A new and general strategy for highly functional furo[3,4-c]coumarins and related furyl coumarin derivatives has been developed, which is based on an extraordinarily facile intramolecular Wittig reaction, starting from α,β-unsaturated ketones, tributylphosphine, and acyl chlorides. The phosphorus ylides were proposed to be the key intermediates for constructing the crucial furan ring, leading t...

Vlasouliolides A-D (1-4), four rare sesquiterpene lactone dimers, were isolated from Vladimiria souliei. The common structural characteristic of 1-4 is the C32 skeleton comprising two sesquiterpene lactone units linked by a C11-C13' single bond with one acetyl connected to the C-13 position of one of the two sesquiterpene lactone units. The stereochemistries of 1-4 were assigned by a combinatio...

(E)-Alkyl ortho-hydroxycinnamates cyclize to coumarins at elevated temperatures of 140-250 °C. We find that the use of tri-n-butylphosphane (20 mol %) as a nucleophilic organocatalyst in MeOH solution allows cyclization to take place under much milder conditions (60-70 °C). Several coumarins were prepared, starting from ortho-hydroxyarylaldehydes, by Wittig reaction with Ph(3)P=CHCO(2)Me to (E)...

Coumarins have much importance in dyes, drugs, perfumes and pesticides. In the demonstrated research work, a benignant series of chlorinated coumarins was synthesized and screened against different enzymes. First, 6-Chloro-7-hydroxy-4-methyl-2H-chromen-2-one (3) was geared up by the reaction of 4-chlororesorcinol (1) and ethyl acetoacetate (2) in the presence of concentrated H(2)SO(4). Second, ...

Silica sodium carbonate (SSC) has been used as a valuable silica-supported catalyst for the preparation of a range of known and novel pyrano coumarins via the three-component reactions of aryl aldehydes, active methylene compound (malononitrile or ethyl cyanoacetate), and hydroxycoumarin (5,7-dihydroxy-4-substituted coumarins or 4-hydroxycoumarin). The heterogeneous catalyst showed much the sam...

Coumarins, which have low toxicity, are present in some natural foods, and are used in various herbal remedies, have attracted interest in recent years because of their potential medicinal properties. In this study, we report the isolation of two natural coumarins, namely umbelliferone (1) and 6-formyl umbelliferone (2), from Angelica decursiva, and the synthesis of 8-formyl umbelliferone (3) f...

Effect of addition of a permeabilizing agent dimethyl sulfoxide (DMSO) and a solid adsorbent, XAD -7, on growth and coumarin production in hairy root cultures of C. intybus was studied. Continuous permeabilization of the hairy root cultures of C. intybus with DMSO has been shown to be an effective strategy for enhanced release of coumarins while preserving the root viability. DMSO at 0.2% (v/v)...

The present study was undertaken to investigate fragmentation of a set of thirteen coumarins that bear amino-, alkylamino-, alkyl-, fluoroalkyl-groups, and heterocyclic rings, in a high-resolution (>10,000) quadrupole time-of-flight mass spectrometer equipped with an the electron ionization source and interfaced to a gas chromatograph. We have demonstrated how our data processing software is us...

Natural products (NPs) have proven to be an invaluable source of new chemotherapies yet very few have been explored to source small molecule carbonic anhydrase (CA) inhibitors. CA enzymes underpin physiological pH and are critical to the progression of several diseases including cancer. The present study is the first to more widely investigate NP coumarins for CA inhibition following the recent...

Fe deficiency compromises both human health and plant productivity. Thus, it is important to understand plant Fe acquisition strategies for the development of crop plants which are more Fe-efficient under Fe-limited conditions, such as alkaline soils, and have higher Fe density in their edible tissues. Root secretion of phenolic compounds has long been hypothesized to be a component of the redu...