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Synthesis of hexahydro-1,4-thiazepine derivatives with expected pharmacological activity. Part I. N-alkyl(hydroxyalkyl)-hexahydro-1,4-thiazepines and 2-(hexahydro-1,4-thiazepinyl)-ethyl esters of phenoxyacetic acids.

New N-alkyl or N-hydroxyalkyl derivatives of hexahydro-1,4-thiazepine(compounds 1--6, Table 2) were obtained by condensation of 2-chloroethyl-3-chloropropyl sulfide with appropriate primary amines. Estrification of 2-hydroxyethylhexahydro-1,4-thiazepine by chloride of appropriate phenoxyacetic acids yielded 2-(hexahydro-1,4-thiazepinyl)-ethyl esters of phenoxyacetic acids (compounds 7--12, Table 4).

Animals

Case-control study: soft-tissue sarcomas and exposure to phenoxyacetic acids or chlorophenols.

In 1977 a number of patients with soft-tissue sarcomas and previous exposure to phenoxyacetic acids were described. Following from these observations a matched case-control study was made. Exposure to chlorophenols was also included in this study. The results showed that exposure to phenoxyacetic acids or chlorophenols gave an approximately 6-fold increase in the risk for this type of tumour. It was not possible to determine, however, whether the carcinogenic effect was exerted by these compounds or by impurities such as chlorinated dibenzodioxins and dibenzofurans that in almost all cases were part of the commercial preparations.

2,4,5-Trichlorophenoxyacetic Acid

Fate and distribution of the herbicides 2,4-dichlor-phenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in the dogfish shark.

1. The urinary and biliary excretion, tissue distribution and metabolism of 14C-labelled 2,4-dichloro- or 2,4,5-trichloro-phenoxyacetic acids (2,4-D or 2,4,5-T) were measured in dogfish sharks, Squalus acanthias. 2. Both herbicides are extensively metabolized (greater than 90%) to the corresponding taurine conjugates, and are excreted predominantly via the urine, where ca. 70% of the administered dose appears within 4-6 days after treatment. 3. The highest tissue levels of 2,4-D or 2,4,5-T were found in liver and kidney. Penetration of both herbicides into the CNS was restricted. 4. Plasma elimination was rapid and the 0.5 for either phenoxyacetic acid was less than 45 min. Similarly, rapid clearance as seen from renal tissue. Final t0.5 values for muscle were about 2-3 days while the major organ showing 2,4-D or 2,4,5-T retention was the liver, where t0.5 values were about 5 days for both the herbicides. 5. The overall pharmacokinetics in the dogfish shark for these herbicides resembled those seen in some mammals.

2,4,5-Trichlorophenoxyacetic Acid

Malignant lymphoproliferative diseases in occupations with potential exposure to phenoxyacetic acids or dioxins: a register-based study.

The Swedish Cancer Environment Register (CER) is a linkage of census data (e.g., on occupations) with the Swedish Cancer Register. It has been used in different studies to generate hypotheses on occupational risk factors for malignant tumors. In this study the risk for malignant lymphoma and multiple myeloma in occupations with potential exposure to phenoxyacetic acids or other related substances were investigated. An increased standardized incidence ratio (SIR) of 1.3 for multiple myeloma was verified in farmers (no. of cases = 335). This finding applied to both sexes, and the SIR increased over successive time periods. Regarding malignant lymphoma an increased SIR of 1.2 was found in farmers (no. = 227) for the latest time period studied (i.e. 1979-1984). When non-Hodgkin's lymphoma was studied separately, an increased risk (SIR = 1.2) was found only in carpenters (no. = 149), whereas for Hodgkin's disease, sawmill workers (no. = 10) had an increased SIR of 2.1. Physicians also had an elevated risk for malignant lymphoma. A major shortcoming in register studies such as CER is that no individual exposure data on different agents are available. Lack of an association between an occupation and a specific malignant disease, therefore, may not be taken as evidence that persons within that occupation are not at increased risk for that disease.

