丁酸氯维地平降解杂质的合成

以4-(2,3-二氯苯基)-1,4-二氢-2,6-二甲基-3,5-吡啶二羧酸(2-氰基乙基)（甲基）酯(5)为起始原料,合成了丁酸氯维地平的5种降解杂质：4-(2,3-二氯苯基)-1,4-二氢-2,6-二甲基-3,5-吡啶二羧酸单甲酯(A), 4-(2,3-二氯苯基)-1,4-二氢-2,6-二甲基-3-吡啶羧酸甲酯(B), 4-(2,3-二氯苯基)-2,6-二甲基-3,5-吡啶二羧酸单甲酯(C), 4-(2,3-二氯苯基)-2,6-二甲基-3,5-吡啶二羧酸（丁酰氧基甲基）（甲基）酯(D)和4-(2,3-二氯苯基)-2,6-二甲基-3-吡啶羧酸甲酯(E)。其中A由5水解制得;B由A脱羧制得;C由5氧化后再经水解制得;D由C和丁酸氯甲酯缩合制得;E由C脱羧制得,化合物结构经¹H NMR和MS（ESI）确证。     

Effect of acyl chain length and branching on the enantioselectivity of Candida rugosa lipase in the kinetic resolution of 4-(2-difluoromethoxyphenyl)-substituted 1,4-dihydropyridine 3,5-diesters.

Since 2,6-dimethyl-4-aryl-1,4-dihydropyridine 3,5-diesters themselves are not hydrolyzed by commercially available hydrolases, derivatives with spacers containing a hydrolyzable group were prepared. Seven acyloxymethyl esters of 5-methyl- and 5-(2-propoxyethyl) 4-[2-(difluoromethoxy)phenyl]-2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate were synthesized and subjected to Candida rugosa lipase (CRL) catalyzed hydrolysis in wet diisopropyl ether. A methyl ester at the 5-position and a long or branched acyl chain at C3 gave the highest enantiomeric ratio (E values). The most stereoselective reaction (E = 21) was obtained with 3-[(isobutyryloxy)methyl] 5-methyl 4-(2-difluoromethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, and this compound was used to prepare both enantiomers of 3-methyl 5-(2-propoxyethyl) 4-[2-(difluoromethoxy)phenyl]-2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate. The absolute configuration of the enzymatically produced carboxylic acid was established to be 4R by X-ray crystallographic analysis of its 1-(R)-phenylethyl amide.     

An efficient chemoenzymatic approach to enantiomerically pure 4-[2-(difluoromethoxy)phenyl] substituted 1,4-dihydropyridine-3,5-dicarboxylates

An efficient chemoenzymatic synthesis of (−)-3-methyl 5-(2-propoxyethyl) (4R)-4-[2-(difluoromethoxy)phenyl]-2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate has been achieved. The key step is a highly stereoselective Candida rugosa lipase (CRL)-mediated asymmetrisation of the prochiral bis[(isobutyryloxy)methyl]-4-[2-(difluoromethoxy)phenyl]-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate.     

Rearrangements of 4-(2-Aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylic acid diethyl ester

The treatment of 4-(2-aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinecarboxylic acid diethyl ester (III) with refluxing toluene or pyridine afforded 1,2,3,6-tetrahydro-2,4-dimethyl-2,6-methano-1,3-benzodiazocine-5,11-dicarboxylic acid diethyl ester (IV) as the major product. In addition, the following minor products were isolated: 2-methyl-3-quinolinecarboxylic acid ethyl ester (V), 3-(2-aminophenyl)-5-methyl-6-azabicyclo[3,3,1]-hept-1-ene-2,4-dicarboxylic acid diethyl ester (VI), and 5,6-dihydro-2,4-dimethyl-5-oxobenzo[c][2,7]naphthyridine-1-carboxylic acid ethyl ester (VII). In contrast, acidic conditions caused the conversion of III into V in a 95% yield. The formation of the latter appears to involve IV as an intermediate, since IV degraded rapidly in acid to give V in a quantitative yield.     

