Nature of π-Electronic Transitions in UV Spectra of Deoxyvasicinone and Its Derivatives

The principal types of electronic transitions in absorption spectra of deoxyvasicinone and its 6-amino- and 6-nitro-derivatives were determined by analyzing the electron-density distributions in excited states calculated using ZINDO/S.     

Crystal and Molecular Structure of <Emphasis Type="Italic">Bis</Emphasis>(2,3-pentamethylene-3,4-dihydro-4-oxoquinazolinium) Tetrachlorocuprate(II) Sesquihydrate

The structure of bis-(2,3-pentamethylene-3,4-dihydro-4-oxoquinazolinium) tetrachlorocuprate (II) sesquihydrate, (C₁₃H₁₅N₂O)₂[CuCl₄]·1.5H₂O, was determined by single crystal X-ray diffraction. In contrast to the previously studied analogs, the compound contains crystallization water molecules.Original Russian Text Copyright © 2004 by K. K. Turgunov, B. Tashkhodzhaev, L. V. Molchanov, and Kh. M. Shakhidoyatov__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 955–959, September–October, 2004.     

Conformations, Energy and Spectral Characteristics of 2,3-Trimethylene- and 2,3-Pentamethylene-3,4-dihydro-4-quinazolinones

Quantum-chemical calculations and IR spectroscopy were used to study the conformations as well as the energy and spectral characteristics of 2,3-trimethylene- and 2,3-pentamethylene-3,4-dihydro-4-quinazolinones. The shift of -electron density from the heterocyclic system to the carbonyl group and, thus, the proton affinity of the oxygen atom of this group increase with expansion of the bond angle at the nitrogen atom in going from a five-membered to seven-membered ring.     

Structures of deoxypeganine salts

The structures of deoxypeganine (DOP) hydrochloride and oxalate were solved by x-ray structure analysis. An infinite chain along the crystallographic c axis was formed in the crystal structure of DOP oxalate. A molecular framework consisting of Cl anions and DOP cation protonated at N1 was found in the structure of unhydrated DOP hydrochloride. The molecular packing of the “host” (DOP cation) was pseudoisostructural in the studied ion-molecular crystals but differed from other known DOP salts. The “guest” molecules (acid anions) in the studied and known DOP salts formed different intermolecular contacts. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 280–283, May–June, 2006.     

Synthesis,methylation, and acylation of 1,2-dihydrodeoxyvasicinones and their homologs

2,3-Trimethylene- and 2,3-pentamethylene-1,2,3,4-tetrahydro-4-quinazolones and their 6-methyl and 6-bromo derivatives have been obtained by the reduction of deoxyvasicinone and its 6-methyl and 6-bromo derivatives and also their seven-membered homologs at the cycloalkane ring with sodium tetrahydroborate in ethanol. The alkylation and acylation reactions of the above-mentioned reducing compounds have been studied. Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 659–663, September–October, 1990.     

Composition and inhibiting action of a fraction of secondary metabolites from cotton plant leaves

The qualitative and quantitive compositions of fractions from the leaves of two self-pinching-out lines of cotton plant and of the standard variety 108-F have been determined in parallel by mass chromatography, and differences in their contents of the main metabolites have been determined. A fraction of the secondary metabolites (SMs) obtained from mature leaves of a cotton plant of the self-pinching-out line L-49 has shown a retardant activity in treatment of the growth points of plants of the Tashkent-1 variety. Deceased.     

Synthesis, tautomeric states and crystal structure of (Z)-ethyl 2-cyano-2-(3H-quinazoline-4-ylidene) acetate and (Z)-ethyl 2-cyano-2-(2-methyl-3H-quinazoline-4-ylidene) acetate

The new compounds (Z)-ethyl 2-cyano-2-(3H- and 2-methyl-3H-quinazoline-4-ylidene) acetate (1 and 2, respectively) were synthesized by multi-step reactions. The structures in a solution have been determined by (1)H-NMR spectroscopy and in the crystal form by X-ray analysis. Molecule 1 crystallized in a primitive monoclinic cell, space group capital ER, P2(1/c). The cell dimensions are a=7.970(6) A, b=7.061(2) A, c=20.537(7) A, beta=97.69(5) degrees , V=1145.3(10) A(3). Molecule 2 crystallized in a triclinic cell, space group P-1, the cell dimensions are a=8.196(5) A, b=8.997(6) A, c=9.435(4) A, alpha=74.22(4) degrees, beta=89.75(4) degrees , gamma=74.07(5) degrees , V=641.9(6) A(3). In both compounds the presence of intra-molecular NH---O=C hydrogen bonding between the nitrogen atom in position 3 of the quinazoline ring and a carbonyl group of the ethyl cyanoacetate residue was proven by quantum-chemical, (1)H-NMR and X-ray methods.     

Mass spectra of 2,3-polymethylene-3,4-dihydroquinazolin-4-ones with substituents at C9

Summary The main fragments in the mass spectra of the 2,3-polymethylene-3,4-dihydroquinazolin-4-one with six- and seven-membered alicyclic rings are formed by the decomposition of ring C through the stage of the cleavage of the C₉-C₁₀ bond, while the compound with a five-membered ring ejects a hydrogen atom.A hydroxy group at C₉ initiates the appearance of fragments due to the initial cleavage of the C₂-C₉ bond. In the spectra of the halogen and acetoxy derivatives the fragmentation of the alicyclic ring is suppressed and the main fragmentation pathway is the splitting out of the substituent. The hypothesis of the protonation of the N₁ nitrogen atom has been adopted to explain the stability of a number of the ions.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 180–187, March–April, 1979.     

Synthesis of 2-alkylthioquinazol-4-ones

Alkylation of 2-thioxoquinazol-4-one by different alkylating agents was studied, and it was found that the reaction proceeds at the exocyclic sulfur atom with the formation of 2-alkylthioquinazol-4-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 254–256, February, 1987.