Synthesis and properties of heterocyclic analogs of isoflavones

The condensation of cyanomethyl derivatives of furan and benzofuran with di- and trihydric phenols has given the corresponding 2,4-dihydroxy- and 2,4,6-trihydroxy--heterylacetophenones. The latter have been converted by reaction with acid anhydride, ethoxalyl chloride, and trifluoroacetic anhydride into 3-heterylchromones with methyl, trifluoromethyl, and ethoxycarbonyl groups in position 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1202–1208, September, 1973.     

Chemistry of heteroanalogs of isoflavones

Thiazole analogs of isomeric isoflavones were synthesized from -(2,4-dimethyl-5-thiazolyl)-2-hydroxyacetophenones, and their reaction with hydrazine hydrate and alkylating and acylating agents was studied. The reaction of thiazole derivatives of 7-hydroxychromone with hydrazine hydrate proceeds with opening of the pyrone ring and subsequent cyclization of the intermediate to o-hydroxyphenylpyrazole derivatives. The reaction of hydrazine hydrate with thiazole derivatives of 5-hydroxychromone, which proceeds with retention of the pyrone ring, leads to hydrazones. The structures of the new compounds were confirmed by the PMR spectra.See [1] for communication 6.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 25–28, January, 1979.     

Aluminium(III)-derivate zweiwertiger,dreizähnigerSchiffscher Basen

Several newSchiff base derivatives of aluminium have been synthesized by the reaction of aluminium isopropoxide with theSchiff bases having the donor system, O–N–O. The reactions in 11 and 23 molar ratios [Al(OPr ⁱ)₃:Schiff base] have yielded Al(OPr ⁱ)(SB) and Al₂(SB)₃ types of products [where SB^–- represents the anion of theSchiff base andSBH₂= (2-hydroxy-1-naphthylidene)-2-hydroxyethylamine, (2-hydroxy-1-naphthylidene)-3-hydroxy-1-propylamine, (2-hydroxy-1-naphthylidene)-1-hydroxy-sec.-butylamine and (o-hydroxyacetophenone)-3-hydroxy-1-propylimine, resp. In these resulting monoisopropoxy aluminiumSchiff base and dialuminium tris-Schiff base derivatives, the central aluminium atom appears to be penta-and tetracoordinated, resp., as indicated by their dimeric and monomeric states determined ebullioscopically. The infrared spectra of the resulting derivatives have also been recorded and tentative assignments have been made.     

Synthesis and Some Transformations of Derivatives of Pyrido[3,2-b]indole (δ-Carboline)

The reactions of 2-dimethyliminomethyl-3-(p-nitrophenyl)aminoindole chloride with compounds with an active methylene center have been studied. A series of derivatives of -carboline have been synthesized. By the reaction of 3-ethoxycarbonyl-2-methyl-1-p-nitrophenylpyrido[3,2-b]indolinium chloride with the diethyl acetal of DMF the corresponding 2-dimethylaminovinyl derivative was synthesized which was converted into 5-p-nitrophenyl-1-oxo-1,10-dihydropyrano[3',4':5,6]pyrido[3,2-b]indol-5-ium chloride in the presence of acid.     

Thiourea derivatives of β-dicarbonyl compounds

Under the action of polyphosphoric acid (PPA), N-2-aryl- and N-(2-methylindan-1, 3-dion-2-yl)thioureas are converted into isoindolo[2, 33,4]imidazole-2-thione derivatives (III), which can also by synthesized by cyclizing derivatives of 4-(o-carboxyphenyl)imidazole-2-thiones (II) by means of PPA or acetic anhydride. The interconversion of III and II under the action of alkalis and cyclizing agents has been shown. Their structures have been confirmed by IR and UV spectroscopy.     

Derivatives of 1-aryl-5-methoxyindoles

By fusion with potassium hydroxide, derivatives of 1-aryl-3-ethoxycarbonyl-5-methoxy-2-methylindole are converted into the corresponding indole-3-carboxylic acids. When the indole-3-carboxylic acids are heated to their melting points, they are readily converted into derivatives of 1-arylindoles with unsubstituted -positions. A similar cycle of conversions has been carried out for 3-ethoxycarbonyl-5-methoxy-2-methyl-1-phenylbenzoindole. The reactions of derivatives of 1-aryl-5-methoxy-2-methylindoles with formaldehyde and dimethylamine hydrochloride gives Mannich bases.     

Chemistry of heteroanalogs of isoflavones

3-Hetaryl-7-methoxychromones were obtained by reaction of -(5-ethoxycarbonyl-2-furyl)-, -(2-benzofuryl)-, and -(2-methoxy-carbonyl-5-benzofuryl)-2-hydroxy-4-methoxyacetophenones with methyl formate or ethyl orthoformate, and 3-hetaryl-4-hydroxy-7-methoxy-coumarins were obtained by reaction of the same compounds with diethyl carbonate. Methods for the synthesis of 3-hetaryl-7-hydroxy-chromones from -furyl- and -benzofuryl-substituted, 2,4-dihydroxyacetophenones were investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 174–179, February, 1975.     

