Synthesis of some chromono (7, 8) oxazoles and their antibacterial activity

The synthesis of a few 2-substituted aryl-8-methyl-chromono (7, 8) oxazoles is described. A study of the antibacterial activities of these compounds has revealed that 2-(p-nitrophenyl) 8-methyl-chromono (7, 8) oxazole is active in 1 in 10,000 parts concentration.     

Search for physiologically active compounds: Part XXVIII. Synthesis of 7-chloro-2-methyl and 2-(2-furyl), 3-aryl-4-quinazolones

A number of 2-methyl-3-aryl-7-chloro and 2-(2-furyl)-3-aryl-4-quinazolones have been synthesised by condensing N-acyl anthranilic acids with primary aromatic amines using phosphorus trichloride in dry toluene. All these quinazolone derivatives have been screened for their antibacterial, antifungal and fishtoxic properties.     

Reactions of tetrahalogeno-o-benzoquinones part VI: Reactions of tetrachloro-o-benzoquinone with methyl naphthols—Formation of naphthoquinone methides

The oxidation of a few methyl naphthols with tetrachloro-o-benzoquinone (1) has been described. Reaction of 1-methyl-2-naphthol (4) with the quinone (1) was found to give the spirodimer, 1,1′,2,2′-tetrahydro-3H-benzo (f) chromen-3-spiro-1′-naphthalene-2′-one (6) and a yellow solid which has been assigned the structure of 5,6,7,8-tetrachloro-1,4-benzodioxan-2-spiro-1′-naphthalen-2′-one (7) on the basis of chemical and spectral data. Among the other naphthols studied, 4-methyl-2-t-butyl-1-naphthol afforded 5,6,7,8-tetrachloro-1,4-benzodioxan-2-spiro-1′-naphthalen-3′-t-butyl-4′-one (22) while 2-methyl-1-naphthol and 4-methyl-1-naphthol gave 2-methyl-4,4-(tetrachloro-o-phenylenedioxy) naphthalen-1(4H)-one(15) and 4-methyl-2,2-(tetrachloro-o-phenylenedioxy) naphthelen-1(2H)-one (19) respectively. The present study has shown that oxidation of suitably substituted naphthols with the quinone (1) gives rise to naphthoquinone methides.     

Condensed cyclic and bridged-ring systems. VII. Acid-catalysed cyclisation of methyl substituted benzylcyclohexanols. Factors influencing the nature of cyclisation products

The gross structures of the cyclised products from the acid-catalysed cyclisations of 2-benzyl-1, 3-dimethylcyclohexanol (6) and 1-benzyl-3, 5-dimethylcyclohexanol (11) revealing the influence of the structure of the benzylcyclohexanol derivative, and of the cyclisation reagent, have been evaluated. Polyphosphoric acid and aluminium chloride catalysed cyclisations of (6) result in the formation of predominantly 1, 4a-dimethyl-1, 2, 3, 4, 4a, 9a-hexahydrofluorene (7) and 4, 9-dimethyl-7, 8-benzobicyclo [3.3.1] non-7-ene (9) respectively. Under the same conditions, (11) produced cyclised products consisting mostly the benzobicyclo [3.3.1] non-7-ene derivative (12), characterised through 1,3-dimethyl-7,8-benzobicyclo [3.3.1] non-6-oxo-7-ene (14) by oxidation with chromium trioxide. Phosphorus pentoxide induced cyclisation of (6), followed by oxidation gave a mixture of the bridged-ring ketone (10) and the 9-oxohydrofluorene (8) in a ratio ofca. 3 : 2, whereas 2-benzyl-5-methylcyclohexanol (19) resulted in mostly 2-methyl-7,8-benzobicyclo [3.3.1] non-6-oxo-7-ene (19).     

Isoxazolo (7,8 -d) flavones

A few isoxazolo (7, 8-d) flavones have been synthesised from 7-hydroxy-8-carbonyl flavones by preparing the oximes and cyclising them with sulphuric acid. The ultraviolet, infrared and mass spectra of some of these compounds have been recorded. The antibacterial activity of these derivatives has also been evaluated.     

Search for physiologically active compounds

7-Hydroxy-3-methyl 4-phenylcoumarin andα-methyl dihydrofurano,α andγ-pyrono ring systems have been built on 7, 8-position of 4-phenylcoumarin. The bacteriostatic activity of these compounds as well as that of mammeisin and mesuol isolated fromMesua ferrea seeds has been evaluated. Structure-activity relationship among these compounds is discussed.     

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.     

Synthesis of phenyl substituted furanobenzopyrones

Proceedings - Mathematical Sciences - The syntheses of 1, 2-diphenyl-6-methyl-8-oxo-8H-furo-[2, 3-h] (1) benzopyran, 2, 3-diphenyl-5-methyl-7-oxo-7H-furo [2, 3-g] (1) benzopyran and 1,...     

