A New Convenient Synthesis of α-Arylpropionic Acid Esters and α-Arylpropionitriles

Various types of α-arylpropionic acid esters were effectively obtained by the coupling reaction of aryl Grignard reagents and α-bromopropionic acid esters in the presence of nickel catalysts. α-Arylpropionitriles, precursors of α-arylpropionic acids, were also synthesized by the reaction of α-methanesulfonyloxypropionitrile and arylcopper reagents prepared from equimolar amount of arylmagnesium halides and copper(I) bromide.     

New α-Functionalized Phosphorus Acid Surfactants: Synthesis,Dissociation Constants and Molecular Aggregation

Abstract

Pursuing our investigation into h e reactivity of red phosphorus. its hydrolysis derivatives (PH₃, and H₃,PO₂).^1,2 and P-H labile compounds? we report here a convenient method for the direct synthesis of free a-hydroxyalkyl phosphinic acid surfactants from aqueous hypophosphorous acid and the long-chain aldehydes or imincs under sonication.     

New general synthesis of α-alkoxyketones via α'-alkylation, α-alkylation and α,α'-dialkylation of α-alkoxyketimines

α-Methoxy- and α-ethoxyketones, as important intermediates in organic synthesis and flavor compounds in food chemistry, were synthesized by deprotonation of N-(1-alkoxy-2-propylidene)isopropylamine, prepared by condensation of the corresponding α-alkoxyacetone with isopropylamine, and subsequent reaction of the corresponding 1-azaallylic anions with alkyl halides to afford α'-alkylated, α-alkylated and α,α'-dialkylated ketimines. Hydrolysis of the imino function led to the desired substituted α-alkoxyketones. The ratio of α-, α'-, and α,α'-(di)alkylated compounds depended on the amount of base used and on the nature of the alkylating reagent.     

α-Alkylioene-γ-Lactone Synthesis: α-Methyl and α-Benzylcinnamic Acid Dianion Addition to Ketones

α-methyl and α-benzylcinnamic acids and lithium diisopropylamlde (DIPA) generate stable dianlons that as addition reagents are useful for the synthesis of α-methylene-and α-benzyl Idene-γ-lactones.     

Trichloroisocyanuric Acid,A Swimming Pool Disinfectant: New Developments and Role in UV-Induced Skin Inflammation†

This article is a highlight of the paper by Snell et al. in the current issue of Photochemistry and Photobiology (Snell et al. Photochem. Photobiol. 2022). The authors utilized an organotypic human skin model and transgenic SKH-1 mice to determine the oxidative stress response induced by topical treatment of trichloroisocyanuric acid (TCIC), a common disinfectant used in swimming pool. Additionally, they determined molecular mechanisms associated with topical TCIC pretreatment followed by ultraviolet (UV) radiation exposure. This work provides the first example that cutaneous delivery of TCIC significantly increases UV-induced skin inflammation, suggesting a previously unidentified potential of TCIC. If translatable to human skin, these findings could be important for human skin health implications.     

Addition of carbonyl fluoride to aliphatic nitriles: Formation of α,α-difluoroalkyl isocyanates

Carbonyl fluoride will add to alkane- and perfluoroalkanenitriles and alkanedinitriles in anhydrous acids to form the corresponding α,α-difluoroalkyl isocyanate, perfluoroalkyl isocyanate, or α,α,ω,ω,-tetrafluoro-α,ω-diisocyantoalkane. With acetonitrile the reaction proceeded slowly in anhydrous hydrogen fluoride or in the presence of anhydrous hydrogen chloride in benzene to yield a clear colorless liquid identified as α,α-difluoroethyl isocyanate. Increasing yields based on the lesser reactant were achieved by making the ratio of acetonitrile to carbonyl fluoride greater or less than one, having the optimum amount of anhydrous acid, the presence of an alkali metal fluoride and/or an increase in reaction time. The α,α-difluoroethyl isocyanate reacted with anhydrous ethyl alcohol to form the corresponding carbamate which slowly decomposed by splitting out hydrogen fluoride. The addition reaction proceeded more rapidly with propionitrile and less rapidly with trifluoroacetonitrile than with acetonitrile. Cyanamide yielded trifluoromethyl isocyanate and cyanuric acid. Adiponitrile produced 1,6-diisocyanato-1,1,6,6-tetrafluorohexane and 1-isocyanato-5-cyano-1,1-difluoropentane.     

Regiospecific Baeyer-Villiger Oxidation of α,α-Dichlorocyclobutanones: A Norbisabolide γ-lactone Analogue1

Details and methodological comparisons are presented on the preparation of a norbisabolide γ-lactone analogue (4) via dichloroketene cycloaddition to limonene followed by regioselective Baeyer-Villiger oxidation (CH₃CO₃H) of the α,α-dichlorocyclobutanones 3 and C-Cl reduction (Zn/HOAc). The sequence of reduction followed by oxidation (HOCI) applied to 3 produced 4 in much better yield.     