Chemistry of heteroanalogs of isoflavones

It is shown that treatment of 3-hetarylchromones with alkalis and hydrazine hydrate leads to opening of the pyrone ring and subsequent conversion of the intermediate to -hetaryl-2-hydroxyacetophenones and 2-hydroxyphenylpyrazole derivatives.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1474–1476, November, 1976.     

Heterocyclic analogs of pleiadiene

N-substituted derivatives of perimidine and aceperimidine are readily aminated by sodium amide in position 2 with the formation of previously unknown 2-amino derivatives. Some other reactions taking place at the -carbon atom of perimidine have also been studied: direct hydroxylation with caustic potash, the ammonolysis of the 2-chloro derivatives, the action of alkalis on the quarternary salts, and the direct thiolation of the perimidines with sulfur, leading to 2-mercaptoperimidines.For Communication III, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1129–1132, August, 1970.     

A convenient and facile synthesis of pyridine,pyridazine, pyrimido‐[4,5‐c]pyridazine,pyrido[3,4‐c]pyridazine, 1,6‐naphthyridine and phthalazine derivatives

Ethyl 2‐arylhydrazono‐3‐butyrates 2 reacted with 2‐cyano‐N‐(4‐methylphenyl) acetamide 1a and 2‐cyano‐N‐(thiazol‐2‐yl)acetamide 1b to give the pyridinedione, 4 and pyridazine 5 derivatives in 3:1 ratio. The products 4 and 5 have been transformed into different phthalazine, pyrimido[4,5‐c]‐pyridazine, pyrido[3,4‐c]pyridazine and 1,6‐naphthyridine derivatives. The chemical structures have been confirmed by analytical and spectral analysis.     

Free-energy correlation for catalysis of outer sphere electron-transfer reactions by noncoordinated pyridine derivatives

Recent experimental data concerning the rate constants and their free energy of the outer sphere electron-transfer reactions, as catalyzed by noncoordinated pyridine derivatives in aqueous solution, are examined for possible correlation. For the electron transfer reactions between V or Eu and the bipyridyl derivatives, such as N,N'-dimethyl-4,4′-bipyridyl (paraquat) or diquat, the data are correlated quite well by the Marcus equation. The electron exchange rate constant, 5 × 10⁷M^?1·s^?1, for an organic radical ion and its parent molecule obtained from semiquinones or their related compounds can be applied to these pyridine derivatives. However, in some cases such as electron transfer from paraquat or diquat cation radical to Co(en), positive departures from the Marcus model are observed. These positive departures are interpreted in terms of interaction between the molecular orbitals of electron donors and electron acceptors in the transition state.     

2-Amino-4-[2-(5-nitro-furyl)vinyl]thiazole and its derivatives

The reactions of 4-bromo-1-(5-nitro-2-furyl)but-1-en-3-one and its 2-methyl and 2-chloro derivatives with thiourea and its N-allyl and N-phenyl derivatives have yielded 2-amino-4-[-5-nitro-2-furyl)-vinyl]thiazole and its - and N-substituted derivatives. 2-Amino-4-[-(5-nitro-2-furyl)vinyl]thiazole and its -methyl derivative have also been prepared by the direct reaction of the corresponding , -unsaturated ketones with bromine and an excess of thiourea in chloroform, as was shown by a comparison of UV spectra. A series of N-acyl derivatives of the aminothiazoles has been obtained. UV and IR spectra are given.     

Reactions of the OH adducts of cytosine and its derivatives with TEMPO and TEMPOL: A steady state γ-radiolysis and pulse radiolysis study

The reactions of the OH adducts of cytosine and its derivatives with nitroxides namely TEMPO and TEMPOL have been followed by steady state -radiolysis and pulse radiolysis. Pulse radiolysis studies show that the transient OH adducts of cytosine and its derivatives react with TEMPO and TEMPOL by electron transfer reaction and not by adduct formation as was observed in the case of thymine. The second order rate constants for these electron transfer reactions are of the order of 10⁷ - 10⁸ dm³ mol^-1 s^-1.     

Reactions of 1,3,3,3-tetrafluoro-2-methoxycarbonylpropenesulfenyl chloride with enamines

1,3,3,3-Tetrafluoro-2-methoxycarbonylpropenesulfenyl chloride readily reacts with enamines (derivatives of -oxo acids) to give sulfenylation products. The reactions with N-aryl-substituted enamines are accompanied by cyclization to form N-aryl-2-(2,2,2-trifluoro-1-methoxycarbonylethylidene)-2,3-dihydrothiazoles.     

Some reactions of 2-chloro-3-(β-chloroethyl)-4,6-dihydroxypyridine

The chemical properties of 2-chloro-3-(-chloroethyl)-4,6-dihydroxypyridine (I) have been studied. It has been shown that this compound, which is relatively stable in acids and in neutral and, particularly, in alkaline media, readily splits off hydrogen chloride under mild conditions and is converted into derivatives of 2, 3-dihydro-5-azabenzofuran. The dehalogenation of I in an acid medium yielded 3-(-chloroethyl)-4, 6-dihydroxypyridine, which was converted into 4, 6-dichloro-3-(-chloroethyl)pyridine and into 6-chloro-4-methoxy-3-vinylpyridine.     

