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The present research study describes a combined experimental-modelling approach to examine the three-phased catalyst-free reversible aza-Michael addition of NH3 to the vinyl sulfone pharmaceutical intermediate in water. A series of batch experiments using gaseous NH3 were performed to thoroughly evaluate the impact of reaction temperature, NH3 pressure, starting material loading, and starting material quality on reactant solubility, convective mass transfer, and reaction kinetics in the system. A rigorous in-house mechanistic mathematical model was developed. All unknown parameters were determined through nonlinear regression fitting of experimental and simulated quantitative results. Aza-Michael addition kinetics and starting material equilibrium solubility were found to be highly temperature-dependent and had the biggest applicative effect on the maximum aza-Michael reaction rate, which was also confirmed by sensitivity analysis technique. Boundary diffusion of reactants was shown not to be the limiting controlling factor under the chosen operating conditions. Ammonia pressure was found to be important through its impact on the saturated concentration of NH3. Varying starting material load had impact solely on the time required to reach system equilibrium due to solute concentration limitations. Reverse NH3 elimination reaction kinetics was shown to be independent on changing all input operating conditions. The specific methodology grants a novel engineering approach for treating complex interrelated multi-phased heterogeneous compositions in active pharmaceutical ingredient reaction systems, which may be applied early in industrial process development, when a small continuous amount of raw data sets is available, the quantity of impurities varies, and simulations can aid intensification. It may be easily transferred to other similar environments for assistance in process development, optimization, and scale-up.

A sustainable D-glucosamine ligand is successfully introduced into iron-catalysed CC cross-coupling reactions for the first time. The Fe(acac)2/D-glucosamine·HCl/Et3N catalytic system was effective at 5 mol% loading in coupling reactions of Grignard reagents with organic bromides. Moderate to high efficiency was achieved with preserved stereochemistry when allyl (Csp3) or alkenyl (Csp2) bromides were coupled with phenylmagnesium (Csp2) or benzylmagnesium (Csp3) bromides. The catalytic system developed was also successfully applied for the novel and economic preparation of a Michael-acceptor-like starting material used in an alternative synthesis of the drug sitagliptin, a known blockbuster for the treatment of type II diabetes mellitus. Copyright © 2015 John Wiley & Sons, Ltd.

A metal-free reaction system of air, NH4NO3(cat), 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)(cat), and H+(cat) is introduced as a simple, safe, inexpensive, efficient and chemoselective mediator for aerobic oxidation of various primary and secondary benzyl and alkyl alcohols, including those bearing oxidizable heteroatoms (N, S, O) to the corresponding aldehydes or ketones. Air oxygen under slight overpressure plays the role of the terminal oxidant, which is catalytically activated by redox cycles of nitrogen oxides released from a catalytic amount of NH4NO3 and cocatalyzed by TEMPO (nitroxyl radical compound), under acidic conditions, which are essential for an overall activation of the reaction system. The synthetic value of this reaction system and its green chemical profile was illustrated by a 10 g scale-up experiment, performed in an open-air system by using a renewable and reusable polymer-supported form of TEMPO (OXYNITROX®S100). The reaction solvent was recovered by distillation under atmospheric pressure, and the pure final product was isolated under reduced pressure; the acid activators (HCl or H2SO4) were recovered as ammonium salts.

The efficient 'on water' β-borylation using bis(pinacolato)diboron agent was achieved with a newly developed catalytic system based on basic copper carbonate and various ligands. The catalytic system was used for β-borylation of various Michael acceptors, alkenes and alkynes. The presented methodology was successfully applied to the novel synthesis of β-alcohol type sitagliptin side chain precursor via water-based highly enantioselective β-borylation followed by an oxidation process. Copyright © 2013 John Wiley & Sons, Ltd.

Sarcosine was discovered to be an excellent ligand for cobalt-catalyzed carbon–carbon cross-coupling of Grignard reagents with allylic and vinylic bromides. The Co(II)/sarcosine catalytic system is shown to perform efficiently when phenyl and benzyl Grignards are coupled with alkenyl bromides. Notably, previously unachievable Co-catalyzed coupling of allylic bromides with Grignards to linearly coupled α-products was also realized with Co(II)/sarcosine catalyst. This method was used for efficient preparation of the key intermediate in an alternative synthesis of the antihyperglycemic drug sitagliptin.

