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A common challenge in Pt(IV) prodrug design is the limited repertoire of linkers available to connect the Pt(IV) scaffold with the bioactive payload. The commonly employed linkers are either too stable, leading to a linker artifact on the payload upon rel

(E)-Methyl/ethyl-3-(2-hydroxyphenyl)acrylates 3a-x have been prepared by the reaction of salicylaldehydes 1a-l with Wittig reagents such as methyl (triphenylphosphoranylidene)acetate 2a and ethyl (triphenylphosphoranylidene)acetate 2b in dry DCM at room t

o-Alkenylation of unprotected phenols has been developed by direct C?H functionalization catalyzed by PdII. This work features phenol group as a directing group and realizes highly site-selective C?H bond functionalization of phenols to achieve the corresponding products in moderate to excellent yields at 60 °C. The advantages of this reaction include unprecedented C?H functionalization using phenol as a directing group, high regioselectivity, good substrate scope, mild reaction conditions, and high efficiency. To the best of our knowledge, this is the first example of a regioselective C?H alkenylation of unprotected phenols utilizing phenolic hydroxyl group as a directing group. The alkenylation of unprotected tyrosine and intramolecular cyclization are also successfully carried out under this catalytic system in good yields. Furthermore, this novel method enables a late-stage modification of complex phenol-containing bioactive molecules toward a diversity-oriented drug discovery.

An unprecedented deformylative coupling of salicylaldehydes to acrylates and acrylamides under Rh-catalyzed conditions is reported. These deformylative couplings afforded o-hydroxycinnamates and o-hydroxycinnamamides with broad functional group tolerance and high chemoselectivity under milder reaction conditions.

A versatile and DES-compatible bipyridine palladium complex has been developed as a general pre-catalyst for different cross-coupling reactions (Hiyama, Suzuki-Miyaura, Heck-Mizoroki and Sonogashira) in deep eutectic solvents. Hydrogen bond capacity of the ligand allows to keep the excellent level of results previously obtained in classical organic solvents. Palladium pre-catalyst showed a high catalytic activity for many cross-coupling reactions, demonstrating a great versatility and applicability. Also, this methodology employs sustainable solvents as a reaction medium and highlights the potential of DES as alternative solvents in organometallic catalysis. The catalyst and DES were easily and successfully recycled. The formation of PdNPs in DES has been confirmed by TEM and XPS analysis and their role as catalyst by mercury test. The dynamic coordination of bipyridine-type ligand in the palladium complex formation has been studied via UV/Vis. (Figure presented.).

A series of caffeic acid derivatives were synthesized via a modified Wittig reaction which is a very important tool in organic chemistry for the construction of unsaturated carbon–carbon bonds. All reactions were performed in water medium at 90?C. The aqueous Wittig reaction worked best when one unprotected hydroxyl group was present in the phenyl ring. The olefinations in the aqueous conditions were also conducted with good yields in the presence of two unprotected hydroxyl groups. When the number of the hydroxyl groups was increased to three, the reaction yields were worse, and the derivatives 12, 13, and 18 were obtained with 74%, 37%, and 70% yields, respectively. Nevertheless, the Wittig reaction using water as the essential medium is an elegant one-pot synthesis and a greener method, which can be a safe alternative for implementation in organic chemistry. The obtained compounds were tested for their antioxidant activity, and 12, 13, and 18 showed the highest activities. Moreover, all synthesized compounds displayed no cytotoxicity, and can therefore be used in the pharmaceutical or cosmetic industry.

Candida albicans is an important opportunistic fungal pathogen capable of provoking infection in humans. In the present study, we evaluated the antifungal effect of 23 ester derivatives of the cinnamic and benzoic acids against 3 C. albicans strains (ATCC-76645, LM-106 and LM-23), as well as discuss their Structure–Activity Relationship (SAR). The antifungal assay results revealed that the screened compounds exhibited different levels of activity depending on structural variation. Among the ester analogues, methyl caffeate (5) and methyl 2-nitrocinnamate (10) were the analogues that presented the best antifungal effect against all C. albicans strains, presenting the same MIC values (MIC?=?128?μg/mL), followed by methyl biphenyl-2-carboxylate (21) (MIC?=?128, 128 and 256?μg/mL for C. albicans LM-106, LM-23, and ATCC-76645, respectively). Our results suggest that certain molecular characteristics are important for the antifungal action.

Centrally chiral bisoxazolines connected directly to a planar chiral [2.2]paracyclophane backbone were synthesized and evaluated as asymmetric ligands in Cu-catalyzed intermolecular ethanolic O-H insertion reactions of α-diazo esters. The reactivities and enantioselectivities of Cu complexes of the synthesized bisoxazoline ligands were lower than those of ligands without central chirality. However, planar chiral [2.2] paracyclophane-based bisoxazoline ligands with an inserted benzene spacer that had a sterically demanding isopropyl substituent showed good enantioselectivities in inter- and intramolecular aromatic O-H insertion reactions, without the aid of central chirality.