Light-induced Dehydrodimerization of 3-Hydroxypyrroles

Irradiation (λ > 280 nm) of 3-hydroxy-1H-pyrrole-2-carboxylates 1 in CH₃CN gives the [2.2′-bi(3-oxo-2,3-dihydro-1H-pyrrole)]-2-,2′-dicarboxylates 2 in reasonable to good yields. The corresponding N-methylpyrroles 3 only undergo slow photodecomposition under similar conditions. Several 2-methyl-3-oxo-2,3-dihydro-1H-pyrrole-2-carboxylates 4 and 5 were synthesized to compare their spectral data with those of the dehydrodimers 2 . A X-ray structure analysis was performed for diethyl [2,2′-bi(4,5-dimethyl-3-oxo-2,3-dihydro-1 H-pyrrole)]-2,2′-dicarboxylate ( 2b ). The originally proposed [3,3′-bi(3H-pyroole)] structure for compounds 2a - e proves incorrect.     

Reactions of N- and C-alkenylanilines: X. Synthesis of 2-vinyldihydroindoles from 4-methyl-2-(pent-3-en-2-yl)aniline

2-(1-Iodoethyl)-3,5-dimethyl-1-(4-methylphenylsulfonyl)-2,3-dihydro-1H-indole reacted with pyridine, piperidine, N-alkylpiperidines, and dimethylformamide to give dehydrohalogenation and halogen substitution products whose ratio depended on the reagent structure. Heating of 2-(1-iodoethyl)-3,5-dimethyl-1-methylsulfonyl-2,3-dihydro-1H-indole with piperidine resulted in the formation of only dehydroiodination products.     

Synthesis of 1,4-dihydropyridine-5-phosphonates and their calcium-antagonistic and antihypertensive activities: novel calcium-antagonist 2-[benzyl(phenyl)amino]ethyl 5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-1,4-dihydro-2,6-dim ethyl-4-(3-nitrophenyl)-3-pyridinecarboxylate hydrochloride ethanol (NZ-105) and its crystal structure.

The effect of the 3-carboxylic-ester variation in 2,2-dimethyltrimethylene 3-alkoxycarbonyl-4-aryl-1,4-dihydro-2,6-dimethyl-5-pyridinephosphonat es (1) was investigated with relation to the calcium-antagonistic and antihypertensive activities: the analogs containing the alkyl groups of not more than 12 carbons and an amino functionality in the carboxylic-ester moiety were synthesized to be examined for biological activities. Among them, 2-[benzyl(phenyl)amino]-ethyl 5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-1,4-dihydro-2, 6-dimethyl-4-(3-nitrophenyl)-3-pyridine-carboxylate hydrochloride ethanol (NZ-105) showed particularly beneficial activities and was selected for further pharmacological studies and clinical development. Some aspects of the structure-activity relationships and solid-state structure of NZ-105 by X-ray crystallographic analysis were described.     

Asymmetric reduction of 7,8-difluoro-3-methyl-2H-1,4-benzoxazine. Synthesis of a key intermediate of (S)-(-)-ofloxacin (DR-3355)

An efficient, highly enantioselective synthesis of (S)-(-)-7,8-difluoro-2,3-dihydro-3-methyl-4H-1,4-benzoxazine, a key intermediate of (S)-(-)-ofloxacin, using various chiral sodium triacyloxyborohydrides as reducing agents is reported.     

Pseudosymmetry in the crystal structure of 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′,3′-dichlorophenyl)-1,4-dihydropyridine

Within the framework of a detailed crystallochemical analysis a comparison of the structures of symmetrically independent molecules was performed and the energy of intermolecular interaction was calculated for a triclinic bisystem crystal, 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′,3′-dichlorophenyl)-1,4-dihydropyridine. Pseudosymmetrical operations were detected and identified. The presence of highly efficient layers with pseudomonoclinic symmetry was disclosed in this structure.     

Effect of salts on the reaction direction of (2R*,3R*)-2-[(1R*)-1-iodoethyl)]-3-methyl(3,5-dimethyl)-1-(4-methylphenylsulfonyl)-2,3-dihydro-1H-indoles with dimethylformamide

Transformations of (2R*,3R*)-2-[(1R*)-1-iodoethyl)-3,5-dimethyl-1-(4-methylphenylsulfonyl-2,3-dihydro-1H-indole on heating in boiling dimethylformamide in the presence of various salts were studied.     

Synthesis and pharmacological effects of optically active 2-[4-(4-benzhydryl-1-piperazinyl)phenyl]-ethyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate hydrochloride

Optically active 2-[4-(4-benzhydryl-1-piperazinyl)phenyl]ethyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate [(S)-(+)-1 and (R)-(-)-1] hydrochlorides were synthesized with high optical purities from (R)-(-)- and (S)-(+)-1,4-dihydro-5-methoxycarbonyl-2,6-dimethyl-4-(3-nitrophenyl)- 3-pyridinecarboxylic acids [(R)-(-)-6 and (S)-(+)-6], which are available from (+/-)-6 by optical resolution using quinidine and cinchonidine, respectively. From pharmacological investigations of (S)-(+)-1 and (R)-(-)-1 such as the antihypertensive effect on spontaneously hypertensive rats and inhibition of [3H]nimodipine binding to rat cardiac membrane homogenate, the active form of 1 was defined to be the (4S)-(+)-enantiomer of 1.     

