Protection Of Carbonyl Groups Research Articles

Innovative Piperidine-Catalyzation in Protecting Carbonyl Compounds with Implications for Angiogenesis and Inflammation

Introduction: This study explores the application of piperidine-catalyzed protection, an innovative technique, for safeguarding various carbonyl compounds functioning as acetals in a generic reaction. Specifically, we investigate the catalysis of 2-amino-1,3-propanediol-2-methyl with various aromatic aldehydes, leading to the production of cis and trans-5-methyl-2-(mono or di-substitutions-phenyl)-1,3-dioxane-5-amine. Methods: Identification of all newly formed products is achieved through the utilization of spectroscopic techniques, including IR, 1H-NMR, and 13C-NMR spectroscopy. Molecular interactions and potential therapeutic applications of compounds E1 and E2 are demonstrated with cAMP-specific phosphodiesterase (1zkl) and oxidized purine nucleoside triphosphate hydrolase (5ws7). Detailed structural analyses highlight specific hydrogen bonds, pi-pi stacked interactions, and alkyl contacts formed by these compounds with target proteins. A comprehensive bioinformatics approach involves GO enrichment, STRING protein-protein association networks, KEGG pathway analysis, and Reactome pathways to elucidate biological processes, molecular functions, and cellular components associated with the compounds. Results: Compounds E1 and E2 exhibit diverse enrichment profiles, suggesting their involvement in various signaling cascades, neurotransmission, immune responses, and cancer pathways. Comparative analysis of five compound pairs (A1/A2, B1/B2, C1/C2, D1/D2, E1/E2) reveals subtle distinctions in enrichment patterns, implying unique pharmacological advantages for each pair. Conclusion: This study introduces a separate investigation on piperidine-catalyzed protection of carbonyl groups in aldehydes, presenting a practical approach. Emphasizing the significance of understanding distinct biological signatures, our findings guide therapeutic applications and compound optimization, particularly in the context of anti-cancer therapeutics. The compounds show potential in modulating neuronal function, neurotransmission, cancer mechanisms, and immune responses, suggesting promising avenues for future research and development.

Metal-based Lewis acid catalysts for conversion of a variety of aldehydes with acetic anhydride to gem 1,1-diacetates

Selective protection of carbonyl groups such as oxathioacetals, acylals, acetals and dithioacetals is the vital steps in organic chemistry. Among these groups, protection of aldehydes such as diacetates (acylals) has attracted more attention in the organic chemistry due to its superior applications such as commodity chemical in various fields of chemistry, their ease of preparation and their stability toward basic and neutral conditions. Beyond their protecting role, 1,1-diacetates are important precursors for the synthesis of acetoxydienes, starting materials as valuable intermediates for Diels–Alder cycloaddition reactions and neutral and basic media. Also acylals have been used as intermediates in industry as cross-linking agents for cellulose in cotton. Protection of carbonyl group of aldehydes by acetic anhydride in the presence of acid catalyst is the most convenient way. This review precises chemoselective procedure for the preparation of acylals by using the metal-based Lewis acid catalysts, magnetic nanocatalysts, ionic liquids, strong protic acid and solid acids.

Novel Carbon-based Solid Acid from Green Pistachio Peel as an Efficient Catalyst for the Chemoselective Acylation, Acetalization and Thioacetalization of Aldehydes, Synthesis of Biscoumarins and Antimicrobial Evaluation

