which are finally condensed with 4-amino-5-chloro-2-ethoxybenzoic acid (XI) by means of 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide (WSC) in dichloromethane, yielding the (S)- and (R)-enantiomers of mosapride.

合成路线4

8) The synthesis of the 4-(4-fluorophenyl)-2-isobutyryl-4-oxo-N-phenylbutyramide (XXXII) is carried out as follows: The condensation of 4-methyl-3-oxo-N-phenylpentanamide (XLIV) with benzaldehyde (XLV) gives 2-benzylidene-4-methyl-3-oxo-N-phenylpentanamide (XLVI), which is then condensed with 4-fluorobenzaldehyde (XLVII) by means of triethylamine in hot ethanol. 9) The cyclization of (XXXII) with intermediate (XLII) (preceding synthesis) in refluxing toluene yields the protected dehydroxyheptanoate (XLIII), which is deprotected with HCl in methanol and finally hydrolyzed with NaOH and treated with calcium acetate in water.

合成路线5

The synthesis of ring labeled [14C]-atorvastatin has been described: The Grignard reaction of phenylmagnesium chloride (I) with [14C]-labeled CO2 (II) in THF/ethyl ether gives the benzoic acid (III), which is reduced with LiAlH4 in ethyl ether to the benzyl alcohol (IV). The oxidation of (IV) with pyridinium dichromate affords the benzaldehyde (V), which is condensed with the isobutyrylacetamide (VI) by means of beta-alanine in acetic acid yielding a mixture of the cis- and trans-benzylidene derivatives (VII). The condensation of (VII) with 4-fluorobenzaldehyde (VIII) by means of triethylamine and a thiazolium bromide catalyst affords the 1,4-dione (IX), which is cyclized with the chiral amino ester (X) in hot heptane/toluene/THF providing the protected pyrroloheptanoic ester (XI). The deprotection of (XI) in acidic medium, followed by the hydrolysis of the ester group with NaOH affords the sodium salt (XII), which is finally treated with calcium acetate in THF/water.

合成路线6

The synthesis of atorvastatin has been described: The condensation of benzaldehyde (I) with the isobutyrylacetamide (II) by means of beta-alanine in acetic acid yields a mixture of cis- and trans-benzylidene derivatives (III). The condensation of (III) with 4-fluorobenzaldehyde (IV) by means of triethylamine and a thiazolium bromide catalyst affords the 1,4-dione (V), which is cyclized with the chiral amino ester (VI) in hot heptane/toluene/THF to provide the protected pyrroloheptanoic ester (VII). The deprotection of (VII) in acidic medium, followed by the hydrolysis of the ester group with NaOH affords the sodium salt (VIII), which is finally treated with calcium acetate in THF/water.

合成路线7

The synthesis of atorvastatin has been described: The condensation of benzaldehyde (I) with the isobutyrylacetamide (II) by means of beta-alanine in acetic acid yields a mixture of cis- and trans-benzylidene derivatives (III). The condensation of (III) with 4-fluorobenzaldehyde (IV) by means of triethylamine and a thiazolium bromide catalyst affords the 1,4-dione (V), which is cyclized with the chiral amino ester (VI) in hot heptane/toluene/THF to provide the protected pyrroloheptanoic ester (VII). The deprotection of (VII) in acidic medium, followed by the hydrolysis of the ester group with NaOH affords the sodium salt (VIII), which is finally treated with calcium acetate in THF/water.

合成路线8

The synthesis of atorvastatin has been described: The condensation of benzaldehyde (I) with the isobutyrylacetamide (II) by means of beta-alanine in acetic acid yields a mixture of cis- and trans-benzylidene derivatives (III). The condensation of (III) with 4-fluorobenzaldehyde (IV) by means of triethylamine and a thiazolium bromide catalyst affords the 1,4-dione (V), which is cyclized with the chiral amino ester (VI) in hot heptane/toluene/THF to provide the protected pyrroloheptanoic ester (VII). The deprotection of (VII) in acidic medium, followed by the hydrolysis of the ester group with NaOH affords the sodium salt (VIII), which is finally treated with calcium acetate in THF/water.

