Alkyl Aldehydes Research Articles

Efficient and Site-Specific 125I-Radioiodination of Bioactive Molecules Using Oxidative Condensation Reaction.

In this report, the novel and site-specific radioiodination of biomolecules by using aryl diamine and alkyl aldehyde condensation reaction in the presence of a Cu2+ catalyst under ambient conditions was reported. 125I-labeled alkyl aldehyde was synthesized using a tin precursor with a high radiochemical yield (72 ± 6%, n = 5) and radiochemical purity (>99%). The utility of the radioiodinated precursor was demonstrated through aryl diamine-installed c[RGDfK(C)] peptide and human serum albumin (HSA). Radioiodinated c[RGDfK(C)] peptide and HSA protein were synthesized with high radiochemical yields and purity. 125I-HSA protein showed excellent in vivo stability and negligible thyroid uptake as compared with directly radioiodinated HSA by using the tyrosine group. Excellent reaction kinetics and the in vitro and in vivo stabilities of 125I-labeled alkyl aldehyde have suggested the usefulness of the strategy for the radioiodination of bioactive molecules.

Metal-Free Oxidative Decarbonylative [3+2] Annulation of Terminal Alkynes with Tertiary Alkyl Aldehydes toward Cyclopentenes.

A new metal-free oxidative decarbonylative [3+2] annulation of terminal alkynes with tertiary alkyl aldehydes is presented, which features broad substrate scope and excellent selectivity. The selectivity of this reaction toward cyclopentenes and indenes relies on the nature of the aldehyde substrates. While treatment of tertiary γ,δ-unsaturated aldehydes with common terminal alkynes assembles cyclopentenes, 2-methyl-2-arylpropanals succeed in accessing indenes.

A Bifunctional Photoaminocatalyst for the Alkylation of Aldehydes: Design, Analysis, and Mechanistic Studies

A bifunctional photoaminocatalyst based on imidazolidinone and thioxanthone is presented. The preparation of these catalysts proceeds in a two-step synthesis that allows an easy tuning of the steric properties. The photophysical and electrochemical data of the imidazolidinone photocatalysts have been determined, indicating that the catalysts can work under visible light conditions. To corroborate the experimental observations, ground state geometry optimization and energy transition studies of thioxanthone and bifunctional catalyst 4c were optimized by time-dependent density functional theory (TD DFT) calculations. The alkylation of aldehydes with this photoaminocatalyst works with high enantioselectivities and yields due to the stereoelectronic properties of the catalyst. A rational mechanistic cycle based on different mechanistic experiments, TD DFT calculations, and laser flash photolysis is presented.

Method for Catalytic Enantioselective Alkylation of Aldehydes Using Grignard Reagents as Alkyl Sources.

Alkyltitanium reagents, generated in situ from Grignard reagents and ClTi(O iPr)3, can be employed without further manipulation in the enantioselective alkylation of aldehyde by the catalysis of a chiral titanium complex derived from DTBP-H8-BINOL. The reaction is performed with good stoichiometry [1.5 equiv each of Grignard reagents and ClTi(O iPr)3] at a low catalyst loading (2 mol %), affording a variety of chiral secondary alcohols in high enantioselectivity and yields and, hence, realizing an asymmetric version of the Grignard reaction in an indirect manner.

Rigid and concave, 2,4-cis-substituted azetidine derivatives: A platform for asymmetric catalysis

A series of single enantiomer, 2,4-cis-disubstituted amino azetidines were synthesised and used as ligands for copper-catalysed Henry reactions of aldehydes with nitromethane. Optimisation of ligand substituents and the reaction conditions was conducted. The enantiomeric excess of the formed products was highest when alkyl aldehydes were employed in the reaction (>99% e.e.). The absolute stereochemistry of one representative azetidine derivative salt was determined by analysis of the Flack parameter of an XRD single crystal structure. The origin of selectivity in catalysis was investigated computationally, revealing the importance of the amino-substituent in determining the stereochemical outcome. A racemic platinum complex of a cis-disubstituted azetidine is examined by XRD single crystal structure analysis with reference to its steric parameters, and analogies to the computationally determined copper complex catalyst are drawn. A preliminary example of the use of a cis-disubstituted azetidine scaffold in thiourea H-bonding catalyst is noted in the supporting information.

