合成路线1

The cyclization of 2,2'-di(benzyloxycarbonylamino)pimelic acid (I) with PCl5 in methylene chloride gives the bis-N-carboxy anhydride (II), which by reaction with tert-butyl carbazate (A) is converted into the bis(tert-butyloxycarbonylhydrazide) compound (III). The enzymatic hydrolysis of (III) with an aminopeptidase from Streptomyces sapporonensis affords the mono-tert-butoxycarbonylhydrazide (IV), which by selective protection of the amino group with benzyloxycarbonyl chloride (B) under copper chelate conditions yields the selectively protected hydrazide (V). Full protection of (V) with tert-butoxycarbonyl anhydride (C) affords the fully protected monohydrazide (VI), which is condensed with benzyl glycinate (VII) to give the protected dipeptide (VIII). Hydrogenolysis of (VIII) with H2 over Pd/C in methanol-acetic acid yields the di-tert-butoxycarbonyldipeptide (IX), which is condensed with 2-acetoxypropanoylalanylglutamic acid monobenzyl ester (X) by means of isobutoxycarbonyl chloride (D) yielding the protected FK-156 (XI).

合成路线2

1) The cyclization of meso-2,6-bis(benzyloxycarbonylamino)heptanedioic acid (I) with PCl5 gives the corresponding bis oxazolidinedione (II), which is treated with tert-butyl carbazate (III) yielding the bis hydrazide (IV). Enzymatic hydrolysis of (IV) with Streptomyces sapporonensis affords the (S)-monoacid (V), which is selectively protected with benzyl chloroformate and copper chelate (VI). A second protection reaction of (VI) with tert-butoxycarbonyl anhydride gives the amino protected acid (VII) , which is condensed with D-alanine benzyl ester (VIII) by means of isobutyl chloroformate to afford the acylated D-alanine (IX). Elimination of the benzyloxycarbonyl groups of (IX) by hydrogenolysis yields compound (X) with a free amino group, which is condensed with N-heptanoyl-D-glutamic acid 1-benzyl monoester (XI) to give the protected FK-565 precursor (XII). Finally, this compound is deprotected with trifluoroacetic acid and sodium periodate.

合成路线3

1) The reaction of 4-bromobenzaldehyde (I) with trimethylorthoformate (II) and p-toluenesulfonic acid in methanol gives ketal (III), which is condensed with 2-pyridylmagnesium bromide in THF, yielding 4-(2-pyridyl)benzaldehyde (IV). The reaction of (IV) with tert-butyl carbazate (V) in refluxing ethanol affords hydrazone (VI), which is reduced with H2 over Pd/C in methanol to the hydrazine (VII). The condensation of (VII) with the epoxide (VIII) in hot isopropanol gives the expected addition product (IX), which by treatment with HCl or formic acid results in the fully deprotected intermediate (X). Finally, this compound is condensed with N-(methoxycarbonyl)-L-tert-leucine (XI) by means of O-(2-oxo-1,2-dihydro-1-pyridyl)-N,N,N',N'-tetramethyluronium tetrafluoroborate (TPTU) in dichloromethane or DMF.

合成路线4

2) Intermediate (IX) can also be obtained as follows: The cyclization of 4-cyanobenzoic acid methyl ester (XII) with acetylene at 15 Atm by means of cobaltocene in toluene at 180 C gives 4-(2-pyridyl)benzoic acid methyl ester (XIII), which is saponified with NaOH in methanol to the corresponding acid (XIV). The activation of (XIV) with isobutyl chloroformate yields the mixed anhydride (XV), which is condensed with N-(tert-butoxycarbonyl)-L-phenylalaninal (XVI) and KCN in dichloromethane, affording (XVII). The reaction of (XVII) with tert-butyl carbazate (V) by means of acetic acid in methanol gives hydrazone (XVIII), which is reduced to hydrazine (XIX) by means of sodium cyanoborohydride in THF. The isomerization of (XIX) by means of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTDE) in hot diglyme yields hydrazide (XX), which is finally reduced to intermediate (IX) with diisobutylaluminum hydride in dichloromethane/THF.

