改进(R)-N-乙酰四氢噻唑-2-硫酮-4-羧酸的纯化方法并拆分D,L-对羟基苯甘氨酸

目的 改进新型手性拆分试剂(R)-N-乙酰四氢噻唑-2-硫酮-4-羧酸[(R)-N-Ac-TTCA]的纯化方法,拆分外消旋氨基酸.方法 使用重结晶法提纯(R)-N-Ac-TTCA,在三乙胺存在下,用其拆分外消旋对羟基苯甘氨酸.结果 (R)-N-Ac-TTCA的产率提高了20.5%,比旋光度为-65.2(c 0.20,EtOH),比原来提高8.4%.应用其拆分D,L-对羟基苯甘氨酸得到D-对羟基苯甘氨酸的同时也得到了L-对羟基苯甘氨酸.结论 重结晶的方法简便有效,用(R)-N-Ac-TTCA拆分D,L-对羟基苯甘氨酸可行.     

1-(α-萘甲基)-2甲基-6,7-二甲氧基-1,2,3,4-四氢异喹啉盐酸盐的HPLC手性拆分法及半制备

1-(α-Naphthylmethy)-2-methyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinehydrochloride (code No, 86040)is a new kind of calcium antagonist. It has(+)and(一)enantiomers.Accordingly .the resolution and quantification of these two enantiomers have received agreat deal of attention,In this report the application of direct HPLC separation and semipreparation tothe determination of the enantiomeric composition of the new drug are described. All analysis andsemipreparation were performed with 25 cm×4. 6 mm i.d, 25 cm×8 mm i,d.and 30 cm×8 mmi.d. stainless steel column packed with a chiral β-cycledextrin bonded phase. Detection wavelengthwas 284 nm, The optimal composition of the mobile phase was EtOH─pH 4.0 phosphate buffer(35:65) at flow rate of 0. 3 ml·min^-1 for analysis and l.0 ml·min^-1 for semipreparation. Theseparation factor of the enantiomers was l.25. Purity of the semipreparation was 8l.4%,Quantityof semipreparation was 1 mg. This procedure was simple ,rapid and gave good resolution,The effectsof the composition of mobile phase, pH value, flow rate and column temperature on the resolution hadbeen sudied.     

四氢-1，3-噻嗪-2，6-二酮的制备

四氢-1,3-噻嗪-2,6-二酮(1)在合成肽类化合物时应用广泛,例如在合成L-肌肽时,应用1可以简化反应步骤,减少副产物生成,提高收率等。1属硫代环羧酸酐类,具有环羧酸酐特性,可用于合成硫醇、硫代碳酸酯、烯烃、烷烃、S-活     

3-取代-1,2,3,9-四氢-4H-咔唑-4-酮衍生物的合成

根据已知5-HT_3受体拮抗剂的结构特点,本文设计并合成了3-(2-烷基-1H-苯并咪唑-1-基)甲基-1,2,3,9-四氢-4H-咔唑-4-酮(Ⅶa-b)及3-(1H-苯并三唑-1-基)甲些-1,2,3,9-四氢-4H-咔唑-4-酮(IXa,b)衍生物共10个。目的物从相应的1,2,3,9-四氧-4H-咔唑-4-酮(Ⅳ,Ⅴ)经过Mannich反应,成盐反应、与2-烷基苯并咪唑或苯并三唑缩合反应制得,并经光谱确证。     

6-甲氧基-1,2,3,9-四氢-4H-咔唑-4-酮的合成

4-甲氧基苯肼盐酸盐和1,3-环己二酮在乙酸催化下缩合得到3-[（4-甲氧基苯基）亚肼基]环己-1-烯醇盐酸盐,然后在二苯醚中经Fischer反应闭环生成6-甲氧基-1,2,3,9-四氢-4H-咔唑-4-酮,总收率约为57%。     

