Non-cytotoxic 3-Acetylcoumarin as an Attractive Target for Human Monoamine Oxidase (HMAO) Enzymes.

BACKGROUND/AIM: Coumarins are a broad class of naturally occurring oxygen-heterocyclic compounds found in plants with diverse biological properties, making them attractive for evaluation as novel therapeutic agents. We herein report the in vitro cytotoxic and monoamine oxidase (MAO) inhibitory activities of 3-acetylcoumarins (6a-e). MATERIALS AND METHODS: The cytotoxic activity was evaluated using crystal violet dye binding assay, and those compounds unable to induce cytotoxicity were further tested for the monoamine oxidase (MAO) activity using the MAO-GloTM kit. RESULTS: The 3-acetylcoumarins (6a-e) were non-cytotoxic (inactive) against MDA MB-231 (estrogen receptor-negative, ER-, highly invasive) and MCF-7 (estrogen receptor-positive, ER+, weakly invasive) breast cancer cell lines, but showed interesting MAOs inhibition activities. Among the synthesized compounds, 3-acetylcoumarin bearing dichloro (-diCl) (6d; IC50=0.31±0.04 µM) at Carbon-7, 8 positions showed higher inhibition, MAO B/A non-selectivity (selectivity index, SI=3.10), reversible inhibition against the hMAO-B enzyme, and neuroprotection against H2O2-treated human neuroblastoma (N2a) cells. CONCLUSION: Compound (6d) can be considered a promising scaffold for further investigation in developing hMAO-B inhibitors (MAOIs).

7,8-Diacetoxy-3-(4-methylsulfonylphenyl)-4-phenylcoumarin Induces ROS-dependent Cell Death in the A549 Human Lung Cancer Cell Line.

BACKGROUND/AIM: Coumarins comprise of a very large class of naturally occurring compounds with growing interest in their synthesis and possible applications in the treatment of various diseases. We herein report the in-vitro cytotoxic activity of 3,4-Diarylcoumarins (4a-i) in A549 (lung) and PC-3 (prostate) cancer cell lines. MATERIALS AND METHODS: The cytotoxic activity was evaluated using crystal violet dye-binding. The most active compound effect on the cell-cycle phases, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production and apoptosis were also evaluated. RESULTS: Among the synthesized compounds that were evaluated, 7,8-Diacetoxy-3-(4-(methylsulfonyl)phenyl)-4-phenylcoumrin (4f) showed highest cytotoxicity (CC50=13.5%±0.15µM) in A549 cancer cell line. The mechanism of its cytotoxic action indicated significant cell arrest in G1/G0, S and G2 phases of the cell cycle, loss of mitochondrial membrane potential (MMP), increase in reactive oxygen species (ROS) production and induction of apoptotic cell death. The cell viability result of pretreated A549 cells with antioxidant N-acetylcysteine (NAC), followed by compound 4f treatment confirmed ROS-dependent cell death. CONCLUSION: The presence of 3-4-methylsulfonyl and 7,8-diacetoxy groups on 3,4-Diarylcoumarin is critical in modulating higher cytotoxic activity and could serve as a valuable template for the development of novel synthetic compounds as potential anticancer agents for lung cancer treatment.

Identification of 7,8-dihydroxy-3-phenylcoumarin as a reversible monoamine oxidase enzyme inhibitor.

We herein report the biological evaluation of 3-arylcoumarin derivatives (3a-l) as potential human monoamine oxidase-A and -B (hMAO-A and hMAO-B) inhibitors. The result indicated that 7,8-dihydroxy-3-(4-nitrophenyl)coumarin (3j) was most effective against MAO-A (inhibition concentration [IC50 ] = 6.46 ± 0.02 µM) and MAO-B (IC50 = 3.8 ± 0.3 µM) enzymes than other synthesized compounds and reference compounds (pargyline and moclobemide). Furthermore, compound (3j) showed (a) nonselectivity against hMAO enzymes, (b) reversible hMAO enzymes inhibition, and (c) neuroprotection against H2 O2 -treated human neuroblastoma (N2a) cells. Finally, a molecular modeling study revealed that the hMAO enzymes inhibitory activity of the compound (3j) may be due to the orientation where the nitro (NO2 ) group lies deep into the receptor and the phenyl ring directed toward flavin adenosine dinucleotide via hydrogen bond interaction, and possible π-π interaction with various important residues. Thus, the results of the present study demonstrate that compound (3j) can be considered as a promising scaffold for the development of hMAO-A and hMAO-B inhibitors.

