Phenylmercury derivatives of aminomethylene- and hydroxymethylene-substituted 1-methyloxindoles, 1-indanones,and 1,3-indanediones

A number of phenylmercury derivatives of 3-hydroxymethylene- and 3-aminomethylene-substituted 1-methyloxindoles, 1-indanones, and 1,3-indanediones were synthesized. It is shown that the preferred tautomeric structures of the potentially metallotropic and prototropic hydroxymethylene keto (hydroxy vinyl aldehyde) derivatives of the indicated compounds and 3-hydroxybenzo[b]-2-formylthiophene coincide precisely. An aminomethylene structure with an N-H bond is realized for the phenylmercury derivatives of the corresponding azomethines in all cases.Communication 28 from the series Benzenoid-Quinoid Tautomerism of Azomethines and Their Structural Analogs. See [1] for communication 27.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 65–68, January, 1979.     

Local doses associated with119mSn isomeric transition

The energy absorbed by immediate surrounding of disintegrating^119mSn nuclei have been estimated by comparing the Mössbauer emission spectra of¹¹⁹Sn in some tin compounds with the absorption spectra of the same substances after -irradiation and by simple calculations of Auger electrons energy losses. The results obtained indicate that the observed post-effects of the^119mSn decay are due to self-radiolysis and other processes, whose contributions depend on the individual properties of the matrices.     

Extended average energy perturbation calculation of the 2s2 and 2p21S resonance state energies of two-electron atoms

An extended average energy (EAE) calculation of the 2s² and 2p²¹S resonance state energies of two-electron atoms is carried out. We take the bare-nucleus hamiltonian as the initial approximation and treat the zeroth-order degeneracy by van Vleck perturbation theory, For both H^? and He the lower state energies agree quite well with experiment while the upper state is about 1–2 eV too high. Our remits for He are comparable in accuracy to those obtained by the 1/Z Hartree—Fock perturbation method. A brief concluding discussion of ways to improve the simple EAE technique is presented.     

Influence of mobility of medium on dynamics of metallotropy in tin-containing 2-R-oxyphenoxyls

The rate of intramolecular migration of the triphenylstannyl group in 3,6-ditert-butyl-2(triphenylstannyl) oxyphenoxyl decreases with increasing viscosity of the medium. A linear relationship _ex=·_c is observed between the characteristic time of stannotropy _ex and the correlation time for reorientational motions of the radical _c within a range of temperature variation no greater than 30°C. The parameter depends on the medium; this is explained by the possibility of complexation of the radical with the solvent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 781–786, April, 1990.     

Gibberellin metabolites from ent-kaura-2,16-dien-19-ol and its succinate in Gibberella fujikuroi

Exposure of ent-kaura-2,16-dien-19-ol (1) or its succinate (2) to resuspended mycelia of G. fujikuroi has produced a complex mixture of acids which after methylation gave the esters of two C₁₉ (24) and (30) and five C₂₀ gibberellins (4, 11, 20, 32 and 33). The triester (32) and the lactone ester (24) have been prepared before from the esters of gibberellin A₁₃ (8) and gibberellin A₄ (26) respectively. The structures of the other metabolites were assigned on spectroscopic data and by chemical transformations. Thus the lactone diester (4) has been converted to the known keto triester (6). The epoxide (11) has been related to gibberellin A₁₄ (14) and the aldehyde (33) has been related to gibberellin A₁₃ trimethyl ester (8) by way of the triol (34). Selective de-epoxidation of the 16,17-epoxy function in diepoxides has provided a route from the dienes (20 and 24) to the epoxides (11 and 30) respectively, but not from the ester of gibberellin A₅ (23) to that of gibberellin A₆ (29). On the other hand the latter can be obtained by epoxidation of gibberellin A₅ methyl ester trifluoroacetate. Backfeeding experiments carried out with the epoxy diacid (12), the diene diacid (21) and the derived diol (39) indicate pathways connecting the various metabolites. The natural gibberellins A₅ and A₆ were shown to be formed in some of the backfeeding experiments.     

Determination of the position of the acyl groups and the nature of some amino alcohols in native ester alkaloids of the genusVeratrum

Conclusions 1. On the basis of literature data on the structure of theVeratrum alkaloids, a definite law for the arrangement of the acyl radicals in these ester alkaloids and an interrelationship between the melting point and the structure of the substituent in the C₇ position, and between the melting point and the types of amino alcohols upon which the ester alkaloids are based, has been found.2. The features mentioned may be used in studying the structure of theVeratrum ester alkaloids according to a scheme which we propose.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 4, pp. 440–443, 1970     

Retention of85Sr and147Pm on insoluble hydroxides and phosphates prepared by the sol-gel procedure

Retention of strontium and promethium on hydroxides (hydrated oxides) and phosphates of iron and chromium prepared by the sol-gel method was studied. The sorption was determined under static conditions depending on the pH of the solution. The sorption isotherms and retention were investigated under dynamic conditions.     

Enantioselective reduction of ketophosphonates using chiral acid adducts with sodium borohydride

A method for asymmetric reduction of α-and β-ketophosphonates using a chiral complex prepared from sodium borohydride and D-or L-tartaric acid is developed. Reduction of α-or β-ketophosphonates by these reagents led to formation of corresponding (S)-or (R)-hydroxyphosphonates. Reduction of chiral di(1R,2S,5R)-menthylketophosphonates by the chiral complex NaBH₄/(R,R)-tartaric acid due to the dual compliant asymmetric induction resulted in increased stereoselectivity of the reaction and led to formation of the hydroxyphosphonates with ee 90% or higher. On the other hand, reduction of di(1R,2S,5R)-methylketophosphonates by the chiral complex NaBH₄/(S,S)-tartaric acid proceeded as non-compliant dual asymmetric induction and resulted in decreased reaction stereoselectivity leading to formation of hydroxyphosphonates with ～45–60% ee. The developed methodology was applied to the synthesis of (R)-phosphocarnitine in multigram amounts.