2-吡啶甲醇及2-吡啶甲醛的合成

以 2 -甲基吡啶为原料、过氧化氢为氧化剂制备 2 -吡啶甲醇和 2 -吡啶甲醛,工艺方法经济、安全     

Synthesis and immunosuppressive activity of 2-substituted 2-aminopropane-1,3-diols and 2-aminoethanols

A series of 2-substituted 2-aminopropane-1,3-diols was synthesized and evaluated for their lymphocyte-decreasing effect and immunosuppressive effect on rat skin allograft. A phenyl ring was introduced into the alkyl chain of the lead compound 3, which is an immunosuppressive agent structurally simplified from myriocin (1, ISP-I) via compound 2. The potency of the various compounds was dependent upon the position of the phenyl ring within the alkyl side chain. The most suitable length between the quaternary carbon atom and the phenyl ring was two carbon atoms. 2-Substituted 2-aminoethanols were successively synthesized and evaluated for their T-cell-decreasing effect and immunosuppressive effect using a popliteal lymph node gain assay in rats. The absolute configuration at the quaternary carbon affected the activity, and the (pro-S)-hydroxymethyl group of compound 6 was essential for potent immunosuppressive activity. Favorable substituents for the (pro-R)-hydroxymethyl group of 6 were hydroxyalkyl (hydroxyethyl and hydroxypropyl) or lower alkyl (methyl and ethyl) groups. 2-Amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol hydrochloride (6, FTY720) was found to possess considerable activity and is expected to be useful as an immunosuppressive drug for organ transplantation.     

2-苯基-1-丁醇与2-二甲氨基-2-苯基丁腈的合成

目的为马来酸曲美布汀的重要中间体2-二甲氨基-2-苯基-1-丁醇的合成奠定基础。方法苯乙腈与溴乙烷进行烃化反应得2-苯基-1-丁腈,所得产物经水解得2-苯基-1-丁酸,然后通过硼氢化钠-碘体系还原得2-苯基-1-丁醇;苯乙腈与N-溴代丁二酰亚胺进行卤代反应得溴代苯乙腈,所得产物与二甲胺进行烃化反应得2-二甲氨基苯乙腈,然后与溴乙烷进行烃化反应得2-二甲氨基-2-苯基丁腈。结果合成了2-苯基-1-丁醇和2-二甲氨基-2-苯基丁腈,总收率为分别为51%和59.4%。目标产物的结构经核磁共振氢谱、质谱确证。结论本合成方法原料易得,操作简单,收率较高,适合于工业化生产。     

Metabolism and metabolic effects of 2-azahypoxanthine and 2-azaadenosine

The metabolism and metabolic effects of 2-azahypoxanthine and 2-azaadenosine were studied to elucidate the biochemical basis for their known cytotoxicities. 2-Azaadenosine is a known substrate for adenosine kinase. That 2-azahypoxanthine is a substrate for hypoxanthine (guanine) phosphoribosyltransferase is shown by the observations that, in cell-free fractions from HEp-2 cells supplemented with 5-phosphoribosyl-1-pyrophosphate, 2-azahypoxanthine inhibited the conversion of hypoxanthine to IMP but not the conversion of adenine to AMP, and hypoxanthine, but not adenine, inhibited the conversion of 2-azahypoxanthine to 2-azaIMP. [8-14C]2-Azahypoxanthine was synthesized from [8-14C]hypoxanthine via [2-14C]-4-amino-5-imidazolecarboxamide. In HEp-2 cells in culture, the principal metabolite of [8-14C]-2-azahypoxanthine was 2-azaATP; there was no detectable 14C in deoxynucleotides or in DNA or RNA fractions. 2-Azaadenosine was much more toxic than 2-azahypoxanthine, and, when used in the presence of an adenosine deaminase inhibitor, 2'-deoxycoformycin, was converted in HEp-2 cells to 2-azaATP in amounts that exceeded those of ATP in control cells. The pool of ATP was reduced by as much as 75% as 2-azaATP accumulated. In a short-term experiment (4 hr), 2-azaadenosine selectively reduced the pools of adenine nucleotides, whereas 2-azahypoxanthine reduced the pools of guanine nucleotides selectively. Both 2-azahypoxanthine and 2-azaadenosine inhibited the incorporation of formate into purine nucleotides and were without effect on the conversion of thymidine and uridine to nucleotides. 2-Azahypoxanthine inhibited the incorporation of thymidine into macro-molecules but not that of uridine or leucine; 2-azaadenosine inhibited the incorporation of all three of these precursors non-selectively. 2-AzaIMP inhibited IMP dehydrogenase competitively with IMP (Ki = 66 microM). The difference in effects of 2-azahypoxanthine and 2-azaadenosine perhaps may be due to the production, from 2-azahypoxanthine but not from 2-azaadenosine + 2'-deoxycoformycin, of 2-azaIMP, which inhibits synthesis of guanine nucleotides and thereby results in inhibition of DNA synthesis. Specific sites of action for 2-azaadenosine are yet undefined.     

