Benzophenone reductions, using

Benzophenone reductions using commercially available CRED enzymes. 

Decacarbonyldimanganese(O), Mn2(CO)io, a golden-yellow solid, (mp 154 C) was first obtained by reaction of Mnl2 with Mg, Cu, and Culj at room temperature in diethyl ether under CO at 200 atm P. Yields are low ( 1%). The most frequently used reducing agents for carbonylation of Mn(II) salts are (1) Na metal or Na in the presence of benzophenone or (2) aluminum alkyls. The sodium-benzophenone reduction occurs at superatmospheric CO pressures (2Ci0-700 atm)... 

Using transition state analog [136] benzophenone reduction by ruthenium half-sandwich complex... 

In addition to measuring the activity of the imprinted polymer, Polburn et al. also examined the selectivity of the catalytic site. Use of the diphenylphosphinate ligand creates cavities that resemble the transition state for the reduction of benzo-phenone. It should follow that the MIP should be most effective towards benzo-phenone reduction. A series of competition reductions with equimolar amounts of benzophenone and a cosubstrate was conducted using polymers P-1 and P-2 as catalysts (Table 1). It is interesting to note that both the imprinted catalyst and nonim-printed catalyst show a preference towards benzophenone reduction. The MIP P-1 shows approximately 1.3-2.0 fold enhancement of selectivity. As indicated by entries 4-6, the aromatic ketones were not as easily differentiated by the MIP P-I, however, P-1 showed a preference forbenzophenone over other aromatic ketones demonstrating the ability to differentiate structurally similar substrates. 

The benzopinacol obtained by photochemical reduction of benzophenone (p. 8) may be used directly without purification. 

The reduction is general for a variety of substituted benzophenones Such substituents as CH3 OH, OCH3, F, Br. N(CH3)2, NO2. COOH, COOCH3, NHCOC Hreaction conditions and do not alter the course of the reduction Diarylmethanols are reduced to diarylmethanes under the same conditions and probably are the intermediates in the reduction of ketones [26] Triethylsilane also can be used as a reducing agent in trifluoroacetic acid medium [27J This reagent is used for the reduction of benzoic acid and some other carboxylic acids under mild condiUons (equation 14) Some acids (phthalic, sue cinic, and 4-nitrobenzoic) are not reduced under these conditions [27]... 

The reduction of carbonyl compounds is most often better achieved by electrochemical methods or by using conventional hydride or hydrogenation reactions. Nevertheless the formation of benzpinacol from benzophenone, although now known for more than eighty years, is still a matter of study (4.16) 418>. 

As mentioned, electronically excited states are both easily reduced (since an electron can be accepted in the half vacant HOMO) and easily oxidized (since an electron can be donated from the half-hlled LUMO) under much milder conditions than the corresponding ground states. As an example, reducing the ground state of benzophenone requires the use of a highly reactive reductant, such as sodium metal... 

Nonloaded and loaded SLN were already investigated with respect to use in cosmetics. Although adequate controls are difficult to prepare, first experiments indicate an increase in skin hydration and a reduction in wrinkle depth following SLN application [68]. Moreover, cetyl palmitate-nanodispersions act both as particulate ultraviolet (UV) blockers themselves and as carriers for UV absorbing agents (e.g., 2-hydroxy-4-methoxy benzophenone Eusolex 4360). This results in a threefold... 

Complex 71a (0.5 mo 1%) was used as the catalyst for the TH of acetophenone and benzophenone at room temperature in PrOH in the presence of KOH. In the case of acetophenone, 50% conversion was reached after 5h with a KOH catalyst ratio of 2, whereas for the reduction of benzophenone, a strong excess of base was required (25 equiv. to the catalyst) in order to obtain a meaningful conversion (92% after 3.5 h). 

Photoreduction was quenched by high concentrations of biacetyl, slightly retarded by iodonaphthalene, but not affected by azulene or anthracene.113 These observations led to the unsatisfying conclusion that reduction proceeded via a triplet state which could be only selectively quenched. However, later work114 using flash photolysis showed that the benzophenone ketyl radical was generated upon irradiation of solutions of benzophenone and acridine, and that its predominant mode of disappearance was by reaction with... 

The use of ketones with (ir, n) triplet states to sensitize photoreductions will be attended by chemical sensitization for example, with benzophenone in isopropyl alcohol and 0.5M acceptor, 1% of the sensitizer triplet will still abstract from the solvent even if the acceptor quenches at the diffusion controlled rate. Failure to determine that the quantum yield of reduction was greater than 0.01 might lead to the conclusion that triplet sensitization was occurring. 

Metal carbonyl cluster compounds which contain three ruthenium or three osmium atoms in the cluster core are common.1 Potentially useful reagents for syntheses of these compounds are the triruthenium and triosmium dianions [M3(CO)h]2 (M = Ru, Os).2 Therefore, it is desirable to develop good synthetic routes to obtain [M3(CO)11]2- (M = Ru, Os) of high purity in high yields. A method that is particularly useful for generating [M3(CO)n]2 (M = Ru, Os) is the designed stoichiometric reduction of M3(CO)12 (M = Ru, Os) using an electron carrier such as potassium-benzophenone.3... 

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