Transformation rates ofortho-substituted thiophene and benzene carboxylic esters: Application to thifensulfuron-methyl and metsulfuron-methyl herbicides

Results are presented from experiments addressing the anaerobic biotransfoimation of high concentrations of three chlorinated aliphatics, dichloromethane (DCM), chloroform (CF), and 1,1,1-trichloroethane (TCA), when fed alone and in mixtures. Experiments were conducted to address the effect of feeding mixtures of these compounds on the transformation rates of individual components in the mixture, and to assess the effect of acetate loading rates on the extent of transformation of the chlorinated aliphatics. Feeding mixtures of chlorinated aliphatics caused decreased transformation of TCA, increased the transformation of DCM, and had mixed effects on CF transformation. The systems fed higher acetate loading rates demonstrated an increased ability to transform the chlorinated aliphatics.

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IMPACT OF WHEAT ESTABLISHMENT METHODS AND WEED MANAGEMENT PRACTICES ON WEED FLORA, YIELD AND NUTRIENT UPTAKE OF WHEAT IN RICE-WHEAT CROPPING SYSTEM

Journal of AgriSearch ◽

10.21921/jas.v6i02.15754 ◽

2019 ◽

Vol 6 (02) ◽

Cited By ~ 1

Author(s):

MOHAN SINGH ◽

OMBIR SINGH ◽

ROHITASAV SINGH

Keyword(s):

Nutrient Uptake ◽

Weed Management ◽

Conventional Tillage ◽

Research Centre ◽

Zero Tillage ◽

Phalaris Minor ◽

Weed Population ◽

Metsulfuron Methyl ◽

Transplanted Rice ◽

Weed Flora

A field experiment was conducted at the Crop Research Centre of Govind Ballabh Pant University of Agriculture and Technology Pantnagar, Udham Singh Nagar during continuous two years to study the weed flora, yield and nutrient uptake of wheat (Triticum aestivum L.) under different wheat establishment methods in main plots and seven weed management in sub plots. Phalaris minor was the most dominant weed at 60 DAS contributed 55.0 per cent of total weed population. Melilotusindica was the major non grassy weeds in wheat which contributed 11 per cent to total weed population during respective years. Sowing of wheat with zero tillage significantly reduced the Phalaris minor density as compared to conventionally tilled wheat after transplanted rice, 60 per cent Phalaris minor emerged from 0-3 cm in reduced and conventional tillage where as in zero tillage after transplanted rice there was 55 per cent emergence from 0-3 cm layer.The highest grain yield was obtained in two hand weedings done at 30 and 60 DAS and was at par with Isoproturon 1.0 kg ha-1 + Metsulfuron methyl 4 g ha-1 at 30 DAS and Clodinafop – Propargyl 60 g ha-1 at 30 DAS fb. Metsulfuron methyl 4 g ha-1 at 37 DAS. Zero tillage resulted in significantly higher uptake of NPK by wheat plants as compared to conventional tillage, whereas reduced tillage recorded minimum NPK, which was significantly lower over the other treatments of wheat establishment methods.

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17O and 13C NMR spectra of some geminal diacetates

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19880588 ◽

1988 ◽

Vol 53 (3) ◽

pp. 588-592 ◽

Cited By ~ 10

Author(s):

Antonín Lyčka ◽

Josef Jirman ◽

Jaroslav Holeček

Keyword(s):

13C Nmr ◽

Nmr Spectra ◽

Chemical Shifts ◽

The Other ◽

13C Nmr Spectra ◽

Other Hand ◽

Carboxylic Esters ◽

C Nmr ◽

Oxygen Atoms

The 17O and 13C NMR spectra of eight geminal diacetates RCH(O(CO)CH3)2 derived from simple aldehydes have been measured. In contrast to the dicarboxylates R1R2E(O(CO)R3)2, where E = Si, Ge, or Sn, whose 17O NMR spectra only contain a single signal, and, on the other hand, in accordance with organic carboxylic esters, the 17O NMR spectra of the compound group studied always exhibit two well-resolved signals with the chemical shifts δ(17O) in the regions of 183-219 ppm and 369-381 ppm for the oxygen atoms in the groups C-O and C=O, respectively.

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DFT study on the hydrolysis of metsulfuron-methyl: A sulfonylurea herbicide

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633618500505 ◽

2018 ◽

Vol 17 (08) ◽

pp. 1850050 ◽

Cited By ~ 1

Author(s):

Qiuhan Luo ◽

Gang Li ◽

Junping Xiao ◽

Chunhui Yin ◽

Yahui He ◽

...

Keyword(s):

Free Energy ◽

Water Molecule ◽

Carbonyl Group ◽

Energy Barrier ◽

Density Functional ◽

Free Energy Barrier ◽

Functional Theory ◽

Metsulfuron Methyl ◽

Catalytic Role ◽

Hydrolysis Of

Sulfonylureas are an important group of herbicides widely used for a range of weeds and grasses control particularly in cereals. However, some of them tend to persist for years in environments. Hydrolysis is the primary pathway for their degradation. To understand the hydrolysis behavior of sulfonylurea herbicides, the hydrolysis mechanism of metsulfuron-methyl, a typical sulfonylurea, was investigated using density functional theory (DFT) at the B3LYP/6-31[Formula: see text]G(d,p) level. The hydrolysis of metsulfuron-methyl resembles nucleophilic substitution by a water molecule attacking the carbonyl group from aryl side (pathway a) or from heterocycle side (pathway b). In the direct hydrolysis, the carbonyl group is directly attacked by one water molecule to form benzene sulfonamide or heterocyclic amine; the free energy barrier is about 52–58[Formula: see text]kcal[Formula: see text]mol[Formula: see text]. In the autocatalytic hydrolysis, with the second water molecule acting as a catalyst, the free energy barrier, which is about 43–45[Formula: see text]kcal[Formula: see text]mol[Formula: see text], is remarkably reduced by about 11[Formula: see text]kcal[Formula: see text]mol[Formula: see text]. It is obvious that water molecules play a significant catalytic role during the hydrolysis of sulfonylureas.