Agricultural Workers' Diseases

Chlorinated phenoxyacetic acid derivatives and tetrachlorodibenzo-p-dioxin in foliage after application of 2,4,5-trichlorophenoxyacetic acid esters.

Six reforestation areas were sprayed with 2,4,5-T esters. Leaf samples from the areas were analyzed for the esters, tetrachlorodioxin, and dehalogenated phenoxyacetic acid esters. Tetrachlorodioxin was found in one leaf sample only, but the level found, relative to the amount of 2,4,5-T ester found, was lower than in the formulation material used in the study. The concentration of the dichlorophenoxyacetic acid esters present in several leaf samples was greater, relative to the 2,4,5-T ester, which indicated a photochemical breakdown of the 2,4,5-T in the environment.

2,4,5-Trichlorophenoxyacetic Acid

Biodegradation of phenoxyacetic acid in soil by Pseudomonas putida PP0301(pR0103), a constitutive degrader of 2,4-dichlorophenoxyacetate.

The efficacy of using genetically engineered microbes (GEMs) to degrade recalcitrant environmental toxicants was demonstrated by the application of Pseudomonas putida PP0301(pR0103) to an Oregon agricultural soil amended with 500 micrograms/g of a model xenobiotic, phenoxyacetic acid (PAA). P. putida PP0301(pR0103) is a constitutive degrader of 2,4-dichlorophenoxyacetate (2,4-D) and is also active on the non-inducing substrate, PAA. PAA is the parental compound of 2,4-dichlorophenoxyacetic acid (2,4-D) and whilst the indigenous soil microbiota degraded 500 micrograms/g 2,4-D to less than 10 micrograms/g, PAA degradation was insignificant during a 40-day period. No significant degradation of PAA occurred in soil inoculated with the parental strain P. putida PP0301 or the inducible 2,4-D degrader P. putida PP0301(pR0101). Moreover, co-amendment of soil with 2,4-D and PAA induced the microbiota to degrade 2,4-D; PAA was not degraded. P. putida PP0301-(pR0103) mineralized 500-micrograms/g PAA to trace levels within 13 days and relieved phytotoxicity of PAA to Raphanus sativus (radish) seeds with 100% germination in the presence of the GEM and 7% germination in its absence. In unamended soil, survival of the plasmid-free parental strain P. putida PP0301 was similar to the survival of the GEM strain P. putida PP0301(pR0103). However, in PAA amended soil, survival of the parent strain was over 10,000-fold lower (< 3 colony forming units per gram of soil) than survival of the GEM strain after 39 days.

2,4-Dichlorophenoxyacetic Acid

Hydrophobic binding of phenoxyacetic and phenylacetic acids to horseradish peroxidase and human serum albumin: structure-activity relationships.

Studies of protein binding in homologous series of drugs are of great interest for drug research. Apparent binding constants of phenoxyacetic and phenylacetic acids to horseradish peroxidase and to human serum albumin are evaluated by NMR studies and an optical method. These constants are good parameters to describe hydrophobic interactions, and the results are in a good agreement with our protein binding model described previously.

Chemical Phenomena

Prenatal effects of 2,4,5-T, 2,4,5-trichlorophenol, and phenoxyacetic acid in mice.

The herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and two structurally related compounds, phenoxyacetic acid and 2,4,5-trichlorophenol, were suspended in a 1:1 solution of honey:water and administered by gavage to pregnant mice on one of gestation days 8-15 (copulation plug day = day 1) or on three consecutive days (7-9, 10-12, or 13-15). Doses were 800-900 mg/kg for single and 250-300 mg/kg/day for multiple treatments. With the exception of 2,4,5-trichlorophenol treatment on day 14, only 2,4,5-T treatment significantly increased prenatal mortality, and only 2,4,5-T was associated with decreased fetal weight when comparisons were made with the solvent controls. Although low incidences were seen in all treatment groups, only 2,4,5-T significantly increased cleft palate or other gross malformations. Significant skeletal, visceral or histopathological defects were not observed. These results indicate that both the carboxyl group and chlorination of the aromatic ring are essential for an unambiguous teratogenic response.

