Bonds thiophosphate

The reaction of thioethers with ethyleneimine in the presence of acid yields sulfonium compounds. The reaction is reversible under alkaline conditions (125). Compounds in which double-bonded sulfur can exist in tautomerism with a form having a free SH group, such as thiourea (126,127), thiocarboxyhc acids (128), and thiophosphates (129), react to give aminoaLkylated products. The P-aminoethyl thiocarboxylate rearranges to give the amide. 

Presumably intermediate thiophosphoric acids are first formed and, indeed, when the hydrolysis is carried out in aqueous NaOH solution at 100°, substantial amounts of the mono- and di-thiophosphates are obtained. P-S bonds are also retained during reaction of P4S10 with alcohols or phenols and the products formed are used extensively in industry for a wide variety of... 

Note It is occasionally recommended that sodium acetate be added to the reagent [2]. Thiophosphate insecticides with a simple P—S bond yield yellow chromatogram zones and those with a P=S double bond yield brown ones on a light brown background [10]. Further treatment of the stained chromatogram with iodine vapors increases the detection sensitivity [7] more than does spraying afterwards with caustic soda solution, which is also occasionally recommended [16, 17, 20, 21]. 

Demeton-S-methyl sulfone (hRf 0-5), dimethoate (h/ f 5-10), demeton-S-metlq (hRf 20-25), triazophos (h/ f 40-45), azinphos-methyl (hRf 40-45), azinphos-ethj (hRf 50-55), malathion (h/ f 60-65), parathion-methyl (hRf 75-80) and parathioo ethyl (h/ f 80-85) yielded yellow to brown chromatogram zones on a light brown bact ground, with thiophosphate insecticides with P = S double bonds appearing as brow zones and those with single P — S bonds as yellow zones. 

Metabolism of most OP pesticides yields alkylphosphates or alkyl-(di)-thiophosphates as a result of the hydrolysis of the P-X bond in the OP... 

The author hopes that this chapter has convinced the readers of the value of homogeneous catalysis for the synthesis of organophosphorus compounds and for organo-heteroatom compounds in a broader sense. Hydrosilylation and hydroboration are indispensable modern synthetic reactions in this category. The H-P addition reactions herein described joins them as a third member. Although this chapter does not cover, the addition reactions of the S-P and Se-P bonds in thiophosphates [39] and selenophosphates [40] to alkynes also proceed in the presence of transition metal catalysts. In view of the wide use of phosphorus compounds, the new procedures will find practical applications. 

N Reactions of the betaines I with initial cleavage of the P-N bond (type B) are rarely observed. One example is the reaction with hydrogen halides leading to dihalogeno phosphates and -thiophosphates ... 

A convenient method for the production of phosphorus-containing indoles with P-O-C bond may be the reaction of hydroxyindoles with the chlorides of phosphorus acids [59, 60, 158], 5-Hydroxyindole, obtained by the Nenitzescu reaction [160, 161], and amidophosphite (toluene, 110°C) form the unstable 5-phosphitoindoles 62 (132-124 ppm), which are isolated in the form of thiophosphates 63 (62-64 ppm) [159] ... 

There is a vast chemistry of organophosphorus compounds, and even for arsenic, antimony, and bismuth, the literature is voluminous. Consequently only a few topics can be discussed here. It must also be noted that we discuss only the compounds that have P—C bonds. Many compounds sometimes referred to as organophosphorus compounds that are widely used as insecticides, nerve poisons, and so on, as a result of their anticholinesterase activity, do not, in general, contain P—C bonds. They are usually organic esters of phosphates or thiophosphates examples are the well-known malathion and parathion, (EtO)2Pv(S)(0C6H4NO2). Compounds with P—C bonds are almost entirely synthetic, though a few rare examples occur in Nature. 

Further examples of the applications of thiophosphates in organic synthesis have been reported. The methodology based on intermediate thiophosphates (138) constitutes a general and convenient route to a wide range of conjugated non-linear trienynes (139). Thiophosphate (138) reacts readily with sodium derivative of dienynes to form (139) in one operation via single and double carbon-carbon bond formation (Scheme 41). ... 

Solubility products of collector-metallic ion compounds (see Appendix C) suggest that the sulfide mineral collectors such as xanthates, mercaptans and thiophosphates containing sulfur bonding atom in the minerophilic group can form compounds of low solubility products with ions of elements with affinity for copper(II). They can not form insoluble... 

S.2.3.4. Comparison of thiocarbonates with thiophosphates and thiocarbamates There are three types of reagents possessing the same bonding atoms but different central or linking atoms are shown below ... 

The mechanism of an actual hydrolysis reaction catalyzed by this prototype phosphomonoesterase has never been studied stereochemically. This apparent omission is presumably explained by the very low catalytic efficiency of the enzyme toward phosphorothioate monoesters as compared to phosphate monoesters (75) certainly, chiral [ O, 0]phosphorothioate 0-ester substrates already exist, and methodology is available for the configurational analysis of the chiral [ 0, 0, 0]thiophosphate that would be produced if the chiral substrate were hydrolyzed in H2. In fact, the low catalytic reactivity of phosphorothioate O-esters and the high reactivity of phosphorothioate S-esters has been explained by the enzyme utilizing nucleophilic catalysis (an associate mechanism) to achieve hydrolysis of the phosphate ester bond 40). 

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