Search for physiologically active compounds

α-Methyldihydrofurano,γ andα-pyrono ring systems have been built on 7, 8-position of 2-(2-furyl)-3-methyl chromone. The structure-activity relationship among 2-(2-furyl)-chromones is discussed.     

Kinetics of reaction of benzyl halides with amines in mixed solvents

The reactions of benzyl chloride,p-methyl benzyl chloride,p-chloro benzyl chloride, benzyl bromide andp-nitro benzyl bromide with aromatic and heterocyclic bases have been studied in carbon tetrachloride-phenol mixtures. The reactions of amines and pyridine with benzylchloride andp-methyl benzyl chloride have been extended to solvent mixtures like benzene-phenol, nitrobenzene-phenol, nitro-benzene-ethanol and carbontetrachloride-ethanol mixtures and those of amines and pyridine with benzyl bromide andp-nitrobenzyl-bromide have been extended to DMF-phenol mixtures. The results are discussed in the light of basicity, nucleophilicity, electronic, steric and medium effects.     

Synthesis of some chromono (6, 7) oxazoles and their physiological activity

The synthesis of a few chromono (6, 7) oxazoles has been carried out by condensing 6-amino-8-bromo-7-hydroxy-2-methyl chromone with various aromatic aldehydes in nitrobenzene medium. The ultraviolet and infrared spectral characteristics of these compounds have been described. A study of antibacterial and antifungal activities of these compounds has revealed that 2-m-hydroxyphenyl-7-methyl-9-bromo-chromono (6, 7) oxazole and 2-p-Anisyl-7-methyl-9-bromo-chromono (6, 7) oxazole possess antifungal activity.     

Proton magnetic resonance studies of the association of amino methyl pyridines

Proton magnetic resonance studies of the solutions of (a) 2-amino, 3-methyl pyridine and (b) 2-amino, 6-methyl pyridine in carbontetrachloride show that in these molecules there is an equilibrium between monomers and hydrogen-bonded dimers. The equilibrium constants for the two cases have been obtained. Evidence has also been obtained to show that chloroform forms hydrogen bond with the ring nitrogen of these compounds. These NMR results have been compared with those obtained earlier from infra-red studies.     

Every 4k-edge-connected graph is Weakly 3k-linked

We prove:

1. Fork ≥ 2 andα = 0, 1, every (4k + 2α)-edge-connected graph is weakly (3k + 2α)-linked.
2. IfG is ak-edge-connected graph (k ≥ 2),s, t are vertices andf is an edge, then there exists a pathP betweens andt such thatf ? E(P) andG ? E(P) ? f is (k ? 2)-edge-connected, whereE(P) denotes the edge set ofP.

     

Infrared absorption spectra of ethyl,n-propyl andn-butyl stearates

X-ray K-line intensity ratiosα ₂/α ₁,β ₃/β ₁ andβ ₂ ^II /β ₂ ^I have been calculated following the method due to Payne which accounts for the retardations. In addition screening has been included. It is found thatα-line intensity ratios are given best by Sommerfeld screening but that Slater screening is better for theβ-lines. Field theoretically corrected energies have also been used and it is found that the agreement is less favourable. The necessity of including the potentials corresponding to these effects as perturbations to the wavefunctions has been pointed out.     

Homogeneous hydrogenations ofα, β-unsaturated compounds using pentacyanocobaltate (II) anion as catalyst system

Hydrogenation of someα, β-unsaturated carbonyl compounds using potassium pentacyanocobaltate (II), K₃Co(CN)₅, as a homogeneous catalyst has been investigated. Thus, hydrogenation of 1-carvone (I), mesityl oxide (4), 2-cyclohexenone (8) and benzalacetone (6) afforded the corresponding dihydrocompounds. Hydrogenation ofβ-ionone (10) afforded a mixture of theα, β-dihydrocompounds (14) and (15). In all these cases, it was observed that the reaction proceeded to completion only in the presence of added base. Hydrogenation of 5α-androst-l-en-17β-ol-3-one acetate (19) afforded the saturated compound, 5α-androst-17β-ol-3-one (20) in 60% yield. It was found that other steroid enones and dienones were not reduced by this catalyst system.     