合成路线9

4-[(tert-Butyldimethylsilyloxy)methyl]pyridine (II) was prepared by silylation of 4-hydroxymethylpyridine (I) with tert-butyldimethylsilyl chloride and imidazole. Deprotonation of (II) by means of LDA in cold THF, followed by condensation with 4-fluorobenzaldehyde (III), furnished the protected diol adduct (IV), which was further desilylated upon treatment with tetrabutylammonium fluoride in THF. Oxidation of the resultant diol (V) under Swern conditions provided diketone (VI). The triaryl imidazole (VIII) was then obtained by condensation of diketone (VI) with 4-(methylsulfanyl)benzaldehyde (VII) in the presence of ammonium acetate in refluxing HOAc. Finally, oxidation of the thioether function of (VIII) with K-2S2O8 furnished the title sulfoxide.

合成路线10

The reaction of 2-chloropyridine (I) with 2-(methyl-amino)ethanol (II) by heating at 150 C gives 2-[N-methyl-N-(2-pyridyl)amino]ethanol (III), which is condensed with 4-fluorobenzaldehyde (IV) by means of NaH in DMF, yielding 4-[2-[N-methyl-N-(2-pyridyl)amino]-ethoxy]benzaldehyde (V) (1-3). The reaction of (V) with thiazolidine-2,4-dione (VI) by means of piperidinium acetate in refluxing toluene affords 5-[4-[2-[N-methyl-N-(2-pyridyl)- amino]ethoxy]benzylidene]thiazolidine-2,4-dione (VII). Finally, this compound is reduced with H2 over Pd/C (1), Mg in methanol (2,3) or biocatalytically by incubation with whole cells of the yeast Rhodotorula rubra CBS 6469 at pH 7.5-8.0 (4-6). Under acidic conditions, pH 3.0-5.0, this microbial biotransformation is enantioselective, giving the (+)-(R)-enantiomer of rosiglitazone.

合成路线11

The reaction of 1,3,5-tribromobenzene (I) with 4-fluorobenzaldehyde (II) by means of BuLi in ethyl ether gives the benzhydrol (III), which is condensed with ethyl acrylate (IV) by means of palladium acetate and tri o-tolylphosphine in refluxing acetonitrile yielding the phenylenebisacrylate (V). The acetylation of (V) with acetic anhydride and DMAP in dichloromethane affords the acetate (VI), which is hydrogenated with H2 over Pd/C in ethyl acetate providing the bispropanoate (VII). Selective hydrolysis of (VII) with NaOH in ethanol gives the monoacid (VIII), which is treated with oxalyl chloride in dichloromethane yielding the monoacyl chloride (IX). The reaction of (IX) with NH4OH affords the corresponding amide (X), which is treated with NaOCl and NaOH to perform degradation of the amide group and simultaneous hydrolysis of the ester group providing the amino acid (XI). Finally, this compound is sulfonated with 4-chlorophenylsulfonyl chloride (XII) and NaOH.

合成路线12

Condensation of p-fluorobenzaldehyde (I) with propionic anhydride (II) by means of sodium propionate at 140 C affords p-fluoro-alpha-methylcinnamic acid (III), which is then hydrogenated over Pd/C in EtOH to provide p-fluoro-alpha-methylhydrocinnamic acid (IV). Derivative (IV) is subjected to cyclization by treatment with polyphosphoric acid (PPA) to give 6-fluoro-2-methylindanone (V), which is converted into 5-fluoro-2-methylindenyl-3-acetic acid (VII) by first condensation with cyanoacetic acid (VI) by means of acetic acid and ammonium acetate in refluxing toluene, followed by hydrolysis with KOH in hot ethanol. Condensation of derivative (VII) with p-methylthiobenzaldehyde (VIII) by means of sodium methoxide in hot MeOH affords 5-fluoro-2-methyl-1-[p-(methylsulfanyl)benzylidene]-3-indenyl acetic acid (IX), which is then oxidized in MeOH/acetone by means of an aqueous solution of sodium periodate to yield methylsulfinylbenzylidene derivative (X). Finally, the target product is obtained by further oxidation of (X) with H2O2 in the presence of sodium methoxide and sodium bicarbonate in MeOH/acetonitrile at -10 C.