2,4,5-Trichlorophenoxyacetic Acid

[Cytogenetic study of the mutagenic properties of the repellents dimethyl phthalate and phenoxyacetic acid N,N-diethylamide].

Animal experiments ascertained that the repellent N,N-diethylamide of phenoxyacetic acid (P-203) increases the frequency of chromosomal aberration in the bone marrow cells of mice following its intraperitoneal introduction and also in the cells of a regenerating liver of rats after its repeated skin application. Dimethylphthalate displayed a mutagenic action only with respect to the rats' hepatocytes when applied repeatedly to the skin.

Administration, Topical

[Chloroderivatives of phenoxyacetic acid as antagonists of thyroid hormones].

A 24-hour stay of the Rana temporaria tadpoles in solutions of the sodium and diethylamine salts of 2,4-dichlorophenoxyacitic acid (with 1 and 2 mg/l, respectively) significantly inhibits their metamorphosis. An addition of these salts to a solution containing thyroidin in a concentration of 1--5 mg/l hinders the action of hormone stimulating metamorphosis. The effect of the sodium salt of 2,4-dichlorophenoxyacetic acid prevents the destruction of some tadpoles by toxic concentrations of thyroidin. The above data justify referring the chloroderivatives of the phenoxyacetic acid to antagonists of the thyroid hormones.

2,4-Dichlorophenoxyacetic Acid

Distribution and cytogenetic test of 2,4-D and 2,4,5-T phenoxyacetic acids in mouse blood tissues.

The phenoxyacetic acids 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), extensively used as herbicides, were tested for cytogenetic effects by means of induced micronuclei in erythrocytes of mouse bone marrow. Because of the hig experimental resolution power this is a particularly suitable test system for the detection of weak chromosome breaking activity in mammals. The cytogenetic tests were supplemented with chemical analyses of the concentration the the test substances reaching the target cells...

2,4,5-Trichlorophenoxyacetic Acid

Mechanism of the lethal and mutagenic effects of phenoxyacetic acids in Saccharomyces cerevisiae.

MCPA and salicylic acid, two compounds with similar structures and almost the same dissociation pattern, were tested for lethal and mutagenic effects on, and uptake by, cells of Saccharomyces cerevisiae strain rad18. The results obtained with the two compounds were similar, suggesting a common mechanism of action. It is proposed that they act by increasing the concentration of hydrogen ions within the cell, so that killing and mutation occur. Mutations were induced only when killing reached 95--99%. The compounds are considered weak mutagens for yeast cells. The methyl ester of MCPA also induced killing and reverse mutation, but only at concentrations about 100 times higher than for the undissociated acid. MCPA methyl ester did not increase the number of revertants in the Salmonella/liver microsome test. It is suggested that the effects of the methyl ester of MCPA depends on the ester being hydrolysed to the acid by yeast cells and the liver microsome preparation.

Drug Evaluation, Preclinical

Gas-liquid chromatographic method with electron-capture detection for the determination of residues of some phenoxyacetic acid herbicides in water as their 2,2,2-trichloroethyl esters.

A gas-liquid chromatographic method with electron-capture detection was developed for the determination of residues of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylpenoxyacetic acid (MCPA) in water as their 2,2,2-trichloroethyl esters, and the sensitivity was compared with that for 2-chloro- and 2,2,2-trifluoroethyl esters. The residue is isolated by sorption of the phenoxy acid on Amberlite XAD-4, eluted with benzene and then esterified with 20% (v/v) 2,2,2-trichloroethanol in trifluoroacetic anhydride in the presence of sulphuric acid. The recoveries at the 0.4 ppb level are 92.1 +/- 3.4% (2,4-D) and 87.8 +/- 2.1% (MCPA) and the detection limits for a 1-1 sample of water are 0.096 ppb (2,4-D) and 0.06 ppb (MCPA).

2,4-Dichlorophenoxyacetic Acid