6,7-二氢-5H-环戊烯并[b]吡啶的合成

己二酸二乙酯经缩合、氨化、闭环、水解后脱羧、氯化及脱氯等6步反应制得头孢匹罗的中间体6，7-二氢-5H-环戊烯并[b]吡啶，总收率31％。     

5-氧代-1,2,4-噁二唑化合物的合成工艺改进

氰基化合物在盐酸羟胺和三乙胺作用下于85～90℃反应20～24h得到N-羟基脒化合物,收率由文献的26%～68%提高到90%以上.再与氯甲酸异丁酯反应后脱醇环合即可得到5-氧代-1,2,4-噁二唑化合物.以TAK-536甲酯为例总收率可达49%.     

4-氨基-5-氯-2-乙氧基苯甲酸的合成

目的合成4-氨基-5-氯-2-乙氧基苯甲酸。方法以对氨基水杨酸钠为原料,经酸化、甲酯化、乙酰化、乙基化、氯代、水解等六步反应得到枸橼酸莫沙必利的主要中间体4-氨基-5-氯-2-乙基苯甲酸。结果与结论本合成工艺提高了收率,降低了成本,更适合工业化生产,本工艺总收率为62.4%。     

6,7-二氢-5H-环戊烯并[b]吡啶的制备

1-氨基-2-氰基环戊烯经乙酰化、闭环和氯化反应制得4-氨基-2-氯-6,7-二氢-5H-环戊烯并[b]吡啶,再经Sandmeyer溴化和钯炭催化氢化脱卤制得6,7-二氢-5H-环戊烯并[b]吡啶,总收率为61%。     

5-氯-6-苯基-2H-哒嗪-3-酮的合成

6-苯基-2H-哒嗪-3-酮(2)经三氯化磷/氯气氯代制得3,5-二氯-6-苯基哒嗪,经氢氧化钠皂化,再用盐酸调至pH 8.5得到5-氯-6-苯基-2H-哒嗪-3-酮,总收率约24%(以2计).副产物3-氯-5-羟基-6-苯基哒嗪可作为氯代反应的原料回收使用.     

(2S,3S,5S)-2,5-二氨基-3-羟基-1,6-二苯基己烷的合成

L-苯丙氨酸用氯苄进行MO-苄基化、氰化、格氏反应、还原制得（2S，3S，5S）-5-氨基-2-二苄胺基-1，6-二苯基-3-己醇，再经钯炭催化脱苄制得抗病毒药洛匹那韦中间体（2S，3S，5S）-2,5-二氨基-3-羟基-1，6-二苯基己烷，总收率约为63％。     

3,5-二叔丁基-4-羟基苯甲酸的合成

以2，6-二叔丁基-4-甲基苯酚为原料，在乙酸溶液中与溴反应形成3，5-二叔丁基-4-羟基苯甲醛，然后经Jones氧化得到3，5-二叔丁基-4-羟基苯甲酸，总收率63．7％。     

5-(2-溴乙基)-2,3-二氢苯并呋喃的制备

2,3-二氢苯并呋喃-5-乙酸与氯甲酸乙酯反应得混酐后,再经硼氢化钠还原制得5-羟乙基-2,3-二氢苯并呋喃,在三苯膦作用下经N-溴代琥珀酰亚胺溴代,制得达非那新中间体5-(2-溴乙基)-2,3-二氢苯并呋喃,总收率约83%。     

3-氯-4-氟苯胺基亚甲丙二酸二乙酯制备的改进

3-氯-4-氟苯胺在 Lewis 酸存在下直接同原甲酸三乙酯、丙二酸二乙酯反应,除得到60～70%收率的主产物3-氯-4-氟苯胺基亚甲丙二酸二乙酯(1)外,还分离到三个产物,经 IR、MS、~1HNMR 及元素分析,证明其结构分别是甲脒3的盐酸盐、4和5。可用本法代替原用乙氧亚甲丙二酸二乙酯制备1的工艺。     

2-氯-4-氨基-6,7-二甲氧基喹唑啉的合成

目的合成2-氯-4-氨基-6,7-二甲氧基喹唑啉。方法以香草醛为原料,经甲基化、硝化、氧化、还原、环合、氯化、胺化等反应制得目标化合物。结果及结论该实验方法总收率26%,反应条件温和,操作简便,适合工业化生产。     

Kinetic studies with 5-azacytidine-5'-triphosphate and DNA-dependent RNA polymerase.