Herein we describe a one-pot microwave-assisted method for the synthesis of cinnamic acid and coumarin derivatives. The synthesis begins with an aldehyde synthon, and the chosen reaction conditions determine whether a cinnamic acid or coumarin derivative is formed. A regioselective Claisen rearrangement was also efficiently incorporated into the synthetic sequence to further increase the complexity of the product. Notably, this approach provides high product yields and selectivities without the need of a phenol protecting group.

An efficient palladium(II)-catalyzed intermolecular direct ortho-alkenylation and acetoxylation of phenols has been developed. The reaction proceeded via a seven-membered cyclopalladated intermediate and showed complete regio- and diastereoselectivity. The approach also provided an efficient route for the synthesis of coumarins and benzofurans.

Treatment of benzofurans with bis(pinacolato)diboron and Cs2CO3 under nickel-NHC catalysis resulted in the insertion of a boron atom into the C2-O bond of benzofurans to afford the corresponding oxaborins. The scope of benzofuran substrates is wide, and the reactions proceeded without loss of functional groups such as fluoro, methoxy, and ester that are potentially reactive under nickel catalysis. The boron-inserted products proved to be useful building blocks and subsequently underwent a series of transformations, one of which led to the synthesis of fluorescent π-expanded oxaborins.

The present invention is directed to novel macrocyclic compounds of formula (I) and their pharmaceutically acceptable salts, hydrates or solvates: wherein R1, R2, R3, R4, R5, R6, n1, m, p Z1, Z2, and Z3 are as describe in the specification. The invention also relates to compounds of formula (I) which are antagonists of the motilin receptor and are useful in the treatment of disorders associated with this receptor and with or with motility dysfunction.

This manuscript describes the preparation of new small molecule inhibitors of Bacillus anthracis lethal factor. Our starting point was the symmetrical, bis-quinolinyl compound 1 (NSC 12155). Optimization of one half of this molecule led to new LF inhibitors that were desymmetrized to afford more drug-like compounds.

The development of new synthetic fluorination reactions has important implications in medicinal, agricultural, and materials chemistries. Given the prevalence and accessibility of alcohols, methods to convert alcohols to trifluoromethanes are desirable. However, this transformation typically requires four-step processes, specialty chemicals, and/or stoichiometric metals to access the trifluoromethyl-containing product. A two-step copper-catalyzed decarboxylative protocol for converting allylic alcohols to trifluoromethanes is reported. Preliminary mechanistic studies distinguish this reaction from previously reported Cu-mediated reactions.

(E)-Alkyl ortho-hydroxycinnamates cyclize to coumarins at elevated temperatures of 140-250 °C. We find that the use of tri-nbutylphosphane (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 Ph3P=CHCO2Me to (E)-methyl ortho-hydroxycinnamates, followed by the phosphane catalyzed cyclization.

Trans-cinnamaldehyde (CA) and its analogs 2-hydroxycinnamaldehyde and 2-benzoyloxycinnamaldehyde have been reported to possess antitumor activity. CA is also a known Nrf2 activator. In this study, a series of ortho-substituted cinnamaldehyde analogs was s

(Chemical Equation Presented) A facile synthesis of xanthenes and acridines based on a cascade nucleophilic addition-cyclic Michael addition process of arynes and phenols/anilines substituted with α,β-unsaturated groups at the ortho positions is described

A task-specific imidazolium-based phosphinite ionic liquid (IL-OPPh2) was used as the dual solvent-reagent for the synthesis of E-cinamates and coumarin derivatives via the one-pot Horner-Wadsworth-Emmons-type reaction. The ionic liquid containing its cor

Efficient synthesis of a variety of 3-substituted coumarins via NaOMe-catalyzed Knoevenagel condensation and one-pot preparation of 3,4-unsubstituted coumarins in the presence of NaOMe via Wittig reaction in room-temperature ionic liquids are described. Knoevenagel condensation of 2-hydroxybenzaldehyde with dimethyl- and diethylmalonate was performed with excellent yields in room-temperature ionic liquids. Although diethyl- and dimethylchloromalonates were mostly recovered unchanged in Knoevenagel condensation, higher conversions were observed via Wittig reaction of these compounds with 2-hydroxybenzaldehyde derivatives and triphenylphosphine. Other 2-hydroxybenzaldehyde derivatives, methyl- and ethylchloroacetates, were reacted in ionic liquids to afford simple coumarins in good yields. These reactions widen the applicability of ionic liquid in organic synthesis. Copyright Taylor & Francis Group, LLC.