合成路线13

The condensation of 4-fluorobenzaldehyde (I) with 4-methyl-3-oxopentanoic acid ethyl ester (II) by means of piperidine/AcOH in refluxing benzene gives the corresponding benzylidene derivative (III), which is cyclized with S-methylisothiourea (IV) and oxidized with DDQ, affording the pyrimidine derivative (V). The oxidation of (V) with m-chloroperbenzoic acid (m-CPBA) gives the expected methanesulfonyl derivative (VI), which is treated first with methylamine and then with methanesulfonyl chloride to provide the N-methylmethanesulfonamide (VII). The reduction of the ester group of (VII) with DIBAL in toluene, followed by selective oxidation of the resulting alcohol with TPAP, affords the aldehyde (VIII), which is submitted to a Wittig condensation with the phosphorane (IX) in acetonitrile to give the protected heptenoate (X). The deprotection of (X) with FH and the controlled reduction of the resulting keto alcohol with Et2BOMe and NaBH4 affords the chiral dihydroxyheptenoate (XI), which is hydrolyzed with NaOH in ethanol, yielding the corresponding sodium salt (XII). Finally, this compound is treated with calcium chloride.

合成路线14

Condensation of 4-fluorophenol (I) with 4-fluorobenzaldehyde (II) by heating with K2CO3 in N,N-dimethylacetamide provides 4-(4-fluorophenoxy)benzaldehyde (III), which is finally converted into the target product by reaction with semicarbazide hydrochloride (IV) and NaOAc in the refluxing mixture EtOH/H2O.

合成路线15

The condensation of p- fluorobenzaldehyde (I) with p-toluenesulfinic acid (II) in the presence of camphorsulfonic acid in formamide produced the tosylmethyl formamide (III). This was dehydrated to the required isocyanide (IV) using POCl3 and Et3N in cold dimethoxyethane.

合成路线16

Heating p-fluorobenzaldehyde (I) with propionic anhydride (II) in the presence of sodium propionate affords methyl cinnamic acid derivative (III), which is then hydrogenated over Pd/C in EtOH to provide methyl hydrocinnamic acid derivative (IV). Ring closure of (IV) is then performed by heating with polyphosphoric acid to yield methylindanone derivative (V). Condensation of (V) with cyanoacetic acid (VI) by means of ammonium acetate and HOAc in refluxing toluene, followed by treatment with KOH in refluxing EtOH, provides acetic acid derivative (VII), which is then condensed with 3,4,5-trimethoxybenzaldehyde (VIII) by heating with NaOMe in MeOH to give substituted benzylidene derivative (IX). The target product can be finally obtained either by direct condensation of (IX) with benzylamine (XI) by means of DMAP and EDC in DMA or by first conversion of (IX) into the corresponding acetyl chloride by reaction with oxalyl chloride in refluxing THF, followed by coupling with benzylamine (XI) in CH2Cl2. Alternatively, the desired compound can also be obtained by coupling of acetic acid derivative (VII) with benzylamine (XI) by means of DMAP, EDC in DMA to afford N-benzyl acetamide derivative (XII), followed by condensation with 3,4,5-trimethoxybenzaldehyde (VIII) by heating with NaOMe in MeOH.