Molecular modeling of 2-alkyloxy- and 2-aralkyloxy-adenosine A1- and A2-agonists

The C2-region of adenosine A1- and A2-receptors by a molecular modeling technique has been extended and applied to a series of 2-substituted adenosines reported by Olsson, et al. The similarity and dissimilarity of the structure maps obtained by molecular modeling have been used as a basis for the mapping of the analysed receptor domain. The proposed model of the C2-region of the A1-receptor consists of a narrow and sterically limited area that interacts well electrostatically with small and electron rich moieties. Olsson's provisional model of the C2-region of the A2-receptor has been extended with two subsites, as well as with a forbidden area near the C2-position of the purine ring. The conformational analysis performed in the study does not support the hypothesis of Olsson et al. that adenosine C2 substituents may partly occupy the same receptor domain as the N6 substituents of the A1-receptor. The occupation of the cycloalkyl subsite increases the receptor selectivity while the occupation of the other subsite by aryl rings, fixed at a parallel position to the purine system, highly enhances the receptor affinity.     

Synthesis and antiviral evaluation of carbocyclic analogues of 2'-azido- and 2'-amino-2'-deoxycytidine

Carbocyclic analogues of 2'-azido- and 2'-amino-2'-deoxycytidine, compounds 8 and 9, were synthesized by an eight-step synthesis from (+/-)-(1 alpha,2 alpha,3 beta,5 beta)-3-amino-5-(hydroxymethyl)-1,2- cyclopentanediol (1), which was prepared from cyclopentadiene via an eight-step route. These compounds were tested in vitro against herpes simplex virus type 1 (HSV-1). The 2'-amino analogue was found to show moderate antiviral activity, with an ED50 of 50 microM. However, the 2'-azido analogue was not active at a concentration up to 400 microM.     

2-Fluoroformycin and 2-aminoformycin. Synthesis and biological activity

Syntheses of 2-fluoroformycin [7-amino-5-fluoro-3-(beta-D-ribofuranosyl)pyrazolo[4,3-d]pyrimidine] (2b) and 2-aminoformycin [5,7-diamino-3-(beta-D-ribofuranosyl)pyrazolo[4,3-d]pyrimidine] (2c) are described. Cytotoxicity data are given for 2b and 2c alone as well as with added pentostatin. Kinetic parameters for adenosine deaminase are also provided. 2-Fluoroformycin, although a much poorer substrate for adenosine deaminase than formycin A, is not nearly as cytotoxic to cells in culture.     

Antioxidant properties of 2-imidazolones and 2-imidazolthiones

Uric acid has been postulated to be an important antioxidant and free radical scavenger in humans. Other purines, such as xanthine, that lack an 8-oxo group on the imidazole ring do not show antioxidant properties. For this reason, the antioxidative activities of 2-imidazolones and 2-imidazolthiones were compared to that of uric acid. 2-Imidazolthiones reacted with the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) at rates comparable to those of uric acid and other antioxidants. 2-Imidazolones also reacted with DPPH, although at a much slower rate than the 2-imidazolthiones. The 2-imidazolthiones protected oxyhemoglobin from oxidation to methemoglobin by sodium nitrite; the 2-imidazolones had little effect on the oxidation of oxyhemoglobin by nitrate. Most of the 2-imidazolthiones and 2-imidazolones protected both porcine and bovine erythrocytes from hemolysis by t-butyl hydroperoxide. Although 2-imidazolthiones were more reactive than 2-imidazolones in the assays using DPPH and the oxidation of oxyhemoglobin, both types of compounds may be useful as antioxidants in vivo.     

