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Visible Light Induced Reduction and Pinacol Coupling of Aldehydes and Ketones Catalyzed by Core/Shell Quantum Dots
We present an efficient and versatile visible light-driven methodology to transform aryl aldehydes and ketones chemoselectively either to alcohols or to pinacol products with CdSe/CdS core/shell quantum dots as photocatalysts. Thiophenols were used as proton and hydrogen atom donors and as hole traps for the excited quantum dots (QDs) in these reactions. The two products can be switched from one to the other simply by changing the amount of thiophenol in the reaction system. The core/shell QD catalysts are highly efficient with a turn over number (TON) larger than 4 × 104 and 4 × 105 for the reduction to alcohol and pinacol formation, respectively, and are very stable so that they can be recycled for at least 10 times in the reactions without significant loss of catalytic activity. The additional advantages of this method include good functional group tolerance, mild reaction conditions, the allowance of selectively reducing aldehydes in the presence of ketones, and easiness for large scale reactions. Reaction mechanisms were studied by quenching experiments and a radical capture experiment, and the reasons for the switchover of the reaction pathways upon the change of reaction conditions are provided.
Xi, Zi-Wei,Yang, Lei,Wang, Dan-Yan,Feng, Chuan-Wei,Qin, Yufeng,Shen, Yong-Miao,Pu, Chaodan,Peng, Xiaogang
p. 2474 - 2488
(2021/02/05)

A Combined Experimental–Theoretical Study on Diels-Alder Reaction with Bio-Based Furfural: Towards Renewable Aromatics
The synthesis of relevant renewable aromatics from bio-based furfural derivatives and cheap alkenes is carried out by using a Diels-Alder/aromatization sequence. The prediction and the control of the ortho/meta selectivity in the Diels-Alder step is an important issue to pave the way to a wide range of renewable aromatics, but it remains a challenging task. A combined experimental-theoretical approach reveals that, as a general trend, ortho and meta cycloadducts are the kinetic and thermodynamic products, respectively. The nature of substituents, both on the dienes and dienophiles, significantly impacts the feasibility of the reaction, through a modulation on the nucleo- and electrophilicity of the reagents, as well as the ortho/meta ratio. We show that the ortho/meta selectivity at the reaction equilibrium stems from a subtle interplay between charge interactions, favoring the ortho products, and steric interactions, favoring the meta isomers. This work also points towards a path to optimize the aromatization step.
van Scodeller,De Oliveira Vigier, Karine,Muller, Eric,Ma, Changru,Guégan, Frédéric,Wischert, Raphael,Jér?me, Fran?ois
p. 313 - 323
(2020/10/19)

Bimetallic Bis-NHC-Ir(III) Complex Bearing 2-Arylbenzo[d]oxazolyl Ligand: Synthesis, Catalysis, and Bimetallic Effects
Herein, an unprecedented bimetallic bis-NHC Cp*Ir complex 1 bearing 2-arylbenzo[d]oxazolyl and NHC ligands is reported. A significant increase in activity was observed for N-methylation of amines and reduction of aldehydes with MeOH catalyzed by 1 compared to the monometallic analogues (2-11). Under the optimal conditions, it showed to be highly effective in N-methylation of nitroarenes with MeOH as both C1 and H2 source. Substrates, including aromatic amines, ketones, and nitro compounds with various functional groups, can be well-tolerated. Mechanistic studies and DFT calculation highlight the significance of bimetallic centers cooperativity.
Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhan, Bing,Li, Zhi-Ming,Hou, Xiu-Feng
p. 3514 - 3523
(2020/10/09)

Linear β-amino alcohol catalyst anchored on functionalized magnetite nanoparticles for enantioselective addition of dialkylzinc to aromatic aldehydes
A linear β-amino alcohol ligand, previously found to be a very efficient catalyst for enantioselective addition of dialkylzinc to aromatic aldehydes, has been anchored on differently functionalized superparamagnetic core-shell magnetite-silica nanoparticles (1a and 1b). Its catalytic activity in the addition of dialkylzinc to aldehydes has been evaluated, leading to promising results, especially in the case of 1b for which the recovery by simple magnetic decantation and reuse was successfully verified. This journal is
Ciprioti, Stefano Vecchio,De Angelis, Martina,Di Pietro, Federica,Iannoni, Marika,Pilloni, Luciano,Primitivo, Ludovica,Ricelli, Alessandra,Righi, Francesco,Righi, Giuliana,Sappino, Carla,Suber, Lorenza
p. 29688 - 29695
(2020/10/26)

Bulky N-Heterocyclic-Carbene-Coordinated Palladium Catalysts for 1,2-Addition of Arylboron Compounds to Carbonyl Compounds
The synthesis of primary, secondary, and tertiary alcohols by the 1,2-addition of arylboronic acids or boronates to carbonyl compounds, including unactivated ketones, using novel bulky yet flexible N-heterocyclic carbene (NHC)-coordinated 2,6-di(pentan-3-yl)aniline (IPent)-based cyclometallated palladium complexes (CYPs) as catalysts is reported. The PhS-IPent-CYP-catalyzed reactions are efficient at low catalyst loadings (0.02–0.3 mol% Pd), and the exceptional catalytic activity for 1,2-addition is attributed to the steric bulk of the NHC ligand. These reactions can yield a wide range of functionalized benzylic alcohols that are difficult to synthesize by classical protocols using highly active organomagnesium or lithium reagents.
Okuda, Yuta,Nagaoka, Masahiro,Yamamoto, Tetsuya
p. 6291 - 6300
(2020/11/30)