7,8-Dihydroxy-3-arylcoumarin Induces Cell Death Through S-Phase Arrest in MDA-MB-231 Breast Cancer Cells.

BACKGROUND/AIM: Coumarins remain one of the most versatile classes of compounds for anticancer drug design and discovery. The present study aimed to evaluate the in vitro cytotoxic activity of 7,8-Dihydroxy-3-arylcoumarin derivatives (7a-i) in A549, MDA-MB-231and PC-3 cancer cell lines. MATERIALS AND METHODS: Cell viability, cell-cycle progression and regulatory protein expression were evaluated using crystal violet dye-binding assay, flow cytometry and western blot analysis. RESULTS: 7,8-Diacetoxy-3-(4-nitrophenyl)coumarin (7h) showed the highest cytotoxic activity with CC50 of 7.51±0.07 µM in MDA-MB-231 cell line. The mechanism of cytotoxic action indicated that 7h caused significant (p<0.05) MDA-MB-231 cells arrest in the S phase as well as moderate cells arrest in the G2/M phase; confirmed by up-regulation of cyclins A/B1, p21 and CDKs 4/6, and down-regulation of cyclin E2 and CDK2 regulatory proteins. CONCLUSION: These results suggest that 7h could serve as a valuable template for the development of novel synthetic compounds for breast cancer treatment.

7,8-Dihydroxy-3-(4-nitrophenyl)coumarin induces cell death via reactive oxygen species-independent S-phase cell arrest.

We herein report the synthesis and in vitro cytotoxicity of 3-arylcoumarin derivatives (6a-f and 7a-f) in human liver (HepG2), prostate (LNCap), and pancreatic (BxPC3) cancer cell lines. Among the tested compounds, 7,8-dihydroxy-3-(4-nitrophenyl) coumarin (7b) showed the highest cytotoxicity in the HepG2 cell line. The mechanism of cytotoxic action indicated that compound (7b) arrested HepG2 cells at the S phase of the cell cycle progression, induced loss of mitochondrial membrane potential, and caused reactive oxygen species (ROS)-independent cell death. The cell viability result of pretreated HepG2 cells with antioxidant N-acetylcysteine followed by compound (7b) treatment and the free radical scavenging activities of compound (7b) confirmed the ROS-independent cell death. These results demonstrate that compound (7b) could serve as a valuable template for the development of novel synthetic compounds as potential anticancer agents for hepatocellular carcinoma treatment.

Identification of 7,8-Diacetoxy-3-Arylcoumarin Derivative as a Selective Cytotoxic and Apoptosis-inducing Agent in a Human Prostate Cancer Cell Line.

BACKGROUND/AIM: Coumarins are a member of the benzopyrone family of compounds with diverse and interesting pharmacological properties. In the present study, we report the in vitro cytotoxicity evaluation of 7,8-Diacetoxy-3-arylcoumarin derivatives (5a-h) in human prostate (PC-3) and breast (MDA-MB-231) cancer cell lines. MATERIALS AND METHODS: The cytotoxic activity was evaluated using crystal violet dye-binding assay. Furthermore, the most active compound in vitro cytotoxic activity in human non-cancerous cell line and its effect on the cell-cycle phases, apoptosis proteins expression, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production and Glutathione (GSH) level were performed. RESULTS: Among the eight compounds that were evaluated, 7,8-Diacetoxy-3-(4-methylsulfonyl phenyl)coumarin (5f) was the most active derivative with highest cytotoxic activity and selectivity against the PC-3 cell line vs. the non-cancerous WPE1-N22 cell line. The cytotoxic action of compound 5f in PC-3 cells is associated with the cell-cycle arrest at -G0/G1 phase, apoptosis, loss in mitochondrial membrane potential (MMP), induced reactive oxygen species (ROS) production and depletion of Glutathione (GSH) level. CONCLUSION: The result indicates that the presence of p-methylsulfonylphenyl group on compound 5f is critical in modulating selective cytotoxic activity and induction of apoptosis via the mitochondrial apoptotic signaling pathway that is independent of cytochrome c release.

