Clofentezine

Chloro benzoyl chloride chlorphoxim, clofentezine, fenarimol... 

Hydrazine bisthiosemi, clethodim, clofentezine, diclomazine, difenzoquat, ferimzone, flupoxam, maleic hydrazide, metamitron, methidathion, metribuzin, pymetrozine, tebuthiuron, thiazafluron, triclopyr Hydrazine (acetyl) metamitron Hydrazine (tertiobutyl) tebufenozide Hydrazine (p.tertio butyl benzyl) pyridaben Hydrazine (2.4 dichloro phenyl) sulfentrazone Hydrazine (dimethyl) daminozide Hydrazine (2.6 dimethyl phenyl) oxadixyl... 

Tetrazine acaricides are derivatives of tetrazine. Clofentezine is an acaricide/ovicide for eggs of various phytophagous mites on deciduous fruits, citrus, cotton, vines, and ornamentals. Its oral LD50 in rats is >5200 mg/kg. 

Barnes and coworkers pioneered in this area. They reported the analysis of diflubenzuron in mushrooms [39], and of diflubenzuron and clofentezine in various fmit drinks [73], and the development of a multiresidue study for ten pesticides in fmit, involving ionization polarity switching in LC-APCI-MS [123]. In these studies, significant attention is paid to matrix-dependent ion suppression or enhancement effects (Ch. 6.7), which is observed even in APCI. Matrix effects in food analysis must be studied in detail for each fmit or vegetable. Obviously, optimization of the sample pretreatment procedures plays an important role in method development for pesticide residue analysis in food. 

K.A. Barnes, R.J. FusseU, J.R. Startin, S.A. Thorpe, S.L. Reynolds, Determination of the pesticides diflubenzuron and clofentezine in plums, strawberries and blackcurrent-based fruit drinks by LC-APCI-MS, Rapid Commun. Mass Spectrom., 9 (1995) 1441. 

A high-performance liquid chromatographic/atmospheric pressure chemical ionization-mass spectrometric (HPLC/APCI-MS) method has been developed for the determination of the pesticide clofentezine (3,6-bis(2-chlorophenyl)-l,2,4.5-tetrazine) in plum-, strawberry-, and blackcurrant-based fruit drinks <1995RCM1441>. The structural characterization and the mass spectrometric behavior of pyridazinofurocoumarins, prepared by the inverse electron demand Diels-Alder reaction between furocoumarinones and 3,6-bis(methoxycarbonyl)-l,2,4,5-tetrazine, were studied under electron ionization conditions via sequential product ion fragmentation experiments <2004RCM564>. 

APCl and ESl-LC-MS were compared to determine, besides other substances, acaricidic clofentezine and fungidddic thiabendazole in fruits. Detection hmits observed were equivalent to 0.002-0.033 mg per kg of crop [358]. APCI ionisation was found to be more effident than ESI. When clofentezine was also determined in plums, strawberries and blackcurrant-based fruit drinks [384] mean overall recoveries of 70% from spiked extracts were observed. An effident APCf-LC-MS/... 

Mite Growth Inhibitors (Clofentezine, Hexythiazox, Etoxazole)... 

Many different biochemical targets in mites have been addressed in recent decades for the development of new acaricides [1, 2]. One group of acaricides are known as mite growth inhibitors and are classified in group 10 of the IRAC (Insecticide Resistance Action Committee) mode of action classification scheme (www.irac-online.org). Mite growth regulators such as clofentezine (1), diflovidazin (2) hexythiazox (3) and etoxazole (4) are presented in this chapter, because they share some common characteristics (Fig. 26.2.1). 

Scheme 26.2.1 shows the synthesis routes leading to clofentezine and difiovidazin. 

The synthesis of clofentezine starts with a twofold acylation of hydrazine hydrate with 2-chlorobenzoyl chloride, followed by a phosphorous pentachloride mediated activation and a second reaction with hydrazine hydrate to give the 1,2-dihydrotetrazine derivative, which is finally oxidized to clofentezine using sodium nitrite [4, 11]. 

Clofentezine and difiovidazin have been developed for the control of a wide range of spider mite species such as Tetranychus spp., Panonychus spp. and Eriophyid... 

Scheme 26.2.1. Synthesis of the tetrazine acaricides clofentezine and diflovidazin.

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