Ethoxycarbonyl Group Research Articles

Structure-Activity Relationship Study of CYM51010, an agonist for the µ-δ Opioid Receptor Heterodimer.

Although opioid analgesics are indispensable in treating pain, these drugs are accompanied by life-threatening side effects. While clinically relevant opioid drugs target the µ opioid receptor (MOR), a heterodimer between the MOR and the δ opioid receptor (DOR) has emerged as another target to develop safer analgesics. Although some heterodimer-preferring agonists have been reported so far, it is still difficult to activate the MOR/DOR heterodimer selectively in the presence of MOR or DOR monomers/homodimers. To gain insights to develop selective agonists for MOR/DOR, herein we prepared analogs of CYM51010, one of the reported heterodimer-preferring agonists, and collected structure-activity relationship information. We found that the ethoxycarbonyl group was needed for the activity for the heterodimer, although this group could be substituted with functional groups with similar sizes, such as an ethoxycarbonyl group. As for the acetylaminophenyl group, not a type of substituent, but rather a substituent located at a specific position (para-position) was essential for the activity. Changing the linker length between the acetylaminophenyl group and the piperidine moiety also had deleterious effects on the activity. On the other hand, the substitution of the acetylamino group with a trifluoroacetylamino group and the substitution of the phenethyl group with a benzyl group diminished the activities for the monomers/homodimers while keeping the activity for MOR/DOR, which enhanced the selectivity. Our findings herein will play an important role in developing selective agonists for MOR/DOR and for elucidating the physiological roles of this heterodimer in analgesic processes and in the establishment of side effects.

Alkoxycarbonyl Groups in Metalloesters Showing Oxocarbenium‐like Structure and Alkylating Reactivity

AbstractIn contrast to the well‐documented acylating reactivity, the alkylating reactivity of the alkoxycarbonyl group, as signified by its oxocarbenium‐like resonance structure, remains almost unexplored. Herein, the first series of Co/Ni dinuclear metalloesters exhibiting the novel oxocarbenium‐like alkoxycarbonyl groups were synthesized and characterized. In these deformed alkoxycarbonyl groups, the Ccarbonyl−Oalkoxyl bonds were contracted to 1.177(11)~1.191(9) Å with the elongations of the Ccarbonyl=Ocarbonyl bonds to 1.368(13)~1.441(9) Å. Meanwhile, the O−Calkyl bonds were also elongated to 1.522(11) ~1.607(15) Å, and were by far the longest O−Calkyl bonds reported for alkoxycarbonyl groups. As triggered by the long O−Calkyl distances, the alkylating reactivity of the oxocarbenium‐like methoxycarbonyl group towards a series of C/N/O‐nucleophiles via the rare BAL2 mechanism at ambient conditions was examined. Furthermore, the homo‐etherifications of alcohols mediated by the Co/Ni dinuclear metalloesters were investigated. The yields followed the trend ethanol≫n‐propanol≫n‐butanol ≈n‐pentanol, that closely related to the structure features of the alkoxycarbonyl groups in corresponding metalloesters: while the ethoxycarbonyl group showed the reactive oxocarbenium‐like framework, the n‐propoxycarbonyl group displayed the dioxocarbenium‐like skeleton with a shorter O−Calkyl bond; In comparison, the classical frameworks with unactivated alkyl moieties were observed for n‐butoxycarbonyl and n‐pentoxycarbonyl groups.

Alkoxycarbonyl Groups in Metalloesters Showing Oxocarbenium-like Structure and Alkylating Reactivity.

In contrast to the well-documented acylating reactivity, the alkylating reactivity of the alkoxycarbonyl group, as signified by its oxocarbenium-like resonance structure, remains almost unexplored. Herein, the first series of Co/Ni dinuclear metalloesters exhibiting the novel oxocarbenium-like alkoxycarbonyl groups were synthesized and characterized. In these deformed alkoxycarbonyl groups, the Ccarbonyl-Oalkoxyl bonds were contracted to 1.177(11)~1.191(9) Å with the elongations of the Ccarbonyl=Ocarbonyl bonds to 1.368(13)~1.441(9) Å. Meanwhile, the O-Calkyl bonds were also elongated to 1.522(11) ~1.607(15) Å, and were by far the longest O-Calkyl bonds reported for alkoxycarbonyl groups. As triggered by the long O-Calkyl distances, the alkylating reactivity of the oxocarbenium-like methoxycarbonyl group towards a series of C/N/O-nucleophiles via the rare BAL2 mechanism at ambient conditions was examined. Furthermore, the homo-etherifications of alcohols mediated by the Co/Ni dinuclear metalloesters were investigated. The yields followed the trend ethanol≫n-propanol≫n-butanol ≈n-pentanol, that closely related to the structure features of the alkoxycarbonyl groups in corresponding metalloesters: while the ethoxycarbonyl group showed the reactive oxocarbenium-like framework, the n-propoxycarbonyl group displayed the dioxocarbenium-like skeleton with a shorter O-Calkyl bond; In comparison, the classical frameworks with unactivated alkyl moieties were observed for n-butoxycarbonyl and n-pentoxycarbonyl groups.