A water-soluble octahedral Pd nanocage acting as a reaction vessel templates the photodimerization of substituted trans-cinnamic acid methyl esters in water. Irradiation of the host-guest complexes of trans-cinnamic acid methyl esters with the Pd nanocage resulted in selective formation of a syn head-head dimer in addition to the corresponding cis isomer. These results suggest that the guest molecules are preoriented in a selective fashion with the hydrophilic ester group facing water and the hydrophobic aryl group tucked within the cavity of the host. Such an orientation occurs at the hydrophobic-hydrophilic interface between the nanocage exterior and interior. Weak intermolecular C-H-π and π-π interactions between the host and the guest(s) are likely to be responsible for the lack of mobility of the reactant olefins during their short excited-state lifetime.

In the course of search for potent chitin synthase inhibitors from natural resources, a novel chitin synthases inhibitor, 2′-benzoyloxycinnamaldehyde (2′-BCA) (I), was isolated from the aerial parts of Pleuropterus ciliinervis NAKAI. 2′-BCA inhibited chit

A novel class of macrocyclic peptidomimetics was identified and optimized as potent antagonists to the human motilin receptor (hMOT-R). Well-defined structure-activity relationships allowed for rapid optimization of potency that eventually led to high aff

Herein we report regioselective substitution reactions of a series of 2- and 3-hydroxybiaryls including BINOL via a new directed ortho-metalation procedure. O-Aryl N-isopropylcarbamates, conveniently prepared from phenols and isopropyl isocyanate, are tem

A convenient and useful esterification was realized, and this reaction proceeded without a dehydrating reagent or water removal equipment. A series of ortho -hydroxyphenyl carboxylic acids and benzoic acids were transformed to their corresponding methyl esters under CAN/CH3OH reaction conditions. Whereas in an aprotic solvent, acetonitrile, sp3-C tethered ortho-hydroxyphenyl carboxylic acids undergo simultaneous o,p-dinitration and intramolecular esterification reactions in good yields. Also, 2-((1E)-2-nitrovinyl)-4-nitro-phenol (3e) showed selective cytotoxicities to ward MCF-7, HEP G2, and HEP 3B cell lines with IQovalues of 23.50, 7.33, and7.59ug/mL,respectively.

Phenols are converted to salicylaldehydes with paraformaldehyde, MgCl 2-Et3N in THF, and subsequent treatment with methyl (triphenylphosphoranylidene)acetate gave the corresponding methyl ortho-hydroxycinnamate derivatives. The sequence is conveniently carried out as a one-pot procedure.

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A compound of formula (I), in which: R1is lower alkyl, cyclo(lower)alkyl, optionally substituted aryl, optionally substituted heterocyclic group, cyclo(lower)alkyl(lower)alkyl, or ar(lower)alkyl; R2is hydrogen, hydroxy or protected h

The acrylic acid esters of Formula I are useful for the delivery of organoleptic compounds, especially for flavors, fragrances, masking agents and antimicrobial compounds. They can also deliver fluorescent whitening agents.

A series of cinnamaldehydes was synthesized for the study of inhibitory activity against cyclin dependent kinases (CDKs). A couple of compounds selectively inhibited cyclin D1-CDK4 with an IC50 value of 7-18 μM. (C) 2000 Elsevier Science Ltd. All rights reserved.

A new water soluble phosphine-ligand: diphenylphosphinyl) phenylphosphonic acid (DPPPA) was used in Heck reaction. The Heck reaction is efficiently and rapidly achieved by a palladium-catalysed reaction in water performed in a Teflon autoclave under microwave irradiation with a commercial microwave oven. The Log P was used for correlating the solubility of the aryl iodide in water with the observed yield.

