Kucherov reaction

KUCHEROV REACTION. The hydration of acetylenic hydrocarbons with dilute sulfuric acid in the presence of mercuric sulfate or boron trifluoride as catalyst. 

Cyclohydration of alkoxyIvinylacetylenic alcohols 180 (prepared from methoxy-butenyne by the Favorsky reaction) leads to dihydropyran-4-ones 181-183 xmder conditions of the Kucherov reaction (75MI1 88MI1 93MI2). 

The formation of 4-oxo-4//-pyrido[l,2- ]pyrimidines from 2-aminopyridines and )S-oxo esters has been studied in detail by a number of workers. The works of Khitrik,37 Kucherov,38 40 and Shur and Israelstam41 are of special interest. Khitrik found that the reaction of 2-aminopyridine and ethyl acetoacetate yields 4-oxo-4//-pyrido[l,2-a]pyrimidine (41 R = H)... 

Whereas Kucherov and co-workers99 had previously obtained only noncyclized products of type 64 and 65 from the reaction of 2-amino-5-halopyridines and diethyl malonate, Lappin et al.91 succeeded in cyclizing the 5-halo (Cl and Br) derivatives of 64 to pyrido[l,2-a]pyrimidines (63) by applying semimicro sublimation to induce cyclization. 

Kucherov and Slinkin reported solid-state reactions of H-mordenite and HZSM-5 zeolites with metallic oxides such as CuO (13), Cr2O-, Mo03, and V205 (14-17). The resulting samples were studied by EPR (electron paramagnetic resonance) spectrometry. The authors have shown that the metal cations migrate to cationic sites, where they are coordinately unsaturated. 

Catalytic conversions were experimentally studied in Russia toward the end of the nineteenth century, and especially in the twentieth century, and regularities were empirically established in a number of cases. The work of A. M. Butlerov (1878) on polymerization of olefins with sulfuric acid and boron trifluoride, hydration of acetylene to acetaldehyde over mercury salts by M. G. Kucherov (1881) and a number of catalytic reactions described by V. N. Ipatieff beginning with the turn of the century (139b) are widely known examples. S. V. Lebedev studied hydrogenation of olefins and polymerization of diolefins during the period 1908-13. Soon after World War I he developed a process for the conversion of ethanol to butadiene which is commercially used in Russia. This process has been cited as the first example of commercial application of a double catalyst. Lebedev also developed a method for the polymerization of butadiene to synthetic rubber over sodium as a catalyst. Other Russian chemists (I. A. Kondakov I. Ostromyslenskif) were previously or simultaneously active in rubber synthesis. Lebedev s students are now continuing research on catalytic formation of dienes. 

Kucherov studied the reaction of 2-amino-5-halopyridines with ethyl acetoacetate and obtained 4-oxo-4H-pyrido[l,2-a]pyrimidines (41 R = 7-halo) in 20 25% yield at 190-195°C, and crotonic amides (40 R = R = 5-halo) in 60-65% yield and crotonates (39 R = 5-halo) in... 

In the same vein ESR technique has been used to try to characterize solid-solid reaction between a given salt or oxide and a zeolite matrix particularly by Kucherov, Slinkin and others (19, 20, 57) with elements as Cu, Cr, Fe, V on HZSM-5 (19) and on H-Ga ZSM-5 (20) and Fe and Mn on ZSM-5 (57). Usually the interpretation consists in assigning the interaction to cationic exchange of H" " or Na" by the added elements. This holds probably true but as mentionned above for B2O3 impregnated on HZSM-5, part of the element may be isomorphously substituted as T element in the framework. Exchange of cations as Cr " and their characterization was already studied on Y-type zeolite in the early 70 ies (60,61). 

Kucherov, A. V Slinkin, A. A. Beyer, G. K. and Borbely, G., Zeolites H-[Ga]ZSM-5 and H-ZSM-5 A comparative study of the introduction of transition-metal cations by a solid-state reaction, Journal of the Chemical Society, Faraday Transactions 1 Physical Chemistry in Condensed Phases 85(9), 2737-2747 (1989). 

Lazar, K. Micheaud, N. Mihalyi, M. R., Pal-Borbely, G. and Beyer, H. K., Attempts to exchange iron into H-Y and H-ZSM-5 zeolites by in situ formed chloride-containing mobile species, Reaction Kinetics and Catalysis Letters 74(2), 289-298 (2001). Kucherov, A. V. and Slinkin, A. A., Zeolite modification by in situ formed reactive gas-phase species. Preparation and properties of Mo-containing zeolites, Studies in Surface Science and Catalysis 118(Preparation of Catalysts VII), 567-576 (1998). 

The solid-state reaction between HZSM-5 and iron compounds (FeO, Fe304, FeCl3) was investigated by Kucherov and Slinkin [171]. The formation of isolated extra-framework Fe + species was observed only in samples treated with FeCl3, while no migration of the trivalent element within the porous structure was observed after high temperature treatment with iron oxides. Similar results were obtained by Wichterlova et al. [172]. 

Kucherov and Slinkin also showed that in the solid-state reaction between CuO and Fe,H-ZSM-5 (vide supra) at least 99% of the Fe + ions were replaced by Cu + cations. The ESR signals with g2 = 5.65 and g3 = 6.25 were entirely eliminated, and only a trace of the signal with gi = 4.27 was left. This shows that essentially all of the Fe was in extra-framework positions (vide supra) and no or only negligible insertion of Fe + into the framework had occurred. Thus, SSIE of FeCl3 and H-ZSM-5 did not result in any isomorphous substitution. 

Then, the spectrum looked quahtatively like that reported by Kucherov and Shnkin for the product of a sohd-state reaction between V2O5 and H-ZSM-5 (cf. Fig. 52), confirming the axial symmetry of the ions. However, the character-... 

Similar to their interpretation of the incorporation of V(IV) or Mo(V) cations into zeolites by solid-state reaction, Kucherov and Slinkin suggested that in high-silica zeolites the respedive cation sites are too distant to allow a balance of the negative framework charges by bare Cr cations. Rather, they proposed incorporation of Cr( V) in the form of complex cations such as CrO under participation of framework ligands, in analogy to VO(OH)+ (vide supra) or MoCl (vide infra). 

Kucherov et al. [128,129] carried out a comparative study of solid-state reaction between CrOj and the gallosilicate analog of H-ZSM-5, i.e., H-[Ga]ZSM-5,... 

The first hydration of an alkyne was discovered in 1881 by Mikhail Kucherov, a Russian chemist from the Imperial Forestry Institute in St. Petersburg, using mercury(II) bromide as the catalyst [97] producing acetaldehyde. This reaction has been extensively applied in synthesis, although due to the toxicity of mercury compounds and the relatively low turnover numbers (<500), much effort has been done to find new catalysts. Thus, transition-metal-complexes containing Pd (II) [98], Pt(II) [99], Ru(ll) [100], Rh [101], and other metal centers [91] have been used, although in most cases the catalytic efficiency was only moderate. 

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