A facile solvent free Claisen-Schmidt reaction: synthesis of α,α'-bis-(substituted-benzylidene)cycloalkanones and α,α'-bis-(substituted-alkylidene)cycloalkanones

Solvent-free Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes (aryl aldehydes) using solid NaOH (20 mol%) and applying a grinding technique were studied. Quantitative yields (96-98%) of α,α'-bis-(substituted-benzylidene)cycloalkanones were obtained. Aliphatic aldehydes also provided α,α'-bis-(substituted-alkylidene)cycloalkanones in very good yields with minor amounts of a-(substituted-alkylidene)cycloalkanones. The catalytic performance of solid NaOH was examined. The molar ratio of NaOH was optimized. The catalytic effect of solid NaOH was also evaluated by comparing it with KOH, NaOAc, and NH(4)OAc and it turns out that 20 mol% of solid NaOH was good enough to catalyze the Claisen-Schmidt reactions of cycloalkanones with various substituted benzaldehydes. Additionally, the regioselectivity of the Claisen-Schmidt reaction of acetone with benzaldehyde was examined. Using the same method, we could synthesize the corresponding bis-benzylidene- and mono-benzylideneacetone separately in 98% and 96% yields, respectively.     

Amino Acid Derivatives, VII [1]: Synthesis and Antiviral Evaluation of α-Amino Acid Esters Bearing an Indazole Side Chain

A series of peptide and dipeptide derivatives conjugated with an indazole residue were synthesized. The new compounds were evaluated in vitro for cytotoxicity against Hepatitis-A virus (HAV-27), Herpes Simplex virus-1 (HSV-1), and Hepatitis-B virus (HBV) and showed moderate to high activity.     

Amino Acid Derivatives,VII [1]: Synthesis and Antiviral Evaluation of α-Amino Acid Esters Bearing an Indazole Side Chain

Summary. A series of peptide and dipeptide derivatives conjugated with an indazole residue were synthesized. The new compounds were evaluated in vitro for cytotoxicity against Hepatitis-A virus (HAV-27), Herpes Simplex virus-1 (HSV-1), and Hepatitis-B virus (HBV) and showed moderate to high activity.     

A Proline-Based Aminophosphinic Acid Ligand and It’s Vanadyl Complex: Synthesis,Characterization and In Vitro Inhibitory Effects on α-Amylase And α-Glucosidase

Abstract

A proline-based aminophosphinic acid ligand and it's vanadium complex have been synthesized and characterized by spectroscopic techniques. The inhibitory activity on pancreatic α-amylase and Baker's yeast α-glucosidase has been examined in vitro. The novel complex showed more inhibitory potency against pancreatic α-amylase and Baker's yeast α-glucosidase compared to acarbose as an antidiabetic drug.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

A New Co(Ⅱ) Coordination Compound Constructed by Tripyridyltriazole and Pyromellitic Acid:Synthesis,Crystal Structure and Antifungal Activity

A new coordination compound, [Co(L~(223))_2(H_2O)_2]·H_2pm(1, L~(223) = 3,4-bis(2-pyridyl)-5-(3-pyridyl)-1,2,4-triazole and H4 pm = pyromellitic acid), has been synthesized. The structure of complex 1 has been characterized by X-ray single-crystal diffraction, elemental analysis, IR spectrum analysis and thermogravimetric analysis. Single-crystal X-ray diffraction analysis reveals that complex 1 belongs to the triclinic system, space group P1 with a = 10.2470(8), b = 10.2879(9), c = 10.2951(11) ?, α = 109.398(2), β = 97.6590(10), γ = 95.3260(10)°, V = 1003.60(16) ?3, Z = 1, Dc = 1.565 g/cm~3, μ = 0.508 mm~(-1), Mr = 945.73, F(000) = 485, the final R = 0.0562 and w R = 0.0783 with I 2σ(I). Two L223 as chelating ligands link one Co(II) ion to form a 0D motif. Furthermore, the 0D motifs are linked into a 2D coordination pattern with hydrogen bonds. In addition, the antifungal effects of the ligand and the complex were evaluated by the disc diffusion method against Colletotrichum gloeosporioides Penz. 1 represents antifungal activity with high levels of inhibitory potency which is larger than the corresponding ligand.     

The Palladium Catalyzed Hydrostannation of 1-Alkenylphosphonates: A New Approach to Stereodefined α,β-Disubstituted Vinylphosphonates

Abstract

The palladium catalyzed hydrostannation of 1-alkenylphosphonates gives the (E)-α-stannyl 1-alkenylphosphonates 2 stereospecifically. 2 can be transferred to α,β-disubstituted vinylphosphonates with the retention of the configuration.     

