Phosphonates s. Phosphonic

Phosphonate betaines 24,112 Phosphonates s. Phosphonic acid esters... 

If alkyl groups are attached to the ylide carbon atom, cis-olefins are formed at low temperatures with stereoselectivity up to 98Vo. Sodium bis(trimethylsilyl)amide is a recommended base for this purpose. Electron withdrawing groups at the ylide carbon atom give rise to trans-stereoselectivity. If the carbon atom is connected with a polyene, mixtures of cis- and rrans-alkenes are formed. The trans-olefin is also stereoseiectively produced when phosphonate diester a-carbanions are used, because the elimination of a phosphate ester anion is slow (W.S. Wadsworth, 1977). 

Adducts from various quaternary salts have been isolated, in reactions with aldehydes, a-ketoaldehydes, dialkylacylphosphonates and dialkyl-phosphonates, isocyanates, isothiocyanates, and so forth (Scheme 15) (36). The ylid (11) resulting from removal of a Cj proton from 3.4-dimethyl-S-p-hydroxyethylthiazolium iodide by NEtj in DMF gives with phenylisothiocyanate the stable dipolar adduct (12) that has been identified by its NMR spectrum and reactional product, such as acid addition and thiazolidine obtention via NaBH4 reduction (Scheme 16) (35). It must be mentioned that the adduct issued from di-p-tolylcarbodiimide is separated in its halohydrogenated form. An alkaline treatment occasions an easy ring expansion into a 1,4-thiazine derivative (Scheme 17) (35). 

Oligomeric Cyclic Phosphonates. Albright Wilson s Antiblaze 19 and 1045 are mixtures of the material shown where x = 1 has the CAS... 

Oligomeric Phosphate—Phosphonate. A commercially used reactive oligomeric alcohol, Akzo s Eyrol 51 [70715-06-9] has a stmcture approximately represented by (110) ... 

Antlblaze 19. Antiblaze 19 (Mobil), a flame retardant for polyester fibers (134), is a nontoxic mixture of cycHc phosphonate esters. Antiblaze 19 is 100% active, whereas Antiblaze 19T is a 93% active, low viscosity formulation for textile use. Both are miscible with water and are compatible with wetting agents, thickeners, buffers, and most disperse dye formulations. Antiblaze 19 or 19T can be diffused into 100% polyester fabrics by the Thermosol process for disperse dyeing and printing. This requires heating at 170—220°C for 30—60 s. 

The alkyl and alkoxy substituents of phosphate or phosphonate esters also affect the phosphorylating abiUty of the compound through steric and inductive effects. A satisfactory correlation has been developed between the quantitative measure of these effects, Tafts s O, and anticholinesterase activity as well as toxicity (33). Thus long-chain and highly branched alkyl and alkoxy groups attached to phosphoms promote high stabiUty and low biological activity. 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

CP can also be prepared by the reaction of cellulose with phosphoms oxychloride in pyridine (37) or ether in the presence of sodium hydroxide (38). For the most part these methods yield insoluble, cross-linked, CP with a low DS. A newer method based on reaction of cellulose with molten urea—H PO is claimed to give water soluble CP (39). The action of H PO and P2 5 cellulose in an alcohol diluent gives a stable, water-soluble CP with a high DS (>5% P) (40). These esters are dame resistant and have viscosities up to 6000 mPa-s(=cP) in 5 wt % solution. Cellulose dissolved in mixtures of DMF—N2O4 can be treated with PCl to give cellulose phosphite [37264-91-8] (41) containing 11.5% P and only 0.8% Cl. Cellulose phosphinate [67357-37-5] and cellulose phosphonate [37264-91 -8] h.a.ve been prepared (42). 

Nucleophiles like alcohols [2, S], hydrogen sulfide [2], thiols [2,10], ammonia, amines, hydrazines, hydroxylamines [2 11, 12, 13, 14, 75], azides [2], other pseudohalides [2], phosphonates [2,16,17,18,19, 20], and phosphanes [2,19] add rapidly across the CO or CN double bond to yield stable adducts The phosphonate adduets undergo a subsequent aleohol—lester rearrangement [19, 20] (equation 2)... 

The chiral BOX-copper(ll) complexes, (S)-21a and (l )-21b (X=OTf, SbFg), were found by Evans et al. to catalyze the enantioselective cycloaddition reactions of the a,/ -unsaturated acyl phosphonates 49 with ethyl vinyl ether 46a and the cyclic enol ethers 50 giving the cycloaddition products 51 and 52, respectively, in very high yields and ee as outlined in Scheme 4.33 [38b]. It is notable that the acyclic and cyclic enol ethers react highly stereoselectively and that the same enantiomer is formed using (S)-21a and (J )-21b as the catalyst. It is, furthermore, of practical importance that the cycloaddition reaction can proceed in the presence of only 0.2 mol% (J )-21a (X=SbF6) with minimal reduction in the yield of the cycloaddition product and no loss of enantioselectivity (93% ee). 