Background: Much attention has been focused on heterogeneous catalysts. Reactions with these recoverable and reusable catalysts are clean, selective with high efficiency. Among the heterogeneous solid acid catalyst in organic synthesis, Carbon-Based Solid Acids (CBSAs), which are important solid acid with many practical and research applications have been extensively studied. In this work, green Pistachio peel, a biomass waste, was converted into a novel carbon-based solid acid catalyst (Pis-SO3H). Objective: The aim of this work is to synthesize highly sulfonated carbon as an efficient, recyclable, nontoxic solid acid catalyst by simultaneous sulfonation, dehydration and carbonization of green Pistachio peel as biomass and investigate the catalytic activity of Pis-SO3H in acetalization, thioacetalization, acylation of aldehydes and synthesis of 3,3'-Arylmethylene-bis(4-hydroxycoumarin) derivatives. Method: Pis-SO3H was synthesized by an integrated fast one-step hydrothermal carbonization and sulfonation process in the presence of sulfuric acid. The characterization of the physicochemical properties of Pis-SO3H was achieved by XRD, FT-IR, FE-SEM, and elemental analysis. Results: The result of acid-base titration showed that the total acidity of the catalyst was 7.75 mmol H+g−1. This new heterogeneous catalyst has been efficiently used for the chemoselective thioacetalization, acetalization and acylation of aldehyde and the synthesis of biscoumarins under solvent-free conditions. All the reactions work easily in high yields. The antimicrobial activity of some of the biscoumarins was evaluated in screening by disk diffusion assay for the zone of inhibition. Conclusion: The catalytic activity of the Pis-SO3H was investigated during acetalization, thioacetalization, acylation and synthesis of biscoumarins. The results of protection of carbonyl groups and synthesis of biscoumarins in the present work offer effective alternatives for environmentally friendly utilization of abundant biomass waste.

Studies of the Catalytic Activity of Iron (III) Porphyrins for the Protection of Carbonyl Groups in Homogeneous Media

The protection of carbonyl groups that produce acetal products is a key reaction in fine chemistry due to the high reactivity of aldehydes and ketones in certain media. This process can be catalyzed by protic or Lewis acids. Since metalloporphyrins often possess free axial positions in the central metal, they can be applied as Lewis acid catalysts, allowing the additional coordination of substrates. Therefore, three ferric complexes were selected to be evaluated as catalysts for the acetalization of benzaldehyde with ethanol and triethyl orthoformate (TEOF) in the homogeneous phase: (i) 5,10,15,20-tetrakis(phenylporphyrin) iron (III) chloride (Fe0F); (ii) 5,10,15,20-tetrakis(2,6-difluorphenylporphyrin) iron (III) chloride (Fe2F); and (iii) 5,10,15,20-tetrakis(pentafluorphenylporphyrin) iron (III) chloride (Fe5F). The complex Fe5F showed the highest catalytic activity, and kinetic parameters were evaluated for this reaction, exhibiting an increasing rate of reaction of about 550-fold in comparison with the non-catalyzed reaction. The reaction scope was also investigated, and Fe5F was found to be active for the acetalization of benzaldehyde and acetophenone, with different protective agents such as alcohols, glycols, glycerol, and epoxide being selective for the formation of cyclic acetals. The protection of benzaldehyde with ethylene glycol and propylene glycol were also studied at different temperatures, and turnover frequency (TOF) values of up to 360 h−1 were determined at 40 °C in homogenous media without the need for solvent or drying agents.

A new hexamolybdate-based copper-2,2'-biimidazole coordination polymer serving as an acid catalyst and support for enzyme immobilization.

The hydrothermal reaction of (NH4)3[CoMo6O24H6]·7H2O (CoMo6), CuCl2·2H2O and 2,2'-biimidazole (H2biim) led to the formation of a new coordination polymer, namely poly[diaquabis(2,2'-biimidazole)hexa-μ3-oxo-octa-μ2-oxo-hexaoxodicopper(II)hexamolybdate(VI)], [Cu2Mo6O20(C6H6N4)2(H2O)2]n (Cu-Mo6O20), at pH 2-3. It is obvious that in the formation of crystalline Cu-Mo6O20, the original Anderson-type skeleton of heteropolymolybdate CoMo6 was broken and the new isopolyhexamolybdate Mo6O20 unit was assembled. In Cu-Mo6O20, one Mo6O20 unit connects four [Cu(H2biim)(H2O)]2+ ions in a pentacoordinate mode via four terminal O atoms, resulting in a tetra-supported structure, and each CuII ion is shared by two adjacent Mo6O20 units. Infinite one-dimensional chains are established by linkage between two adjacent Mo6O20 units and two CuII ions, and these chains are further packed into a three-dimensional framework by hydrogen bonds, π-π interactions and electrostatic attractions. The catalytic performance of this crystalline material used as an efficient and reusable heterogeneous acid catalyst for carbonyl-group protection is discussed. In addition, Cu-Mo6O20 was applied as a new support for enzyme (horseradish peroxidase, HRP) immobilization, forming immobilized enzyme HRP/Cu-Mo6O20. HRP/Cu-Mo6O20 showed good catalytic activity and could be reused.