Search for physiologically active compounds

The synthesis of a number of 3-(2-furyl) coumarins adopting three different methods is described. The comparative merits of the methods are also discussed. The presence of a furyl moiety at the 3-posiiton of the coumarin ring has been shown to be comparatively better than a phenyl moiety in regard to the fish toxicity of the molecule. Among the coumarins tested on fish, 7-bromo-4-methyl-3-(2-furyl) coumarin has the maximum activity and is one-third as active as rotenone. The U.V., I.R. and N.M.R. spectral data of some of the compounds are also presented.     

Search for physiologically active compounds

A number of 3-(3-pyridyl) coumarins with and without 4-methyl substituent have been prepared following Oglialoro and modified Perkin reactions. These compounds have been tested against fish and bacteria. Of all the compounds tested, 7-bromo-4-methyl-3-(3-pyridyl) coumarin exhibited maximum activity. A few have also shown bacteriostatic activity.     

Application of Pschorr reaction to N-(o-aminobenzoyl)-benzyl and phenethyl amines and to N-(o-aminophenylacetyl) anilines

Decomposition of the diazonium chloride from N-(o-aminobenzoyl)-N-methylbenzylamine led to the formation of 3-benzyl-3, 4-dihydrobenzo-triazin-4-one (8), N-benzoylbenzylamine (11), N-benzylphthalimidine (13) ando-diphenic acid N-methyl amide (14), the last one presumably through the intermediary, the expected dibenzazepinone 16. From the analogue, N-(o-aminobenzoyl)-4-methoxybenzyl amine (4), triazinone 10 and N-benzoyl-4-methoxybenzyl amine (12) were obtained. Application of Pschorr reaction to N-(o-aminobenzoyl)-N-methyl-β-(4-methoxyphenyl) ethyl amine (23) afforded 2-methoxy-7-methyl-5, 6, 7, 8- tetrahydrodibenzo (c, e) azocin-8-one (26), with an interesting conformation. From N-(o-aminophenylacetyl)-p-methoxyaniline were obtained under these conditions, indazole-3-carboxylic acidp-anisidide (35) and N-[2-(4-methoxyphenyl carbamoylmethyl) phenyl]-1-(p-methoxyphenyl) isatin-β-hydrazone (37). The structure of 37 was deduced from spectral data and hydrolysis to the acid 42. Diazotisation of N-(o-aminophenylacetyl)-1, 2, 3, 4-tetrahydroquinoline (47) led to the formation of tetrahydroquinoline (49) ando-hydroxyphenyl acetic acid (50) presumably through the salicylamide 48. A similar reaction on N-(o-aminophenylacetyl) tetrahydroisoquinoline (52) gave the benzofurandione hydrazone 55, besides tetrahydroisoquinoline. Oxindole 45 and benzofuranone 56 were likely precursors for 37 and 55 respectively. Salicylamides 5, 7, 24 and 34 were byproducts in the Pschorr reaction.     

Electrical and magnetic properties of 3d-transition metal vanadates

The electrical and magnetic properties of vanadates of the general formula (MO) _n .V₂O₅, where M=Mn, Co, Ni, Cu and Zn, andn=1, 2 and 3, are discussed. Conduction in these materials occurs due to small deviations from the stoichiometric composition in the form of anion-(n-type) or cation—(p-type) vacancies. The mechanism of electrical transport is of a thermally activated hopping of charge carriers on equivalent cation lattice sites. It has been found that the meta vanadates (n=1) are alln-type while the pyro—(n=2) and ortho—(n=3) compounds of Mn, Co and Ni arep-type; but Cu and Zn analogues remainn-type only. The vanadates obey Curie-Weiss law at 80–340 K. The effective magnetic moments for MV₂O₆ are nearly the same as spin only values for the magnetic M²⁺ ions, and diminish with increasing MO contents. The predominant exchange interactions are the weak 90° MOM super-exchange and M—O—O—M super-super exchange. The Weiss constant is negative (antiferro-) for all the compounds except Co₃V₂O₈ which has a positive (ferro-) value. Cooperative phenomena, if any, have not been observed in this temperature range.     

On the complexity of growth of the number of distinct fuzzy switching functions

Several attempts have been made to enumerate fuzzy switching (FSF's) and to develop upper and lower bounds for the number of FSF's of n variables in an effort to better understand the properties and the complexity of FSF's. Previous upper bounds are 2⁴ⁿ [9] and 2^{2–3n—2n—1} [7].It has also been shown that the exact numbers of FSF's of n variables for n = 0, 1, 2, 3, and 4 are 2, 6, 8, 84, 43 918 and 160 297 985 276 respectively.This paper will give a brief overview of previous approaches to the problem, study some of the properties of fuzzy switching functions and give improved upper and lower bounds for a general n.     