Induction of phase 2 enzymes (e.g., glutathione transferases, NAD(P)H:quinone reductase, glucuronosyltransferases, epoxide hydrolase) is a major strategy for reducing the susceptibility of animal cells to neoplasia and other forms of electrophile toxicity. In a search for new chemoprotective enzyme inducers, a structure-activity analysis was carried out on two types of naturally occurring and synthetic substituted phenylpropenoids: (a) Ar- CH=CH-CO-R, where R is OH, OCH3, CH3, or Ar, including cinnamic, coumaric, ferulic, and sinapic acid derivatives, their ketone analogues, and chalcones; and (b) bis(benzylidene)cycloalkanones, Ar-CH=C(CH2)(n)(CO)C=CH-Ar, where n = 5, 6, or 7. The potencies of these compounds in inducing NAD(P)H:quinone reductase activity in murine hepatoma cells paralleled their Michael reaction acceptor activity (Talalay, P.; De Long, M. J.; Prochaska, H. J. Proc. Natl. Acad. Sci. U.S.A. 85, 1988, 8261-8265). Unexpectedly, the bis(benzylidene)cycloalkanones also powerfully quenched the lucigenin- derived chemiluminescence evoked by superoxide radicals. Introduction of o- hydroxyl groups on the aromatic rings of these phenylpropenoids dramatically enhanced their potencies not only as inducers for quinone reductase but also as quenchers of superoxide. These potentiating o-hydroxyl groups are hydrogen-bonded, as shown by moderate down field shift of their proton NMR resonances and their sensitivities to the solvent environment. The finding that the potencies of a series of bis(benzylidene)cycloalkanones in inducing quinone reductase appear to be correlated with their ability to quench superoxide radicals suggests that the regulation of phase 2 enzymes may involve both Michael reaction reactivity and radical quenching mechanisms.

Flash vacuum pyrolysis of 3-(2-hydroxyaryl)propenoic esters gives coumarins (and other fused α-pyrones) in high yieid.

Flash vacuum pyrolysis of 2-allyloxypropenoic esters (e.g. 7) gives benzo[b]furans (e.g. 32) in synthetically useful yields by sequential generation of a phenoxyl radical, cyclisation and ejection of the carboxylic ester function as a free radical leaving group. The method is compatible with a range of substituents on either the benzene ring or the propenoate chain, and is particularly effective for 2-substituted benzo[b]furans. The natural products 5-methoxybenzo[b]furan 1 and angelicin 2 have been synthesised in three and four steps respectively from commercially available starting materials by this route. Related cyclisations to give naphtho[2,1-b]furan 40 were complicated by competitive formation of naphtho[2,1-b]pyran-3-ones (e.g. 41 and 42), but the yield of the required product could be optimised by the choice of the radical precursor. Annelation of a furan ring onto a thlophene is also possible by this method, but lower yields are obtained in such pyrolyses.

A new synthesis of the pyrrolo[1,2-a]pyrazine system from pyrrole is described. In light of the ab initio calculations carried out on this heterocyclic system some of its basic chemistry was investigated and included electrophilic substitution, addition o

Mono and di (i.e. 2,6) o-chloro- and o-methoxycinnamic acids undergo photocyclization to give the corresponding coumarins.The reaction occurs in aqueous and organic media, with a prototypical reaction giving evidence of being favored at pH > 6.Cyclization of the dimethoxy acid is relatively inefficient (Φ for the PSS = 0.0015), and a photostationary state of the cis/trans acids is formed early into the reaction.The photocyclization of the dichloro analog is more efficient (Φ exceeds 0.04) and therefore time dependent since product formation competes with trans/cis isomerization.Methyl o-chlorocinnamate also photocyclizes (Φ for the PSS = 0.0022 in acetonitrile) but the o-methoxy ester is virtually photoinert.It is proposed that the acid photocyclizes through intramolecular nucleophilic attack by the carboxylate group followed by heterolysis of the nucleofuge.Methyl o-chlorocinnamate appears to photocyclize through a cycloaddition of the carbonyl group followed by homolysis of the Cl and Me moieties, possibly through the intermediacy of a ketene as proposed by earlier workers.

Novel compounds of the general formula STR1 wherein R1 is lower alkyl, lower cycloalkyl, lower alkenyl, lower alkynyl, lower alkyl carboxymethyl, aryl carboxymethyl, aryl, or aralkyl; A is a direct bond, lower alkylene, or lower alkenylene; x is 1 or 2, provided that when x is greater than 1, different occurrences of the STR2 group may be the same or different; Ar is heterocyclic, unsubstituted aromatic or aromatic substituted with lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, halogen, acetamido, amino, nitro, lower alkylamino, hydroxy, lower hydroxyalkyl or cyano; W is alkylene containing from 1 to about 10 carbon atoms; and B is --NR2 COR3, --NR2 CONR3 R4, --NR2 SO2 R3, --NR2 SO2 NR3 R4, or --NR2 COOR5, wherein R2, R3, R4 and R5 may be the same or different and may be hydrogen, alkyl, alkoxyalkyl, alkoxyaryl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, or aralkyl, except that R3 and R5 are not hydrogen when B is --NR2 SO2 R3 or --NR2 COOR5, or R3 and R4 may together with N form a 5 to 7 membered heterocyclic group; and the pharmaceutically acceptable salts thereof.

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Coumarin compounds may be produced by the conversion of o-hydroxycinnamates or o-hydroxycinnamic acids in the presence of catalysts comprising compounds containing metals of Group VIII of the Periodic Table.