2-取代亚胺基-3-[N-(2-氯乙基)]氨甲酰四氢噻唑的合成及其抗肿瘤活性研究

本文通过2-氯乙基异氰酸酯与各种N-取代-2-氨基-2-噻唑啉反应合成了十三个未见文献报道的2-取代亚胺基-3-[N-(2-氯乙基)]氨甲酰四氢噻唑化合物,其结构均经~1HNMR,IR、MS等得到证实。初步药效表明:2-苄基亚胺基-3-(N-(2-氯乙基)]氨甲酰四氢噻唑(2)对小白鼠爱氏腹水癌(EAC)有较高的抑制率(60.5％)。     

血吸虫病化学治疗的研究 ⅩⅩⅩⅥ.4-苯基(或烯丙基)-5-(吡嗪-2)-1,2,4-三唑-3-硫酮衍生物的合成

本文报导28个4-苯基(或烯丙基)-5-(吡嗪-2)-1,2,4-三唑-3-硫酮衍生物的合成。这类化合物的合成是以吡嗪甲酸乙酯与水合肼反应得2-吡嗪甲酰肼,再与不同的异硫氰酸酯作用后,在2N氢氧化钠溶液中环合而得Ⅱ或Ⅲ,然后经烷化、酰化及Mannich反应,分别制得相应的化合物。其中Ⅲ_1和Ⅲ_2对感染日本血吸虫小白鼠有明显肝移作用。     

4-(4-甲氧基苯基)-3,4-二氢-2(1H)-喹啉酮的合成及抗惊厥作用研究

目的筛选抗惊厥活性的化合物,寻找新型抗癫痫药物。方法以肉桂酸为原料,对其化学结构进行优化,合成了4-(4-甲氧基苯基)-3,4-二氢-2(1H)-喹啉酮。采用最大电休克发作实验(MES)测定其抗癫痫活性。结果采用红外光谱、核磁共振氢谱和质谱确定了化学结构。经药理活性筛选发现4-(4-甲氧基苯基)-3,4-二氢-2(1H)-喹啉酮具有抗惊厥作用。结论本合成路线简单、产物易分离,为开发新的抗癫痫药物提供了新思路。     

(±)-2-甲基-2-羟基-5,8-二甲氧基-1,2,3,4-四氢萘的简便合成法

报道蒽环酮关键中间体AB环的一种简便合成方法。从对苯醌和异戊二烯起始,经Diels-Alder加成、甲基化、羟基化三步反应,以总收率58％得到(±)-2-甲基-2-羟基-5,8-二甲氧基-1,2,3,4-四氢萘。这是迄今已报道的路线中较为简捷的一条。     

1－（α－萘甲基）－2甲基－6，7－二甲氧基－1，2，3，4－四氢异喹啉盐酸盐的HPLC手性拆分法及半制备

１－（α－萘甲基）－２甲基－６，７－二甲氧基－１，２，３，４－四氢异喹啉盐酸盐的ＨＰＬＣ手性拆分法及半制备王义明，罗国安，彭健斌，詹少卿，刘子列，林炳承（清华大学化学系，北京１０００８４）目前已知药物中约有３０～４０％是手性对映体（ｅｎａｎｔｉｏｍｅ...     

Identification and determination of 2-thiothiazolidine-4-carboxylic acid in urine of workers exposed to carbon disulfide

A compound was isolated from the urine of workers exposed to carbon disulfide during the production of rayon. The compound was identified as 2-thiothiazolidine-4-carboxylic acid (TTCA) by GC/MS and NMR. A HPLC method for the quantitative determination of TTCA was elaborated and applied to urine samples. The method allowed detection of TTCA concentrations in urine as low as 5 × 10^–7 M.No TTCA was detected in urine of workers occupationally exposed to organic solvents other than CS₂. High concentrations of TTCA (upto 32×10^–5 M) were shown to be present in urine of spinners exposed to CS₂ concentrations of approximately 100 mg/m³. It is suggested that the assay of urinary TTCA is suitable for detection of occupational exposure to CS₂.     