合成路线5

The intermediate carbazate (VI) has been obtained as follows. The condensation of phenylboronic acid (I) with 2-bromopyridine (II) by means of Pd(PPh3)4 gives 4-(2-pyridyl)benzaldehyde (III), which is condensed with tert-butyl carbazate (IV) in hot toluene/isopropyl alcohol to yield the benzylidenehydrazone (V). Finally, this compound is reduced with sodium formate over Pd/C in ethanol to afford the target intermediate; the carbazate (VI). The selective monosilylation of the primary OH group of diol (VII) with Tbdms-Cl, TEA and DMAP followed by reaction of the secondary OH group with MsCl gives the protected mesylate (VIII), which is desilylated with NH4F and AcOH yielding the primary alcohol (IX). The epoxidation of (IX) with t-BuOK in isopropyl alcohol affords the chiral epoxide (X), which is condensed with the intermediate carbazate (VI) in refluxing isopropanol to provide the adduct (XI). Elimination of the two Boc protecting groups of (XI) with HCl in hot THF gives the diamino compound (XII), which is finally condensed with two moles of N-(methoxycarbonyl)-L-tert-leucine (XIII) by means of WSC, HOBt and DIEA in dichloromethane to provide the target Atazanavir.

合成路线6

Reaction of triethyl orthopropionate (I) with malononitrile (II) at reflux temperature provided (1-ethoxypropylidene)malononitrile (III). Cyclopentanone (IV) was condensed with tert-butyl carbazate (V) to afford the corresponding hydrazone (VI). Subsequent reduction with sodium cyanoborohydride, followed by acid deprotection furnished cyclopentylhydrazine (VII). Then, condensation of (VII) with malononitrile derivative (III) produced pyrazole (VIII). Partial hydrolysis of the cyano group of (VIII) using concentrated sulfuric acid gave carboxamide (IX).

合成路线7

The compound was prepared by solid-phase synthesis. Condensation of tert-butyl carbazate (I) with 1,1'-carbonyldiimidazole (II) afforded the acyl imidazole (III). Coupling of (III) with amino resin produced the Boc-protected semicarbazide-linked resin (IV), which was deprotected with trifluoroacetic acid to give (V). Condensation of (V) with protected L-argininal (VI) provided the semicarbazone resin (VII). Further solid-phase peptide synthesis by means of sequential coupling with L-alanine, D-serine and phenethylsulfonyl chloride yielded the peptide-resin (VIII). Finally, deprotection of both Boc groups of (VIII) with concomitant resin cleavage by means of aqueous trifluoroacetic acid furnished the target compound.

合成路线8

In an alternative synthesis of hydrazine (XXIII), aldehyde (IX) was condensed with tert-butyl hydrazinecarboxylate (XXIV), producing hydrazone (XXV), which was further reduced to the hydrazinecarboxylate (XXVI) in the presence of NaBH(OAc)3. Acidic cleavage of the N-Boc group of (XXVI) provided hydrazine (XXIII).

合成路线9

Reductive alkylation of tert-butyl carbazate (VI) with 4-methylbenzaldehyde (VII) under catalytic hydrogenation conditions affords the N-p-methylbenzyl carbazate (VIII). This is then condensed with trimethylsilyl isocyanate to form the semicarbazide derivative (IX). Subsequent acidic Boc group cleavage in (IX) yields (X). Semicarbazide (X) is then acylated with acid chloride (V) producing (XI). Cyclization of the acyl semicarbazide (XI) in the presence of CSA leads to triazolone (XII). Finally, alkaline hydrolysis of the ethyl ester group of (XII) furnishes the title carboxylic acid.

合成路线10

6-Aminocaproic acid (I) is condensed with maleic anhydride (II) in refluxing AcOH to provide maleimidocaproic acid (III). After activation of acid (III) as the corresponding mixed anhydride with isobutyl chloroformate, coupling with tert-butyl carbazate (IV) affords the N-Boc hydrazide (V). Subsequent acidic cleavage of the Boc group of (V) furnishes hydrazide (VI). Finally, hydrazide (VI) is condensed with doxorubicin (VII) to produce the title hydrazone conjugate.

合成路线11