Synthesis of isoquinoline alkaloid derivatives from eugenol

Alkylation under phase-transfer catalysis conditions (18-crown-6/KOH) of eugenol was used for cyclocondensation with nitriles (Ritter reaction), the products of which were isoquinoline derivatives.     

Mosaic approximations of discrete analogs of Calderón-Zygmund operators

Asymptotic estimates of the form mrA = O(InN · ln ^d ɛ ⁻¹), whered is the dimension of the initial space, for mosaic ranks of discrete analog of Calderón-Zygmund operators are obtained for various mosaic covers. Translated fromMatematicheskie Zametki, Vol. 63, No. 1, pp. 81–94, January, 1998.     

Bearing-error spectra of low-altitude source moving over irregular surface

The interference produced by radio-wave reflection from a statistically irregular interface is studied. Formulas for the bearing-error correlation functions and spectra are derived by the Kirchhoff method for a source moving over a diffusely scattering surface. Asymptotic formulas and inequalities are derived for the low-altitude case. Shadowing is taken into account. Comparison with experimental data provides satisfactory agreement.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, Nos. 3, 4, pp. 264–274, March–April, 1992.     

Magnetorotational instability in nonmagnetized plasma

It is shown that the magnetorotational instability (MRI) can be driven in nonmagnetized plasma. In this case, in contrast to the case of strongly magnetized plasma, radial derivative of plasma rotation frequency should be positive for such a driving. The characteristic wave lengths of MRI in nonmagnetized plasma are of the same order of magnitude as those for the Weibel instability.     

Estimates of the influence of the transverse strain in a contact problem with free boundary

We use the contact problem with free boundary for a “heavy cylindrical shell-over-support reinforcement ring” system as an example to study the influence of transverse shear on the stress state in the shell. To obtain the equilibrium equations for the shell and the reinforcement ring, we apply an express algorithm developed by one of the authors to take into account transverse strains in Kirchhoff versions of the theory of shells. The contact problem with free boundary is solved by the generalized reaction method proposed earlier. We use numerical examples to show that the corrections introduced in the stress state by taking into account the transverse shears are by an order of magnitude larger than the traditional estimate of errors in the Kirchhoff hypotheses.     

Synthesis of 2,2-dimethyl-1,2-dihydrobenzo[<Emphasis Type="Italic">f</Emphasis>]-isoquinolines displaying antifungal activity

The reaction of 2,2-dimethyl-1,2-dihydrobenzo[f]isoquinoline with malonic acid gave (2,2-dimethyl-1,2,3,4-tetrahydrobenzo[f]isoquinolin-4-yl)acetic acid, the acid chloride of which readily forms esters with alcohols and phenols. Reaction of the same azomethine with thioglycolic acid leads to (2,2-di-methyl-1,2,3,4-tetrahydro-benzo[f]isoquinolin-4-yl)thioacetic acid. Activation of the initial azomethine by iodomethylation enables reaction with 1,3-indanedione to be carried out. The obtained substances display antifungal action.     

Reaction of pyrrolo[2,1-a]isoquinoline-2,3-diones with carbon-centered nucleophiles

Knoevenagel condensations of 5,5-dimethyl-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-diones with malononitrile, ethyl cyanoacetate, indan-1,3-dione, and Drotaverine base involved the ketone carbonyl group in the former with formation of deeply colored dark blue substances. The lactam ring in the products can be opened by the action of nitrogen-centered nucleophiles, e.g., p-toluidine. The reaction of 5,5-dimethyl-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione with methyl magnesium iodide gave 2-hydroxy-2,5,5-trimethyl-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinolin-3-one.