N-(4-methoxybenzyl)-L-tyrosine ethyl ester: Synthesis, structural analysis, and reaction with formaldehyde

This paper describes the structural analysis by single crystal X-ray diffraction (SCXRD) of N-(4-methoxybenzyl)-L-tyrosine ethyl ester; a scorpion-like conformation was revealed between the ethoxycarbonyl group and the 4-hydroxyphenyl group. Zig-zag linear arrangements having head-to-tail intermolecular hydrogen bonds (OH⋯N) were also observed between N-(4-methoxybenzyl)-l-tyrosine ethyl ester units. It was determined that this amine reacts with formaldehyde to form linear dimers, trimers, and tetramers made up of N-(4-methoxybenzyl)-l-tyrosine ethyl ester units linked by methylene bridges.

Synthesis of the diazatricycloundecane scaffold via gold(I)-catalysed Conia-ene-type 5-exo-dig cyclization and stepwise substituent assembly for the construction of an sp3-rich compound library.

The bridged diazatricycloundecane sp3-rich scaffold was synthesised via the gold(I)-catalysed Conia-ene reaction. The electron-donating property of the siloxymethyl group on alkyne 1 enabled 6-endo-dig cyclization, whereas the ethoxy carbonyl group on alkyne 4 led to 5-exo-dig cyclization with complete regioselectivity in the Conia-ene reaction. The resulting bridged diazatricycloundecane scaffold 5 allowed the construction of a library of sp3-rich compounds. Among the compounds synthesised, compounds 6e and 6f inhibited the hypoxia inducible factor 1 (HIF-1) downstream signaling pathway without affecting HIF-1α mRNA expression.

Hypervalent iodine mediated Pd(II)‐catalyzed ortho‐C(sp2−H) functionalization of azoles deciphering Hantzsch ester and malononitrile as the functional group surrogates

AbstractC−H bond activation has surfaced as a transformative toolbox for the efficient assembly of biologically important molecules. However, despite of major advances in palladium, rhodium and silver catalysis, yet palladium(II)‐ catalyzed, iodobenzene diacetate (PIDA) mediated C−H bond activation in azole skeleton has deluged with interesting wining outcome. Concentrating on that we herein report on the involvement of 4‐functionalized 1,4‐dihydropyridines (R‐DHPs) as the representative surrogates of benzoyl, pivalyl and ethoxycarbonyl groups and in presence of PIDA it releases appropriate functional radical (following single electron transfer oxidation of R‐DHPs under thermal condition)to become the part of ortho‐ functionalized azoles via Pd(II) catalysis. In case of cyanation reaction, malononitrile has served the key source of nitrile functionality by undergoing oxidative C−CN bond cleavage in presence of PIDA and with the help of Pd(II) catalyst it offers ortho‐cyanated azoles. Additionally, the selective formation of C‐3 benzoyl and ester functionalized indazole derivatives in absence of Pd(II)‐catalyst and the unprecedented formation of homo‐coupling products between two identical 2H‐indazoles are also notable outcome of present strategic access. Overall this protocol operates under mild condition, tolerates a wide range of structural moieties and gives versatile azole derivatives in high efficiency. The antioxidant properties of the synthesized 2‐thiophenyl benzoyl selenazole and isoselenazole are further evaluated using a chemically defined method. The Copper‐ascorbate (Cu−As) was utilized as an oxidative stress generator. Out of screened azoles, the 2‐benzoyl isoselenazole compound (3 i) displays magnificent antioxidant property as compared to the 2‐thiophenyl benzoyl selenazole (3 g).

