Mikhail Yu. Kornilov

Tungsten pentacarbonyl as a potential protecting group for soft lewis base centres in alkylation of multifunctional molecules

Abstract Reaction of W(CO) 6 or (PhNH 2 )W(CO) 5 with the molecules which possess both diphenylphosphanyl- and dialkylamino group or nitrogen — containing hetcrocyclic ring proceeds selectively through “soft” Lewis base groups and can be used for the protection of the groups from alkylalion. As a rule, the diphenylphosphanyl group participates in the co-ordination, but in some cases an sp 2 -hybridized nitrogen was shown to be the preferable co-ordination site. The new synthesized compounds have been characterized by NMR, IR spcctroscopy, and elemental analysis.

Phosphorylation of 1,3-Di(N-alkyl)Azoles by Phosphorus(V) Acid Chlorides — a Route to Potential Haptens Derived from Phosphinic Acids

Abstract Phosphorylation of N-alky lated imidazoles and benzimidazoles at C-2 by CH3POCl2, PhPOCl2-POCl3 in pyridine-triethylamine solution is described. The formed heteroaryl-substituted phosphinic or phosphonic acid chlorides were transformed without isolation into the corresponding phosphinic (phosphonic) acids, their salts or amides with moderate yields This reaction opens a simple way to potential haptens derived from phosphinic acids These haptens mimic tetrahedral transition state of many reactions and can be used to obtain catalytic antibodies The functionalized heteroarylsubstituted phosphinic acids which have been used as hapten precursors were obtained by phosphorylation of 1-alkyl-5-nitrobenzimidazole or by usage of a new phosphorylating reagent —(4-trichloromethylphenyl)phosphonic dichlonde

Direct Phosphorylation of N-Protected Imidazoles and Benzoimidazoles-A Route to 1H-Imidazol(benzoimidazol)-2-yl Phosphonic and Phosphinic Acids and Their Derivatives

Abstract Synthetic approaches to 1H-imidazol-2-yl and 1H-benzoimidazol-2-yl phosphinic and phosphonic acids and their derivatives are reported, based on phosphorylation of N-protected heterocylcles by PhPOCl2 or MePOCl2. Reaction of N-alkylbenzoimidazoles with POCl3 did not lead to C-phosphorylated products in a reasonable yield, [2,2′]-bis-benzoimidazolyles being formed instead.

Synthesis of chiral functionalized phosphine ligands based on camphor skeleton

Abstract Reactions of some nucleophiles with (+)-8- and (+)-9-bromocamphors have been studied. It has been demonstrated that these reactions offer an attractive route for chiral compounds with the rigid camphor skeleton possessing both soft diphenylphosphanyl and hydroxyl or carbonyl groups. The compounds could be used as ligands for asymmetric catalysts realizing a secondary interaction with substrates in the substrate-catalyst complex. Different synthetic strategies have been developed for 8- and 9-substituted camphor derivatives. Reactions of (+)-8-bromocamphor with some nucleophilic reagents give compounds having a 4-oxatricyclo[4.3.0.0 3,7 ]nonane skeleton. Analogously, reaction of 8,10-dibromocamphor with Ph 2 PLi can lead to a functionalized tricyclic diphosphine which is more attractive as a ligand for asymmetric catalysts than monophosphines. It is noteworthy, that the formation of the tricyclic structure prevents the known ring cleavage at the C(1)–C(2) bond of 10-bromosubstituted camphor derivatives.

Remarkably strong polarization of amidine fragment in the crystals of 1-imino-1H-isoindol-3-amine

Results of the X-ray diffraction studies of 1-imino-1H-isoindol-3-amine and its derivatives reveal unusual distribution of bond lengths within the NH2–C=N amidine fragment in the considered crystals. In the crystal phase, single C–N bond is shorter or at most has the same length as double C=N bond, while in isolated molecules both these bonds have expected lengths, according to the calculations by MP2/6-311G(d,p) and MP2/cc-pvtz methods. It is demonstrated that so unusually strong polarization of the amidine fragment is induced by polar environment in solid state. This effect stabilizes the amino-imino tautomer of 1-imino-1H-isoindol-3-amine, which becomes more stable than the diimino tautomer possessing the lowest energy in the gas phase.

Direct Phosphorylation of Benzothiazoles and 4-Methyltthiazole

Abstract Simple procedures for preparation of 2-(4-methylthiazolyl) dichlorophosphine and wide variety of 2-phosphorylated benzothiazoles are reported. Efficient promoters and catalysts were found for the key transformation, direct phosphorylation of the heterocyclic compounds by PCl3 (PBr3 as a promoter) or by P(V) acid chlorides (HgCl2 as a catalyst).

Selective catalytic hydrogenation in the presence of lanthanide tris-β-diketonates as protecting¨ reagents

Abstract The selectivity of > C tris -β-diketonates for unsaturated aldehydes and ketones possessing highly susceptible to reduction carbonyl group. It is a result of the selective co-ordination between the lanthanide complex added and the carbonyl group of a substrate. In most cases the complete protection of carbonyl groups is observed if the complex is added in equimolar amount to the substrate. A number of tris -β-diketonates have been tested; the complexes with flourinated ligands were demonstrated to ensure the highest selectivity of the hydrogenation. The correlation between the constants of equilibrium in reaction mixture and “protecting” activity of the complexes is discussed. A few examples demonstrate the practical utilization of the lanthanum tris -β-diketonates to the selective hydrogenation of unsaturated aldehydes and ketones.

A new approach to the selective alkylation of difunctional compounds

Abstract Alkylation of some diamines containing both tertiary and primary amino groups is described; it proceeds exclusively with less nucleophilic tertiary amino group when an appropriate lanthanide chelate is added to the reaction mixture. Under similar conditions the alkylation of 3-(tetrahydro-2-thienyl)-pyridine affects both of its nucleophilic centers. Plausible explanations of this fact is discussed. The effect of the presence of different lanthanide complexes upon difunctional compound alkylation has been investigated.

Synthesis of strained Bi- and tricyclic systems by rearrangements of some bromosubstituted camphor derivatives

Abstract Bromosubstituted camphor derivatives can be conveniently used to create some sterically congested bi- and tricyclic compounds by rearrangement reactions with nucleophilic reagents. The ease of these thermo-dynamically unfavorable reactions is explained by alignment of the migrating and breaking bonds within the rigid framework of camphor-derived skeleton.

Direct Phosphorylation of Thiazoles and Naphtothiazoles by Phosphorus(V) Acid Chlorides

Abstract Direct C(2)‐phosphorylation of 4,5,6,7‐tetrahydrobenzothiazole, isomeric naphtho[1,2‐d][1,3]‐ and naphtho[2,1‐d][1,3]thiazoles with HgCl2 as catalyst is reported. An analogous reaction of unsubstituted thiazole did not require catalyst.