合成路线17

A new synthesis of the title compound, very similar to that already published, is reported: The condensation of 6-(benzyloxy)-2,5,7,8-tetramethyl-3,4-dihydro-2H-1-benzopyran-2-ylmethyl methanesulfonate (I) with 2-(methylamino)ethanol (II) by heating at 120 C gives the tertiary amine (III), which is condensed with 4-fluorobenzaldehyde (IV) by means of NaH in DMF yielding the 4-alkoxy benzaldehyde (V). A new condensation of (V) with thiazolidine-2,4-dione (VI) by means of piperidine in refluxing toluene affords the benzyloxy derivative of the target compound (VII). Finally, the target compound is obtained by treatment of (VII) with HCl in acetic acid.

合成路线18

The target compound was obtained by several related ways. Indolylethanol (III) was either prepared by alkylation of indole (I) with methyl bromoacetate, followed by reduction of the resulting indolylacetate (II) with LiAlH4 or by alkylation of (I) with 2-bromoethanol. Alkylation of (III) with 4-fluorobenzaldehyde (IV) in the presence of NaH or condensation with 4-hydroxybenzaldehyde (V) under Mitsunobu conditions provided ether (VII). Alternatively, (VII) was prepared by alkylation of indole (I) with 4-(bromoethoxy)benzaldehyde (VI). Then, Knoevenagel condensation of aldehyde (VII) with 2,4-thiazolidinedione (VIII) in the presence of piperidinium benzoate in refluxing toluene with azeotropic removal of water yielded benzylidene compound (IX). Reduction of the olefinic double bond by either hydrogenation in the presence of an excess of Pd/C or by chemical reduction with Mg in MeOH provided the target benzyl compound. Alternatively, indolylethanol (III) was condensed with hydroxybenzyl compound (X) in the presence of tributyl phosphine and 1,1'-(azodicarbonyl)dipiperidine (ADDP) in benzene to give (XI), which was finally deprotected by hydrogenation in the presence of an excess of Pd/C in dioxan.

合成路线19

The condensation of pyruvic aldehyde dimethyl acetal (I) with dimethylformamide dimethyl acetal (II) afforded ketoenamine (III), which was condensed with N-methyl guanidine (IV) to give pyrimidine (V). Acid hydrolysis of the acetal function of (V) yielded pyrimidine carboxaldehyde (VI), which was converted to the imine (VIII) by treatment with 1-Boc-4-aminopiperidine (VII). Isonitrile (XII) was prepared by condensation of 4-fluorobenzaldehyde (IX) with formamide and p-thiocresol (X), followed by dehydration of the resulting formamide (XI) by means of POCl3 and Et3N. Reaction of isonitrile (XII) with imine (VIII) in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) produced imidazole (XIII). Finally, acid deprotection of the Boc group of (XIII) provided the title compound.

合成路线20

In a related procedure, condensation of 4-fluorobenzaldehyde (IX) with formamide and p-toluenesulfinic acid (XIV) produced the tosyl formamide (XV), which was dehydrated by means of POCl3 and Et3N to give isonitrile (XVI). Imidazole (XIII) was then obtained by reaction of this isonitrile with imine (VIII). Finally, the Boc protecting group of (XIII) was removed by acid treatment as above.

合成路线21

Two related syntheses have been reported for this compound. The intermediate alpha-tosyl-(4-fluorobenzyl)isonitrile (V) was prepared by condensation of 4-fluorobenzaldehyde (I), p-toluenesulfinic acid (II) and formamide (III) in the presence of chlorotrimethylsilane (1-4), followed by dehydration of the resulting formamide derivative (IV) with POCl3 and triethylamine.

合成路线22

Condensation of pyruvic aldehyde dimethyl acetal (I) with dimethylformamide dimehylacetal provided ketoenamine (II). This was cyclized with guanidine to afford aminopyrimidine (III). Then, hydrolysis of the dimethyl acetal of (III) with 3 M HCl yielded aldehyde (IV). 4-Fluorobenzaldehyde (V) was condensed with thiocresol (VI) and formamide in refluxing toluene to give 4-fluorophenyl-tolylthiomethyl formamide (VII), which was dehydrated to isocyanide (VIII) with POCl3 and Et3N at -30 C. Finally, imine (X), (obtained from pyrimidine aldehyde (IV) and 4-(3-aminopropyl)morpholine (IX)), was condensed with isocyanide (VIII) in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene to furnish the title imidazole.