Photophysical and thermophysical behavior of D-π-A-type fluorinated diphenylacetylenes bearing an alkoxy and an ethoxycarbonyl group at both longitudinal molecular terminals

Fluorinated diphenylacetylenes have recently attracted significant attention because they exhibit intense photoluminescence (PL) in the crystalline state owing to their electron-density distribution and the formation of H···F hydrogen bonds. In this study, fluorinated diphenylacetylenes bearing alkoxy and ethoxycarbonyl (COOEt) groups at both longitudinal molecular terminals were synthesized, and their photophysical and thermophysical behavior were evaluated, along with their structure–property relationship. The COOEt-substituted fluorinated diphenylacetylenes exhibited blue PL in the solution and crystalline states. Both the fluorine atom and the COOEt substituent play a crucial role in forming a large electron-density distribution and restricting the molecular motion of diphenylacetylenes through H···F and O···H hydrogen bonds in the crystalline state. The alkoxy-chain length of the fluorinated diphenylacetylenes not only affected their PL behavior in the crystalline state, but also their thermophysical behavior. Notably, fluorinated diphenylacetylenes with long alkoxy chains, such as heptyloxy and octyloxy chains, displayed a nematic liquid-crystalline (LC) phase. These findings facilitate the development of promising multifunctional molecules possessing PL and LC characteristics.

Microwave-promoted Synthesis and Optoelectronic Properties of Ethoxycarbonyl-substituted Coumarin and Benzo[f]coumarin

Microwave-assisted potassium fluoride-catalyzed synthesis of coumarin derivatives via tandem Knoevenagel condensation and intramolecular cyclization was established under solvent-free conditions. Satisfactory product yields were obtained with 67.87 and 90.21% as the highest recorded yields for the target compounds 3a (ethyl 2-oxo-2H-chromen-3-carboxylate) and 3b (ethyl 2-oxo-2H-benzo[f]chromen-3-carboxylate), respectively. The changes in the optoelectronic properties of the synthesized coumarin derivatives relative to the parent coumarin (2H-chromen- 2-one) molecule were also characterized to study, to some degree, the structure-to-property relationship of the compounds. Generally, extending the π-conjugation at position-3 by adding the ethoxycarbonyl group and expanding the π-system of the coumarin molecule at position-f shifts the absorption maxima to longer wavelengths, decreases the HOMO-LUMO energy band gap, and increases the light absorptivity of the coumarin compound.

Titania-mediated photoinduced fluorination of nitrone spin traps in acetonitrile (an EPR study)

Cyclic nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and its derivatives were applied in an EPR study of paramagnetic intermediates generated by in situ photoexcitation of TiO2 nanoparticles dispersed in acetonitrile with fluorinated ions. The UVA irradiation of deoxygenated acetonitrile titania suspensions containing the spin traps in the presence of fluoride or tetrafluoroborate, and Ag(I) or Cu(II) as photoelectron acceptors, resulted in the generation of the corresponding fluorine spin-adducts with well-resolved EPR signals. The EPR spectra of β-fluorine spin-adducts of the DMPO analogs, featuring ethoxycarbonyl (EMPO), diethoxyphosphoryl (DEPMPO), or diisopropoxyphosphoryl (DIPPMPO) groups at position 5 of the pyrroline ring, are reported for the first time. The reaction mechanisms leading to the β-fluorine spin-adduct formation in the given photocatalytic system are discussed.

Photophysical and Thermophysical Behavior of D-Π-A-Type Fluorinated Diphenylacetylenes Bearing an Alkoxy and an Ethoxycarbonyl Group at Both Longitudinal Molecular Terminals

Photophysical and Thermophysical Behavior of D-Π-A-Type Fluorinated Diphenylacetylenes Bearing an Alkoxy and an Ethoxycarbonyl Group at Both Longitudinal Molecular Terminals

Asymmetric synthesis of a cyclopropanecarboxylic acid derivative – the potential agonist/antagonist of GABA receptors

The synthesis of enantiomerically pure (1S,2S,S P)-1-[hydroxy(methyl)phosphonyl]-2-aminocyclopropanecarboxylic acid (1) (a potential agonist/antagonist of GABA receptors) was accomplished in six steps based on optically inactive methyl 2-[methoxy(methyl)phosphonyl]acrylate (2). The key steps of this synthesis included the cyclopropane ring formation by the asymmetric cyclopropanation reaction of 2 with (S)-dimethylsulfonium(p-tolylsulfinyl)methylide (3), regio and stereoselective installation of ethoxycarbonyl group in the cyclopropane ring, and the chemoselective desulfinylation reaction conducted with phenylsilane under the basic conditions.

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet-Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids.