Reactions of 3,5-dibromo-1-(thiiran-2-ylmethyl)-1,2,4-triazole with NH-azoles

Reactions of 3,5-dibromo-1-(thiiran-2-ylmethyl)-1,2,4-triazole with 3,5-dimethylpyrazole, 1,3-dimethyl-3,7-dihydropurine-2,6-dione, 3,5-dibromo-1,2,4-triazole, 2,4,5-tribromoimidazole, and 2-chlorobenzimidazole lead to the formation of 5-azolylmethyl-2-bromo-5,6-dihydrothiazolo[3,2-b]-1,2,4-triazoles. In the case of 8-bromo-1,3-dimethyl-3,7-dihydropurine-2,6-dione the intermediate thiolate anion undergoes cyclization into 7-[(3,5-dibromo-1,2,4-triazol-1-yl)methyl]-1,3-dimethyl-6,7-dihydrothiazolo[2,3-f]purine-2,4(1H,3H)-dione. The structure of reaction products depends on the relative rate of substitution of leaving groups in the reagents.     

The synthesis of some dialkyl 4-(3-substituted amino)phenyl-1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylates

Dialkyl 4-(3-aminophenyl)-1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylates 1 were transformed into alkyl 4-(3-(((2-benzoylamino-2-methoxycarbonyl)ethenyl)amino)phenyl)-1,4-dihydro-2,6-dimethyl-pyridine-3,5-dicarboxylates 4 and with 2,2-disubstituted-1-dimethylaminoethenes 7 into dimethyl 4-(3-(((2,2-diacyl- or 2-acyl-2-alkoxycarbonyl)ethenyl)amino)phenyl)-1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylates 8 and their ethyl methyl analogues 9.     

Synthesis of novel 1-(2,3-dihydro-5H-4,1-benzoxathiepin-3-yl)-uracil and -thymine, and their corresponding S-oxidized derivatives

On the basis of molecular variations on isosteric replacements from the prototype 1-(2,3-dihydro-5H-1,4-benzodioxepin-3-yl)-5-fluorouracil a series of 3-(2,3-dihydro-5H-4,1-benzoxathiepin-3-yl)-uracil or -thymine O,N-acetals was prepared. The nature of the cis- and trans-sulfoxide isomers was established by means of their conformational analyses carried out with Sybyl and after comparing the theoretical results with the ¹H NMR responses of the target molecules. (RS)-3-(1,1-Dioxo-2,3-dihydro-5H-4,1-benzoxathiepin-3-yl)thymine and (1S*,3S*)-1-(1-oxo-3,5-dihydro-2H-4,1-benzoxathiepin-3-yl)thymine were found to be inhibitors of the MCF-7 cell growth.     

4-Aryldihydropyridines,a New Class of Highly Active Calcium Antagonists

The aryldihydropyridines first prepared by Hantzsch almost 100 years ago have recently been found to be highly effective calcium antagonists with suitable pharmacological profiles. An illustrative example is dimethyl-l,4-dihydro-2,6-dimethyl-4-(o-nitrophenyl)pyridine-3,5-dicarboxylate (Nifedipine) which is already employed therapeutically. This substance lowers the frequency of attack of angina pectoris and reduces blood pressure. The discovery of the therapeutic activity of this class of substances initiated renewed investigation of the Hantzsch condensation and the synthesis of numerous 4-aryldihydropyridines and related compounds. Qualitative and quantitative structure/activity relationships of these substances can be deduced from their biological data.     

Cyclization of a cysteine conjugate of N-(3,5-Dichlorophenyl)succinimide

N-(3,5-Dichlorophenyl)-2-cysteinylsuccinimide methyl ester hydrochloride ( 5 ) was prepared from N-(3,5-dichlorophenyl)maleimide ( 3 ) and cysteinyl methyl ester hydrochloride. Attempted neutralization of the cysteine conjugate salt with triethylamine resulted in spontaneous cyclization of 5 to form the more stable 2-(N-3,5-dichlorophenylcarbamoylmethyl)-5-carbomethoxy-1,4-thiazine- 3-one ( 6 ). Similar results might be expected in vivo should these metabolites of succinimides be formed.     