In order to further understand the biochemical mode of action of 5-azacytidine, a potent antileukemic agent, kinetic studies were performed with 5-azacytidine-5'-triphosphate (5-aza-CTP) and purified DNA-dependent RNA polymerase from Escherichia coli and calf thymus. RNA polymerase could catalyze the incorporation of the fradulent nucleotide, 5-aza-CTP, into RNA. The apparent K_m value for 5-aza-CTP was estimated to be 350 and 390 for the E. coli and calf thymus enzymes respectively. The K_m value for 5-aza-CTP was about 18-fold greater than the K_m value for CTP (20 μM). The apparent V_max value for CTP was about 2-fold greater than the V_max value for 5-aza-CTP. 5-Aza-CTP was a weak competitive inhibitor with respect to CTP; the apparent K_i value for 5-aza-CTP was estimated to be 680 and 810 μM for the E. coli and calf thymus enzymes respectively. On the other hand, CTP was a potent competitive inhibitor with respect to 5-aza-CTP; the apparent K_i value of CTP was estimated to be 16 μM. 5-Aza-CTP did not appear to inhibit the incorporation of UTP into RNA in the reaction catalyzed by RNA polymerase. These data suggest that the inhibition of RNA synthesis in cells by 5-aza-cytidine is not produced by the inhibition of RNA polymerase by 5-aza-CTP.     

Mechanism of block by fluoxetine of 5-hydroxytryptamine3 (5-HT3)-mediated currents in NCB-20 neuroblastoma cells

The effect of fluoxetine (Prozac) on 5-hydroxytryptamine(3) (5-HT(3))-mediated currents in NCB-20 neuroblastoma cells was examined using the whole-cell patch-clamp technique. Fluoxetine produced a significant reduction of peak amplitude without altering the activation time course of 5-HT(3)-mediated currents. These effects were concentration-dependent, with an IC(50) value of 4.15 microM. No voltage dependence was evident in fluoxetine's block of 5-HT(3)-mediated currents over the entire voltage range tested. The extent of block by pre-application of fluoxetine was significantly greater than that by co-application. Fluoxetine also increased the apparent rate of current desensitization to 5-HT application. Using a first-order kinetics analysis, the open-channel blocking rate constants were 0.06 microM(-1)s(-1) (k(+1), association rate constant) and 0.05 s(-1) (k(-1), dissociation rate constant), with an apparent K(d) (=k(-1)/k(+1)) of 0.83 microM. This value is close to an IC(50) of 1.11 microM obtained from the reduction in tau, the time constant of desensitization. Intracellular application of fluoxetine for long durations had no effect on the amplitude or kinetics of 5-HT(3)-mediated currents. Similarly, norfluoxetine, the major metabolite of fluoxetine, reduced the peak current, and enhanced the rate of current desensitization in a concentration-dependent manner with an IC(50) of 2.66 microM, indicating that norfluoxetine is more potent than fluoxetine in blocking 5-HT(3)-mediated currents. These results indicate that, at clinically relevant concentrations, fluoxetine and its metabolite, norfluoxetine, block 5-HT(3)-mediated currents in NCB-20 neuroblastoma cells.     

5'-deoxy-5'-methylthioadenosine phosphorylase--II. Role of the enzyme in the metabolism and antineoplastic action of adenine-substituted analogs of 5'-deoxy-5'-methylthioadenosine