Polypyridyl iridium(III) based catalysts for highly chemoselective hydrogenation of aldehydes
Iridium-catalyzed transfer hydrogenation (TH) of carbonyl compounds using HCOOR (R = H, Na, NH4) as a hydrogen source is a pivotal process as it provides the clean process and is easy to execute. However, the existing highly efficient iridium catalysts work at a narrow pH; thus, does not apply to a wide variety of substrates. Therefore, the development of a new catalyst which works at a broad pH range is essential as it can gain a broader scope of utilization. Here we report highly efficient polypyridyl iridium(III) catalysts, [Ir(tpy)(L)Cl](PF6)2 {where tpy = 2,2′:6′,2′'-Terpyridine, L = phen (1,10-Phenanthroline), Me2phen (4,7-Dimethyl-1,10-phenanthroline), Me4phen (3,4,7,8-Tetramethyl-1,10-phenanthroline), Me2bpy (4,4′-Dimethyl-2–2′-dipyridyl)} for the chemoselective reduction of aldehydes to alcohols in aqueous ethanol and sodium formate as the hydride source. The reaction can be carried out efficiently in broad pH ranges, from pH 6 to 11. These catalysts are air stable, easy to prepare using commercially available starting materials, and are highly applicable for a wide range of substrates, such as electron-rich or deficient (hetero)arenes, halogens, phenols, alkoxy, ketones, esters, carboxylic acids, cyano, and nitro groups. Particularly, acid and hydroxy groups containing aldehydes were reduced successfully in basic and acidic reaction conditions, demonstrating the efficiency of the catalyst in a broad pH range with high conversion rates under microwave irradiation.
Pandrala, Mallesh,Resendez, Angel,Malhotra, Sanjay V.
p. 283 - 288
(2019/09/30)

Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry
The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ± 0.007 μM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ± 0.5 μM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 μM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 μM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.
Cao, Jiangying,Ma, Chunhua,Zang, Jie,Gao, Shuai,Gao, Qianwen,Kong, Xiujie,Yan, Yugang,Liang, Xuewu,Ding, Qin'ge,Zhao, Chunlong,Wang, Binghe,Xu, Wenfang,Zhang, Yingjie
p. 3145 - 3157
(2018/06/01)

IRIDIUM-BASED CATALYSTS FOR HIGHLY EFFICIENT DEHYDROGENATION AND HYDROGENATION REACTIONS IN AQUEOUS SOLUTION AND APPLICATIONS THEREOF
A series of iridium-based catalysts for dehydrogenation of formic acid, and hydrogenation using formic acid as the hydrogen source, and the process using the catalyst(s) to produce hydrogen gas from formic acid solution, or to reduce aldehydes using formic acid, are disclosed and claimed. More specifically, the present invention relates to a group of pentamethylcyclopentadienyl (Cp*) iridium complexes with different Ν,Ν-bidentate ligands that catalyze dehydrogenation from formic acid, and chemo-selective hydrogenation of aldehydes, in the aqueous solution system in a highly efficient, and long life-time manner.
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(2018/11/22)

Oxidative cyanide-free cyanation on arylboronic acid derivatives using aryl/heteroaryl thiocyanate using novel IL-PdCl4 catalyst under mild condition
An efficient and simple method is reported for the cyanation on arylboronic acid using various simple/indole thiocyanates using a new IL-PdCl4 catalyst. The cascade process involves a coupling reaction without any additive to give a wide range of cyanide derivatives. Cyanation on various arylboronic acids underwent smoothly affording the corresponding arylnitriles in good to high yields.
Vaghasiya, Beena K.,Satasia, Shailesh P.,Thummar, Rahul P.,Kamani, Ronak D.,Avalani, Jemin R.,Sapariya, Nirav H.,Raval, Dipak K.
p. 507 - 515
(2018/05/15)

Synthesis of Renewable meta-Xylylenediamine from Biomass-Derived Furfural
We report the synthesis of biomass-derived functionalized aromatic chemicals from furfural, a building block nowadays available in large scale from low-cost biomass. The scientific strategy relies on a Diels–Alder/aromatization sequence. By controlling the rate of each step, it was possible to produce exclusively the meta aromatic isomer. In particular, through this route, we describe the synthesis of renewably sourced meta-xylylenediamine (MXD). Transposition of this work to other furfural-derived chemicals is also discussed and reveals that functionalized biomass-derived aromatics (benzaldehyde, benzylamine, etc.) can be potentially produced, according to this route.
Scodeller, Ivan,Mansouri, Samir,Morvan, Didier,Muller, Eric,de Oliveira Vigier, Karine,Wischert, Raphael,Jér?me, Fran?ois
supporting information
p. 10510 - 10514
(2018/08/17)

