- Complexation Zn2+ and Co2+/3+ with primary diamines: Synthesis, structure and thermal properties
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New types of polyfunctional molecules formed by Co2+/3+ and Zn2+ ions with various diamines - biogenic 1,4-diaminobutane (dab, putrescine) and 1,1′-binaphthyl-2,2′-diamine (dabn) - have been obtained. The structure of the compounds was determined by single crystal X-ray diffraction analysis. Dab in the binuclear complex [Zn2(piv)2(dab)2(Hdab)2]·4piv·2H2O (1) plays the role of a bridging ligand. The H-binding in 1 promotes the formation of a supramolecular layer which, according to STA data, predetermines the thermal stability up to 100 °C. In the mononuclear complex of cobalt(III), [CoIII(piv)2(dab)2]+Cl? (2), dab is chelated with the metal center. Replacement of dab with dabn leads to solely chelate coordination in complexes of cobalt(II), [Co3(OH)(piv)5(dabn)2]·0.5MeCN (3), and zinc, [Zn(dabn)2(NO3)(MeCN)]·2NO3·0.5MeCN (4).
- Babeshkin, Konstantin S.,Efimov, Nikolay N.,Eremenko, Igor L.,Khoroshilov, Andrey V.,Kiskin, Mikhail A.,Lutsenko, Irina A.,Nelyubina, Yulia V.,Primakov, Petr V.,Shmelev, Maksim A.,Sidorov, Aleksey A.
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- Formation of Polynuclear Cadmium Pivalates in Exchange Reactions
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Abstract: The exchange reaction of CdCl2 ? 2H2O with KPiv affords cadmium(II) trimethyl acetate complexes (K[Cd6(Piv)12Cl] ? 2MeCN (I), [K2Cd3(Piv)8(H2O)6] (II), and [Cd(Piv)2(Н2О)2] (III) as a mixture with complex II and [K3Cd2(Piv)7(MeCN)2]n (IV) (HPiv is trimethylacetic acid). The exchange reaction of CdSO4 ? 8/3H2O with Ba(Piv)2 makes it possible to obtain complex III in a quantitative yield. Complex III can also be isolated by the recrystallization of {Cd(Piv)2} from water. The recrystallization of complex III or {Cd(Piv)2} from MeCN affords hexanuclear complex [Cd6(Piv)12(MeCN)2] (V), which transforms into complex III upon recrystallization from water. All new compounds are characterized by the data of single-crystal X-ray diffraction analysis (CIF files CCDC no. 1572202–1572206), IR spectroscopy, and C,H,N analysis.
- Gogoleva,Sidorov,Nelyubina, Yu. V.,Shmelev,Aleksandrov,Kuznetsova,Kiskin,Eremenko
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p. 473 - 482
(2018/09/09)
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- Mono-Oxidation of Bidentate Bis-phosphines in Catalyst Activation: Kinetic and Mechanistic Studies of a Pd/Xantphos-Catalyzed C-H Functionalization
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Kinetic, spectroscopic, crystallographic, and computational studies probing a Pd-catalyzed C-H arylation reaction reveal that mono-oxidation of the bis-phosphine ligand is critical for the formation of the active catalyst. The bis-phosphine mono-oxide is
- Ji, Yining,Plata, R. Erik,Regens, Christopher S.,Hay, Michael,Schmidt, Michael,Razler, Thomas,Qiu, Yuping,Geng, Peng,Hsiao, Yi,Rosner, Thorsten,Eastgate, Martin D.,Blackmond, Donna G.
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supporting information
p. 13272 - 13281
(2015/11/09)
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- Process for producing halomethyl ester of aliphatic carboxylic acid
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The present invention provides a process for producing a halomethyl ester of an aliphatic carboxylic acid in which a metal salt of an aliphatic carboxylic acid is reacted with a dihalomethane in the presence of a phase transfer catalyst, whereby the efficient production of a halomethyl ester of an aliphatic carboxylic acid has been made possible without the formation of a halomethyl ether as a by-product. The bis compound bis[aliphatic carbonyloxy)methane], which is obtained as a by-product, is hydrolyzed to enable the quantitative recovery of an aliphatic carboxylic acid and its reuse. Thus, the present process is preferable as a process for industrial production of a halomethyl ester of an aliphatic carboxylic acid.
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- Radical-Induced Fragmentations of Ketoepoxides
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The cleavage of α-ketoepoxycarbinyl radicals has been investigated for six substrates using two methods of radical formation.Products resulting from carbon-oxygen bond cleavage were observed in each case, but vinyl ethers derived from epoxide carbon-carbon cleavage were isolated in one case.
- Breen, Anthony P.,Murphy, John A.,Patterson, Christopher W.,Wooster, Nicholas F.