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Dynamic Kinetic Resolution of Carboxylic Esters Catalyzed by Chiral PPY N-Oxides: Synthesis of Nonsteroidal Anti-Inflammatory Drugs and Mechanistic Insights

ACS Catalysis ◽

10.1021/acscatal.1c01438 ◽

2021 ◽

pp. 8183-8196

Author(s):

Ming-Sheng Xie ◽

Ning Li ◽

Yin Tian ◽

Xiao-Xia Wu ◽

Yun Deng ◽

...

Keyword(s):

Kinetic Resolution ◽

Dynamic Kinetic Resolution ◽

Inflammatory Drugs ◽

Anti Inflammatory ◽

Carboxylic Esters

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Carbene-Catalyzed Alkylation of Carboxylic Esters via Direct Photoexcitation of Acyl Azolium Intermediates

ACS Catalysis ◽

10.1021/acscatal.1c00165 ◽

2021 ◽

pp. 2925-2934

Author(s):

Shi-Chao Ren ◽

Wen-Xin Lv ◽

Xing Yang ◽

Jia-Lei Yan ◽

Jun Xu ◽

...

Keyword(s):

Carboxylic Esters

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Studies on the control of water-dropwort (Oenanthe pimpinelloides) in South Australia

Australian Journal of Experimental Agriculture ◽

10.1071/ea9950483 ◽

1995 ◽

Vol 35 (4) ◽

pp. 483

Author(s):

GJ Mitchell ◽

RJ Carter ◽

SR Chinner

Keyword(s):

Stem Elongation ◽

South Australia ◽

Perennial Herb ◽

Metsulfuron Methyl ◽

Rate Of Spread ◽

Herbicide Treatments ◽

Direct Drilling ◽

Water Dropwort

Water-dropwort (Oenanthe pimpinelloides L.), a tuberous perennial herb, is currently known in South Australia from only a single locality in the Mount Lofty Ranges. There is little information on water-dropwort control, and 2 experiments were conducted to assess the effects of sowing pasture, with or without presowing herbicides, on the control of this weed. Phalaris (Phalaris aquatica L.) and perennial clovers were successfully introduced into infested pastures by direct drilling in autumn. Water-dropwort regenerated from seed more densely in unsown plots than plots of established perennial pasture, suggesting that upgrading pastures may be a strategy to reduce the rate of spread by seed of this weed. A range of herbicide treatments applied to waterdropwort at the stem elongation stage in spring before autumn sowing of pastures provided effective shortterm control. The best short-term control was provided by glyphosate at 1440 g a.i./ha; metsulfuron methyl at 6, 12, and 36 g a.i./ha; and metsulfuron methyl at 12 g a.i./ha tank-mixed with glyphosate or 2,4-D amine at 720 or 1000 g a.i./ha, respectively. These treatments, and chlorsulfuron at 21 g a.i./ha, also significantly (P<0.05) reduced water-dropwort abundance (relative to untreated areas) for up to 18 months after sowing and initially improved the density of sown pasture species, but these improvements were not evident 14 months after resowing. Although prior season herbicide treatments controlled water-dropwort in newly sown pastures, 2 separate applications of herbicides, in May and October, gave no better control of water-dropwort than a single herbicide application in spring. Water-dropwort infestations do not appear to prevent successful direct drilling of phalaris and perennial clovers. Although pasture renovation did not provide long-term suppression of water-dropwort, the maintenance of vigorous pastures may reduce the rate of population growth from seedlings of this weed. Recropping restrictions may limit the role of chlorsulfuron for water-dropwort control in pasture renovation situations.

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Carboxylic Ester Hydrolases in Bacteria: Active Site, Structure, Function and Application

Crystals ◽

10.3390/cryst9110597 ◽

2019 ◽

Vol 9 (11) ◽

pp. 597 ◽

Cited By ~ 4

Author(s):

Changsuk Oh ◽

T. Doohun Kim ◽

Kyeong Kyu Kim

Keyword(s):

Acyl Chain ◽

Data Bank ◽

Industrial Applications ◽

Head Group ◽

Carboxylic Ester ◽

Site Structure ◽

Domains Of Life ◽

Carboxylic Esters ◽

Hydrolysis Of ◽

Ester Hydrolases

Carboxylic ester hydrolases (CEHs), which catalyze the hydrolysis of carboxylic esters to produce alcohol and acid, are identified in three domains of life. In the Protein Data Bank (PDB), 136 crystal structures of bacterial CEHs (424 PDB codes) from 52 genera and metagenome have been reported. In this review, we categorize these structures based on catalytic machinery, structure and substrate specificity to provide a comprehensive understanding of the bacterial CEHs. CEHs use Ser, Asp or water as a nucleophile to drive diverse catalytic machinery. The α/β/α sandwich architecture is most frequently found in CEHs, but 3-solenoid, β-barrel, up-down bundle, α/β/β/α 4-layer sandwich, 6 or 7 propeller and α/β barrel architectures are also found in these CEHs. Most are substrate-specific to various esters with types of head group and lengths of the acyl chain, but some CEHs exhibit peptidase or lactamase activities. CEHs are widely used in industrial applications, and are the objects of research in structure- or mutation-based protein engineering. Structural studies of CEHs are still necessary for understanding their biological roles, identifying their structure-based functions and structure-based engineering and their potential industrial applications.

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