合成路线1

The reaction of p-chlorobenzoic acid (I) with SOCl2 gives p-chlorobenzoyl chloride (II), which is esterified with 4-fluorophenol (III) affording 4-fluorophenyl-4-chlorobenzoate (IV). The isomerization of (IV) with AlCl3 yields 4-chloro-2'-hydroxy-5'-fluorobenzophenone (V), which is condensed with 4-aminobutyric acid (VI) by means of sodium methoxide in ethanol giving 4-[[alpha-(p-chlorophenyl)-5-fluoro-2-hydroxybenzylidene]amino]butyric acid (VII). The reaction of (VII) with SOCl2 in THF affords the corresponding acyl chloride (VIII), which is then treated with NH3. An alternative way of converting the acid (VII) into its amide is by treatment with carbonyldiimidazole (A) and liquid NH3 in THF.

合成路线2

The title compound has been obtained by condensation of methanesulfonate (I) with 4-fluorophenol (II) by means of NaNH2 in DMF.

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The condensation of 2-iodophenylacetic (I) with 4-fluorophenol (II) by means of K2CO3 in nitrobenzene al 160 C gives 2-(4-fluoophenoxy)phenylacetic acid (III), which by treatment with refluxing SOCl2 is converted to the corresponding acid chloride (IV). The cyclization of (IV) by means of AlCl3 in refluxing dichloroethane affords 2-fluoro-10,11-dihydro-11-oxodibenzo[b,f]oxepin (V), which is treated with 2-(dimethylamino)ethylthiol (VI) and boron trifluoride ethereate in acetic acid yielding 2-fluoro-11-[2-(dimethylamino)ethythio]dibenzo[b,f]oxepin (VII). The reaction of (VII) with phenyl chloro-formate (VIII) by means of K2CO3 in methylene chloride affords 2-fluoro-11-[2-(N-methyl-N-phenyloxycarbonylamino)ethythio]dibenzo[b,f]oxepin (IX), which is finally hydrolyzed with KOH-ethylene glycol al 155 C.

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1) The cyclization of 4-fluorophenol (I) with chronic acid (II) by means of polyphosphonic acid (PPA) at 120 C gives 6-fluoro-2-methyl-chroman-4-one (III), which is then condensed with KCN and ammonium carbonate in hot acetamide.

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2) The condensation of 4-fluorophenol (I) with ethyl (S)-lactate (II) by means of diethyl azodicarboxylate and triphenylphosphine in THF gives ethyl 2(R)-(4-fluorophenoxy)propionate (III), which is reduced with LiAlH4 in THF yielding 2(R)-(4-fluorophenoxy)propanol (IV). The reaction of (IV) with Br2 and triphenylphosphine in DMF affords 1-bromo-2(R)-(4-fluorophenoxy)propane (V), which is condensed with N-benzoyl-2-hydroxyglycine (VI) by means of methanesulfonic acid to give (RS)-N-benzoyl-2-[2-(1-bromo-2(R)propoxy)-5-fluorophenyl]glycine (VII). The cyclization of (VII) by means of acetic anhydride and K2CO3 in acetone yields 6-fluoro-2(R)-methyl-2'-phenylspiro[2,3-dihydro-4H-1-benzopyran-4(RS),4'-oxazolidin]-5'-one (VIII), which is hydrolyzed with refluxing formic acid-HCl affording 4(RS)-amino-6-fluoro-2(R)-methyl-2,3-dihydro-4H-1-benzopyran-4-carboxylic acid (IX). The esterification of (IX) with Cl2SO and methanol gives the corresponding methyl ester (X), which is submitted to optical resolution with alpha-chymotrypsine to yield methyl 4(S)-amino-6-fluoro-2(R)-methyl-2,3-dihydro-4H-1-benzopyran-4-carboxylate (XI). Finally, this compound is cyclized with sodium cyanate in acetic acid.

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The chiral amine intermediate (XV) has been obtained as follows: The alkylation of 4-fluorophenol (I) with allyl bromide (II) and K2CO3 gives the allyl ether (III), which by thermal rearrangement at 210 C yields 2-allyl-4-fluorophenol (IV). The silylation of (IV) with TBDMS-Cl and imidazole affords the silyl ether (V), which is submitted to hydroboration with BH3 and H2O2 to provide the propanol (VI). The oxidation of (VI) with Dess Martin periodinane (DMP) gives the aldehyde (VII), which is condensed with the phosphorane (VIII) to yield the pentenoic ester (IX). The reduction of (IX) with DIBAL affords the unsaturated alcohol, which is desilylated with TBAF in THF furnishing the diol (XI). The treatment of (XI) under the Sharpless asymmetric epoxidation conditions ((-)-DET and titanium tetraisopropoxide) gives, after cyclization with NaOH, 1(R)-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2(S)-yl)-1,2-ethanediol (XII), which is selectively tosylated with TsCl and pyridine yielding the monotosylate (XIII). The reaction of (XIII) with sodium azide in DMF affords the azide (XIV), which is reduced to the corresponding amine (XV) with H2 over Pd/C in ethanol.