We present a systematic investigation on an improved variant of the N-acyl-Pictet–Spengler condensation for the synthesis of 1-benzyltetrahydroisoquinolines, based on our recently published synthesis of N-methylcoclaurine, exemplified by the total syntheses of 10 alkaloids in racemic form. Major advantages are a) using ω-methoxystyrenes as convenient alternatives to arylacetaldehydes, and b) using the ethoxycarbonyl residue for both activating the arylethylamine precursors for the cyclization reaction, and, as a significant extension, also as protective group for phenolic residues. After ring closure, the ethoxycarbonyl-protected phenols are deprotected simultaneously with the further processing of the carbamate group, either following route A (lithium alanate reduction) to give N-methylated phenolic products, or following route B (treatment with excess methyllithium) to give the corresponding alkaloids with free N–H function. This dual use of the ethoxycarbonyl group shortens the synthetic routes to hydroxylated 1-benzyltetrahydroisoquinolines significantly. Not surprisingly, these ten alkaloids did not show noteworthy effects on TPC2 cation channels and the tumor cell line VCR-R CEM, and did not exhibit P-glycoprotein blocking activity. But due to their free phenolic groups they can serve as valuable intermediates for novel derivatives addressing all of these targets, based on previous evidence for structure–activity relationships in this chemotype.

Rhodium‐Catalyzed Additive‐Free C−H Ethoxycarbonylation of (Hetero)Arenes with Diethyl Dicarbonate as a CO Surrogate

AbstractA rhodium‐catalyzed C(sp2)‐H ethoxycarbonylation of indoles and arylpyridines using diethyl dicarbonate was developed. The catalytic process features an additive‐free ethoxycarbonylation reaction, in which only ethanol and CO2 are produced as byproducts, providing a CO‐free and operationally simple protocol. The introduced ethoxycarbonyl group is easily transformed into other ester and amide functionalities in a single step. Moreover, the reaction can be successfully applied on gram scale, and allows for the efficient synthesis of indole‐2‐carboxylic acid esters and isophthalates.

A three-component condensation of cyclic enamino ketones, phenylglyoxal hydrate, and ethyl cyanoacetate

A three-component condensation of cyclic enaminones, phenylglyoxal hydrate, and ethyl cyanoacetate in EtOH gave a number of 4,5,6,7-tetrahydroindole functional derivatives. The corresponding intermediates, 2,3,4,5,6,7-hexahydroindoles, are formed under mild conditions. Under more severe conditions (heating under reflux in DMF), cleavage of the ethoxycarbonyl group takes place.

Efficient synthesis of β-nitro amides by aminocarbonylation of ethoxycarbonyl-containing nitroalkenes with carbamoylsilane

Direct aminocarbonylation of β-nitroalkenes bearing β-positioned ethoxycarbonyl group using carbamoylsilane as an amide source afforded β-nitro amide derivatives under mild conditions without use of catalysts.

Synthesis of bis-azobenzene derivatives with reactive bromohexyl unit and carboxylic acid group based on Disperse Yellow 7

In this work, two types of azobenzene derivatives based on Disperse Yellow 7 (DY7, 4-[4-(phenylazo)phenylazo]-o-cresol) were synthesized, which are bis-azobenzenes bearing flexible functional 6-bromohexyl chain or carboxylic acid moiety. The first one was synthesized by alkylation of DY7 with an excess of 1,6-dibromohexane in the presence of a mild base (K2CO3). The second one (azo dye with carboxylic acid functionality) was obtained by the alkaline hydrolysis of the ester bond of the newly obtained DY7 derivative with the ethoxycarbonyl group. The synthesized compounds were characterized by different spectral analytical techniques such as 1H NMR, 13C NMR, FT-IR, and UV-Vis. They can be employed for the synthesis of a wide variety of azo-based materials, which may be suitable for photochromic systems and molecular electronics applications.

Синтез и свойства 1-аминокарбонилметил-5-арил- 4-ароил-3-гидрокси-3-пирролин-2-онов