Synthesis of dibromo ketones by the reaction of the environmentally benign H2O2-HBr system with oximes

Abstract It was found that oximes undergo deoximation in the presence of the H2O2aq-HBraq system to form ketones and bromo ketones. This reaction provided the basis for the synthesis of dibromo ketones in yields varying from 40% to 94%. This method is environmentally friendly, sustainable, and easy to perform. The results of this investigation extend the potential of the use of oximes for the protection of carbonyl group, thus offering the ability to perform not only conventional deoximation but also the subsequent bromination of ketones. The reaction is easily scaled up and dibromo ketones can be prepared in gram amounts.

Control of Morphology and Catalytic Activity of a Cationic Layered Material

We have discovered three new synthetic pathways to our two-dimensional cationic inorganic material, antimony oxide hydroxide ethanedisulfonate, [Sb4O4(OH)2](O3SCH2CH2SO3)·H2O. These new methods include room temperature conditions and allow control of crystal size and morphology for improved catalytic performance of the material. As a benchmark reaction, we studied ketalization of 2-butanone with 1,2-ethanediol, a common step for carbonyl group protection. Our material is easily recovered for reuse and gives a higher yield and turnover rates than the typical iodine or toluenesulfonate homogeneous catalyst. The yield ranged between 79 and 92%, with the crystals from reflux conditions giving the highest yield when used as-synthesized. The morphology and properties for each crystal growth method are described in detail. A repeated catalysis study with powdered samples increases the yield to ca. 97%.

Total Synthesis of Optically Active Lycopladine A by Utilizing Diastereoselective Protection of Carbonyl Group in a 1,3-Cyclohexanedione Derivative

We successfully synthesized two enantiomers of bicyclic enones, (7R,7aR)- and (7S,7aS)-9, from the hemiacetal 2a, which we first synthesized from the symmetrical diketone 1a via diastereoselective carbon-oxygen bond formation between one of the carbonyl groups and the chiral alcohol on the C2 side chain in a 2,2-disubstituted 1,3-cycloalkanedione derivative. We also report the total synthesis of natural (+)-lycopladine A [(+)-6] from (7R,7aR)-9 and the formal synthesis of unnatural (-)-lycopladine A [(-)-6] from (7S,7aS)-9.

Microwave assisted synthesis of fine chemicals in solvent-free conditions over mesoporous zirconium phosphate

Synthesis of various industrially important fine chemicals under microwave irradiation (MWI) in solvent-free conditions over mesoporous zirconium phosphate (m-ZrP) is reported. m-ZrP is synthesized by MWI in basic medium using a precursor solution of zirconium carbonate complex as zirconium source and CTAB as a pore-directing agent. MWI time and MWI power were found to have significant influence on the textural properties of synthesized m-ZrP. Microscopic analyses of the synthesized m-ZrP indicate the presence of worm like pores with spherical morphology. DRIFT analysis of pyridine adsorbed m-ZrP and NH3-TPD measurements indicate the presence of appreciable amount of Brönsted acid sites. Synthesized m-ZrP exhibits high catalytic activity towards Claisen–Schmidt condensation reaction in solvent-free conditions under microwave irradiation. The m-ZrP showed high activity towards other acid catalyzed reactions such as Friedel–Craft benzylation, Pechmann condensation and carbonyl group protection reaction, and also for the synthesis of benzo-xanthenes in solvent-free conditions under MWI. The catalytic activity of m-ZrP is substantially higher than that of conventional layered ZrP. The synthesized catalysts are re-usable for at least five times after regeneration, without losing their catalytic activity significantly.