In vitro evaluation of 3-arylcoumarin derivatives in A549 cell line.

UNLABELLED: Coumarins are naturally-occurring compounds with diverse and interesting biological activities. In the present study, we evaluated the in vitro cytotoxic effect of 8-(acetyloxy)-3-[4-(acetyloxy)phenyl]-2-oxo-2H-chromen-7-yl acetate (6); 8-(acetyloxy)-3-(4-methanesulfonyl phenyl)-2-oxo-2H-chromen-7-yl acetate (7); 4-(2-oxo-2H-chromen-3-yl)phenyl acetate (8); 3-(4-methanesulfonylphenyl)-2H-chromen-2-one (9); 4-(4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate (10); 3-(4-methanesulfonylphenyl)-4-methyl-2H-chromen-2-one (11); 8-(acetyloxy)-3-[4-(acetyloxy)phenyl]-4-methyl-2-oxo-2H-chromen-7-yl acetate (12); and 5-(acetyloxy)-3-[4-(acetyloxy) phenyl]-2-oxo-2H-chromen-7-yl acetate (13) in human lung (A549) cancer and normal lung (MRC-9) cell lines at different concentrations for 48 h using crystal violet dye binding assay. The cytotoxic effect of these coumarin derivatives were compared to the standard drug, docetaxel. Furthermore, the effect of the most active compound on the cell-cycle using propidium iodide, mitochondrial membrane potential (MMP) using tetramethyl rhodamine methyl ester (rhodamine-123) and reactive oxygen species (ROS) production using 2',7'-dichlorofluorescin diacetate (PCFDA) were also evaluated. RESULTS: Compound 7: had the greatest cytotoxic effect (cytotoxic concentration, CC50=24 µM) and selectivity (MRC-9; CC50>100 µM; inactive) in the A549 cell line, and caused cells to arrest in the S phase of the cell cycle, loss of MMP and increased ROS production in a concentration-dependent manner. CONCLUSION: These findings suggest that compound 7: could serve as a new lead for the development of novel synthetic compounds with enhanced anticancer activity.

Synthesis and in vitro evaluation of 3-(4-nitrophenyl)coumarin derivatives in tumor cell lines.

Coumarins are naturally-occurring compounds that have attracted considerable interest due to their numerous biological activities depending on their pattern of substitution on the coumarin molecule. In this present investigation, we synthesized 3-(4-nitrophenyl)coumarin derivatives (9a-e) and evaluated their in vitro cytotoxic effect on human lung (A549), breast (MDA-MB-231) and prostate (PC3) cancer cell lines for 48 h using crystal violet dye binding assay. Cytotoxic effects of the most active compound on normal human lung (MRC-9) and breast (MCF-10A) cell lines, cell cycle analysis using flow cytometry and mitochondrial membrane potential (MMP) using Tetramethyl Rhodamine Methyl Ester (TMRM; rhodamine-123) fluorescent dye were also examined. Among the compounds that were evaluated, 9c showed cytotoxic effect (active), caused significant cells arrest (p<0.05) in G0/G1 and S phases of cell cycle and loss of MMP in A459, MDA-MB-231 and PC3 cell lines. Additionally, the cytotoxic effect of 9c was compared to reference drugs (Coumarin and Docetaxel) for comparative study. These results further demonstrate that acetoxy group at C-7 and C-8 positions of 9c are responsible for the observed cytotoxic effect in these cancer cell lines.

Cytotoxic activity of N, N'-Bis (2-hydroxybenzyl) ethylenediamine derivatives in human cancer cell lines.

BACKGROUND: Compounds containing ethylenediamine (-NCH2CH2N-) moiety are known to exhibit antimicrobial, -fungal, -bacterial, -tuberculosis and -cancer activities. MATERIALS AND METHODS: In the present study, we evaluated the in vitro cytotoxic activity of N,N'-bis(2-hydroxybenzyl)- (6), N,N'-bis(5-bromo-2-hydroxybenzyl)- (7) and N,N'-bis(5-chloro-2-hydroxybenzyl) (8)- ethylenediamine dihydrochlorides; and N,N'-bis(2-hydroxybenzyl)- (9), N,N'-bis(5-bromo-2-hydroxybenzyl)- (10) and N,N'-bis(5-chloro-2-hydroxybenzyl) (11)- ethylenediamine toward human lung (A549), breast (MDA-MB-231) and prostate (PC3) cancer cell lines after 24-h treatment using crystal violet dye binding assay. Effects on the cell cycle the using flow cytometry, and mitochondrial membrane potential using rhodamine-123 florescent dye were also evaluated. RESULTS: Compounds 7 and 8 exhibit cytotoxic activity, causing cell arrest at different phases of the cell cycle and loss of mitochondrial membrane potential in the above cancer cell lines. CONCLUSION: These findings clearly demonstrate, to our knowledge for the first time, that ethylenediamine dihydrochloride salts-compounds 7 and 8-exhibit concentration-dependent cytotoxic activity towards A549, MDA-MB-231 and PC3 cancer cell lines, which may serve as a basis for future work on novel therapeutic agents.