Iridium-catalyzed highly efficient chemoselective reduction of aldehydes in water using formic acid as the hydrogen source
A water-soluble highly efficient iridium catalyst is developed for the chemoselective reduction of aldehydes to alcohols in water. The reduction uses formic acid as the traceless reducing agent and water as a solvent. It can be carried out in air without the need for inert atmosphere protection. The products can be purified by simple extraction without any column chromatography. The catalyst loading can be as low as 0.005 mol% and the turn-over frequency (TOF) is as high as 73 800 mol mol-1 h-1. A wide variety of functional groups, such as electron-rich or deficient (hetero)arenes and alkenes, alkyloxy groups, halogens, phenols, ketones, esters, carboxylic acids, cyano, and nitro groups, are all well tolerated, indicating excellent chemoselectivity.
Yang, Zhanhui,Zhu, Zhongpeng,Luo, Renshi,Qiu, Xiang,Liu, Ji-Tian,Yang, Jing-Kui,Tang, Weiping
supporting information
p. 3296 - 3301
(2017/07/28)

Visible light-induced heterogeneous Meerwein-Ponndorf-Verley-type reduction of an aldehyde group over an organically modified titanium dioxide photocatalyst
An organically modified titanium dioxide photocatalyst prepared by a simple impregnation method chemoselectively and almost quantitatively converted benzaldehydes having other reducible functional groups to the corresponding benzyl alcohols under visible
Fukui, Makoto,Tanaka, Atsuhiro,Hashimoto, Keiji,Kominami, Hiroshi
supporting information
p. 4215 - 4218
(2017/04/21)

Cooperative Multifunctional Catalysts for Nitrone Synthesis: Platinum Nanoclusters in Amine-Functionalized Metal–Organic Frameworks
Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine-functionalized Zr metal–organic framework (MOF), UiO-66-NH2 (Pt@UiO-66-NH2) as a multifunctional catalyst in the one-pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO-66-NH2, Pt@UiO-66-NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO-66, and Pd@UiO-66-NH2. Pt@UiO-66-NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO-66-NH2). To our knowledge, this work demonstrates the first examples of one-pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.
Li, Xinle,Zhang, Biying,Tang, Linlin,Goh, Tian Wei,Qi, Shuyan,Volkov, Alexander,Pei, Yuchen,Qi, Zhiyuan,Tsung, Chia-Kuang,Stanley, Levi,Huang, Wenyu
supporting information
p. 16371 - 16375
(2017/11/28)

Remote meta-C–H Cyanation of Arenes Enabled by a Pyrimidine-Based Auxiliary
An easily removable pyrimidine-based auxiliary has been employed for the remote meta-C?H cyanation of arenes. The scope of this Pd-catalyzed cyanation reaction using copper(I) cyanide as the cyanating agent was demonstrated with benzylsilanes, benzylsulfonates, benzylphophonates, phenethylsulfonates, and phenethyl ether derivatives. The method was utilized for the synthesis of pharmaceutically valuable precursors.
Bag, Sukdev,Jayarajan, Ramasamy,Dutta, Uttam,Chowdhury, Rajdip,Mondal, Rahul,Maiti, Debabrata
supporting information
p. 12538 - 12542
(2017/09/12)

Photoinduced Copper(I)-Catalyzed Cyanation of Aromatic Halides at Room Temperature
The first photoinduced copper(I)-catalyzed cyanation of aromatic halides at room temperature has been developed. The sp2 cyanation reaction exhibits outstanding tolerance to functional groups including primary amines and carboxylic acids, and chemoselectivity to SN2-reactive alkyl chlorides. Mechanistic investigations indicate that the reaction occurs via a single-electron transfer (SET) between the aryl halide and an excited copper(I) cyanide catalytic intermediate. (Figure presented.).
Kim, Kicheol,Hong, Soon Hyeok
supporting information
p. 2345 - 2351
(2017/07/22)

An Efficient, Stable and Reusable Palladium Nanocatalyst: Chemoselective Reduction of Aldehydes with Molecular Hydrogen in Water
Palladium nanoparticles (Pd-BNP) stabilized by a binaphthyl-backbone can be efficiently used for the chemoselective reduction of aldehydes in the presence of hydrogen at room temperature in water. The Pd-BNP catalyst is easily recovered and reused for five catalytic cycles. (Figure presented.).
Kotha, Surya Srinivas,Sharma, Nidhi,Sekar, Govindasamy
supporting information
p. 1694 - 1698
(2016/10/13)

A Homogeneous Method for the Conveniently Scalable Palladium- and Nickel-Catalyzed Cyanation of Aryl Halides
Homogeneous conditions for the palladium-catalyzed cyanation of aryl halides were developed. This new system features a broad scope of aryl chlorides and bromides, uses 2-propanol or 1-butanol as solvent, and is readily scalable. The same conditions can also provide simple benzonitriles using the recently developed (TMEDA)NiCl(o-tolyl) precatalyst in conjunction with 1,1′-bis(diphenylphosphino)ferrocene (dppf) as a ligand.
Burg, Finn,Egger, Julian,Deutsch, Johannes,Guimond, Nicolas
p. 1540 - 1545
(2016/08/30)

