Phenylthiouracil

When 1 -(4-bromo-3,3-dimethylbutyl)-3-methyl-6-phenylthiouracil (185) was allowed to react with Ph3SnH in the absence and presence of eobaloxime [Co] complex reaction mixtures were obtained, containing a few... 

I, Umezu K, Walker RT, Mori S, Ito M, Shigeta S, Miyasaka T. Potent and selective inhibition of human immunodeficiency virus type 1 (HIV-1) by 5-ethyl-6-phenylthiouracil derivatives through their interaction with the HIV-1 reverse transcriptase. Proc Natl Acad Sci USA 1991 88 2356-2360. 

The most important and powerful thyreostatic drugs used hitherto are the thiouracil analogues, such as thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil and die mercaptoimidazole analogues such as tapazole or methimazole. New thyreostatics as mercaptobenzimidazole are said to have been misused recently in some EU countries. 

A more comprehensive approach was reported in 1975 by Brabander and Verbeke (612). In this method, tissue samples were extracted with methanol and the acidified extract defatted with petroleum ether to be loaded onto a Dowex 50W-X8 anion-exchange resin. Following elution with aqueous methanol, the concentrated buffered extract was further defatted with diethyl ether. The sample was derivatized with 7-chloro-4-nitrobenzo-2-oxa-l,3-diazole (NBD-Cl) to be further spotted on a silica high-performance thin-layer chromatographic plate developed in two dimensions using chloroform/ethanol and chloroform/propionic acid consecutively as eluents. Detection of the propylthiouracil, phenylthiouracil, and tapazole residues was carried out on the basis of the fluorescence induction of the NBD derivatives of the drugs with an alkaline cysteine solution. 

The most recent modification of the NBD-Cl method involves a further improvement in its qualitative support (616). It involves the infusion of the extract employed for thin-layer chromatography via an electrospray interface into a mass spectrometer operating in the multiple-stage mass spectrometry mode, thus allowing confirmation of suspect results. The cleanup of the thyroid gland samples was also performed with a selective extraction procedure, based on the specific complex formation of the thiouracil, methylthiouracil, propylthiouracil and phenylthiouracil, tapazole, and mercaptobenzimidazole residues with mercury ions bound in a Dowex 1-X2 affinity column. 

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