Photochemical conjugation of peptides to carrier proteins using 1,2,3-thiadiazole-4-carboxylic acid Immunoreactivity of free C-terminal epitope with specific antibodies

A new heterobifunctional cross-linking reagent, 1,2,3-thiadiazole-4-carboxylic acid, for the photochemical conjugation of peptides to proteins is described. The title compound can be coupled directly to a protected peptide resin during solid-phase peptide synthesis (SPPS) using standard coupling procedures. The probe is stable to TFA deprotection/cleavage mixtures containing ethanedithiol commonly used in Fmoc-SPPS. Furthermore, tritium may easily be introduced into the thiadiazole ring by base-catalyzed hydrogen-exchange. Upon irradiation at 245-300 nm, parent 1,2,3-thiadiazole rapidly eliminates N₂, generating very reactive thioketene which reacts with amines to give a thioamide in high yield, even when the photolysis is carried out in hydroxylic solvents. In order to investigate the potential of the title compound as a heterobifunctional cross-linking reagent a model study with angiotensin II (AII) was conducted. The photoreactive peptide N^α-4-carbonyl-1,2,3-thiadiazole-AII (TDA-AII) was synthesized by Fmoc-SPPS and conjugated to bovine serum albumin (BSA) by photolysis at 245 and 300 nm. By use of a capture competition ELISA, the C-terminal Pro-Phe epitope of photoconjugated AII with the sequence DRVYIHPF was shown to bind specifically to antiAII antibodies (anti-AII abs), although antibodies against both the C- and N-terminal epitopes were present in the assay. A dipeptide His-Leu carboxy-extension form of AII, angiotensin I (AI), only bound to anti-AII abs at 100-200 times higher concentrations, showing that the C-terminal epitope was blocked by the dipeptide. © Munksgaard 1996.     

4-羟基-2-(1H-吡唑-1-基)嘧啶-5-甲酸的合成工艺改进研究

目的对4-羟基-2-(1H-吡唑-1-基)嘧啶-5-甲酸的合成工艺条件进行优化。方法以1-脒基吡唑盐酸盐和乙氧基甲叉基丙二酸二乙酯为起始原料,在三乙胺催化下环合得到中间体4-羟基-2-(1H-吡唑-1-基)嘧啶-5-甲酸乙酯,再经过氢氧化锂在四氢呋喃–水混合溶剂中水解得到目标化合物。结果合成了目标化合物,经MS、1H-NMR确证了结构,质量分数为99.5%,本合成工艺的总收率为87%。结论该合成工艺具有操作简单、反应条件温和、成本低、产率和纯度较高等优点,适合工业化生产。     

3,6-双羧甲基-4-氨基-6H-噻吩并[2,3-B]吡咯-2-羧酸的合成研究

目的设计并合成3,6-双羧甲基-4-氨基-6H-噻吩并[2,3-B]吡咯-2-羧酸。方法以柠檬酸为起始原料,经氧化酯化、Gewald反应、氮取代、环合、水解、脱羧反应制备得到目标化合物。结果合成了目标化合物,并利用质谱和核磁数据确证了结构;HPLC归一化法测得质量分数为96.98%。目标化合物的总收率为2.7%。结论 3,6-双羧甲基-4-氨基-6H-噻吩并[2,3-B]吡咯-2-羧酸的合成为雷奈酸锶中杂质的研究提供了方便。     

Pulmonary exposure to diesel exhaust particles promotes cerebral microvessel thrombosis: Protective effect of a cysteine prodrug l-2-oxothiazolidine-4-carboxylic acid