Structure-guided, single-point modifications in the phosphinic dipeptide structure yield highly potent and selective inhibitors of neutral aminopeptidases
Seven crystal structures of alanyl aminopeptidase from Neisseria meningitides (the etiological agent of meningitis, NmAPN) complexed with organophosphorus compounds were resolved to determine the optimal inhibitor-enzyme interactions. The enantiomeric phosphonic acid analogs of Leu and hPhe, which correspond to the P1 amino acid residues of well-processed substrates, were used to assess the impact of the absolute configuration and the stereospecific hydrogen bond network formed between the aminophosphonate polar head and the active site residues on the binding affinity. For the hPhe analog, an imperfect stereochemical complementarity could be overcome by incorporating an appropriate P1 side chain. The constitution of P1′-extended structures was rationally designed and the lead, phosphinic dipeptide hPhePψ[CH2]Phe, was modified in a single position. Introducing a heteroatom/heteroatom-based fragment to either the P1 or P1′ residue required new synthetic pathways. The compounds in the refined structure were low nanomolar and subnanomolar inhibitors of N. meningitides, porcine and human APNs, and the reference leucine aminopeptidase (LAP). The unnatural phosphinic dipeptide analogs exhibited a high affinity for monozinc APNs associated with a reasonable selectivity versus dizinc LAP. Another set of crystal structures containing the NmAPN dipeptide ligand were used to verify and to confirm the predicted binding modes; furthermore, novel contacts, which were promising for inhibitor development, were identified, including a π-π stacking interaction between a pyridine ring and Tyr372.
Vassiliou, Stamatia,W?glarz-Tomczak, Ewelina,Berlicki,Pawe?czak, Ma?gorzata,Nocek, Bogus?aw,Mulligan, Rory,Joachimiak, Andrzej,Mucha, Artur
p. 8140 - 8151
(2014/12/10)

Electrophilicity and nucleophilicity of commonly used aldehydes
The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
Pratihar, Sanjay
p. 5781 - 5788
(2014/07/22)

Palladium-catalyzed hydroxymethylation of aryl-and heteroarylboronic acids using aqueous formaldehyde
Cyclometallated NHC palladium complexes prepared from palladium(II) acetate [Pd(OAc)2] and unsymmetrical 1,3-diarylimidazolinium salts catalyzed the hydroxymethylation of (hetero)arylboronic acids using an excess amount of formalin to afford (hetero)arylm
Yamamoto, Tetsuya,Zhumagazin, Azamat,Furusawa, Takuma,Tanaka, Ryoji,Yamakawa, Tetsu,Oe, Yohei,Ohtab, Tetsuo
supporting information
p. 3525 - 3529
(2015/01/09)

Chemoselective Hydrogenation and Transfer Hydrogenation of Olefins and Carbonyls with the Cluster-Derived Ruthenium Nanocatalyst in Water
Ion pairing of [H3Ru4(CO)12]- with the quaternary ammonium groups of water-soluble poly(diallyldimethylammonium chloride) gives the precursor of a nanocatalyst for hydrogenation and transfer hydrogenation reactions in water. In hydrogenation reactions, "on water" effect is seen for substrates such as cyclohexanones, methyl pyruvate, acetophenone, and safflower oil. With these substrates, higher turnover numbers are obtained in water than in methanol. The cluster-derived catalyst shows unique chemoselectivity, which is not seen either in a catalyst prepared through ion pairing of [RuCl4]- with the quaternary ammonium groups of the same polymer or in commercial (5%) Ru/Al2O3. In contrast to Ru/Al2O3, the [RuCl4]--derived catalyst, or many other ruthenium-based catalytic systems, the cluster-derived catalyst is totally inert toward the hydrogenation of -NO2, -CN, and aromatic ring functionalities. In water, typical ketones and aldehydes could be reduced by using the cluster-derived catalyst and formate as the hydrogen donor. Industrially important cyano- and nitrobenzyl alcohols could thus be made from the corresponding aldehydes. High-resolution TEM data suggest that unique chemoselectivity is a result of highly crystalline ruthenium nanoparticles that consist mainly of Ru(111) crystal planes.
Indra, Arindam,Maity, Prasenjit,Bhaduri, Sumit,Lahiri, Goutam Kumar
p. 322 - 330
(2013/03/13)

Indium tri(isopropoxide)-catalyzed selective Meerwein-Ponndorf-Verley reduction of aliphatic and aromatic aldehydes
Indium tri(isopropoxide)-catalyzed Meerwein-Ponndorf-Verley reduction of aliphatic and aromatic aldehydes in 2-propanol gave selectively the corresponding primary alcohols in good to excellent yields at room temperature. A wide range of functional groups including alkene, ether, ketone, ester, nitrile, and nitro were tolerated under the optimum reaction conditions. Chemoselective reductions were also achieved not only between aromatic aldehyde, aromatic ketone, and epoxide but also between aliphatic aldehyde and alkene.
Lee, Jaeyoung,Ryu, Taekyu,Park, Sangjune,Lee, Phil Ho
supporting information; experimental part
p. 4821 - 4825
(2012/07/03)