Synthesis and biological activity of the 2-desamino and 2-desamino-2-methyl analogues of aminopterin and methotrexate

The previously undescribed 2-desamino and 2-desamino-2-methyl analogues of aminopterin (AMT) and methotrexate (MTX) were synthesized from 2-amino-5-(chloromethyl)pyrazine-3-carbonitrile. The AMT analogues were obtained via a three-step sequence consisting of condensation with di-tert-butyl N-(4-aminobenzoyl)-L-glutamate, heating with formamidine or acetamidine acetate, and mild acidolysis with trifluoroacetic acid. The MTX analogues were prepared similarly, except that 2-amino-5-(chloromethyl)pyrazine-3-carbonitrile was condensed with 4-(N-methylamino)benzoic acid and the resulting product was annulated with formamidine or acetamidine acetate to obtain the 2-desamino and 2-desamino-2-methyl analogues, respectively, of 4-amino-4-deoxy-N10-methylpteroic acid. Condensation with di-tert-butyl L-glutamate in the presence of diethyl phosphorocyanidate followed by ester cleavage with trifluoroacetic acid was then carried out. Retention of the L configuration in the glutamate moiety during this synthesis was demonstrated by rapid and essentially complete hydrolysis with carboxypeptidase G1 under conditions that likewise cleaved the L enantiomer of MTX but left the D enantiomer unaffected. The 2-desamino and 2-desamino-2-methyl analogues of AMT and MTX inhibited the growth of tumor cells, but were very poor inhibitors of dihydrofolate reductase (DHFR). These unexpected results suggested that activity in intact cells was due to metabolism of the 2-desamino compounds to polyglutamates.     

Synthesis and biological activities of 2-pyrimidinone nucleosides. 2. 5-Halo-2-pyrimidinone 2'-deoxyribonucleosides

1-(2-Deoxy-beta-D-ribofuranosyl)-5-bromo-2-pyrimidinone (BrPdR) and 1-(2-deoxy-beta-D-ribofuranosyl)-5-iodo-2-pyrimidinone (IPdR) have been synthesized by condensation of the appropriate silylated bases 2a and 2b, respectively, with 3,5-bis-O-(p-chlorobenzoyl)-2-deoxy-alpha-D-ribofuranosyl chloride (8) in 1,2-dichloroethane, in the presence of SnCl4, followed by separation of the anomeric blocked nucleosides via column chromatography and subsequent deprotection with methanolic ammonia. Both BrPdR and IPdR exhibited significant antiherpes activities against various strains of HSV-1 and HSV-2, the latter compound (IPdR) showing the higher activity as well as the stronger binding to the virus-specific thymidine kinase.     

2'-Deoxy-2'-methylenecytidine and 2'-deoxy-2',2'-difluorocytidine 5'-diphosphates: potent mechanism-based inhibitors of ribonucleotide reductase

It has been found that 2'-deoxy-2'-methyleneuridine (MdUrd), 2'-deoxy-2'-methylenecytidine (MdCyd), and 2'-deoxy-2',2'-difluorocytidine (dFdCyd) 5'-diphosphates (MdUDP (1) MdCDP (2) and dFdCDP (3), respectively) function as irreversible inactivators of the Escherichia coli ribonucleoside diphosphate reductase (RDPR). 2 is a much more potent inhibitor than its uridine analogue 1. It is proposed that 2 undergoes abstraction of H3' to give an allylic radical that captures a hydrogen atom and decomposes to an active alkylating furanone species. RDPR also accepts 3 as an alternative substrate analogue and presumably executes an initial abstraction of H3' to initiate formation of a suicide species. Both 2 and 3 give inactivation results that differ from those of previously studied inhibitors. The potent anticancer activities of MdCyd and dFdCyd indicate a significant chemotherapeutic potential. The analogous RDPR of mammalian cells should be regarded as a likely target and/or activating enzyme for these novel mechanism-based inactivators.