The rational approximation of convex functions of the class Lip α

It is proved that if a function f(x) is convex on [a, b] and f ∈ Lip_K(f)α, 0<α<1, then the least uniform deviation of this function from rational functions of degree not higher than n does not exceed (v is a natural number; C(α, v) depends only onα andv; K(f) is a Lipschitz constant; and      

The vibrational and electronic spectra of 5-methyl pyrimidine and 4-methyl pyrimidine

The infrared and Raman spectra of 5-methyl pyrimidine and the infrared spectrum of 4-methyl pyrimidine have been examined and vibrational assignments are given for the ground electronic states. The ultra-violet absorption spectra of these molecules corresponding to π* ←n electronic excitation have been studied and vibrational assignments are given for most of the observed bands.     

Homoclinic points and isomorphism rigidity of algebraic ℤ<Superscript><Emphasis Type="Italic">d</Emphasis></Superscript>-actions on zero-dimensional compact abelian groups

Letd>1, and letα andβ be mixing ? ^d -actions by automorphisms of zero-dimensional compact abelian groupsX andY, respectively. By analyzing the homoclinic groups of certain sub-actions ofα andβ we prove that, if the restriction ofα to some subgroup Γ ? ? ^d of infinite index is expansive and has completely positive entropy, then every measurable factor mapφ: (X, α)→(Y, β) is almost everywhere equal to an affine map. The hypotheses of this result are automatically satisfied if the actionα contains an expansive automorphismα ⁿ ,n ∈ ? ^d , or ifα arises from a nonzero prime ideal in the ring of Laurent polynomials ind variables with coefficients in a finite prime field. Both these corollaries generalize the main theorem in [9]. In several examples we show that this kind of isomorphism rigidity breaks down if our hypotheses are weakened.     

On right congruences associated with the input semigroupS of automata

LetA=(M, S, δ) be an automaton without outputs whereM is a nonemptyset andS is a nonempty semigroup. Then the right congruences μM and μ _m associated withS have been expressed in many different ways (μ _M is called the Myhill-Nerode congruence onS). Also, their algebraic properties have been investigated. We have introduced the right congruences μ _S and μ_α onM and we have obtained necessary and sufficient conditions thatS/μ andM/w have nontrivialS-homomorphisms where μ andw are any right congruences onS andM respectively. The faithfulness ofS has been introduced.     

Heats of combustion of some symmetrical dialkyl ureas and their corresponding alkyl carbamates

The standard heats of combustion of the disubstituted ureas, N, N′-diheptyl urea, N, N′-dioctyl urea and N, N′-didecyl urea and the carbamates,n-heptyl ammoniumn-heptyl carbamate,n-octylammoniumn-octyl carbamate andn-decyl ammoniumn-decyl carbamate have been determined. The values found are 2353±1·3, 2658·4±1·1, 3268·5±1·7, 2349·8±1·6, 2654·4±1·2, 3264·6±1·8, K.cals. mole^?1 respectively. The heats of formation of these compounds have been calculated.     

X-ray spectroscopic study of chemical bonding in MnSe2 and CoSe2

X-ray absorption study of two intermetallic compounds MnSe₂ and CoSe₂ has been carried out using a Cauchois type bent crystal spectrograph. The metal K absorption edges in both the compounds are found to shift toward the high energy side with respect to the discontinuities in the pure metals. On the other hand, the Se K absorption edge in both these compounds is found to shift toward the lower energies. Emission study of the compound MnSe₂ has shown that the Mn Kβ ₅ band in this compound is shifted toward the high energy side with respect to that in the pure metal. From the magnetic data and the results obtained in this work it is possible to obtain the chemical bonding pictures in these compounds. For MnSe₂ the bondings sp ³ d ² for the metal atom andsp ³ for the metalloid atom have been suggested. For CoSe₂ the bondings appear to bed ² sp ³ for the metal atom andsp ³ for the metalloid atom. These bondings are compatible with the pyrite type structure of these compounds. It is possible to explain the electrical behaviour of the compounds on the basis of these bonding pictures.     