Zinc phthalocyanine with PEG-400 as a recyclable catalytic system for selective reduction of aromatic nitro compounds
Zinc phthalocyanine with PEG-400 was established as a catalytic system for chemo and regioselective reduction of aromatic nitro compounds to corresponding amines. A large range of reducible functional groups such as acid, amide, ester, halogen, lactone, nitrile, N-benzyl, O-benzyl, hydroxy and heterocycles were well tolerated. Direct synthesis of benzotriazole from O-dinitrobenzene was achieved for the first time. The present catalytic system was successfully employed for the reduction of carbonyl and ester compounds to corresponding alcohols and reductive amination of benzaldehydes with primary amines to form corresponding secondary amines. Remarkable advantages of the present catalytic method include low loading of metal, avoidance of toxic ligands and high isolated yields. The catalyst was recyclable up to four times without any loss of selectivity and activity.
Sharma, Upendra,Kumar, Neeraj,Verma, Praveen Kumar,Kumar, Vishal,Singh, Bikram
supporting information; experimental part
p. 2289 - 2293
(2012/09/10)

Nickel phthalocyanine assisted highly efficient and selective carbonyl reduction in polyethylene glycol-400
Nickel phthalocyanine with polyethylene glycol- 400 is described as a reusable green catalytic system for highly chemo- and regioselective reduction of carbonyl compounds to corresponding alcohols at room temperature. The catalytic system showed wide substrate scope covering aromatic, hetero aromatic and aliphatic carbonyl compounds with high turnover number and frequency. In the present study, 1,3- and 1,4-benzenedicarbaldehydes have been regioselectively reduced to corresponding alcohols for the first time. The catalyst was reused up to seven times without any significance loss in activity. Springer Science+Business Media, LLC 2012.
Verma, Praveen Kumar,Sharma, Upendra,Kumar, Neeraj,Bala, Manju,Kumar, Vishal,Singh, Bikram
experimental part
p. 907 - 913
(2012/10/07)

Palladium-catalyzed direct hydroxymethylation of aryl halides and triflates with potassium acetoxymethyltrifluoroborate
Suzuki-Miyaura cross-coupling reactions of aryl halides and triflates with potassium acetoxymethyltrifluoroborate afforded the corresponding aryl and heteroaryl methanol products in moderate to excellent yields.
Murai, Norio,Yonaga, Masahiro,Tanaka, Keigo
supporting information; experimental part
p. 1278 - 1281
(2012/04/23)

Control of chemoselectivity in hydrogenations of substituted nitro- and cyano-aromatics by cluster-derived ruthenium nanocatalysts
Catalyst precursors 1 and 2, made by ion-pairing [H3Ru 4(CO)12]- with NR4+ groups of functionalized MCM-41 and water-soluble poly(diallyldimethylammonium chloride), PDADMAC, respectively, have been evaluated for the chemoselective hydrogenation of nitro- and cyano-benzaldehydes. They are found to be inert toward -NO2 and -CN groups, but active for the reduction of -CHO and >C=C4 (3) or with (5%)Ru-Al2O3, where both the functional groups are hydrogenated. Kinetic analyses have been carried out for the hydrogenation of 4-nitrobenzaldehyde with 2. Existence of an induction time and two competitive equilibriums followed by the product-forming rate-determining step are inferred from the empirically derived rate expression. The kinetic results, structural evidences, and previous work strongly suggest that the observed chemoselectivity is probably a result of the absence of multiple crystal planes, differing in Miller indices, in the cluster-derived catalysts.
Indra, Arindam,Maity, Niladri,Maity, Prasenjit,Bhaduri, Sumit,Lahiri, Goutam Kumar
experimental part
p. 176 - 183
(2012/02/02)