In contrast to allylic phosphine oxides, phosphonates, sulfones and sulfoxides, the chemistry of lithiated allylic sulfoximines has been less extensively developed25 27. The reaction of lithiated racemic A-phenyl-A -(4-rnethylphenyl)-S -(2-propenyl)sulfoximine with either 2-cy-clopentenone or 2-cyclohexenone gave a complicated mixture with 1,4-oc-ad ducts being slightly favored over the 1,4-7-adducts. The yields of these adducts were poor25. In contrast, lithiated racemic Ar-tert-butyldiphenylsilyl-5-phenyl-5,-(2-propenyl)sulfoximine gives mainly 1,4-y-ad-ducts on reaction with the same enones26. 

NOTE Periodic cleaning of softener resin with an iron stripping formulation based on phosphonate or a terpolymer is useful. The cleaner is introduced into the resin bed, perhaps via the brine draw during resin regeneration, at a level of, say, 1 to 2 U.S. pints/cuft (16-32 ml/l) of resin. The regeneration process is temporarily halted for several hours and the resin is allowed to soak the process is then restarted and the stripped iron goes to drain. 

There are many parallels between phosphates and sulfates of aliphatic alcohols. Both types of surfactants contain ester bonds undergoing hydrolysis in acid solutions. In that case the starting materials are received once more. By dry heating of the salts above a temperature of 140°C destruction will occur forming the corresponding alkenes and an inorganic acid salt. In the same way as sulfonic and sulfinic acids are formed by C-S bonds, C-P bonds lead to phosphonic and phosphinic acids. 

In contrast to the ester bond the P-C-bond of the phosphonic acid is hardly biologically degradable. The P-C bond will be principally but slowly degraded in the environment by the actinic sector of the sun s rays. 

The phosphotriesterase from Pseudomonas diminuta was shown to catalyze the enantioselective hydrolysis of several racemic phosphates (21), the Sp isomer reacting faster than the Rp compound [65,66]. Further improvements using directed evolution were achieved by first carrying out a restricted alanine-scan [67] (i.e. at predetermined amino acid positions alanine was introduced). Whenever an effect on activity/ enantioselectivity was observed, the position was defined as a hot spot. Subsequently, randomization at several hot spots was performed, which led to the identification of several highly (S)- or (R)-selective mutants [66]. A similar procedure was applied to the generation of mutant phosphotriesterases as catalysts in the kinetic resolution of racemic phosphonates [68]. 

C 1H15NO2S 3339-36-4) see. Tiemoniuin iodide (2-oxononyl)phosphonic acid dimethyl ester (C11H23O4P 57497-25-9) see Unoprostone isopropyl (S)-4-[[4-[(2-oxo-4-oxazolidinyl)methyl]phenyl]hydrazo-no]butanenitrile... 

The synthesis of S-phosphonothiazolin-2-one 133 started with 2-bromothiazole 129. Nucleophilic displacement of the 2-bromide proceeded cleanly with hot anhydrous sodium methoxide to give 2-methoxythiazole 130. Low-temperature metalation of 130 with n-butyl lithium occurred selectively at the 5-position (76), and subsequent electrophilic trapping with diethyl chlorophosphate produced the 5-phosphonate 131. Deprotection of 131 was accomplished either stepwise with mild acid to pn uce the thiazolin-2-one intermediate 132, or directly with trimethylsilyl bromide to give the free phosphonic acid 133, which was isolated as its cyclohexylammonium salt. 

De Clercq E, Descamps J, De Somer P, Holy A (1978) (S)-9-(2,3-Dihydroxypropyl)adenine an ahphatic nucleoside analog with broad-spectrum antiviral activity. Science 5 563-565 De Clercq E, Holy, A (2005) Acyclic nucleoside phosphonates a key class of antiviral drugs. Nature reviews 4 928-940... 

Wyles DL, Schooley RT, Kaihara KA, Beadle JR, Hostetler KY (2008) Anti-hepatitis C virus repli-con activity of alkoxyalkyl esters of (S)-HPMPA and other acyclic nucleoside phosphonates. In Abstracts of the 21st international conference on antiviral research, Montreal, QC, Canada, 13-17 April 2008. Antiviral Res 78 A21, no 15... 

Chan T-H, Xin Y-C, von Itzstein M (1997) Synthesis of phosphonic add analogs of siaUc acids (Neu5Ac and KDN) as potential sialidase inhibitors. J Org Chem 62 3500-3504 Chand P, Kotian PL, Dehghani A, El-Kattan Y, Lin T-H, Hutchison TL, Babu YS, Bantia S, Elliott AJ, Montgomery JA (2001) Systematic structure-based design and stereoselective synthesis of novel multisubstituted cyclopentane derivatives with potent antiinfluenza activity. J Med Chem 44 4379 392... 

Shie J-J, Fang J-M, Wang S-Y, Tsai K-C, Cheng Y-SE, Yang A-S, Hsiao S-C, Su C-Y, Wong C-H (2007) Synthesis of Tamiflu and its phosphonate congeners possessing potent anti-influenza activity. J Am Chem Soc 129 11892-11893... 

A nice application of this reaction for the synthesis of cyclic a-sulfanylphos-phonates 63 has been reported [42]. It involves a Rh(II)-catalyzed [2,3]-sigmatropic rearrangement and a ring-closing metathesis of the resulting a-(S-allyl) y,d-unsaturated phosphonates 62 (Scheme 16). However, the last step occurs with a low yield (19%) when R = H. 

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