Synthesis and properties of 4,6-diamino-3-cyano-2(1H)-pyridineselenone: Molecular and crystal structure of 2-allylseleno-4,6-diamino-3-cyanopyridine

Self-condensation of cyanoselenoacetamide gives 4,6-diamino-3-cyano-2(1H)pyridineselenone, which is regioselectively alkylated at the exocyclic heteroatom. The cisoid position of the Se-C bonds of the selenoallyl substituent relative to the N-C bond of the pyridine ring in the N¹C²SeC⁸ fragment favors cyclization into selenazolo[3,2-a]pyridinium salts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2585–2590, November, 1989.     

Stereochemistry of electrophilic annelation of 2-allyl- (and 2-cyclohexen-1-yl)thio-1,5-naphthyridines to thiazolo]3,2-a]-1,5-naphthyridinium salts

Methods have been developed for the synthesis of 3-cyano-5,8-ethano-5,6,7,8-tetrahydro-1,5-naphthyridine-2(1H)-thione and 2-allyl- (and 2-cyclohexen-1-yl)thio-1,5-naphthyridines, and their structures have been studied. X-ray diffraction examination has shown that these compounds contain a disordered contact between the free electron pair of the pyridine nitrogen and the -bond of the allyl grouping, so that they react stereoselectively with halogens to give thiazolo[3,2-a]-1,5-naphthyridinium salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 557–563, April, 1989.     

Synthesis and structure of the heterotrinuclear chromium-palladium clusters (RC5H4CrCl)2-(μ3S)(μ-SCMe3)2Pd(PPh3) with ferromagnetic exchange interactions over the CrSCr system

Reactions of (RC₅H₄)₂Cr₂(SCMe₃)₂S(I, R = H; II, R = Me) with (PPh₃)₂PdCl₂ in benzene at 20°C gives trinuclear complexes (RC₅H₄)₂Cr₂Cl₂(μ₃-S)(μ-SCMe₃)₂Pd(PPh₃)(III, R = H; IV, R = Me). The structure of IV as a monobenzene solvate is established by an X-ray analysis (black-green triclinic crystals space group P$\text{1}$ with a = 11.403(4), b = 14.933(5), c = 14.131(5) Å, α = 99.13(3), β = 112.72(3), γ = 95.65(3)°, V = 2201.6 Å, Z = 2; IV·C₆H₆). The structure was solved by direct methods and refined in an anisotropic approximation to R = 0.046, R_w = 0.058 for 7643 reflections with I ? 2σ(I). In the molecule of IV metal atoms are separated by non-bonding distances (Cr … Cr 4.079(I), Cr … Pd 3.230(I) and 3.380(I) Å) but linked by the bridging tridentate sulphur atom (CrS 2.339(2) and 2.329(2), PdS 2.327(2) Å), and two SCMe₃ groups between Pd and Cr (CrS 2.396(2) and 2.403(2), PdS 2.350(2) and 2.381(2) Å, Cr?Pd 85.14(6) and 89.92(6)°). The Cl atoms are transferred from Pd to Cr atoms (CrCl 2.308(2) Å) and being terminally coordinated are in trans-positions to each other (as well as η-CH₃C₅H₄ rings) with respect to the Cr₂Pd plane. Cr atoms in III and IV exhibit ferromagnetic exchange interactions over the Cr?Cr system (+2J = 28 and 11 cm^?1, respectively).     

Cyclization reactions of nitriles. 50. Regioselectivity in the reactions of quaternized pyridin-3-ylidene malonitrile and cyanoacetate ester derivatives with 1,3-dicarbonyl compounds. Crystal structure of 2-amino-3,5-dicarboethoxy-6-methyl-4-(1-methylpyridinium-3-yl)-4H-pyran iodide

The reaction of quaternized pyridin-3-ylidene malonitrile and cyanoacetate ester derivatives with 1,3-dicarbonyl compounds proceeds highly regioselectively to give substituted 2-amino-4-(1-methylpyridinium-3-yl)-4H-pyran iodides. The structure of 2-amino-3,5-dicarboethoxy-6-methyl-4-(1-methylpyridinium-3-yl)-4H-pyran iodide has been investigated by x-ray structural analysis.See [1] for communication No. 49.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 205–211, February, 1991.