Azomethine derivatives of aluminium containing AlOSiMe3 groups

The synthesis of azomethine derivatives of aluminium containing AlOSiMe₃ groups and resistant to hydrolysis is described. These have been prepared either by the equimolar reactions of bibasic tridentate or bibasic tetradentate azomethines, viz. N-(2- mercaptoethyl) salicylaldimine, N-(2-mercaptophenyl) salicylaldimine, salicylaldehyde sulphisoxazole, salicylaldehyde azine, salicylaldehyde semicarbazone, salicylaldehyde thiosemicarbazone, o-hydroxyacetophenone azine N,N' 1,3-propylene-bis(salicylaldimine) and diacetyl bis(2-mercaptoanil), or of 1 : 2 molar reactions of monobasic bidentate imines viz. N-(2-mercaptophenyl) benzaldimine, benzaldehyde semicarbazone and benzaldehyde thiosemicarbazone with Me₃SiOAl(OPrⁱ)₂ in the medium of dry benzene. The resulting derivatives are coloured solids with sharp m.ps, non-volatile, non-electrolytes, soluble in chloroform, dimethylformamide and dimethylsulphoxide, and monomeric in nature. Their IR,¹H NMR and electronic spectral data have been presented in support of the proposed structures.     

Chemistry of heteroanalogs of isoflavones

Pyrazole analogs of isoflavones were synthesized from substituted -(4-pyrazolyl)-2,4-dihydroxyacetophenones.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1108–1111, August, 1976.     

The band structure of porphyrinatonickel(II). A semiempirical crystal orbital study based on the tight-binding formalism

The band structure of porphyrinatonickel(II) ( 2 ) has been studied by means of crystal orbital calculations that are based on the tight-binding approximation; the computational framework is a recently developed INDO model for transition metal compounds of the 3d series. The porphyrinato polymer has been studied in an eclipsed arrangement ( 2a ) and in a staggered conformation ( 2b ) where neighboring layers are rotated by 41°. The total energy of the metallomacrocycle has been decomposed into one- and two-center contributions; the latter interaction parameters have been fragmented into physically feasible resonance, exchange, and classical electrostatic (electron–electron, electron–core, core–core) interactions. It is shown that individual two-center potentials between atoms in neighboring layers are prevailingly determined by the electrostatic interaction energy. The NiNi coupling in the chain is highly repulsive; important stabilizing interactions are predicted between the 3d center of one cell and the electronegative N atoms in the neighboring layers. Stabilizing and destabilizing electrostatic interaction potentials largely compensate each other; the net stabilization in the polymer comes from the accumulation of resonance and exchange increments. The unoxidized Ni(II) porphyrinato polymer is an insulator. Several ligand bands (π, σ, and lone-pair) are predicted on top of bands with significant Ni 3d admixtures; the conduction band of the unoxidized strand is of ligand π* character. The dense manifold of ligand states in the vicinity of the Ni 3d states (3d, 3d, 3d_xz/3d_yz) prevents the formation of bands in the polymer that are strongly localized at the 3d center. Ni 3d and 3d interact strongly with ligand lone-pair and σ states. Avoided crossings between ?(k) curves in k space lead to compositions in the various bands that differ significantly at the bottom and the top. The INDO crystal orbital formalism predicts a partial oxidation of ligand bands in derivatives of 2 that contain oxidants (e.g., halides). The theoretical findings derived for 2 are compared with available experimental data on highly conducting porphyrinatonicke(II) polymers (tetrabenzo and octamethyltetrabenzo derivatives of 2 ).     

Effect of substituents in the gas-phase elimination kinetics of β-substituted ethyl acetates

The kinetics of gas-phase elimination of 3-methyl-1-butyl acetate and 3,3-dimethyl-1-butyl acetate into acetic acid and the corresponding substituted butenes have been measured over the temperature range of 360–420°C and the pressure range of 63–250 Torr. The reactions are homogeneous in both clean and seasoned vessels, obey first-order law, and are unimolecular. The temperature dependence of the rate constants is given by the Arrhenius equation 3-methyl-1-butyl acetate: 3,3-dimethyl-1-butyl acetate: The points in a plot of log (k/k₀) of β-alkyl and several β-substituted ethyl acetates against E_s values appear aligned in an approximate linear relationship. These results may be interpreted as a consequence of steric effects, namely, steric accelerations.     

Investigation of the influence of a sulfur atom on the mobility of the hydrogen atoms in a methylene group of some heterocyclic compounds

The action of dicyclohexylcaibodiimide on 2-benzimidazolylthioacetic,-(2-benzimidazolylthio)propionic,-(2-benzimidazolyl)propionic and 2-benzimidazolylacetic acids has given the anhydro derivatives of these acids. It has been shown that the hydrogen atoms in the methylene group of anhydro-2-benzimidazolylthioacetic acid have the highest mobility.