Synthesis and biological activity of 3-N-substituted estrogen derivatives as breast cancer agents.

3-N-substituted-estrogen derivatives were synthesized and characterized. Their antiproliferative activities against human ER (+) MCF-7 (Breast), ER (-) MDA-MB-231 (breast) and Ishikawa (endometrial) cancer cell lines were determined after 72 hours drug exposure employing CellTiter-Glo assay at concentrations ranging from (0.01-100,000 nM). The antiproliferative activities of these compounds were compared to tamoxifen (TAM), 4-hydroxytamoxifen (4-OHT, active metabolite of tamoxifen) and raloxifene (RAL). In vitro results indicated that compound 5 (IC50 = 12 µM) displayed comparable antiproliferative activity against MDA-MB 231 cell line; while compounds 6, 7 and 13 (IC50 = 12 µM) displayed higher activity against MCF-7 and Ishikawa cell lines, in comparison to TAM activity (19-33 µM).

Coumarin-based benzopyranone derivatives induced apoptosis in human lung (A549) cancer cells.

In the present investigation, we report on the possible underlying mechanism for the cytotoxicity of compounds: 3-(4-(2-(dimethylamino)ethoxy)-phenyl)-7-methoxy-4-phenyl coumarin 5, 3-(4-(2-(pyrrolidin-1-yl)ethoxy)phenyl)-7-methoxy-4-phenylcoumarin 6, and 3-(4-(2-(diethylamino) ethoxy)phenyl)-7-methoxy-4-methylcoumarin 7 in the human lung (A549) cancer cell line, using Ray Biotech's Human Apoptosis Arrays and apoptotic protein antibodies. Apoptosis array results showed differential apoptotic proteins expression in the extracts of cells treated with compounds 5-7. Western blotting demonstrated that compound 5 induced apoptosis and caused cell death in the A549 cell line via an increase (up-regulation) in Bax protein expression (pro-apoptotic pathway) and a slight decrease (down-regulation) in Bcl-2 protein expression (anti-apoptotic pathway) after 6 h of treatment. These observations may provide valuable information on the mechanism by which these coumarin-based benzopyranone derivatives induce cytotoxicity in the human lung (A549) cancer cell line.

Cytotoxic activity of new acetoxycoumarin derivatives in cancer cell lines.

BACKGROUND: Coumarin and their derivatives are important and useful compounds with diverse pharmacological properties. In the present study, we evaluated the in vitro cytotoxic activity of new acetoxycoumarin derivatives: 4-(7-methoxy-4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate (1), 4-(1-methyl-3-oxo-3H-benzo[f]chromen-2-yl)phenyl acetate (2), 4-(6-propionamido-4-methyl-2-oxo-2H-chromen-3-yl) phenyl acetate (3), 4-(7-acetoxy-2-oxo-4-phenyl-2H-chromen-3-yl)phenyl acetate (4), 4-(2-oxo-4-phenyl-2H-chromen-3-yl)phenyl acetate (5), 4-(6-bromo-2-oxo-4-phenyl-2H-chromen-3-yl)phenyl acetate (6), 4-(7-(diethylamino)-4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate (7), 4-(6,8-dibromo-4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate (8) against A549 human lung cancer, CRL 1548 rat liver cancer and CRL 1439 normal rat liver cells. MATERIALS AND METHODS: The cytotoxic activity was evaluated by crystal violet dye-binding assay. The effect of compounds 5 and 7 on different phases of the cell cycle was determined using flow cytometry. RESULTS: In the A549 lung cancer cell line, the 50% lethal dose (LD50) values for compounds 1-4, 6 and 8 were found to be >100 µM while those for 5 and 7 were 89.3 and 48.1 µM, respectively after 48 h treatment. In the CRL 1548 liver cancer cell line, only compound 7 showed toxicity, with an LD50 of 45.1 µM. Compounds 5 and 7 caused different cell phase arrest in lung and liver cancer cell lines. CONCLUSION: The results indicate that 4-(7-(diethylamino)-4-methyl-2-oxo-2H-chromen-3-yl)phenyl acetate (7) had the highest cytotoxic activity in all of the examined cell lines.