合成路线23

Condensation between p-fluorobenzaldehyde (I), p-toluenesulfinic acid (II) and formamide in the presence of camphorsulfonic acid afforded 4-fluorophenyltosylmethyl formamide (III). Subsequent dehydration of (III) by means of POCl3 and Et3N produced isonitrile (IV). Imine (VII) was prepared by condensation of pyridine-4-carboxaldehyde (V) with 1-Boc-4-aminopiperidine (VI) using MgSO4 as the dehydrating reagent. Dipolar cycloaddition of this imine with the anion of tosyl isonitrile (IV) generated the trisubstituted imidazole (VIII). Finally, acid cleavage of the Boc protecting group furnished the title compound.

合成路线24

Heating p-fluorobenzaldehyde (I) with propionic anhydride (II) in the presence of sodium propionate affords methyl cinnamic acid derivative (III), which is then hydrogenated over Pd/C in EtOH to provide methyl hydrocinnamic acid derivative (IV). Ring closure of (IV) is then performed by heating with polyphosphoric acid to yield methylindanone derivative (V). Condensation of (V) with cyanoacetic acid (VI) by means of ammonium acetate and HOAc in refluxing toluene followed by treatment with KOH in refluxing EtOH provides acetic acid derivative (VII), which is then converted into acetyl chloride compound (VIII) by reaction with oxalyl chloride in refluxing THF. Coupling of (VIII) with benzylamine (IX) in refluxing CH2Cl2 gives indenylacetamide derivative (X), which is finally condensed with 4-pyridinecarboxaldehyde (XI) by means of NaOMe in MeOH to furnish the desired compound.

合成路线25

2-Chloropyridine (I) was condensed with (S)-prolinol (II) to furnish the pyridinylpyrrolidine (III). Subsequent alkylation of the hydroxyl group of (III) with 4-fluorobenzaldehyde (IV) using NaH in hot DMF gave ether (V). Knoevenagel condensation of (V) with 2,4-thiazolidinedione (VI) in the presence of benzoic acid and piperidine afforded the required benzylidene thiazolidine, which was finally treated with maleic acid in acetone to yield the title maleate salt.

合成路线26

Mesylate (I) is heated with L-prolinol (II) to furnish pyrrolidine derivative (III), which can be converted into (VII) by different ways: 1) Treatment of (III) with t-BuOK and reaction with 4-fluorobenzaldehyde (IV) in DMF. 2) Conversion of (III) into chloropiperidine derivative (V) by means of SOCl2 in benzene, followed by reaction with 4-hydroxyaldehyde (VI) and K2CO3 in DMF in and chromatographic separation. 3) Mitsunobu reaction between (III) and 4-hydroxyaldehyde (VI) by treatment with PPh3 and DEAD in THF, followed by chromatographic separation. Derivative (VII) is condensed with 2,4-thiazolidinedione (VIII) in toluene in the presence of piperidine and benzoic acid to afford (IX), which is finally converted into its maleate form by treatment with maleic acid in Et2O.

合成路线27

Knoevenagel condensation of 4-fluorobenzaldehyde (I) with ethyl cyanoacetate (A) gave adduct (II). Subsequent conjugate addition of NaCN to (II), followed by alkylation with ethyl 3-chloropropionate (B) furnished the dicyano diester (III). Acid hydrolysis of (III), with concomitant decarboxylation, afforded tricarboxylic acid (IV), which was further esterified with methanolic HCl to give ester (V). Dieckmann cyclization of (V) using NaOMe, and then hydrolysis and decarboxylation gave rise to the racemic trans ketoacid (VI). Esterification of (VI), and reduction of the resulting keto ester (VII) with NaBH4 produced a mixture of diastereomeric alcohols. The desired trans,trans-isomer (VIII) was then isolated by column chromatography. Ester hydrolysis of (VIII) and re-solution as the corresponding salt with (R)-alpha-methylbenzylamine furnished the (-)-hydroxy acid (IX) that was esterified to (X) with methanolic HCl.