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Ether (III) was prepared by condensation of (S)-4-(hydroxymethyl)butyrolactone (I) and 4-fluorophenol (II) in the presence of diisopropylazodicarboxylate (DIAD) and triphenylphosphine under Mitsunobu conditions. Then, reduction of lactone (III) with DIBAL-H in toluene at -78 C gave lactol (IV), which was converted to silyl ether (V) by treatment with tert-butyldimethylsilyl chloride (TBDMS-Cl) and imidazole. Subsequent reaction of (V) with TBDMS-Br in CH2Cl2 at -78 C, followed by condensation with the lithium acetylide derived from acetylene (VI), yielded compound (VII) as a mixture of isomers. Chromatographic separation of the mixture provided the desired trans isomer, which was deprotected by treatment with tetra-n-butylammonium fluoride to give alcohol (VIII). This was then condensed with N,O-bis(phenoxycarbonyl)hydroxylamine (IX) in the presence of DIAD and Ph3P to furnish the hydroxamic acid derivative (X). Finally, concomitant deprotection of the O-phenoxycarbonyl group and substitution of the remaining phenoxy group for an amino group by treatment with methanolic ammonia in a pressure tube, provided the title compound.

合成路线8

The reaction of 4-fluorophenol (I) with epichlorohydrin (II) by means of K2CO3 in refluxing acetone gives 2-(4-fluorophenoxymethyl)oxirane (III), which is submitted to an enantioselective ring opening with the Jacobsen (R,R)-catalyst yielding a mixture of the (R)-diol (IV) and unaltered epoxide (V), easily separated by column chromatography. The reaction of (IV) with tosyl chloride and pyridine in dichloromethane affords the primary monotosylate (VI), which is converted into the chiral epoxide (VII) by reaction with NaH in THF/DMF. The reaction of (VII) with allylmagnesium bromide (VIII) in ethyl ether gives the 2-hexenol derivative (IX), which is treated with benzenesulfonyl chloride and DMAP yielding the sulfonate (X). The ozonolysis of (X) with ozone in dichloromethane affords the aldehyde (XI), which is condensed with ethoxycarbonylmethylene(triphenyl)phosphorane (XII) yielding the 2-heptenoic ester (XIII). The reduction of (XIII) with diisobutylaluminum hydride (DIBAL) in toluene/dichloromethane provides the 2-hepten-1-ol (XIV), which is epoxidized with cumene hydroperoxide in the presence of diisopropyl (+)-tartrate and Ti(Oi-Pr)4 in dichloromethane to give the chiral epoxyalcohol (XV). The reaction of (XV) with triphenylphosphine/CCl4 in chloroform affords the corresponding chloride (XVI).

合成路线9

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10

Condensation of 4-bromobenzaldehyde (I) with 4-fluorophenol (II) in the presence of K2CO3 in refluxing dimethylacetamide gave ether (III). Subsequent reductive amination of (III) with cycloheptylamine (IV) using ethanolic NaBH4 afforded secondary amine (V). Phenyl carbamate (VIII) was obtained by treatment of aminopyridine (VI) with phenyl chloroformate (VII) and dimethylaniline. Condensation of this carbamate with amine (V) in the presence of Et3N in refluxing toluene furnished urea (IX) (1). Both sulfide groups of (IX) were finally oxidized to sulfone using meta-chloroperbenzoic acid in CH2Cl2.

合成路线11

Condensation of 4-bromobenzaldehyde (I) with 4-fluorophenol (II) in the presence of K2CO3 in refluxing dimethylacetamide gave ether (III). Subsequent reductive amination of (III) with cycloheptylamine (IV) using ethanolic NaBH4 afforded secondary amine (V). Phenyl carbamate (VIII) was obtained by treatment of aminopyridine (VI) with phenyl chloroformate (VII) and dimethylaniline. Finally, condensation of this carbamate with amine (V) in the presence of Et3N in DMF at 100 C furnished the target urea.

合成路线12

2,5-Bis(p-bromophenyl)furan (II) was prepared by cyclodehydration of diketone (I) in refluxing acetic anhydride. Displacement of both bromine atoms by copper(I) cyanide in boiling quinoline generated the dicyano derivative (V). Alternatively, furan (V) was prepared by addition of p-cyanobenzaldehyde (III) to divinyl sulfone (IV) in the presence of a thiazolium catalyst. After conversion of the cyano groups of (V) into bis-imidate (VI), reaccion with ethanolic ammonia furnished amidine (VII). The stable symmetrical carbonate (X) was obtained by reaction of p-fluorophenyl chloroformate (VIII) with p-fluorophenol (IX) in the presence of pyridine. Finally, reaction of the bis(amidine) compound (VII) with carbonate (X) yielded the title compound.

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