Covalently linked ethylmercaptophenyl sulfonic acid and ethylmercaptobenzyl sulfonic acid silica materials—Synthesis and catalytic activity

New covalently linked sulfonic acid modified silicas have been formed and characterised and their catalytic Brönsted activity evaluated. Thus phenylmercaptoethyltrimethoxysilane, (MeO) 3SiCH 2CH 2SC 6H 5 and benzylmercaptoethyltrimethoxysilane, (MeO) 3SiCH 2CH 2SCH 2C 6H 5, were used to prepare the corresponding T-functional silica derivatives silica ∼ CH 2CH 2SC 6H 4-4-SO 3H and silica ∼ CH 2CH 2SCH 2C 6H 4-4-SO 3H by grafting on commercial silica, followed by sulfonation of the aryl group. Solid-state NMR, DTA and surface area characteristics of the materials are reported. The mercaptophenylsulfonic acid materials are thermally robust highly efficient solid catalysts for a range of transformations including, esterification, etherification and carbonyl group protection. An apparent pore size effect on rate of conversion was observed. The mercaptobenzylsulfonic acid materials were comparatively unstable.

Dichloro-bis(trifluoromethanesulfonate)titanium(IV) (TiCl2(SO3CF3)2) as a stable and a non-corrosive solid catalyst for the efficient and highly selective protection of carbonyl groups as their 1,3-dithianes and 1,3-dithiolanes under solvent-free conditions at room temperature

TiCl2(SO3CF3)2 as a non-corrosive solid catalyst has been applied for the efficient and highly regio- and chemoselective protection of carbonyl groups as their 1,3-dithianes and 1,3-dithiolanes under solvent-free conditions at room temperature in excellent yields.

Intermolecular Reactions of Chlorohydrine Anions: Acetalization of Carbonyl Compounds under Basic Conditions

[reaction: see text] Nonenolizable aldehydes and ketones react with 2-chloroethanol and 3-chloropropanol under basic conditions (t-BuOK, DMF/THF) with formation of 2-substituted 1,3-dioxolanes and 1,3-dioxanes, respectively. Conversion of the two-step addition-alkylation process depends on the electrophilicity of the carbonyl group that governs the equilibrium of addition of chloroalkoxides. This method of protection of carbonyl groups in the form of cyclic acetals under kinetically controlled conditions is complementary to the acid-catalyzed reaction with diols.

Preparation and Application of Odorless 1,3‐Propanedithiol Reagents.

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Preparation and Application of Odorless 1,3-Propanedithiol Reagents

2-Dodecyl-1,3-propanedithiol (2a) was prepared without a malodorous procedure as an odorless reagent that was usable in place of 1,3-propanedithiol (1) in organic reactions, e.g., in the reduction of azides and protection of carbonyl groups. The 1,3-dithioacetals obtained in the latter reaction were effectively reduced to methylene with Raney nickel and reconverted to the original carbonyl compounds by hydrolysis with N-bromosuccinimide in aqueous 2-butanone. In addition, the anion of 1,3-dithiane prepared from 2a and formaldehyde could be utilized as a synthetic equivalent of an anionic carbonyl carbon.

Dowex Polymer‐Mediated Protection of Carbonyl Groups.

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Dowex Polymer–Mediated Protection of Carbonyl Groups

Dowex (strongly acidic cationic exchange resin) polymer is employed as solid acid catalyst for the clean and less hazardous protection of carbonyl compounds as phenylhydrazones and 2,4‐dintrophenylhydrazones in ethanol under reflux conditions. The reactions proceed very smoothly and the yields of the derivatives are excellent.

1,2,4‐Trioxepanes: Redox‐Cleavable Protection for Carbonyl Groups.

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Fluorous Glycol Derivatives: Novel Carbonyl Protective Groups.

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1,2,4-trioxepanes: redox-cleavable protection for carbonyl groups.

[reaction: see text] 1,2,4-trioxepanes, readily prepared and easily handled derivatives of aldehydes and ketones, are stable to a variety of synthetic conditions and yet easily deblocked with Zn/HOAc or Mg/MeOH to regenerate the parent carbonyl. Trioxepanes may provide an alternative to 1,3-dithianes for acid-stable protection of carbonyl groups.

Fluorous glycol derivatives: novel carbonyl protective groups

Fluorous glycol derivatives 5 were prepared and evaluated as reagents for the protection of carbonyl groups for use in fluorous synthesis. The acetals formed from fluorous diol 5b (Rf= n-C 8F 17) with carbonyl compounds can be separated and purified by simple fluorous-organic extraction.