合成路线28

Dilithiation of thiophene (I) employing an excess of BuLi in the presence of TMEDA produced the intermediate 2,5-dilithiothiophene (II). Addition of 4-fluorobenzaldehyde (III) to the organolithium compound (II) afforded the bis-carbinol adduct (IV). Alternatively, addition of benzaldehyde (V) to (II) provided adduct (VI). Boron trifluoride-catalyzed condensation of pyrrole (VII) with diol (IV) yielded the bis(alpha-pyrrolylbenzyl)thiophene (VIII). The dithiaporphyrin derivative (IX) was then obtained by condensation between (VIII) and (VI) in the presence of boron trifluoride. Finally, aromatic sulfonation of (IX) with hot sulfuric acid, followed by neutralization with NaOH furnished the title disulfonate disodium salt.

合成路线29

Diazotization of sulfanilamide (I), followed by treatment of the resultant diazonium salt with potassium cyanide/copper sulfate under Sandmeyer conditions, leads to nitrile (II). Stephen reduction of (II) with Raney nickel alloy in 75% aqueous formic acid gives the benzaldehyde (III), which is further reduced to the benzyl alcohol (IV) using NaBH4 in ethanol. Treatment of alcohol (IV) with PBr3 provides the benzyl bromide (V). This is then subjected to Arbuzov reaction with triethyl phosphite to produce phosphonate (VI). Finally, Wittig-Horner condensation of (VI) with 4-fluorobenzaldehyde (VII) furnishes the target stilbene derivative.

合成路线30

合成路线31

Coupling of 6-fluoro-4-nitro-2-benzofuran-1(3H)-one (I) with 1-methyl-1H-1,2,4-triazole-5-carbaldehyde (II) in the presence of Et3N in2-Me-THF affords the (Z)-alkene (III), which by reaction with MeOH in the presence of HCl affords the methyl ester (IV). Condensation of ketone (IV) with 4-fluorobenzaldehyde (V) in the presence of L-proline in DMSO at 45 °C gives the (E)-propene derivative (VI), which then cyclizes by hydrogenation over Pd/C in MeOH to yield the 3,4-dihydroquinolin-1(2H)-ol derivative (VII). Reduction of the hydroxylamine derivative (VII) by means of Fe in the presence of HCl in refluxing MeOH provides the tetrahydroquinolone derivative (VIII), which can also be obtained by reductive cyclization of the nitro derivative (VI) with Fe in the presence of HCl in refluxing MeOH . Alternatively, compound (VIII) can be obtained by reductive cyclocondensation of intermediate (IV) with 4-fluorobenzaldehyde (V) by means of either TiCl3 in THF/MeOH at 30-50 °C, Fe in the presence of HCl in MeOH/THF at 60 °C, SnCl2 in the presence of HCl in MeOH/THF at 45 ° or by hydrogenation over Pd/C in MeOH/AcOH. Chiral resolution of the methyl ester (VIII) by supercritical fluid chromatography (SFC) or simulated moving bed (SMB) unit in MeOH provides the desired (2S,3S)-isomer (IX), which finally reacts with NH2NH2·H2O in EtOH or acetonitrile or MeOH. Alternatively, cyclocondensation of the methyl ester (VIII) with NH2NH2·H2O in MeOH gives the racemate (X) , which is finally resolved through the SFC unit .