The biological activities of several previously synthesized [J. A. Montgomery et al., J. med. Chem. 17, 1197 (1974)] adenine-substituted analogs of 5'-deoxy-5'-methylthio- or 5'-deoxy-5'-ethyl-thioadenosine, including the 2-fluoroadenine, 2-chloroadenine, 2,6-diaminopurine, 8-azaadenine, and 4-aminopyrazolo [3,4-d]pyrimidine-containing derivatives, have been reexamined. It is demonstrated that many of these analogs are cleaved to their respective free base analogs by 5'-deoxy-5'-methyl-thioadenosine phosphorylase (MTAPase), an enzyme associated with polyamine biosynthesis, and that this reaction is necessary for the cytotoxic action of these MTA analogs to be fully expressed. Evidence to support this includes: (1) the growth of two MTAPase-containing human colon carcinoma cell lines (the HCT-15 and DLD-1 lines) was inhibited by these analogs, whereas an MTAPase-deficient cell line, the CCRF-CEM human T-cell leukemia, was relatively insensitive to their cytotoxic action; (2) extracts of the MTAPase-containing colon carcinoma cell lines were able to cleave these analogs to their respective free base analogs; in contrast, extracts of MTAPase-deficient CCRF-CEM cells were unable to cleave these analogs; (3) intact colon carcinoma cells converted these MTA analogs to their corresponding 5'-phosphorylated analog nucleotides, whereas CCRF-CEM cells did not, at least to detectable levels; and (4) the MTA analog, 5'-deoxy-5'-ethylthio-4-aminopyrazolo [3,4-d]pyrimidine ribonucleoside, which is not a substrate of MTAPase, did not form analog nucleotides and was essentially noncytotoxic to all cell lines tested, whereas the corresponding adenine analog, 4-aminopyrazolo [3,4-d]pyrimidine, readily formed analog nucleotides and was highly cytotoxic to all the lines. It is postulated that the corresponding adenine analog 5'-phosphorylated nucleotides are the primary active metabolites of these MTA analogs, having been formed by the cleavage of these nucleosides to free adenine analogs by MTAPase, followed by the conversion of these base analogs to analog nucleotides by adenine phosphoribosyltransferase and the enzymes of adenine nucleotide phosphorylation. This pathway represents a novel drug-activation system for the synthesis of analog nucleotides and has the potential to be exploited chemotherapeutically.     

Discriminating between 5-HT3A and 5-HT3AB receptors

The 5-HT3B subunit was first cloned in 1999, and co-expression with the 5-HT3A subunit results in heteromeric 5-HT₃AB receptors that are functionally distinct from homomeric 5-HT₃A receptors. The affinities of competitive ligands at the two receptor subtypes are usually similar, but those of non-competitive antagonists that bind in the pore often differ. A competitive ligand and allosteric modulator that distinguishes 5-HT₃A from 5-HT₃AB receptors has recently been described, and the number of non-competitive antagonists identified with this ability has increased in recent years. In this review, we discuss the differences between 5-HT₃A and 5-HT₃AB receptors and describe the possible sites of action of compounds that can distinguish between them.     

Effect of clonidine on the 5-hydroxytryptamine and 5-hydroxyindoleacetic acid brain levels

The effects of clonidine on the brain levels of 5-HT and 5-HIAA in rats and mice were studied. Clonidine did not change the levels of 5-HT and 5-HIAA in the whole brains of either animal species but the 5-HT concentrations were elevated in rat brain pons + medulla oblongata. Clonidine antagonized the increase in the brain 5-HIAA levels induced by apomorphine in rats and mice. The decrease in the 5-HT level and the increase in the 5-HIAA level observed in rats after L-dopa (given with peripheral decarboxylase inhibitor RO 4-4602) were counteracted by clonidine.     

2-(取代苯氧基)-5-羟基嘧啶类化合物的制备方法研究

目的探索2-取代苯氧基-5-苯甲氧基嘧啶、2-取代苯氧基．5-羟基嘧啶类化合物的制备方法。方法以2．氯-5-羟基嘧啶为起始原料,经溴苄羟基保护、威廉森醚合成法、脱苄基保护等多步反应制得目标化合物。结果采用该合成路线制得13个未见文献报道的取代苯氧基嘧啶类化合物。结论本研究提出了一条操作简便、条件温和的全新苯氧基嘧啶类化合物合成方法。     

Lack of Association between the Serotonin Transporter (5-HTT) and Serotonin Receptor (5-HT2A) Gene Polymorphisms with Smoking Behavior among Malaysian Malays

An insertion/deletion polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) and a polymorphism (rs6313) in the serotonin 2A receptor gene (5-HT2A) have previously been linked to smoking behavior. The objective of this study was to determine the possible association of the 5-HTTLPR and 5-HT2A gene polymorphisms with smoking behavior within a population of Malaysian male smokers (n=248) and non-smokers (n=248). The 5-HTTLPR genotypes were determined using the polymerase chain reaction (PCR) and were classified as short (S) alleles or long (L) alleles. The 5HT2A genotypes were determined using PCR-restriction fragment length polymorphisms (PCR-RFLP). No significant differences in the distribution frequencies of the alleles were found between the smokers and the non-smokers for the 5-HTTLPR polymorphism (x² = 0.72, P>0.05) or the 5HT2A polymorphism (x² = 0.73, P>0.05). This is the first study conducted on Malaysian Malay males regarding the association of 5-HTTLPR and 5HT2A polymorphisms and smoking behavior. However, the genes were not found to be associated with smoking behavior in our population.     

