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Fifteen novel furoxan-based nitric oxide (NO) releasing hybrids of estradiol derivatives were synthesized and evaluated in vitro anti-proliferative activity in MDA-MB-231, A2780, Hela and HUVEC cell lines. Most of them displayed potent anti-proliferative effects. Among the compounds, 4-bromo-3-((phenylsulfonyl)-1,2,5-oxadiazole 2-oxide)-oxy-propoxy-estradiol (11 b) exhibited the best activity with IC50 values of 3.58–0.0008 μM. Preliminary pharmacological studies showed that 11 b induced apoptosis and hardly affected the cell cycle of MDA-MB-231 cell line. NO-releasing capacity and inhibition of ERK/MAPK pathway signaling might explain the potent antineoplastic activity of these compounds. The preliminary structure-activity relationship (SAR) showed that steroidal scaffolds with a linker in 3-position were favorable moieties to evidently increase the bioactivities of these hybrids. Overall, these results implied that 11 b merited to be further investigated as a promising anti-cancer candidate.

The cross-coupling of aryl bromides with [11C]CH3Li for the labelling of a variety of tracers for positron emission tomography (PET) is presented. The radiolabelled products were obtained in excellent yields, at rt and after short reaction times (3-5 min) compatible with the half-life of 11C (20.4 min). The automation of the protocol on a synthesis module is investigated, representing an important step towards a fast method for the synthesis of 11C-labelled compounds for PET imaging. This journal is

The invention relates to the technical field of organic synthesis and discloses an estradiol derivative as well as a preparation method and application thereof. The estradiol derivative has a structure shown in a formula 1. An estradiol 4 site is modified and coupled with 3-sulfydryl/hydroxyl/amino propionic acid to form a novel derivative containing carboxyl at estradiol 4 site, and compared withan estradiol 3 site derivative, the derivative has better specificity and accuracy, shows good gradient, has a good reaction effect as an antigen and has higher economic value.

The 2-methoxy derivative of estradiol is currently in Phase II clinical trial as an anticancer agent while the 4-methyl derivative has been shown to interact with cytoplasmic and nuclear estrogen receptors in rat pituitary gland and hypothalamus. We hypothesize that the 16α-18F-analogs of these estrogens could be suitable radiotracers to evaluate action mechanisms of the parent compounds. In this study we report the synthesis of the 16α-18F and 16α-19F-analogs of the A-ring substituted estradiols in high yield via stereoselective opening of the intermediate 16β,17β-O-cyclic sulfones with [18F]F- or F- followed by deprotection.

A-ring bromination of estrogens has been achieved by constant current electrolysis of the solutions of these substrates and Et4NBr in appropriate solvents. Thus, electrolysis consuming 2 F mol-1 charge gave mixtures of 2- and 4-estrogens (1:1.1-2.5; up to 97%), whereas 4 F mol -1 charge experiments yielded 2,4-dibromoestrogens as the sole products.

Our earlier studies have shown that over 20 nonpolar 17β-estradiol metabolite peaks were detected following incubations of radioactive 17β-estradiol with human liver microsomes or recombinant human cytochrome P450 isoforms in the presence of NADPH as a co

Thioether-linked 3-mercaptopropionic acid derivatives of 17β-estradiol and estrone were formed at the A-ring 4-position of the steroids by substitution of their 4-bromo analogues. The carboxylic acid terminal was used to link to an oligoethylene glycol (OEG) chain of 15-atoms in length. The OEG derivative of 17β-estradiol was then in situ immobilized on a carboxymethylated dextran-coated gold sensor surface used to detect refractive index changes upon protein binding to the surface by surface plasmon propagation in a BIAcore surface plasmon resonance (SPR) instrument. Two other estradiol-OEG derivatives with Mannich reaction linkage at the 2-position and hemisuccinate linkage at the 3-position were also immobilized on the sensor surfaces for comparison. Binding performance between these immobilized different positional conjugates and monoclonal anti-estradiol antibody, raised from a 6-position conjugate, clearly demonstrated that both 2- and 4-conjugates, not conjugated through existing functional groups, gave strong antibody bindings, whereas the 3-conjugate through an existing functional group (3-OH) gave very little binding (2% compared to the 2-conjugate). Both 2- and 4-position conjugates were then applied in a highly sensitive estradiol SPR immunoassay with secondary antibody mediated signal enhancement that gave up to a 9.5-fold signal enhancement of primary antibody binding, and a detection limit of 25 pg/mL was achieved for a rapid and convenient flow-through immunoassay of estradiol.

We recently detected the formation of estradiol-17β (estradiol) dimers, linked together through a diaryl ether bond between the C-3 phenolic oxygen of one estradiol molecule and the 2- or 4-position aromatic carbon of another estradiol, following incubations of [3H]estradiol with human liver microsomes or cytochrome P450 enzymes in the presence of NADPH. Using estradiol as the starting material, we designed a four-step method for the chemical synthesis of these two estrogen dimers with the Ullmann condensation reaction as a key step. Step 1: Synthesis of 2- or 4-bromoestradiol from estradiol. Step 2: Protection of the C-3 phenolic hydroxyl group of the 2- or 4-bromoestradiol. Step 3: The Ullmann condensation reaction between the phenol-protected bromoestradiol and the estradiol potassium salt under our modified reaction conditions (with a 41% product yield). Step 4: Removal of the C-3 benzyl group by catalytic hydrogenation. The chromatographic and various spectrometric properties of the two synthesized compounds were identical to those metabolically formed by human cytochrome P450 3A4.

The reaction of estradiol and estrone with benzeneselenyl chloride affords mainly 2-phenylselenyl adducts which are readily converted into the corresponding 2-halogenated estrogens upon treatment with a variety of reagents.

A new synthetic route to 2- and 4-methoxyestradiols is described.Benzo-15-crown-5 with CuI catalyzes the specific nucleophilic substitution at the carbon atom carrying a non-activated halogen on ring A of the estradiol.

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Synthesis of 2-methoxy- and 4-methoxy-estrone (6) and (9), 2-methoxy- and 4-methoxy-estradiol (15) and (18), and 2-methoxy- and 4-methoxy-estratriol (24) and (27) are described.Catalytic hydrogenation over Pd/C of 2,4-dibromo or 2,4-diiodo estrogens gave regioselectively the corresponding 4-halogeno derivatives in excellent yields.Reaction of 2-iodo or 4-iodo estradiol and 2-iodo or 4-iodo estriol with NaOCH3 in MeOH and dimethylformamide (DMF) in the presence of CuCl2 gave in an excellent yield and in a good yield, while (6) and (9) were also similarly obtained by the reaction with pyridine instead of DMF.

2-Methoxy- and 4-methoxy-estrogens are easily prepared from the corresponding 2-iodo or 4-bromo derivatives in high yields by a halogen-methoxy group exchange reaction using sodium methoxide-copper(II) chloride.

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