2 -MORPHOLINOPYRIMIDINES AND THEIR USE AS PI3 KINASE INHIBITORS
Morpholino pyrimidines of formula (I): wherein R1 is selected from -Y-R6 and -NR4R5; R2 is a N-containing monocyclic heteroaryl group which is selected from pyridyl, isoxazolyl, imidazolyl, pyrazolyl, pyrrolyl, thiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, oxazolyl, furanyl, thienyl, triazolyl and tetrazolyl and which is unsubstituted or substituted by halo, -CN, -NR10R11, -OR10, -C(O)R10, -NR10C(O)R11, - N(C(O)R11)2, -NR10C(O)NR10R11, -SO2R10R11, -SO2NR10R11, -C(=O)OR10, -C(=O)NR10R11, halo-C1 -C6 alkyl and unsubstituted C1-C12 alkyl; R3 is selected from H, C1-C6 alkyl and C1-C6 alkoxy; Y is selected from a direct bond, -(CR2)m-, C2-C6 alkenylene, C2-C6 alkynylene, -(CR2)p-O-(CR2) t-, -(CR2)p-NR-(CR2) t, -(CR2)p-NR-(CR2)n-C(O)-, -(CR2)p-NR-C(O)- (CR2)n-, -(CR2)p-C(O)-NR-(CR2) t, -(CR2)p-C(O)-(CR2)n-NR-(CR2)t,- and -(CR2)p- C(O)-(CR2)n-; R6 is selected from an unsaturated 5- to 12-membered carbocyclic or heterocyclic ring, a saturated 5-, 6- or 7- membered N-containing heterocyclic group which is unsubstituted or substituted, C1-C6 alkyl, -NR2, -OR, -NR(CO)R and - C(O)NR2; R4 and R5, which are the same or different, are both C1-C6 alkyl which is unsubstituted or substituted, or R4 and R5 together form, with the nitrogen atom to which they are attached, a saturated 5-, 6- or 7- membered N-containing heterocyclic group which is unsubstituted or substituted; each R, which are the same or different when more than one is present in a given group, is independently H, C1-C6 alkyl which is unsubstituted or substituted or a 5- to 12-membered aryl or heteroaryl group which is unsubstituted or substituted; R10 and R11, which are the same or different, are independently selected from H, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl and C3-C8 cycloalkyl; n is 0 or an integer of 1 to 6; m is an integer of 1 to 6; p is 0 or an integer of 1 to 6; and t is 0 or an integer of 1 to 6, with the proviso that t is an integer of 2 to 6 when R6 is linked to Y through a constituent O or N atom of R6; and the pharmaceutically acceptable salts thereof, subject to various provisos, have activity as inhibitors of PI3K and may thus be used to treat diseases and disorders arising from abnormal cell growth, function or behaviour, particularly that associated with PI3 kinase such as cancer, immune disorders, cardiovascular disease, viral infection, inflammation, metabolism/endocrine disorders and neurological disorders. Processes for synthesizing the compounds are also described
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(2009/06/27)

CYCLOALKYLAMINO ACID DERIVATIVES
The invention relates to compounds of formula I and to pharmaceutically acceptable salts, prodrugs, solvates or hydrates thereof; wherein B, D, E, R1, R2, R3, R4, R5, R8, m, n, p, q, r, s, t and u are as defined herein. This invention also relates to a method of using such compounds in the treatment of hyperproliferative diseases and autoimmune diseases in mammals, especially humans, and to pharmaceutical compositions containing such compounds.
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(2008/06/13)

A convenient and general iron-catalyzed hydrosilylation of aldehydes
A general and highly chemoselective hydrosilylation of aldehydes using iron catalysts is reported. Fe(OAc)2 in the presence of tricyclohexylphosphine as ligand and polymethylhydrosiloxane (PMHS) as an economical hydride source forms an efficient catalyst system for the hydrosilylation of a variety of aldehydes. Aryl, heteroaryl, alkyl and α,β-unsaturated aldehydes are successfully reduced to the corresponding primary alcohols. Broad substrate scope and high tolerance against several functional groups make the process synthetically useful.
Shaikh, Nadim S.,Junge, Kathrin,Beller, Matthias
p. 5429 - 5432
(2008/09/19)

On water and in air: Fast and highly chemoselective transfer hydrogenation of aldehydes with iridium catalysts
(Chemical Equation Presented) Water as solvent: A fast, selective, and high-yielding transfer hydrogenation of a wide range of aldehydes is achieved using IrIII catalysts containing simple ethylene-diamine (en) ligands (see scheme; Ts = p-toluenesulfonyl, TOF = turnover frequency). This procedure is suitable for aldehydes with a wide range of functional groups.
Wu, Xiaofeng,Liu, Jianke,Li, Xiaohong,Zanotti-Gerosa, Antonio,Hancock, Fred,Vinci, Daniele,Ruan, Jiwu,Xiao, Jianliang
p. 6718 - 6722
(2007/10/03)

SUBSTITUTED PYRIDINONES
Disclosed are compounds of Formula (I) and pharmaceutically acceptable salts thereof, wherein R1, R2, R3, R4, and R5 are defined herein. These compounds are useful for treating diseases and conditions caused or exacerbated by unregulated p38 MAP Kinase and/or TNF activity. Pharmaceutical compositions containing the compounds, methods of preparing the compounds and methods of treatment using the compounds are also disclosed.
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Page/Page column 282

(2008/06/13)

Palladium-catalyzed cyanation of aryl bromides promoted by low-level organotin compounds
(Equation Presented) A novel method for palladium-catalyzed cyanation of aryl bromides promoted by low-level tri-n-butyltin chloride or cyanide is described. The method features low catalyst loading and mild reaction conditions. KCN is used as the cyanide source. Only trace levels of the tri-n-butyltin compound are required to achieve high conversion and yield in the cyanation of aryl bromides, iodides, and triflates.
Yang, Chunhua,Williams, J. Michael
p. 2837 - 2840
(2007/10/03)

KF-Al2O3 mediated cross-Cannizzaro reaction under microwave irradiation
Aromatic aldehydes are selectively converted to the corresponding alcohols in high yields by cross-Cannizzaro reaction using KF-Al2O3 under microwave irradiation in solvent-free condition.
Subba Reddy,Srinivas,Yadav,Ramalingam
p. 219 - 223
(2007/10/03)