Stability of proton-bound clusters of alkyl alcohols, aldehydes and ketones in Ion Mobility Spectrometry

Significant substances in emerging applications of ion mobility spectrometry such as breath analysis for clinical diagnostics and headspace analysis for food purity include low molar mass alcohols, ketones, aldehydes and esters which produce mobility spectra containing protonated monomers and proton-bound dimers. Spectra for all n- alcohols, aldehydes and ketones from carbon number three to eight exhibited protonated monomers and proton-bound dimers with ion drift times of 6.5–13.3 ms at ambient pressure and from 35° to 80 °C in nitrogen. Only n-alcohols from 1-pentanol to 1-octanol produced proton-bound trimers which were sufficiently stable to be observed at these temperatures and drift times of 12.8–16.3 ms. Polar functional groups were protected in compact structures in ab initio models for proton-bound dimers of alcohols, ketones and aldehydes. Only alcohols formed a V-shaped arrangement for proton-bound trimers strengthening ion stability and lifetime. In contrast, models for proton-bound trimers of aldehydes and ketones showed association of the third neutral through weak, non-specific, long-range interactions consistent with ion dissociation in the ion mobility drift tube before arriving at the detector. Collision cross sections derived from reduced mobility coefficients in nitrogen gas atmosphere support the predicted ion structures and approximate degrees of hydration.

Thermal, Catalytic Conversion of Alkanes to Linear Aldehydes and Linear Amines.

Alkanes, the main constituents of petroleum, are attractive feedstocks for producing value-added chemicals. Linear aldehydes and amines are two of the most important building blocks in the chemical industry. To date, there have been no effective methods for directly converting n-alkanes to linear aldehydes and linear amines. Here, we report a molecular dual-catalyst system for production of linear aldehydes via regioselective carbonylation of n-alkanes. The system is comprised of a pincer iridium catalyst for transfer-dehydrogenation of the alkane using t-butylethylene or ethylene as a hydrogen acceptor working sequentially with a rhodium catalyst for olefin isomerization-hydroformylation with syngas. The system exhibits high regioselectivity for linear aldehydes and gives high catalytic turnover numbers when using ethylene as the acceptor. In addition, the direct conversion of light alkanes, n-pentane and n-hexane, to siloxy-terminated alkyl aldehydes through a sequence of Ir/Fe-catalyzed alkane silylation and Ir/Rh-catalyzed alkane carbonylation, is described. Finally, the Ir/Rh dual-catalyst strategy has been successfully applied to regioselective alkane aminomethylation to form linear alkyl amines.

Facile Aromatisation of Hantzsch 1,4-Dihydropyridines by Autoxidation in the Presence of P-toluenesulfonic Acid in Acetic Acid

A simple protocol to achieve the aromatisation of Hantzsch dihydropyridines in high yield was established using p-toluenesulfonic acid in acetic acid and yields of 90% were obtained at room temperature. With regards to the Hantzsch 1,4-dihydropyridines derived from alkyl aldehydes bearing one or more á-hydrogens, dealkylation products were obtained through a proposed autoxidation mechanism.

AuPd−Fe3O4 Nanoparticle Catalysts for Highly Selective, One‐Pot Cascade Nitro‐Reduction and Reductive Amination

AbstractExceedingly chemoselective preparation of secondary amines from the cascade reaction of nitro reduction followed by reductive amination of the resulting amine with an aldehyde through the use of bimetallic AuPd alloy nanoparticle catalyst is described. We prepared a AuPd alloy nanocatalyst supported on Fe3O4 in gram scale without calcination. One pot synthesis of a number of secondary amines was achieved from a variety of nitroarenes and aryl or alkyl aldehydes under 1 atm of H2 at room temperature. No N‐debenzylation was observed in the case of the reactions involving aryl aldehydes, which is often observed in the reductive amination catalysed by a transition metal catalyst such as palladium. We also accomplished efficient one‐pot synthesis of a number of N‐aryl substituted isoindolinone derivatives from 1‐formylbenzoic acid and several nitroarenes using the same reaction conditions. Furthermore, thanks to the magnetic property of the Fe3O4 support, the AuPd−Fe3O4 NPs could be easily separated and reused up to 20 times without the loss of its catalytic activity.magnified image

Enantioselective 1,2-Difunctionalization of 1,3-Butadiene by Sequential Alkylation and Carbonyl Allylation.

A highly enantioselective three-component coupling of 1,3-butadiene with a variety of fluorinated or nonfluorinated alkyl halides and aldehydes has been achieved relying on a Cr/Co bimetallic catalysis system. The strategy established here facilitates straightforward introduction of the privileged fluoro functionalities into homoallylic alcohols from bulk feedstock materials in a highly anti-diastereo and enantioselective manner.

Readily Available Highly Active [Ti]-Adamantyl-BINOL Catalysts for the Enantioselective Alkylation of Aldehydes.