We present a general protocol for processing cost-beneficial, environmentally benign aqueous-type suspensions containing metal-oxide nanostructured particles, and their patterning with piezoelectric ink-jet printing technology. The critical issues relevant to ink-jet printing are the preparation and stabilization of nanosized particles in a fluid and adjusting its physical properties to the values appropriate for a particular ink-jet printer mechanism. We discuss and illustrate, on a model titania system, the processing of a highly stable, colloidal, water-based suspension containing particles not bigger than 570 nm, prepared by a ball-milling process. For the ink-jet printing experiments, the surface tension and the viscosity of the suspension were modified by the addition of a small amount of the appropriate non-ionic amphiphiles and glycerol. The formation of droplets, their positioning on the substrate, and the shape and uniformity of the dots on the substrate are discussed and correlated with the fluid properties via the inverse Ohnesorge number Z. It was shown successfully that uniform, regular-shaped TiO2 dots with a diameter of 30 μm and a good positioning accuracy on Si/SiO2 substrates could be obtained by jetting a fluid with Z values of 5 and 9 using a piezoelectric ink-jet printer with a nozzle diameter of 21 μm operating at an amplitude of 13 V and a frequency of 5 kHz.

A general approach to prepare aqueous suspensions of inorganic particles suitable for ink-jet printing was developed. Titanium dioxide was used as the model material. Stable colloidal suspensions of TiO2 particles in water were prepared by adjusting the pH. The milling conditions were optimized in order to effectively mill the starting micron-sized powder. After 280 min of milling, the particle size was decreased to dmean = 170 nm. The fluid properties of the suspensions, i.e. viscosity and surface tension, were optimized by increasing the solid load of TiO2 powder and by addition of the surfactant triton X-100. Additionally, glycerol was added to the suspensions to control the drying behavior. The patterns of TiO2 were successfully printed on glass substrates.

Selective and efficient fluorination of organic 1,3-dicarbonyl compounds was achieved using the electrophilic fluorinating reagents Selectfluor ™ F-TEDA-BF 4 (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis-tetrafluoroborate) in aqueous medium or Accufluor ™ NFSi (N-fluorobenzene-sulfonimide) under solvent-free reaction conditions (SFRC). Under both reaction conditions cyclic 1,3-dicarbonyl compounds were transformed into 2-fluoro-substituted derivatives and acyclic analogues into 2,2-difluoro-substituted compounds, while the reactions of 1-trifluoromethyl-substituted 1,3-dicarbonyls in water resulted in the formation of 2,2-difluoro-3,3-dihydroxy-1-one derivatives. The reactivity of the starting material in water was found to be dependent on its enolizability, hydrophobic interactions and aggregate state at the reaction temperature. Reactions under SFRC proceeded in the molten eutectic phase of the reactants. The technique of competitive reactivity was used in order to evaluate and better understand the effects of reaction conditions on the course of these reactions.

A micellar system was developed and applied for direct regioselective fluorination of a variety of cyclic and acyclic ketones to α-fluoroketones in water as reaction medium with Selectfluor F-TEDA-BF 4 as fluorinating reagent. The inexpensive ionic amphiphile sodium dodecyl sulfate (SDS) was found to be an excellent promoter for fluorofunctionalization of hydrophobic ketones without prior activation or use of acid catalysts.

Selective and efficient iodinations of organic compounds were achieved by an aerobic oxidative process catalyzed by sodium nitrite using potassium iodide in acidic media. Using the potasasium iodide (KI)/air/sodium nitrite (NaNO 2 ; cat.)/sulfuric acid (H 2 SO 4 ) iodinating system, activated and moderately deactivated aromatic compounds were exclusively or preferentially iodinated at the para position. In protic solvents ketones and 1,3-dicarbonyl compounds were iodofunctionalized at the a carbonyl position, while in the case of aryl methyl ketones bearing an activated aromatic ring, the regioselectivity of iodination could be directed by the solvent used. In acetonitrile (MeCN) the aromatic ring was selectively iodinated, while in aqueous rethanol (EtOH) functionalization of the methyl carbon atom took place. Alkenes were transformed to vicinal iodohydrins or vicinal iodoalkoxy derivatives following Markovnikov-type regioselectivity and anti stereoselectivity, while 1,2-diiodoalkenes with preferentially E orientation were formed from alkynes.

Iodine has been shown to be an efficient catalyst for transformations of alcohols under solvent-free conditions. In the presence of 5% of iodine, tertiary alcohols underwent dehydration forming the corresponding alkenes, while in the case of 2-phenylpropane-2-ol cyclodimerisation to 1,1,3-trimethyl-3-phenylindane took place. Secondary and primary benzyl alcohols under the same conditions gave the corresponding ethers.