Facile reduction of aromatic aldehydes, ketones, diketones and oxo aldehydes to alcohols by an aqueous TiCl3/NH3 system: Selectivity and scope
A simple and rapid procedure for the almost quantitative reduction of aromatic aldehydes, ketones, diketones and oxo aldehydes to alcohols by use of TiCl3/NH3 in aqueous methanol solution is reported. The reducing system distinguishes between different classes of aldehydes and/or ketones, and many functionalities that usually do not survive under reducing conditions are tolerated well. The concept of reversal of chemoselectivity has also been developed. A mechanism based on two sequential one-electron transfers from TiIII to the carbonyl carbon atom is proposed, the second SET becoming operative only in the presence of ammonium ion (either added or formed in situ). Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Clerici, Angelo,Pastori, Nadia,Porta, Ombretta
p. 3326 - 3335
(2007/10/03)

New Potential and Practical MIBG Analogs for PET: meta-(3-[18F]Fluoroalkyl)benzylguanidines
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Lee, B. C.,Choe, Y. S.,Lee, K. H.,Kim, B.-T.,Chi, D. Y.
p. S404 - S406
(2007/10/03)

Process for producing cyanobenzyl compounds
An industrially advantageous process for producing cyanobenzyl compounds under mild conditions from relatively easily available cyanobenzylamine having a cyano group on the benzene ring or a compound thereof which is ring-substituted with a chlorine atom, a fluorine atom, etc. The process for producing a cyanobenzyl compound includes transforming an aminomethyl group of a cyanobenzylamine compound into a hydroxymethyl group, a halogenomethyl group, or an acyloxymethyl group without causing damage to a cyano group on the benzene ring. The transformation may be carried out by use of nitrosonium ions.
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(2008/06/13)

Efficient reduction of organic compounds with sulfurated calcium borohydride [Ca(S3BH2)2], a new and stable modified borohydride reagent
Sulfurated Calcium, magnesium, and berelium horohydrides are prepared by metathetical reaction between NaBH2S3 and Ca, Mg, and Be chlorides in dry THF and the effect of metal cation exchange on their stability and reactivity has been presented. In this study we have shown that Ca(BH2S3)2 is much more stable and more reactive than its Mg, Be, and Na analogues. Ca(BH2S3)2can easily reduce carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones, α-β-unsaturated carbonyl compounds, aroyl azides, and carboxylic acid chlorides to their corresponding alcohols in good to excellent yields. Epoxides are also effected by this reagent and produce their symmetrical dihydroxydisulfides in good yields.
Firouzabadi, Habib,Tamami, Bahman,Kiasat, Ali Reza
p. 99 - 108
(2007/10/03)

Pd- mediated C-C bond formation with olefins and acetylenes on solid support: A scope and limitations study
In this paper we report the scope and limitations of Pd(0)-mediated coupling reactions between aromatic iodides linked to a polystyrene resin and terminal acetylenes and olefins (Heck reactions). Optimized reaction conditions were evaluated with a number of different reagents. The optimized reaction conditions were frequently found to be superior to those previously reported in the literature and resulted in excellent yields of the products upon cleavage from the solid phase.
Berteina, Sabine,Wendeborn, Sebastian,Brill, Wolfgang K.-D.,De Mesmaeker, Alain
p. 676 - 678
(2007/10/03)

Correlation Analysis of Reactivity in the Oxidation of Substituted Benzyl Alcohols by Pyridinium Hydrobromide Perbromide
Oxidation of monosubstituted benzyl alcohols by pyridinium hydrobromide perbromide (PHPB) leads to the formation of the corresponding benzaldehydes.The reaction is first order with respect to PHPB.Michaelis-Menten-type kinetics were observed with respect to he alcohol.The oxidation of α,α-dideuteriobenzyl alcohol indicated the presence of a substantial kinetic isotope effect.The rates of oxidation of meta- and para-substituted benzyl alcohols were correlated in terms of Taft's and Swain's dual substituent-parameter equations.The rates of the meta compounds correlated best with Taft's ?1 and ?0R values whereas the para-compounds showed an excellent correlation with Taft's ?1 and ?R + constants.The rates of the otho-substituted alcohols showed very good correlation with Charton's triparametric equation.The rate increased with an increase in the polarity of the solvent.A mechanism involving a rapid reversible formation of an intermediate complex and its subsequent decomposition in the rate-determining step has been proposed.
Suri, Deepa,Banerji, Kalyan K.,Kothari, Seema
p. 1734 - 1758
(2007/10/03)

Poly-η-(pyrazine)zinc borohydride as a new stable, efficient and selective reducing agent
Coordination polymer of unstable zinc borohydride and pyrazine is prepared and used as an stable, efficient and selective bench top reducing agent for a variety of organic compounds.
Tamami,Lakouraj
p. 3089 - 3096
(2007/10/03)