Inhaled particulate matter is associated with increased cerebro- and cardiovascular events. However, the systemic mechanisms underlying these effects remain unclear. In the present study, we investigated the mechanisms underlying the relationship between airway and systemic inflammation and pial cerebral venular thrombosis, 24 h after intratracheal (i.t.) instillation of diesel exhaust particles (DEP; 15 or 30 μg/mouse) or saline (control). Doses of 15 and 30 μg/mouse induced a dose-dependent macrophage and neutrophil influx into the bronchoalveolar lavage (BAL) fluid with elevation of total proteins and Trolox equivalent antioxidant capacity (TEAC), but without IL-6 release. Similarly, in plasma, IL-6 concentrations did not increase but the TEAC was significantly and dose-dependently decreased. The number of platelets and the tail bleeding time were both significantly reduced after exposure to DEP (30 μg). Interestingly, the same dose showed platelet proaggregatory effect in mouse pial cerebral venules. Pretreatment with the cysteine prodrug l-2-oxothiazolidine-4-carboxylic acid (OTC, 80 mg/kg) 24 and 1 h before i.t. DEP (30 μg), abolished the DEP-induced macrophage and neutrophil influx, and the increase of TEAC in BAL. Lung histopathology confirmed the protective effect of OTC on DEP-induced lung inflammation. OTC also reversed the decrease of TEAC concentrations in plasma, the shortening of the bleeding time, and the thrombotic effect of DEP in pial cerebral venules. We conclude that pulmonary exposure to DEP cause oxidative stress responsible, at least partially, for the pulmonary and systemic inflammation and thrombotic events in the pial cerebral microvessels of mice. OTC pretreatment abrogated these effects through its ability to balance oxidant–antioxidant status.     

Inhibition of human CYP1A2 oxidation of 5,6-dimethyl-xanthenone-4-acetic acid by acridines: a molecular modelling study

1. The aim of the present study was to investigate the structural requirements for the inhibition of 6-methyl-hydroxylation of the antitumour agent 5,6-dimethyl-xanthenone-4-acetic acid (DMXAA) by acridine analogues and use a CYP1A2 homology model to provide some insight into this interaction. 2. Concentrations causing 50% inhibition (IC50) of the 6-methylhydroxylation of DMXAA were determined in human liver microsomes in the presence of various acridines. Some of the acridines were also tested for their ability to inhibit the CYP1A2-mediated 7-ethoxyresorufin O-de-ethylation. The molecular modelling studies of human CYP1A2 used the crystal structure of rabbit CYP2C5 as a template based on protein sequence homology and an interactive docking procedure using a dynamic hydrogen bond feature. 3. The in vitro IC50 studies for the inhibition of 6-methylhydroxylation of DMXAA indicated: (i) the importance of the position of the carboxamide side-chain on the acridine nucleus (and, to a lesser extent, its composition); (ii) the addition of hydroxyl groups to the 5-, 6- and 7-position of the acridine nucleus diminished the inhibitory potency; and (iii) amsacrine (acridine nucleus with methansulphonanilide side-chain at the 9-position) had no significant inhibitory effect. Similar structural trends were observed for the inhibition of O-de-ethylation of 7-ethoxyresorufin by acridines, supporting the involvement of CYP1A2 in DMXAA 6-methyl hydroxylation. 4. The molecular modelling studies indicated: (i) both DMXAA and N-[2-(dimethylamino)-ethyl]acridine-4-carboxamide (DACA) form two hydrogen bonds plus putative pi-pi stacking interactions with the CYP1A2-binding domain, typical of CYP1A2 substrates and inhibitors; (ii) the DMXAA 6-methyl group is 4.0 A from the central iron atom of the heme moiety and ideal for oxidation; (iii) the known oxidation sites for DACA are orientated away from the heme iron, supporting the non-involvement of CYP1A2; and (iv) amsacrine did not fit the putative CYP1A2 site owing to the steric hindrance of the bulky methanesulphonanilide side-chain. 5. These results suggest that docking studies with this homology model may be useful in the design of further acridine anticancer agents, in particular to identify agents that do not interact either as substrates or inhibitors with the CYP1A2-binding domain.     