A series of enantiopure (R)-adamantyl 1,1′-binaphthalene-2,2′-diols were successfully synthesized in a straightforward one-step reaction from commercial products with excellent overall yields. The activity of chiral titanium catalyst derived from (R)-3,6,6′-tri(adamantan-1-yl)-[1,1′-binaphthalene]-2,2′-diol ligand, (R)-(2)-Ti, in the enantioselective asymmetric alkylation of aldehydes is significantly enhanced (up to 98% yield and 99% ee).

Direct Synthesis of Polysubstituted Aldehydes via Visible-Light Catalysis.

Aldehydes are among the most versatile functional groups for synthetic chemistry. However, access to polysubstituted alkyl aldehydes is very limited and requires lengthy synthetic routes that involve multiple-step functional-group conversion. This paper reports a one-step synthesis of polysubstituted aldehydes from readily available olefin substrates using visible-light photoredox catalysis. Despite a number of competing reaction pathways, commercial styrenes react with vinyl ethers selectively in the presence of an acridinium salt photooxidant and a disulfide hydrogen-atom-transfer catalyst under blue LED irradiation. Alkyl aldehydes with different substitution patterns are prepared in good yields. This strategy can be applied to structurally sophisticated substrates.

Direct Synthesis of Polysubstituted Aldehydes via Visible‐Light Catalysis

AbstractAldehydes are among the most versatile functional groups for synthetic chemistry. However, access to polysubstituted alkyl aldehydes is very limited and requires lengthy synthetic routes that involve multiple‐step functional‐group conversion. This paper reports a one‐step synthesis of polysubstituted aldehydes from readily available olefin substrates using visible‐light photoredox catalysis. Despite a number of competing reaction pathways, commercial styrenes react with vinyl ethers selectively in the presence of an acridinium salt photooxidant and a disulfide hydrogen‐atom‐transfer catalyst under blue LED irradiation. Alkyl aldehydes with different substitution patterns are prepared in good yields. This strategy can be applied to structurally sophisticated substrates.

Shifting zwitterion reactivity

Framework Catalysis Phosphines are often ligands for transition metal catalysts, but they can catalyze reactions at unsaturated carbon atoms by forming phosphonium zwitterions. For example, triphenylphosphine forms a zwitterion with methylvinylketone that acts as a nucleophile to convert n -alkyl aldehydes to β-hydroxy enones (the Morita-Baylis-Hillman reaction). Bauer et al. show that when the reaction is conducted in metal-organic framework compounds with linkers bearing amino groups, rather than in solution, the phosphonium zwitterion can act as an electrophile. The products—1- and 3- n -alkylesters of 2-alkyl-1,3-diols—form through the Aldol-Tishchenko reaction. J. Am. Chem. Soc. 10.1021/jacs.7b10928 (2017).

Determination of Alkaloid Compounds of Datura Stramonium Using Gc-Ms and Ftir and Evaluation of its Antibacterial, Antifungal and Anti-Diabetic Activity

The aim of this study is to assess the compounds of alkaloids extracts from the leaves of Datura stramonium, which can be the basis for the synthesis of new antibiotics. In this study, the alkaloid compounds of Datura stramonium have been evaluated. GC-MS analysis of alkaloid leaves ethanolic extract of Datura stramonium revealed the existence of the Ethyl iso-allocholate, D-asycarpidan-1-methanol, acetate (ester), 3-(1, 5-Dimethyl-hexyl)3a, 10, 10, 12b-tetramethyl1, 2, 3, 3a 4, 6, 8, 9, 10, 10a, 11, 12, 12a, 12b-tetradec-ahydro-benzo[4, 5] cyclohept, 2, 7-Diphenyl-1, 6-dioxopyridazino [4, 5: 2, 3] pyrrolo[4, 5-d] pyridazine, 3, 8, 8-Trimethoxy-3-piperidyl-2, 2-benaphthalene-1, 1, 4, 4-tetrone, [5β] Pregnane3, 20β-diol, 14α, 18α-[4methyl, 3-oxo-[1-oxa-4-azabutane-1, 4-diyl], diacetate, 1-Monolinoleoylglycerol trimethylsilyl ether, and 17-[1, 5-Dimethylhexyl]-10, 13-dimethyl-3sstyrylhexadecahydrocyclopent a[a]phenathren-2-one. The FTIR analysis of Datura stramonium leaves proved the presence of alkanes, and alkyl halide, Amine, Aldehyde, and Alkane which shows major peaks at 875.68, 1018.41, 1149.57, 1238.3, 1269.16, 1740.51, 2330.01, 2341.58, 2854.65, 2910.58, 2926.01, and 3010.88. Clinical pathogens were selected for antibacterial activity namely, Bacillus subtilis, Salmonella typhi, Staphylococcus aureus, Proteus mirabilis, Escherichia coli, Streptococcus faecalis, Streptococcus pyogenes and Klebsiella pneumonia. Datura stramonium has maximum zone against Staphylococcus aureus (5.895±0.20).