Studies on naphthyridines. Part 2 . Synthesis of 4-substituted and 6-substituted 1,6-naphthyridin-5(6H)-ones

Ethyl 4-substituted 2-methyl-5-oxo-5,6-dihydro-1,6-naphthyridine-3-carboxylates 3a-h were synthetized in a one-step reaction from diethyl 2,6-diraethylpyridine-3,5-dicarboxylates 1a-h by aminomethinylation with 1,3,5-triazine (2). The 6-substitued derivatives 6a-z,aa-ff could be obtained from diethyl 2-[2-(dimethylamino)-vinyl]-6-methylpyridine-3,5-dicarboxylate ( 4 ) either directly or via the isolated intermediate 2-[2-(arylamino)-vinyl]pyridine compounds 5a-i.     

Heterocycles from carbohydrate precursors. Part XIX. The X-ray crystal structure determination of the reaction product of 4-(2-acetoxyethylidene)-4-hydroxy-2,3-dioxobutyro-1,4-lactone-2-(p-bromophenylhydrazone) with methylhydrazine

X-ray crystallographic data show that the product obtained in the reaction of 4-(2-acetoxy-ethylidene)-4-hydroxy-2,3-dioxobutyro-1,4-lactone-2-(p-bromophenylhydrazone) with methyl-hydrazine is the bicyclic compound 2,6-dimethyl-3,4-dioxo-2,3,4,6,7,8-hexahydropyridazino-[4,3-c]pyridazine 4-(p-bromophenylhydrazone) ( 10 ) and not as originally suggested 1-methyl-3-(1-methylpyrazolin-3-yl)-4,5-pyrazoledione 4-(p-bromophenylhydrazone) ( 8 ).     

Synthesis of azoles from 3-[(3-hydrazino-3-oxopropyl)anilino]-and 3-[(3-hydrazino-3-oxopropyl)-4-methylanilino]propane hydrazides

Condensation of 3-[(3-hydrazino-3-oxopropyl)anilino]-and 3-[(3-hydrazino-3-oxopropyl)-4-methylanilino]propane hydrazides with 2,4-pentanedione, phenyl isocyanate or phenyl isothiocyanate (with subsequent work up of the semicarbazides obtained by base), and carbon disulfide gave respectively: 1-(3,5-dimethyl-1H-1-pyrazolyl)-3-[3-(3,5-dimethyl-1H-1-pyrazolyl)-3-oxopropylanilino]-1-propanone, 3-(2-{[2-(5-oxo-4-phenyl-4,5-dihydro-1H-1,2,4-triazol-3-yl)ethyl]anilino}ethyl)-4-phenyl-4,5-dihydro-1H-1,2,4-triazol-5-one and its thio analog, and 5-(2-{[2-(2-thioxo-2,3-dihydro-1,3,4-oxadiazol-5-yl)ethyl]anilino}ethyl)-2,3-dihydro-1,3,4-oxadiazole-2(3H)-thione plus their methyl derivatives. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1353–1358, September, 2007.     

Functional polymers and sequential copolymers by phase transfer catalysis. 18. Synthesis and characterization of α,ω-bis(2,6-dimethylphenol)–poly(2,6-dimethyl-1,4-phenylene oxide) and α,ω-bis(vinylbenzyl)–poly(2,6-dimethyl-1,4-phenylene oxide) oligomers

A novel and convenient synthetic method for the preparation of α,ω-bis(2,6-dimethylphenol)–poly(2,6-dimethyl-1,4-phenylene oxide) (PPO-2OH) is presented. It is based on the oxidative copolymerization of 2,6-dimethylphenol (DMP) with 2,2′-di(4-hydroxy-3,5-dimethylphenyl propane) (TMBPA) in a mixture of water–methanol or chlorobenzene–methanol. By using a 4/1 mole ratio of DMP to TMBPA and different solvent mixtures, it was possible to obtain bifunctional PPO-2OHs with number average molecular weights between 1000 and 5000. A phase-transfer-catalyzed etherification of PPO-2OH chain ends with a mixture of m- and p-chloromethylstyrene was used to synthesize α,ω-bis(vinylbenzyl)-poly(2,6-dimethyl-1,4-phenylene oxide)s (PPO-2VBs). The thermal polymerization of the PPO-2VBs was studied by differential scanning calorimetry, and has demonstrated a very high thermal reactivity for this new class of reactive oligomers.