The Photochemistry of Methoxy-Substituted Benzyl Acetates and Benzyl Pivalates: Homolytic vs Heterolytic Cleavage
The multiple methoxy-substituted benzyl acetates (3g-i) and benzyl pivalates (4g-i) have been photolyzed in methanol solution.The products of these reactions are derived from two critical intermediates; the benzyl radical/acyloxy radical pair and the benzyl cation/carboxylate anion pair.As predicted by the meta effect, the yield of ion-derived product, the methyl ether in this case, was enhanced by the presence of the m-methoxy groups.The yield of ether, for the acetate esters, varied from 2percent for the 4-methoxy-substituted ester to 66percent for the 3,4,5-trimethoxy-substituted ester.In contrast, the yield of ether, for the pivalate esters, varied from 1percent for the 4-methoxy-substituted ester to 20percent for the 3,4,5-trimethoxy-substituted one.The meta effect does not explain these differences; electron transfer converting the radical pair to the ion pair is still an important pathway in the mechanism for ion formation.A quantitative analysis of the yield of the ethers was done in order to obtain the electron-transfer rate constants.This analysis revealed that the yield of the ethers was higher than expected based on previous results for other substituted benzyl acetates.A possible explanation for this discrepancy is that internal return of the radical pair to starting material for the acetate esters is more efficient than for the pivalate esters.Also, the esters 3k and 3l, were prepared to study the effect of electron-withdrawing groups in the meta position.For these esters, the benzylic cleavage reactions were inefficient and an isomerization reaction, the benzvalene rearrangement, was competitive.
Pincock, J. A.,Wedge, P. J.
p. 5587 - 5595
(2007/10/02)

Protonation Susceptibility and Fragmentation Capability of Functional Groups in Chemical Ionization Mass Spectrometry of Simple Bifunctional Compounds. Semi-quantitative Interpretation of Spectra.
Positive-ion, methane-mediated chemical ionization mass spectra were measured for simple bifunctional aromatic compounds of the type m-XCH2C6H4CH2Y, where X = NH2 and N(CH3)2, and Y = OH and OCH3.Essentially only three peaks of ions, +, + and +, have appeared for each compound.Since the two functional groups XCH2- and YCH2- do not interact with each other after protonation or after fragmentation, they are assumed to be protonated and to undergo fragmentation independently.The relative protonation susceptibility and fraction of fragmentating + can be estimated for each functional group in these compounds.A semi-quantitative interpretation of the observed spectra is presented.
Nakata, Hisao,Kadoguchi, Kenji,Konishi, Hideyuki,Takeda, Naohito,Tatematsu, Akira
p. 67 - 70
(2007/10/02)

Unusual Regioselectivity in the Carbonylation of Substituted Benzenes via the C-H Activation Catalyzed by RhCl(CO)(PMe3)2
Meta-substituted benzaldehydes were obtained as the major product in the carbonylation of mono-substituted benzenes via the C-H activation catalyzed by RhCl(CO)(PMe3)2 under irradiation.
Sakakura, Toshiyasu,Tanaka, Masato
p. 1113 - 1116
(2007/10/02)

Selective Reductions. 30. Effect of Cation and Solvent on the Reactivity of Saline Borohydrides for Reduction of Carboxylic Esters. Improved Procedures for the Conversion of Esters to Alcohols by Metal Borohydrides
A comparative study of the relative reactivity of saline borohydrides (Li, Na, Ca) for the reduction of carboxylic esters has been made in selected solvents (ether, tetrahydrofuran, diglyme, 2-propanol, and ethanol) at 25 deg C.In ether solvents the reactivity follows the trend LiBH4 > Ca(BH4)2 > NaBH4.On the other hand, in alcohol solvents the order of reactivity is Ca(BH4)2 > LiBH4 > NaBH4.The reactivities of LiBH4 in ethyl ether and THF, of Ca(BH4)2 in THF and 2-propanol, and of NaBH4 in ethanol proved to be promising for the reduction of esters.However, alcoholsolvents are not useful for reductions at elevated temperatures because the decomposition of the reagents becomes competitive with the reduction.A convenient synthetic procedure has been developed for the rapid conversion of esters to alcohols by using LiBH4 in ethyl ether, LiBH4 in THF, and Ca(BH4)2 in THF and utilizing essentially stoichiometric amounts of the reagents.The procedure involves adding toluene to the reaction mixture and bringing the temperature to 100 deg C while allowing the solvent do distill off.Following completion of the reaction, toluene is readily removed under vacuum and the reaction product hydrolyzed.These reductions were generally complete in 0.5 - 2.0 h, and high yields of alcohols (73-96percent) were isolated.A number of ester derivatives, including compounds containing nitro, halo, cyano, and alkoxy groups, diesters, and lactones were reduced by this procedure.The study demonstrated the high selectivity of these reagents, permitting the rapid reduction of the ester group in the presence of many substituents.However, unsaturated esters undergo simultaneous hydroboration when reduced by this procedure.
Brown, Herbert C.,Narasimhan, S.,Choi, Yong Moon
p. 4702 - 4708
(2007/10/02)

Quantitative structure-selectivity relationships. Comparison of the inhibition of Escherichia coli and bovine liver dihydrofolate reductase by 5-(substituted-benzyl)-2,4-diaminopyrimidines
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Li Li,Dietrich,Hansch
p. 535 - 544
(2007/10/02)