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p. 10643 - 10654
(2007/10/02)
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- Bioreversible Protection for the Phospho Group: Bioactivation of the Di(4-acyloxybenzyl) and Mono(4-acyloxybenzyl) Phosphoesters of Methylphosphonate and Phosphonoacetate
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The di(4-acetoxybenzyl) ester of methylphosphonate 4 (X = H, R = Me) and the di(4-acyloxybenzyl) esters of methoxycarbonylmethylphosphonate 4 (X = MeO2C, R = Me, Et, Pr, iPr, Bu or tBu) were prepared from the appropriate benzyl alcohol and phosphonic dichloride.At pD 8.0 and 37 deg C, both series of compounds hydrolyse with half-lives greater than 24 h to the corresponding mono(4-acyloxybenzyl) esters 5 (X = H or MeO2C, R = Me, Et, Pr, iPr, Bu or tBu) which were prepared by treatment of the di(4-acyloxybenzyl) esters 4 with sodium or lithium iodide.The mono(4-acyloxybenzyl) esters 5 (X = H, R = Me) and 5 (X = MeO2C, R = Me, Et, Pr, iPr or tBu) undergo chemical hydrolysis to methylphosphonate 6 (X = H), and methoxycarbonylmethylphosphonate 6 (X = MeO2C), respectively, together with 4-hydroxybenzyl alcohol and the appropriate acylate anion.The rates of hydrolysis of the mono(4-acyloxybenzyl) esters decrease as the length and steric bulk of the acyl group increases, with half-lives ranging from ca. 150 h for the acetyl analogues to 2240 h for the pivaloyl derivative.The hydrolyses of the di- and mono-(4-acyloxybenzyl) esters were catalysed by porcine liver carboxyesterase (PLCE), and in all cases the acylate anion was formed.The rate of enzymatic hydrolysis was most rapid for the 4-butanoyloxybenzyl and 4-isobutanoyloxybenzyl analogues.The methoxycarbonyl ester of the phosphonoacetate analogues was not cleaved by PLCE.The methylphosphonate generated from the reaction of 4 (X = H, R = Me) in the presence of esterase and H2(18)O, did not contain (18)O attached directly to phosphorus.These results suggest that both the chemical and enzymatical hydrolyses of themono(4-acyloxybenzyl) esters and the PLCE-catalysed hydrolyses of the di(4-acyloxybenzyl) esters proceed via hydrolysis of the acyl group to give the acylate anion and the unstable 4-hydroxybenzyl esters.The electron-donating 4-hydroxy group facilitates the cleavage of the benzyl-oxygen bond with the formation of the 4-hydroxybenzyl carbonium ion 9, which readily reacts either with water or the phosphate buffer.The 4-acyloxybenzyl phosphoesters provide the first example of a protecting group which will enable the bioactivation of phosphonate prodrugs at rates appropriate to biological systems.
- Mitchell, Anthony G.,Thomson, William,Nicholls, Dave,Irwin, William J.,Freeman, Sally
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p. 2345 - 2354
(2007/10/02)
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- Potassium Carboxylates by Direct Carbonylation of Potassium Alkoxides
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Reaction of the K+ alkoxide of linalool (1) in benzene with CO at 425-440 bar and 120-130 degC for 12-30 h gave the K+ salt of 2,6-dimethyl-2-vinyl-5-heptenoic acid (4a) in a ca. 25percent yield based on ca. 65percent converted alkoxide.Reaction of the + 18-crown-6> alkoxide of 1 with CO at 50-55 bar and 40 degC for 90-140 h gave a mixture containing mainly the + 18-c-6> salts of 4a (ca. 62percent) and of the homogeranic acids 3a and 6a (together ca. 27percent of the mixture) in a ca. 35percent combined yield based on 50-60percent converted alkoxide.The uncomplexed or complexed K+ alkoxide of (S)-1 gave, with ca. 85percent net retention, the K+ salt of (S)-4a.Reaction of the + 18-c-6> alkoxide of geraniol (2) with CO at 50 bar and 40 degC for 65-70 h gave myrcene (10) and geranyl formate (11) in a ca. 40-50percent yield each based on ca. 85percent converted alkoxide.Reaction of the + 18-c-6> alkoxide of 3-pentyl-1,4-pentadien-3-ol (14) at 50 bar and r.t. for 70 h gave a mixture of the + 18-c-6> salts of 2-pentyl-2-vinyl-3-butenoic acid (15a) (67percent) and the 4-pentyl-2,4-hexadienoic acids 18a and l9a (together 23percent of the mixture) in a ca. 90percent combined yield based on ca. 65percent converted alkoxide.
- Rautenstrauch, Valentin
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p. 593 - 599
(2007/10/02)
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