合成路线32

Intermediate (X) can also be prepared by coupling of 4-amino-6-fluoro-2-benzofuran-1(3H)-one (XI) with 4-fluorobenzaldehyde (V) in the presence of MgSO4 in refluxing CH2Cl2 to afford the benzylidene derivative (XII), which by cyclocondensation with 1-methyl-1H-1,2,4-triazole-5-carbaldehyde (II) in the presence of NaOEt in ethyl propionate at 40 °C yields the tetrahydroquinolone (XIII). Finally, ethyl ester (XIII) is condensed with NH2NH2·H2O in MeOH .
Alternatively, the reaction of alkene (III) with NH2NH2·H2O in THF gives the 1,2-dihydrophthalazine derivative (XIV), which is then condensed with 4-fluorobenzaldehyde (V) in refluxing acetonitrile to yield imine (XV). Finally, intermediate (XV) is submitted to intramolecular cyclizacyclization by means of Cs2CO3 in THF at 55 °C and provides the racemate (X) .

合成路线33

Cycloaddition of norbornene (I) with chlorosulfonyl isocyanate (II) in EtOAc or Et2O followed by treatment with aqueous Na2SO3 affords (±)-exo-3-azatricyclo[4.2.1.O2,5]nonan-4-one (III), which by hydrolysis with HCl gives 3-aminonorbornane-2-carboxylic acid hydrochloride (IV). Treatment of amino acid (IV) with EtOH or MeOH by means of SOCl2 at reflux provides the hydrochloride salts of the corresponding ethyl (Va) or methyl (Vb) esters, respectively, which are neutralized with NaHCO3 to yield the free amines (VIa) and (VIb). Resolution of the racemic amino esters (VIa) or (VIb) with (S)-(+)-CSA in EtOAc/EtOH followed by neutralization of the obtained CSA salts (VIIa) or (VIIb) with Na2CO3 or K2CO3 in EtOAc leads to ethyl (VIIIa) or methyl (VIIIb) (1S,2R,3S,4R)-3-aminonorbornane-2-carboxylate, respectively. Alternatively, amino ester (VIIa) can be obtained by ring opening of racemic lactam (III) with EtOH in the presence of (S)-(+)-CSA in EtOAc at 50-75 °C. Reductive alkylation of amines (VIIIa) and (VIIIb) with 4-fluorobenzaldehyde (IX) by means of NaBH3CN and AcOH or NaOAc in EtOH gives the secondary amines (XIa) or (XIb) , which can also be prepared by alkylation of amines (VIII) with 4-fluorobenzyl bromide (Xa) or iodide (XIb) in the presence of Et3N in DMF at 70 °C . N-Acylation of amino esters (XIa) or (XIb) with the carboxylic acid (XII) using as coupling reagents EDC in the presence of DMAP , or NMM in DMF, or DCC in CH2Cl2/DMF, or HATU and NMM in DMF , yields amides (XIIIa) and (XIIIb) . Finally, amide esters (XIII) are submitted to intramolecular Claisen condensation by means of NaOEt in EtOH at 60 °C or Et3N at 60 °C . Alternatively, methyl ester (XIb) can be condensed with the carboxylic acid (XII) in the presence of DCC, NMM and Et3N in DMF at 50 °C , or in acetonitrile .

合成路线34

Intermediate (XIb) can also be prepared by the following route. Desymmetrization of cis-5-norbornene-exo-2,3-dicarboxylic anhydride (XXVIII) with MeOH in the presence of quinine in toluene/CCl4 at –55 °C affords (1S,2S,3R,4R)-3-(methoxycarbonyl)bicyclo[2.2.1]-hept-5-ene-2-carboxylic acid (XXIX). Activation of carboxylic acid (XXIX) with ClCOOEt in the presence of Et3N in THF followed by reaction of the resulting mixed anhydride with NaN3 results in the corresponding acyl azide, which then undergoes Curtius rearrangement in refluxing benzene to produce isocyanate (XXX). Without isolation, isocyanate (XXX) is treated with benzyl alcohol in the presence of Et3N in refluxing CH2Cl2 to give the Cbz-protected amine (XXXI). Reduction and deprotection of norbornene derivative (XXXI) with H2 over Pd/C in EtOAc followed by treatment with HCl in Et2O/dioxane gives the saturated amino ester (Vb), which is submitted to reductive alkylation with 4-fluorobenzaldehyde (IX) by means of NaBH3CN and NaOAc in MeOH .