3-Hydroxy-3-pyrrolin-2-ones are fully hydrogenated heterocyclic compounds, the base of which is included in a number of biologically active substances and drugs. Scientists' interest in 3-Hydroxy-3-pyrrolin-2-ones is due to the fact that, with their availability and high stability, they also have high reactivity due to the active carbonyl group in the third position of the heterocycle and easily interact with moconucleophiles. In addition, the presence of acyl and ethoxycarbonyl groups in the fourth position of the heterocycle makes it possible to obtain various condensed systems in reactions with binucleophiles, thereby making it possible to expand the range of the indicated compounds. We set the task to prepare 5-aryl-4-acyl-3-hydroxy-3-pyrrolin-2-ones containing an amino-carbonylmethyl substituent in the first position of the heterocycle, which were not previously described in the literature. It was also supposed to establish how the obtained compounds react with hydrazine hydrate. A series of 1-aminocarbonylmethyl-5-aryl-4-aroyl-3-hydroxy-3-pyrrolin-2-ones was obtained by setting up a three-component reaction of aroylpyruvic acid methyl ester with aromatic aldehydes and glycinamide hydrochloride in glacial acetic acid. The structure of the obtained compounds was established on the basis of IR and 1H NMR spectroscopy data. Based on the data of 1H NMR spectroscopy and a positive reaction with an alcoholic solution of iron(III) chloride, the predominant existence of the obtained compounds in the enol form was established. The article describes the mechanism of three-component reactions, the structural formulas of the obtained compounds, their physicochemical properties and spectral characteristics, as well as the yields of the reaction products. We have also studied the interaction of 1-substituted 5-aryl-4-acyl-3-hydroxy-3-pyrrolin- 2-ones with such a binucleophilic reagent as hydrazine hydrate. As a result of refluxing 1-amino-carbonylmethyl-3-hydroxy-4-(4-methoxybenzoyl)-5-(2-chlorophenyl)-3-pyrrolin-2-one and hydrazine hydrate in glacial acetic acid, 2-[4-(2-chlorophenyl)-3-(4-methoxyphenyl)-6-oxo-4,6-dihydropyrrolo [3,4-c] pyrazol-5(1H)-yl] acetamide. The article describes the proposed reaction mechanism, product yield, its physicochemical properties and spectral characteristics.

Synthesis of Functionalized Triptamine Analogues with Dichloroethoxyphosphoryl and Ethoxycarbonyl Groups

A rational method for the synthesis of functionalized tryptamine precursors by reduction of 1- and 2-substituted 3-nitroethylindoles on a nickel catalyst was proposed.

Tunable Cis-cisoid Helical Conformation of Poly(3,5-disubstibuted phenylacetylene)s Stabilized by n→π* Interaction

A series of novel cis poly(phenylacetylene)s (PPAs) substituted at meta-position(s) by two alkoxycarbonyl pendants, i.e., sP-Me-C8/rP-Me-C8, P-Me-C12, sP-Et-C4, sP-2C4 and sP-Oct-C4, were synthesized under the catalysis of [Rh(nbd)Cl]2 (nbd = norbornadiene). The dependence of elongation, screw sense, and stimuli response of helical polyene backbone on the structure of pendant, solvent, and temperature was systematically investigated in both solution and solid states. Because of n→π* interaction between vicinal carbonyl groups, sP-Me-C8/rP-Me-C8 could adopt contracted cis-cisoid helix in THF, toluene, CH2Cl2, and CHCl3. Such an intramolecular interaction was sensitive to the hydrogen bond donating ability of solvent and temperature, but insensitive to the dielectric constant and polarity of solvent. In poly(3-methoxycarbonyl-5-alkoxycarbonylphenylacetylene), the longer the chiral alkyl chain was, the easier the stable cis-cisoid helix could be achieved. However, when the methoxycarbonyl was changed to ethoxycarbonyl, sec-butyloxycarbonyl, and octyloxycarbonyl pendant groups, only cis-transoid helix was obtained at room temperature due to the increased steric hindrance. Moreover, lowering temperature was found to facilitate the stabilization of n→π* interactions, and reversible temperature-dependent stereomutations were achieved in sP-Me-C8 and sP-Et-C4 depending on the solvent where they were dissolved. These results suggested that the long alkyl chain, small pendant size, and lower temperature favored the stabilization of intramolecular n→π* interactions and the formation of contracted, cis-cisoid helices for poly(3,5-diester substituted phenylacetylene)s.

A One-Pot Intramolecular Tandem Michael–Aldol Annulation Reaction for the Synthesis of Chiral Pentacyclic Terpenes

A chiral tricyclic terpene possessing a 6,6,6-tricyclic framework and a 3,3-dimethyl-7-oxooctylidenyl side chain undergoes a double ring-closing reaction to give two chiral pentacyclic terpenes in a ratio of 4:3 via an intramolecular Michael addition followed by aldol condensation under basic conditions. Three new stereogenic centers are introduced in the initial Michael annulation reaction. Stereoselective installation of an ethoxycarbonyl group at C17 of the two pentacyclic terpenes separately gives the corresponding highly functionalized pentacyclic terpenoids with seven stereogenic centers. The structures and stereochemistry of key intermediates and products are established through X-ray crystallographic analysis. A mechanism is proposed for explaining the stereochemistry in the Michael annulation reaction.