In-vitro antiproliferative activity of benzopyranone derivatives in comparison with standard chemotherapeutic drugs.

The cytotoxic activities of five new benzopyranone derivatives containing basic amino side chain are described. Their cytotoxicities against ER(+) MCF-7 and ER(-) MDA-MB-231 human breast cancer cell lines, and Ishikawa human endometrial cell line were determined after 72 h drug exposure employing CellTiter-Glo assay at concentrations ranging from 0.01-1.0 × 10(5) nM. The antiproliferative activities of these compounds were compared to tamoxifen (TAM), 4-hydroxytamoxifen (4-OHT, active metabolite of tamoxifen), and raloxifene (RAL). In-vitro results indicated that compounds 9, 10, 12, and 13 were more potent than TAM against the human breast cancer cell lines with IC(50) < 20 µM. The in-silico structure-activity relationships of these compounds and their binding mode within the estrogen receptor (ER) binding site using AutoDock vina are discussed.

Synthesis and antiproliferative activity of new coumarin-based benzopyranone derivatives against human tumor cell lines.

The synthesis and antiproliferative activity of new coumarin-based benzopyranone derivatives containing basic amino side chain are described. The cytotoxicities against A549 and MCF-7 human cancerous cell lines were determined after 24, 48, 72 h drug exposure employing MTT assay at concentrations ranging from 0-100 µM. The antiproliferative activities of these compounds were compared to tamoxifen (TAM), 4-hydroxytamoxifen (4-OHT), raloxifene (RAL), 17ß-estradiol (E2) and Diethylstilbestrol (DES). In vitro results indicated that compounds 10 and 12 were the most potent showing significant inhibitory activities against these cell lines. Furthermore, their antiproliferative activity against MCF-7 human breast cancer cell line is comparable to that of TAM, RAL and 4-OHT.

In vitro cytotoxicity of benzopyranone derivatives with basic side chain against human lung cell lines.

BACKGROUND: Coumarins belong to an important group of useful drugs with diverse pharmacological properties. In the present study, the in vitro cytotoxicity of new coumarin-based benzopyranone derivatives containing diethylaminoethoxy (5), dimethylaminoethoxy (6), morpholinoethoxy (7), piperidinylethoxy (8) and pyrrolidinylethoxyl (9) amino side chain against human carcinoma (A549) and normal (LL47) lung cell lines was evaluated. MATERIALS AND METHODS: The cytotoxicity was evaluated by crystal violet dye binding assay. The effect of compound 9 on different phases of the cell cycle was determined using flow cytometry. RESULTS: In A549 cells, the 50% lethal dose (LD(50)) for compounds 5-9 were found to be 7.08, 5.0, 34.2, 8.33 and 5.83 µM, respectively, while in LL47 cells, the LD(50) values were found to be 16.7, 20.4, 34.6, 15.4 and 8.75 µM, respectively after 48 h treatment. Cell cycle data indicated that A549 cells were arrested at different phases depending on the concentration. CONCLUSION: Compounds 5-9 showed anticancer activity against lung cancer cell lines, while compound 6 showed highly selective anticancer activity.

Synthesis and Antimicrobial Activity of N,N'-Bis(2-hydroxylbenzyl)-1,2-ethanediamine Derivatives.

A series of N,N'-Bis(2-hydroxylbenzyl)-1,2-ethanediamine derivatives and its schiff bases were synthesized, characterized and screened for in vitro antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica. Result indicated that the ethylenediamine derivatives, N,N'-Bis(2-hydroxy-5-bromobenzyl)-1,2-ethanediamine (21), and N,N'-Bis(2-hydroxy-5-chlorobenzyl)-1,2-ethanediamine (22) showed the most favorable antimicrobial activity exhibiting LC(50) of 11.6 and 8.79 muM against S.enterica, 86 and 138 muM against P. aeruginosa, and 140 and 287 muM against S. aureus, respectively. These compounds displayed highest level of resistance with S. aureus. Thus, the high level of activity seen with the compounds (21, 22) suggests that these compounds could serve as the leads for development of novel synthetic compounds with enhanced antimicrobial activity.