Screening of Bioactive Compounds of Ricinus communis Using GC-MS and FTIR and Evaluation of its Antibacterial and Antifungal Activity

The objectives of this study were detection of the secondary metabolite products and evaluation antibacterial and antifungal activity. Bioactives are chemical compounds often referred to as secondary metabolites. Sixteen bioactive compounds were identified in the methanolic extract of Ricinus communis. The identification of bioactive chemical compounds is based on the peak area, retention time molecular weight and molecular formula. GC-MS analysis of Ricinus communis revealed the existence of the1, 2, 3, 4-Butanetetrol, [S-(R*, R*)]-, Ribitol, 3-Ethoxy-1, 2-propanediol, DL-Arabinose, p-Dioxane-2, 3-diol, D-Limonene, Dodecanoic acid, 3-hydroxy-, Methyl 6-oxoheptanoate, Dithiocarbamate, S-methyl-, N-(2-methyl-3-oxobutyl)-, (5β)Pregnane-3, 20β-diol, 14α, 18α-[4-methyl-3-oxo-(1-oxa-4-, 3-(N, N-Dimethllaurylammonio)propanesulfonate, Cetene, Gibberellic acid, Geranyl isovalerate, Phenol, 4-(1, 1, 3, 3-tetramethylbutyl)-, Picrotoxinin, and α-N-Normethadol. The FTIR analysis of Ricinus communis leaves proved the presence of alkanes, and alkyl halide, Amine, Aldehyde, and Alkane which shows major peaks at 781.17, 875.68, 923.90, 1018.41, 1240.23, 1319.31, 1361.74, 1361.74, 2357.01, 2850.79 and 2920.23. Clinical pathogens were selected for antibacterial activity namely, Pseudomonas eurogenosa, Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, and Proteus mirabili. Ricinus communis has maximum zone against Klebsiella pneumonia (5.000±0.19)

Synthesis of Enantiopure Mixed Alkyl-Aryl Vicinal Diamines by the Diaza-Cope Rearrangement: A Synthesis of (+)-CP-99,994.

The stereoselective synthesis of mixed alkyl-aryl vicinal diamines was demonstrated by the use of 1,2-bis(2-hydroxyphenyl)-1,2-diaminoethene (hpen). A sequential addition of aryl and alkyl aldehyde to hpen gave a fused imidazolidine-dihydro-1,3-oxazine ring stereoselectively, which undergoes the diaza-Cope rearrangement to provide mixed vicinal diimines at elevated temperature in good yields and excellent stereoselectivity. We also showed that (+)-CP-99,994 can be readily prepared by the diaza-Cope rearrangement in overall 42% yield.

Microwave-assisted High Diastereoselective Synthesis of α-Aminophosphonates under Solvent and Catalyst Free-conditions

A simple, efficient and general method has been developed for the high diastereoselective synthesis of α-aminophosphonates through “one-pot” three-component reaction of alkyl and aryl aldehydes with (S)-α-methylbenzylamine or (S)-3,3-dimethyl-2-butylamine and dimethyl phosphite (Kabachnik-Fields reaction), which proceeds in short time using microwave irradiation under solvent and catalyst free-conditions. This method could be useful in the large-scale synthesis of α-aminophosphonates in short reaction time

Copper (II)-catalysed direct conversion of aldehydes into nitriles in acetonitrile

A mild one-pot method for the direct conversion of aryl, heteroaryl and alkyl aldehydes into nitriles was achieved by forming the corresponding oximes in situ with NH2OH and allowing them to react with CuO and acetonitrile. Yields of the 13 nitriles prepared were moderate to very good (62–91%).

Aldehyde Approach to Hydrophobic Modification of Chitosan Aerogels.

Biobased nanofiber aerogels are ones of the attractive emerging materials in the fields of biochemistry and materials chemistry, but their poor humidity stability due to high hydrophilicity has limited their practical uses. In this paper, a new series of hydrophobic nanofibrous aerogels made from regenerated chitosan and alkyl aldehydes were prepared via a simple one-pot reaction followed by supercritical drying. Hexanal-modified chitosan aerogel shows excellent hydrophobicity with a water contact angle of ∼136°, a low density of 0.04-0.07 g cm-3, and structurally homogeneous three-dimensional nanofiber network at the nanoscale. Systematic investigations using various alkyl aldehydes revealed that pentanal-modified aerogel has similar high hydrophobicity and low density compared to the hexanal-modified material, while heptanal- and octanal-modified aerogels show drastic shrinkage during gelation. The aldehyde modification also suppresses permeation of water droplets into aerogel monoliths as well as reducing shrinkage under high humidity conditions.