Schémas en groupe et modules filtrés

Let k be a perfect field of characteristic p > 0. When p ≥ 3, Fontaine has classified p-divisible groups and finite flat commutative p-groups over the Witt vectors W(k) in terms of filtered modules ([9]+[6],[7]). Still assuming p ≥ 3, we extend these classifications over an arbitrary complete discrete valuation ring of unequal characteristic and residue field k by using “generalized” filtered modules. In particular, there is no restriction on the ramification index.     

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.     

Complex formation between cadmium and thiosalicylic acid

Polarographic measurements on the system Cd-thiosalicylic acid (TSA) reveal the formation of a complex, 1:2:: metal: ligand (ammonia buffer pH 9·1,µ=0·2 M, 50% alcoholic medium), dissociation constant of the complex being 6·3 × 10^?8 at 30° C. Potentiometric titrations confirmed this stoichiometry, stepwise stability constants, logk ₁ and logk ₂ being 7·85 and 8·10 respectively. The complex has also been isolated and studied in solid state.     

Periodicities in the series of cyclonic disturbances over India

The time series of yearly occurrence frequency of cyclonic disturbances over the Indian region for 1891–1970 is subjected to power spectrum analysis by the maximum entropy method (MEM) of Burg. Earlier analyses by the conventional Blackman-Tukey method had indicated periodicities atT= 2·3-2·5, 5 and 30–45 years at about 90–95% significance level. The present analysis shows peaks atT = 1·2, 2·4, 2·9, 3·7, 4·7, 6·4, 7·4, 9·2, 10·5, 20 and 40–60 years but the significance level may not be better than the earlier method. When data are analysed separately for first half and latter half, periodicities observed are quite different, the earlier half revealingT= 1· 2, 2·3, 2·9, 4·7, 9·0 and 23 years and the latter half revealingT= 1·2, 2·1, 2·4, 3·8, 6·7 and 21 years. Thus, a change of pattern before and after about 1920 is indicated. However, the power in the various peaks is small and a random origin cannot be ruled out. An analysis of several artificially produced samples of pseudo-Gaussian random white noise of the same mean, standard deviation and length (80 values) as the above physical samples indicated that similar peaks could occur by pure chance also. Physically, T=l·2 years corresponds to the Chandler’s wobble and other peaks could be harmonics of the sunspot cycleT= 11 years or double sunspot cycleT = 22 years. However, no peak is noticed at or nearT= 11 years whereasT near 22 years is noticed.     

The application of invariant theory to the existence of quasi-symmetric designs

Gleason and Mallows and Sloane characterized the weight enumerators of maximal self-orthogonal codes with all weights divisible by 4. We apply these results to obtain a new necessary condition for the existence of 2 − (v, k, λ) designs where the intersection numbers s₁…,s_n satisfy s₁ ≡ s₂ ≡ … ≡ s_n (mod 2). Non-existence of quasi-symmetric 2−(21, 18, 14), 2−(21, 9, 12), and 2−(35, 7, 3) designs follows directly from the theorem. We also eliminate quasi-symmetric 2−(33, 9, 6) designs. We prove that the blocks of quasi-symmetric 2−(19, 9, 16), 2−(20, 10, 18), 2-(20,8, 14), and 2−(22, 8, 12) designs are obtained from octads and dodecads in the [24, 12] Golay code. Finally we eliminate quasi-symmetric 2−(19,9, 16) and 2-(22, 8, 12) designs.     

Search for physiologically active compounds

The synthesis of a few (7, 8) oxazolo-flavones has been carried out starting from 7-hydroxy-8-amino flavone. The ultraviolet and infrared spectra of these new class of heterocyclic compounds have been studied. The anti-bacterial and anti-fungal activities of these compounds have been reported.     

Arithmetic properties of partitions with even parts distinct

In this work, we consider the function ped(n), the number of partitions of an integer n wherein the even parts are distinct (and the odd parts are unrestricted). Our goal is to consider this function from an arithmetical point of view in the spirit of Ramanujan’s congruences for the unrestricted partition function p(n). We prove a number of results for ped(n) including the following: For all n≥0, $$\mathit{ped}(9n+4)\equiv0\pmod{4}$$ and $$\mathit{ped}(9n+7)\equiv0\pmod{12}.$$ Indeed, we compute appropriate generating functions from which we deduce these congruences and find, in particular, the surprising result that $$\sum_{n\geq0}\mathit{ped}(9n+7)q^n=12\frac{ (q^{2};q^{2})_\infty ^{4}(q^{3};q^{3})_\infty ^{6}(q^{4};q^{4})_\infty ^{}}{(q^{};q^{})_\infty ^{11}}.$$ We also show that ped(n) is divisible by 6 at least 1/6 of the time.