Quantification of 4′-geranyloxyferulic acid,a new natural colon cancer chemopreventive agent,by HPLC-DAD in grapefruit skin extract

Oxyprenylated natural products (isopentenyloxy-, geranyloxy- and the less spread farnesyloxy-compounds and their biosynthetic derivatives) represent a family of secondary metabolites that have been consider for years merely as biosynthetic intermediates of the most abundant C-prenylated derivatives. Many of the isolated oxyprenylated natural products were shown to exert in vitro and in vivo remarkable anti-cancer and anti-inflammatory effects. 4′-Geranyloxyferulic acid [3-(4′-geranyloxy-3′-methoxyphenyl)-2-trans-propenoic] has been discovered as a valuable chemopreventive agent of several types of cancer. After development of a high yield and “eco-friendly” synthetic scheme of this secondary metabolite, starting from cheap and non-toxic reagents and substrates, we developed a new HPLC-DAD method for its quantification in grapefruit skin extract. A preliminary study on C18 column showed the separation between GOFA and boropinic acid (having the same core but with an isopentenyloxy side chain), used as internal standard. The tested column were thermostated at 28 ± 1 °C and the separation was achieved in gradient condition at a flow rate of 1 mL/min with a starting mobile phase of H₂O:methanol (40:60, v/v, 1% formic acid). The limit of detection (LOD, S/N = 3) was 0.5 μg/mL and the limit of quantification (LOQ, S/N = 10) was 1 μg/mL. Matrix-matched standard curves showed linearity up to 75 μg/mL. In the analytical range the precision (RSD%) values were ≤2% and the accuracy (bias%) between ±12%. This method was used to evaluate for the first time the presence of this analyte in natural extract of grapefruit. In conclusion, this method showed LOQ values able to selective quantification of this analyte in grapefruit skin extract.     

Synthesis of N‐(2‐diethylamino‐ethyl)‐4‐(4‐fluoro‐benzamido)‐2‐methoxybenzamide (desiodo‐MIP‐1145) by coupling technique and its radioiodination: a potential melanoma imaging agent

Radioiodinated MIP‐1145, which specifically targets melanin, is an ideal candidate for targeted therapy of melanoma. An analogue of MIP‐1145 lacking the iodo‐substituent (desiodo‐MIP‐1145) was synthesized as a labeling precursor in three simple steps. The radioiodination of desiodo‐MIP‐1145 by iodine‐125 was carried out via an electrophilic substitution reaction. An optimization study for the iodination reaction was carried out. The labeled compound was isolated and purified by means of electrophoresis and HPLC. The maximum radiochemical yield, 76%, was obtained with radiochemical purity greater than 99%. The log P value for [¹²⁵I]MIP‐1145 was measured as 4.5.     

Speciation and separation of Cr(VI) and Cr(III) using coprecipitation with Ni/2-Nitroso-1-naphthol-4-sulfonic acid and determination by FAAS in water and food samples

A speciation procedure for chromium(III) and chromium(VI) in the water and food samples has been established in the presented work. The procedure presented based on quantitative recoveries of Cr(III) > 95% using coprecipitation of Ni²⁺/2-Nitroso-1-naphthol-4-sulfonic acid. The total chromium was measured after reduction of Cr(VI) by concentrated H₂SO₄ and ethanol. The Cr(VI) was calculated as the difference between the total Cr content and the Cr(III) contents. The analytical variables, pH, amounts of precipitate, sample volume for optimum recoveries of Cr(III) were investigated. The influences of the some alkaline and earth alkaline ions and some transition metals on the recoveries of analyte ions were also investigated. The preconcentration factor was 50. The detection limit (3σ) of the reagent blank for chromium(III) was 1.33 μg L⁻¹. The relative standard deviations for determinations were found to be <7%, and % of relative error was calculated <6%. The method was validated by certified reference materials of tea (GBW 07605) and bush branches and leaves (GBW 0703). The procedure was successfully applied to the speciation of chromium in natural water and food samples (fish, white cheese, cow’s meat, black tea, boiled wheat).