Synthesis and antiproliferative activity of coumarin-estrogen conjugates against breast cancer cell lines.

The syntheses and cytotoxic activity of coumarin-estrogen conjugates are described. In vitro results indicated that conjugates 10, 11 and 13 show growth inhibitory activities at 5-dose concentration (100, 10, 1, 0.1, 0.01 muM) against the following NCI-7- human breast cancer cell lines: BT-549, HS 578T, MCF 7, MDA-MB-231/ATCC, MDA-MB-435, NCI/ADR-RES, and thus serve as new leads for further development of antibreast cancer agent.

A review of coumarin derivatives in pharmacotherapy of breast cancer.

The coumarin (benzopyran-2-one, or chromen-2-one) ring system, present in natural products (such as the anticoagulant warfarin) that display interesting pharmacological properties, has intrigued chemists and medicinal chemists for decades to explore the natural coumarins or synthetic analogs for their applicability as drugs. Many molecules based on the coumarin ring system have been synthesized utilizing innovative synthetic techniques. The diversity oriented synthetic routes have led to interesting derivatives including the furanocoumarins, pyranocoumarins, and coumarin sulfamates (COUMATES), which have been found to be useful in photochemotherapy, antitumor and anti-HIV therapy, and as stimulants for central nervous system, antibacterials, anti-inflammatory, anti-coagulants, and dyes. Of particular interest in breast cancer chemotherapy, some coumarins and their active metabolite 7-hydroxycoumarin analogs have shown sulfatase and aromatase inhibitory activities. Coumarin based selective estrogen receptor modulators (SERMs) and coumarin-estrogen conjugates have also been described as potential antibreast cancer agents. Since breast cancer is the second leading cause of death in American women behind lung cancer, there is a strong impetus to identify potential new drug treatments for breast cancer. Therefore, the objective of this review is to focus on important coumarin analogs with antibreast cancer activities, highlight their mechanisms of action and structure-activity relationships on selected receptors in breast tissues, and the different methods that have been applied in the construction of these pharmacologically important coumarin analogs.

Medicinal chemistry and emerging strategies applied to the development of selective estrogen receptor modulators (SERMs).

Selective estrogen receptor modulators (SERMs), known previously as "antiestrogens", are a new category of therapeutic agents used for the prevention and treatment of diseases such as osteoporosis and breast cancer. SERMs act as ER-agonist in some tissues while acting as ER-antagonist in others based on conformational change of the receptors, particularly at the helix 12. Currently, there are two classes of clinically approved SERMs; triphenylethylene derivatives (e.g., tamoxifen) and benzothiophene derivatives (e.g., raloxifene). Tamoxifen, raloxifene and toremifene are the most widely used SERMs. Tamoxifen, an antagonist of the breast tissue, is the first clinically identified compound with noticeable SERM activity. Although tamoxifen has been very successful in breast cancer treatment, its agonistic effect on the uterus is said to be associated with increase risk of developing endometrial cancer. Ideally, it is presumed that SERMs should selectively act as an agonist in the bone and brain while simultaneously acting as an antagonist in the breast and uterus. Therefore, the therapeutic goal of SERMs is the prevention of estrogen deficiency diseases without promoting estrogen-associated tumor growth. Therefore, the objective of this review is to summarize various effects that have been applied in improving the tissue-selectivity of SERMs, highlighting the emerging understanding of their mechanism of actions in selected target tissues and the development of the SERMs. The significance in recent discovery of selective estrogen receptor alpha modulators, SERAMs will also be reviewed.

Does the DABCO-catalysed reaction of 2-hydroxybenzaldehydes with methyl acrylate follow a Baylis-Hillman pathway?

Evidence is presented which supports the intermediacy of dipolar Baylis-Hillman-type adducts in the synthesis of coumarin and chromene derivatives from the reaction of 2-hydroxybenzaldehydes with methyl acrylate in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO).