Diazotisation of aromatic amines and solvolysis of diazonium salts in ethylene glycol ethers

Aniline and unhindered alkyl-substituted anilines undergo solvolysis in dioxane and DME saturated with dry hydrogen chloride on diazotisation with isoamyl nitrite to give 2-(2-chloroethoxy)ethyl aryl ethers and 2-methoxyethyl aryl ethers respectively in 36-47% yields. 2,6-Dialkyl-substituted anilines give the corresponding chloro compounds as the major product along with the aryl ethers in lower yields. Diazotisation of aniline in ethylene glycol and monomethyl ethers of ethylene glycol and diethylene glycol gave the corresponding alcoholysis products in low yields. The solvolysis of aniline did not occur on diazotisation in diethyl ether or THF.

A Simple Method for the Preparation of Monomethyl Esters of Dicarboxylic Acids by Selective Esterification of the Nonconjugated Carboxyl Group in the Presence of an Aromatic or Conjugated Carboxyl Group

Various dicarboxylic acids have been converted selectively into monomethyl esters in which the nonconjugated carboxyl group is selectively esterified in the presence of an aromatic or conjugated carboxyl group at room temperature (~ 25–27° C) in methanol using a catalytic amount of thionyl chloride.

Copper(I)/Ligand-Catalyzed 5-endo Radical Cyclization-Aromatization of 2,2,2-Trichloroethyl Vinyl Ethers: Synthesis of 2,3-Difunctionalized 4-Chlorofurans

Copper(I)/ligand-catalyzed one pot synthesis of highly substituted 2,3-difunctionalized-4-chlorofurans has been reported. The reaction proceeds via a Cu(I)-catalyzed regioselective 5-endo-trig radical cyclization of 2,2,2-trichloroethyl vinyl ethers followed by the base-promoted dehydrochlorination. The success of the kinetically disfavored 5-endo cyclization was attributed to the formation of captodatively stabilized radical intermediate in the cyclization step and relatively high reaction temperature. Synthetic application of this protocol was also demonstrated in the preparation of alkyl and aryl substituted 4-chlorofuranonapthoquinones.

Synthesis of 3-alkylbenzoxazolones from N-alkyl-N-arylhydroxylamines by contiguous O-trichloroacetylation, trichloroacetoxy ortho-shift, and cyclization sequence

Benzoxazolone pharmacophore is present in clinical pharmaceuticals, drug candidates, and many compounds having a wide spectrum of biological activities. The methods available for the synthesis of benzoxazolones have limited diversity due to problems in accessibility and air-sensitivity of diversely substituted o-aminophenols from which they are generally prepared by cyclocarbonylation with phosgene or its equivalents. The present paper describes a mild method for the synthesis of 3-alkylbenzoxazolones from easily accessible and air-stable nitroarenes. Nitroarenes were converted to N-alkyl-N-arylhydroxylamines in two steps involving partial reduction to arylhydroxylamines followed by selective N-alkylation. Treatment of N-alkyl-N-arylhydroxylamines with trichloroacetyl chloride and triethylamine afforded 3-alkylbenzoxazolones generally in good yields through an uninterrupted three-step sequence involving O-trichloroacetylation, N→C(ortho) trichloroacetoxy shift, and cyclization in a single pot at ambient temperatures. The present method is mild, wide in scope, economical, and regioselective. Many sensitive groups like alkyl and aryl esters, amide, cyano, and the carbon-carbon double bond survive the reaction.

Food and feeding pattern of Channa punctatus in two different habitats at Tarai region of Uttarakhand

A comparative study was conducted for the food items and feeding pattern of Channa punctatus in pond environment and in reservoir of Tarai region in Uttarakhand state. Observation was made for body length, gut length, food and feeding frequency and qualitative and quantitative analysis of gut content. Both, body length and gut length were in higher side with a ratio of 1:2.1 for the natural fish stock of reservoir. Gut content mainly consists of crustacean, insects, mollusks, small fishes and semi-digested material. There was significant difference for the percent occurrence of the food items (p < 0.01) of natural stock of reservoir and pond reared stock. The study revealed that seasonal variability of natural food items in different habitats and their biological diversity put impacts on the biological needs in terms of food and feeding pattern of the same fish species.

Histophysiological responses in ovary and liver of Cyprinus carpio after short term exposure to safe concentration of mercuric chloride and recovery pattern

Effect of short term (7 days) exposure to safe concentration of HgCl2 (0.5 ppm) and changes 7 days after withdrawl of the treatment on his ophysiologyof ovary and liver in yearlings of Cyprinus carpio were assessed during active phase of reproductive cycle. Noticeable degenerative histophysiological changes were observed in both ovary and liver after exposure which were more prominent in the group with abnormal behaviour. After withdrawl of the HgCl2 treatment the recovery was apparent in both organs but was more appreciable in liver. These observations indicated that even safe concentration of HgCl2 might not be fully devoid of deleterious influence on reproductive functions in Cyprinus carpio.

Ovarian development in Labeo dyocheilus (McClelland) during active reproductive phase under captive and wild conditions

Ovarian development in Labeo dyocheilus was assessed during active reproductive phase under ambient environmental conditions in captivity and wild. Increasing day length and water temperature seemed favourable for ovarian development in female L. dyocheilus under both conditions. Gonadosomatic index (GSI) was lower in May and higher in July in captivity (6.168 and 13.366) and wild (5.798 and 16.166) respectively Ovarian development started little bit in advance in captivity with late yolk vesicle stage oocyte in May when yolk globule stage oocytes were prominent in wild. Fully grown oocytes with germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) stages were observed in July in both conditions. Degree of transformation of developing oogonials into advance stage oocytes was observed to be better in wild fish compared to captivity reared ones. The histophysiological changes in liver corresponded well to the progression of ovarian development. Successive granulation and vacuolization of hepatocyte cytoplasm were indicative of augmented synthetic activity and probably mobilization of energy content for oocyte growth. These observations indicated that normal ovarian development of L. dyocheilus under captivity in Tarai region of Uttarakhand would be useful for success of its seed production in captivity for stock augmentation in wild or species diversification in aquaculture.

Seasonal ovarian cycle in freshwater teleost, Labeo rohita (Ham.) in Tarai region of Uttaranchal

Seasonal ovarian cycle, based on histophysiological changes, and correlative variations in liver were studied in an Indian major carp, Labeo rohita reared in captivity under ambient environmental conditions in Tarai region of Uttaranchal. The oocyte features used for marking ovarian cycle included nuclear-ooplasmic ratio, yolk vesicle incorporation into ooplasm, number and size of nucleolus and differentiation of follicular layer. Based on these features the ovarian cycle in L. rohita was divided into five phases i.e. resting, preparatory, pre-spawning, spawning and post-spawning/regression. The resting and preparatory phases were characterized by the dominating presence of chromatin-nucleolar and yolk-vesicle stage oocytes. The pre-spawning phase ovary was marked by the prevalence of yolk globule stage oocytes having cortical alveoli and differentiating follicular wall. The oocytes containing densely packed yolk-granules and large masses of yolk vesicles and also exhibiting germinal vesicle movement (GVM) signified the ovary of spawning phase. The ovary in regression phase contained pre-ovulatory atretic oocytes and significant number of oogonia. The histophysiological changes in liver showing augmented biosynthetic activity during preparatory and pre-spawning phases seemed well correlated with the gonadal development. The increasing water temperature and day-length apparently was favourable for the gonadal development in L. rohita.

Behavioural and hematological responses of Cyprinus carpio exposed to mercurial chloride

The static bioassay experiments were conducted to study the hematological and behavioural responses of Cyprinus carpio after exposure to mercuric chloride. Three different concentrations i.e. 0.5, 1.0 and 1.5 ppm of mercuric chloride (HgCl2) were used for 8, 16, 24, 48, 72, 96 and 124 hrs for evaluating behavioural responses. Hematological responses were assessed after 60 days exposure to 0.1 ppm of HgCl2. The changes in body colour, movement, sluggishness or activeness, disbalance etc. constituted the observations on behavioural responses. Hematological parameters included total erythrocyte (TEC) and leukocyte (TLC) counts and hemoglobin (Hb) levels. Body colour had changed in all groups after 48 hours. The fish exposed to 0.5 ppm HgCl2 did not show any abnormal activity except colour change throughout the experiment. Though no sign of distress was observed initially in groups exposed to 1.0 and 1.5 ppm HgCl2 but abnormal posturing, disbalance and sluggishness became apparent after 72 hrs and all specimens of 1.5 ppm group had died within 124 hours. TEC and Hb levels decreased whereas TLC increased in both male and female specimens of C. carpio after exposure to 0.1 ppm HgCl2 for 60 days. These observations indicated that mercurial toxicity even at low levels, caused adverse effects on body colour, behavioural responses and hematological parameters like TEC, TLC and hemoglobin levels in C. carpio.

First ovarian maturity and recovery response in common carp, Cyprinus carpio after exposure to carbofuran

The present study embodies the observations on duration (45, 75 and 105 days) dependent effects of toxicologically low concentration (16 ppm) of a carbamate pesticide, carbofuran, on first ovarian maturity with correlative recovery response by withdrawal of treatment for 30 days in virgin yearlings of common carp, Cyprinus carpio var. Communis. In control fish histological organization of ovary and changes in gonado-somatic index (GSI) revealed the initiation of oocyte differentiation and development at the commencement of experiment in December-January and peak of maturation with fully grown yolky oocytes was attained by the time of termination of experiment in the end of March. In carbofuran exposed groups ovaries exhibited retardation of development and growth evident by significantly decreased GSI and predominace of immature oocytes passing through nuclear-cytoplasmic degeneration of variable magnitude. Severity of degenerative changes was more pronounced with prolonged duration. In recovery group ovaries had experienced regeneration as clued by the presence of oocytes of differential stages including vitellogenic and fully grown oocytes. In liver histopathological changes coupled with significant decrease in hepato-somatic index (HSI) attributed hepatic inactivation in all exposure groups whereas in recovery group an increase in HSI value with marked sign of hepatic reactivation was evidenced. No significant change in values of condition (CF) and somatic condition (SCF) factors substantiated the over all normal health of fish. Lipid and water content of ovary, liver and muscle registered the significant decrease at 105th day of exposure with concomitant augmented value for recovery group. These observations suggest that the commercial formulation of carbofuran, even at this toxicologically low concentration, is equally capable of affecting the first ovarian maturity with associated physiological implications but with reversibility in toxicity by withdrawal of pesticide exposure attributing regeneration in affected organs in due course time.

Copper(I)-promoted dechlorinative Surzur-Tanner rearrangement of 2,2,2-trichloroethyl carboxylates

[reaction: see text] 2,2,2-Trichloroethyl carboxylates undergo highly efficient dechlorinative Surzur-Tanner rearrangement with 2 equiv of a 1:1 molar mixture of CuCl and bpy in boiling DCE to give 1-chloroethenyl carboxylates in which copper appears to play an important role, probably by coordinating the initial radical or as a Lewis acid catalyst.

Carbofuran induced impairment in the hypothalamo-neurohypophyseal-gonadal complex in the teleost, Channa punctalus (Bloch)

The effect of chronic exposure to carbofuran (4.5 ppm in static water) for six months on the gonadal histophysiology and hypothalamo-neurohypophyseal complex was studied in Channa punctatus. Experimental observations revealed significant inhibition of gonadal development with associated degenerative abnormalities as evidenced by ovarian and testicular histology and reduced gonadosomatic index. Degenerative changes in ovary were exihibited by stage I (oogonium) and stage II (immature/non-vitellogenic) oocytes as marked by perinuclear ooplasmic lysis, clumping and dissolution resulting in disintigration of nuclear material altogether attributed to complete degeneration of such oocytes. Testicular deleterious changes included degeneration of spermatogenic elements and necrosis of interstitial cells of Leydig. Correlative histophysiological changes were also observed in the pituitary gonadotrophs and hypothalamic, nucleus pre-opticus, neurons that were smaller, inactive and less in number with associated necrosis. Corresponding to the changes in nucleus pre-opticus neurons, significant inhibition of brain monoamine oxidase enzyme activity was also recorded in treated group. These observations suggest that carbofuran even at low concentration level under long-term exposure is capable of inducing retardation of gonadal development which might have been mediated through the impairment of the hypothalamo-neurohypophyseal-gonadal axis in this species.

Comparison of alternative models for predicting the uptake of chlorinated hydrocarbons by oligochaetes

The uptake of chlorinated hydrocarbons from contaminated sediments by oligochaetes was analyzed using three alternative models. Uptake appears to be best explained using a model that explicates the relationship of oligochaete body burden as a function of weight-dependent feeding rates, fractional absorption, and exposure times. The model explains observed variations in body burdens with oligochaete weights. Oligochaetes appear to absorb small fractions of ingested hydrocarbons. Fractional absorption of ingested contaminants appears to have a parabolic relationship with octanol-water partition coefficients and may decrease over time.

Removal of basic dye from waste-water using silica as adsorbent

The kinetics of removal of Basic Blue 3 from a textile effluent was studied using silica as an adsorbent. The adsorption was found to follow a first-order process. The influences on the rate of adsorption of various factors, such as temperature, concentration of dye solution, pH of the system and the amount of adsorbent have been investigated. On the basis of the isotherm studies, the various thermodynamical parameters have been calculated. The effect of electrolytes and surfactants has also been seen on the removal of the dye from the waste-water.

Effects of long-term exposure to cythion on the reproduction of the teleost fish, Channa punctatus (Bloch)

The chronic toxic effects of an organophosphorus pesticide on some aspects of the physiology of reproduction in a teleost fish, Channa punctatus, are described in this investigation. Fish exposed to 2.0 mg litre(-1) of commercial cythion continuously for 6 months, from January (resting phase) to June (spawning phase), exhibited a significant inhibition of gonadal development and gonadosomatic index. These changes were correlated with less active, and a reduced number of, pituitary gonadotrophs, and biochemical changes in the gonads and liver. The immature oocytes of the experimental fish exhibited cytoplasmic proteinaceous 'inclusion bodies', which ultimately led to their degeneration. The results suggest that cythion may act directly on the gonads and/or through the pituitary-gonadal axis, in this species.

Histopathological and biochemical changes in the liver of a teleost fish, Channa punctatus (Bloch) induced by a mercurial fungicide

The chronic toxic effects of a prolonged exposure of 6 months, from January to June, to a 'safe dose' (0.20 mg litre(-1)) of a commercial organomercurial fungicide, Emisan (methoxy ethyl mercuric chloride: MeEHgCl), on the histophysiology of liver in adults and young (yearlings) of Channa punctatus, are described in this investigation. In both of the experimental groups, liver histology exhibited various abnormalities, including hyperplasia, nuclear pyknosis, fatty necrosis, and degeneration of hepatocytes leading to tumour and syncytium formation, which are indicative of carcinogenesis. Apart from this, blood vessel congestion and oedema were also observed in young treated fish. In the livers of both exposed groups, corresponding with this cellular damage, a marked reduction in hepatosomatic index, levels of total protein and lipid, and an elevation in cholesterol and acid and alkaline phosphatase contents were recorded. However, these alterations were more pronounced in young than in adult fish. These Emisan-induced, histopathological and biochemical changes are suggestive of severe hepatic dysfunction, which may result in the impairment of the physio-metabolic process, in this species.