The Acetoxyfulvene Synthesis of Prostaglandins: A New,Versatile Synthesis of dl-PGF1δ, dl-PGF2α, dl-PGE1 and dl-PGE2 from a Common Intermediate

Abstract

In the Corey¹ synthesis of prostaglandins and in our recently published modifications^2,3 a synthon containing carbon atoms 14 to 20^θ is first added to a bicyclic intermediate (C-6 to C-13) and completion of the prostaglandin skeleton by addition of a second synthon containing carbon atoms 1 to 5 forms a subsequent step. In a modification^4,5 of the Corey synthesis¹ PGF_1α and PGE₁ were made by reversing the order in which these two synthons were added to the cyclopentane ring (C-6 to C-13). The major limitation of this modified route^4,5 is that it is restricted to the preparation of prostaglandins of the 1-series,^? because hydrogenolysis of the benzyl group of the intermediate ester (1) reduces the C-5, C-6 double bond to form the saturated alcohol (2), which cannot be converted into prostaglandins of the 2-series^?.     

A New Mn(Ⅱ) Complex Assembled by 2,5-Dihydroxy-1,4-benzenedicarboxylic Acid and 2,2'-Bipyridine: Synthesis,Structure and Theoretical Calculation

A new complex [Mn(DHTA)(bipy)_(0.5)]n(1, H_2 HTA = 2,5-dihydroxy-1,4-benzenedicarboxylic acid, bipy = 2,2'-bipyridine) was hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, single-crystal and power X-ray diffraction. It belongs to monoclinic system, C2/c space group with a = 12.874(13), b = 11.302(12), c = 17.352(18) ?, β = 101.574(15)°, V = 2474(4) ?3 and Z = 4. It displays a one-dimensional zigzag chain-like structure, which was further extended into a three-dimensional supramolecular structure by hydrogen bonds and π-π interactions. Moreover, we analyzed Natural Bond Orbital(NBO) of 1 in using the PBE0/LANL2 DZ method built in Gaussian 03 Program. The calculation results show the obvious covalent interaction between the coordinated atoms and Mn(Ⅱ) ion.     

New Applications of the Lithiated Phosphinimine Ph3P=N-Li: Synthesis of α,β-Unsaturated Nitriles and P=N-P Linked Phosphinimines

Abstract

The reaction of Ph₃P-N-Li⁽¹²⁾ with various α,β-unsaturated esters gives access to new N-(α,β-unsaturated acyl) phosphinimines. which can undergo intramolecular aza-Wittig reaction (at 65 - 110°C) to afford the corresponding nitriles.     

A comparison of the structure,flexibility and mesogenic properties of 4-methoxy-4′-cyanobiphenyl and the α,α,α-trifluorinated derivative

Abstract

The compound 4-cyano-4′-(α,α,α-trifluoromethoxy)biphenyl (1OCBF₃) has been synthesized. Unlike the fully protonated analogue, 4-cyano-4′-methoxybiphenyl (1OCB), it does not show a liquid crystalline phase on cooling from the melting point (51°C) to room temperature. The transition temperature to a monotropic nematic phase was obtained as approximately 0°C by determining the transition temperatures of mixtures with 1OCB. The structures, conformational properties and orientational ordering of both 1OCB and 1OCBF₃ as solutes in a nematic solvent ZLI 1132 have been investigated via the 17 dipolar couplings obtained by analysing the proton and fluorine NMR spectra of these solutions. It is concluded that the major difference between the two molecules lies in the potential, V(φ₂), governing rotation about the ring–oxygen bonds. In 1OCB the potential has the same form as in anisole, with a minimum when the C–O bond is in the plane of the attached ring (φ₂ = 0°), and a maximum of about 15 kJ mol^?1 when φ₂ is 90°. In 1OCBF₃ the barrier to rotation about the ring–O bond decreases substantially to being near zero.     

Amino Acid Derivatives, V [1]: Synthesis and Antiviral Evaluation of α-Amino Acid Esters Bearing an α-d -Mannofuranoside Side Chain

d-Mannose was treated with dry acetone in the presence of conc. H₂SO₄ to afford 2,3:5,6-di-O-isopropylidene-α-d-mannofuranoside. Treating the latter with ethyl chloroacetate gave carboethoxymethyl 2,3:5,6-di-O-isopropylidene-α-d-mannofuranoside, which was hydrolyzed with N₂H₄ · H₂O to afford the acid hydrazide derivative. Treating of the acid hydrazide with acylated amino acides, via the azide-coupling method afforded the corresponding O-glycopeptides. Reaction of the glycopeptide methyl esters with N₂H₄ · H₂O afforded the corresponding hydrazides, which were coupled with the amino acid methyl esters to afford the dipeptides. Deprotection was carried out by using 70% AcOH. The prepared O-glycopeptides were tested for antiviral activity against hepatitis B virus and showed moderate activities.