Generalized prolate spheroidal wave functions

The following equation $$(1 - x^2 )d^2 y/dx^2 + [(\beta - \alpha - (\alpha + \beta + 2)x]dy/dx + (\chi (c) - c^2 x^2 )y = 0$$ has been solved wherex(c) a separation constant is the characteristic value and is a function ofc. This solution is a generalization of spheroidal wave function into the series form ofP _n ^α;β (x),α andβ both separately are greater than ?1. The finite transform and its properties have been defined and a boundary value problem has been solved applying these tools.     

Arithmetical progressions formed byk different Lehmer pseudoprimes

LetU _n=(αⁿ-β²)/(α-β) forn odd andU _n=(αⁿ-βⁿ)/(α²-β²) for evenn, where α and β are distinct roots of the trinomialf(z)=z ²-√Lz+Q andL>0 andQ are rational integers.U _n is then-th Lehmer number connected withf(z). A compositen is a Lehmer pseudoprime for the bases α and β ifU _n??(n)≡0 (modn), where?(n)=(LD/n) is the Jacobi symbol. IfD=L?4Q>0, U _n denotesn-th Lehmer number,p>3 and 2p?1 are primes,p(2p-1)+(α²-β²)², (α^2p-1±β^2p-1)/(α±β) are composite then the numbers (α^2p-1+β^2p-1)/(α+β), (α^2p-β^2p)/(α²-β²), (α^2p-1-β^2p-1)/(α-β) are lehmer pseudoprimes for the bases α and β and form an arithmetical progression. IfD>0 then from hypothesisH of A. Schinzel on polynomials it follows that for every positive integerk there exists infinitely many arithmetic progressions formed fromk different Lehmer pseudoprimes for the bases α and β.     

Studies in the formation of heterocyclic rings containing nitrogen

Eight representative aromatic aldehydes with hydroxy, methoxy, nitro and chloro substituents have been condensed withs-diphenyl urea and ammonium acetate resulting in 2-keto-1, 3, 4, 6-tetra-aryl-hexahydro-s-triazines. The condensation of phenyl urea with five aldehydes and ammonium acetate, however, gave 1-phenyl-1:3-bis-(α-hydroxy aryl) ureas. The ultra-violet and infra-red spectra of these two types of compounds have been recorded.     

Studies on the relation between chemical constitution and ultraviolet absorption spectra of optically active and racemic compounds

The ultraviolet absorption spectra of camphor-β-sulphonyl-phenyl, (o-, m- andp-) tolyl, (α- and β-) naphthylamides have been determined in methyl alcohol, ethyl alcohol, and chloroform. The absorption spectra of all the compounds show two absorption bands: one varying from 267 to 284 mμ, the longer absorption maximum (λ_max) due to selective absorption of the keto group, and the other shorter one, ranging from 226 to 230 mμ, due to general absorption of the saturated molecules. The values of the characteristic wavelengths, λ₀₈ obtained from Drude’s one-term equation, have been compared with the absorption maxima, λ_max obtained by direct measurements. There are marked discrepancies in the values of λ₀ and λ_max. An explanation of the discrepancies is given. The nature of racemic modifications of the compounds has also been discussed.     

The nuclear magnetic resonance spectra of four spin systems

The ring proton resonance spectra ofα, β andγ picolines have been studied at 40 Mc./sec. The spectra which belong to the classes ABCX, ABXY and A₂X₂ respectively have been completely analyzed to determine all the involved parameters.     

A note on the characteristic function of supergames

Theα- andβ-characteristic functions of a supergame coincide.