Tumor 5-fluorodeoxyuridylate concentration as a determinant of 5-fluorouracil response

The antitumor activity of 5-fluoruoracil (5-FU) for two murine colonie adenocarcinomas was correlated with the concentration and the clearance of the active antimetabolite, 5-fluorodeoxyuridylate (FdUMP). Mice inoculated with a cell suspension of murine colonic adenocarcinomas 38 and 51 were treated with 5-FU (100 mg/kg i.p.) on 3 day post-transplantation. For mice bearing adenocarconoma 38, treatment with 5-FU was associated with a 97 per cent reduction in mean tumor weight a day 30 and a 77 per cent reduction at day 37 of tumor growth. In contrast, mice bearing colonic adenocarcinoma 51, treated with the same dose schedule of 5-FU did not demonstrate a reduction in the rate of tumor growth in vivo. Two hr after i.p. injection of 5-FU (100 mg/kg) the intracellular concentration of free FdUMP in the sensitive tumor 38 was 560 fmoles/μg of DNA. The active antimetabolite was maintained at a concentration in excess of 100 fmoles/μg of DNA for 72 hr. In contrast, the 2-hr free FdUMP concentration in the resistant tumor line 51 was 240 fmoles μg of DNA(P < 0.005), and a concentration in excess of 100 fmoles/μg of DNA was maintained for only 24 hr. There was no difference in the rate of progressive accumulation of the competitive metabolite, deoxyuridine monophosphate (dUMP), during the first 24 hr of the study. Two hr after i.p. injection of 5-FU (100 mh/kg), [³H] deoxyuridine ([³H]Udr) incorporation into DNA was reduced in both tumor lines to below 3 per cent of control. However, in the sensitive tumor, adeno-carcinoma 38, DNA synthesis was maximally inhibited for 72 hr, compared to 24 hr in the resistant adenocarcinoma 51. The reinitiation of DNA synthesis corresponded to the reduction of free FdUMP concentration to less than 100 fmoles/μg of DNA. There was no linear relationship between the FdUMP/ dUMP ratio and [³H]UdR incorporation into DNA in either tumor line. These data demonstrate that the peak tumor FdUMP concentration and the kinetics of its clearance correlated with the responsiveness of the two specific murine tumors to 5-FU. The measure of peak FdUMP level should be tested for its potential clinical application as a means of selecting patients with gastrointestinal and breast cancer to be treated with this agent.     

Structure of 3-Acetyl-5-fluorouracil (5-FU): Implication for Its Rearrangements During Hydrolysis and upon Heating

Single-crystal X-ray diffraction data show that the 3-acetyl group in l,3-diacetyl-5-FU (FU = fluorouracil) is perpendicular to the plane of the 5-FU ring, while the 1-acetyl group is coplanar with the ring. Analyses of ¹H NMR and IR spectra provide evidence that the 1-and 3-acyl groups are in different electronic environments, which is consistent with the X-ray diffraction structure. 3-Acetyl-5-FU is thermally unstable, giving mainly l-acetyl-5-FU (80%) and 5-FU (20%) upon heating. The hydrolysis of 3-acyl derivatives of 5-FU showed a biexponential relationship between In concentration and time which had not been previously observed. The behavior of 3-acetyl-5-FU during hydrolysis can be explained by postulating its initial rapid equilibrium with an intermediate, 2-acetyl-5-FU, which subsequently hydrolyzes to 5-FU or rearranges to l-acetyl-5-FU, which hydrolyzes to 5-FU. The 2-acetyl intermediate was trapped by its reaction with formaldehyde. The formaldehyde adducts of the symmetrical 2-acetyl intermediate rearranged to yield equal amounts of 1- and 3-acetyloxymethyl-5-FU.     

5-氰基苯酞的合成新法

目的建立新的5-氰基苯酞合成方法。方法采用5-甲酰基苯酞与盐酸羟胺(1∶1.2,mol/mol)在甲酸中回流反应40 min制得5-氰基苯酞。结果收率可达83%。结论此方法工艺简单、收率高、成本低,具有良好应用前景。