A metal-free reaction system of air, NH4NO3(cat), 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)(cat), and H+(cat) is introduced as a simple, safe, inexpensive, efficient and chemoselective mediator for aerobic oxidation of various primary and secondary benzyl and alkyl alcohols, including those bearing oxidizable heteroatoms (N, S, O) to the corresponding aldehydes or ketones. Air oxygen under slight overpressure plays the role of the terminal oxidant, which is catalytically activated by redox cycles of nitrogen oxides released from a catalytic amount of NH4NO3 and cocatalyzed by TEMPO (nitroxyl radical compound), under acidic conditions, which are essential for an overall activation of the reaction system. The synthetic value of this reaction system and its green chemical profile was illustrated by a 10 g scale-up experiment, performed in an open-air system by using a renewable and reusable polymer-supported form of TEMPO (OXYNITROX®S100). The reaction solvent was recovered by distillation under atmospheric pressure, and the pure final product was isolated under reduced pressure; the acid activators (HCl or H2SO4) were recovered as ammonium salts.

Efficient fluorination of 1,3-dicarbonyl compounds, enol acetates of aromatic ketones, and activated aromatic compounds was achieved under solvent-free conditions using Selectfluor™ F–TEDA–BF 4 or Accufluor™ NFSi.

Iodine has been shown to be an efficient catalyst for transformations of alcohols under solvent-free conditions. In the presence of 5% of iodine, tertiary alcohols underwent dehydration forming the corresponding alkenes, while in the case of 2-phenylpropane-2-ol cyclodimerisation to 1,1,3-trimethyl-3-phenylindane took place. Secondary and primary benzyl alcohols under the same conditions gave the corresponding ethers.

[reaction: see text] Selective and effective fluorination of various types of organic compounds performed in water as the reaction medium using 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor F-TEDA-BF4) is reported. 2-Naphthole and 2-methoxynaphthalene were thus transformed to 1,1-difluoro-2(1H)naphthalenone, estrone to 10beta-fluoro-1,4-estradien-3,17-dione, phenyl-substituted alkenes to vicinal fluorohydrins, and various ketones, 1,3-diketones, or beta-ketoesters to corresponding alpha-fluoro or alpha,alpha-difluoro ketones.

In the framework of research devoted to development of new synthetic methods for alkali niobates with emphasis on the principles of green chemistry, the first example of the efficient synthesis of K0.5Na0.5NbO3 powders from pure aqueous solution under normal reaction conditions is presented. Aqueous solutions of stable Nb(V)–peroxo–citrate at pH 8.50 or Nb(V)–peroxo–glycine at pH 5.50 chelate complexes were prepared, characterized and studied with FT-IR and UV-Vis spectroscopy. The addition of sodium and potassium acetates or nitrates led to the final aqueous precursor solution and it was shown that single phase K0.5Na0.5NbO3 nanopowders could be obtained by simple calcination of these peroxide intermediates at the desired, relatively low temperature (500–550 °C). The results showed that the particle size and morphology, analysed by FE-SEM, strongly depended on the type of Nb(V)–peroxo precursor and the annealing temperature. K0.5Na0.5NbO3 particles prepared through the Nb(V)–peroxo-citrate precursor resulted in the formation of sharp-edged nanocuboids in the size range 50–200 nm, while the synthetic route through the Nb(V)–peroxo–glycine precursor surprisingly also enabled formation of particles with rod-like morphology.

The micellar and supramolecular catalysis of organic reactions in water, utilizing nanometre-sized micelles of ionic, non-ionic amphiphiles or host-guest inclusion complexes using appropriate host macrocyclic molecules able to accommodate a hydrophobic organic substrates are taken under a brief account. A focus on Heck-type C-C couplings, ring closing metathesis, and halo-transformations of organic compounds in aqueous environment, is presented.

Selective and efficient aerobic oxidative iodination of ketones in aqueous media was achieved by using molecular iodine as the source of iodine atoms, air as the terminal oxidant, sodium nitrite (NaNO2) as the catalyst and H2SO4 as the activator of the overall catalytic process. The efficiency of the reaction, resulting in α-iodo ketones, was significantly improved in an aqueous solution of the anionic amphiphile sodium dodecyl sulfate (SDS), capable of self-assembly into micelle-based aggregates, thus forming a reactive micellar system. The regioselectivity of iodofunctionalization of aryl methyl ketones was regulated by the reaction medium used: in an aqueous micelle-based system the methyl group was iodinated, while in anhydrous MeCN aryl iodides were formed with high selectvity.