Cyclic phosphonate

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

The cyclic phosphonate ester analog of the cyclic transition state. Antibodies raised against this phosphonate ester act as enzymes they are catalysts that markedly accelerate the rate of ester hydrolysis. 

Various cyclic phosphonate esters 36 and 37 have been described previously as products from the HHT reaction of 25 with the appropriate cyclic phosphite. A complementary method has also been developed from the V-protected phosphonyl chloride 84, which was readily prepared from the corresponding phosphonic acid 83. Subsequent reaction of 84 with the appropriate diol produced the cyclic phosphonate esters 85 (63). Higher homologs of 85 have also been prepared from the analogous propane or butane diols. 

The cyclic phosphonate (115) is hydrolysed in acid with loss of MeOH whereas in basic solutions ring-opening occurs almost exclusively - a result in accord with the greater restriction on pseudorotation in a penta-covalent intermediate under basic conditions. 

MeO), cyclic phosphonates (50). The formation of (50) is strong evidence for the involvement of carbenes (51). Diethyl alkylphospho-nites (52) deoxygenate aromatic aldehydes upon heating only small amounts of the a-ethoxybenzylphosphinate (53), which is analogous to products obtained from trialkyl phosphites and aromatic aldehydes, are formed. 

ChH,4N505P H20 5 -Deoxy-5 -C-methyleneadenosine 3 -0,5 1-C-cyclic phosphonate, monohydrate (MADCMP)295... 

On the other hand, numerous examples are already known in which monomeric metaphosphoric esters are generated by thermolysis reactions. Most worthy of mention in this context is the gas phase pyrolysis of the cyclic phosphonate 150 which leads via a retro-Diels-Alder reaction to butadiene and monomeric methyl metaphosphate (151) 108,109, no). While most of the phosphorus appears as pyrophosphate and trimeric and polymeric metaphosphate, a low percentage (<5%) of products 152 and 153 is also found on condensation of the pyrolyzate in a cold trap containing diethylaniline or N,N,N, N,-tetraethyl-m-phenylene-diamine. The... 

Cyclic phosphonate analogues of hexopyranoses were debenzylated in MeOH-H20 on Pd/C. The system was purged with H2, and the reaction was run under 1 atm of H2 while being stirred vigorously. The reaction was complete after 12 hours. On the other hand, when sodium iodide in acetonitrile... 

The 2, 3 - (9,0-cyclic //-phosphonates 20a-d were formed, as ca 1 1 mixture of diastereomers (as monitored by 31P-NMR ), in the reaction of 5 -protected ribonu-cleosides 16a-d with diphenyl //-phosphonate in pyridine. Their sulfurization readily afforded the expected cyclic phosphorothioates 21a-d which upon subsequent removal of the 5 -protecting group afforded the respective nucleoside 2, 3 -0,0-cyclophosphorothioates 22a-d in excellent yields (70-90%) (Scheme 8) [23],... 

An alternative approach for the synthesis of 2, 3 -0,0-cyclic //-phosphonate 20a was based on the condensation of a mixture of uridine 3 - and 2 -//-phosphonates (23 and 24 respectively) induced by pivaloyl chloride (Scheme 9) [24], Its reaction with elemental sulfur in carbon disulfide gave 5 -0-DMT-uridine 2, 3 -cyclic phosphorothioate (21a) which after final deprotection afforded the desired 2, 3 -cyclic phosphorothioate 22a (Scheme 9). Its Sp and Rp diastereomers were separated by HPLC [24],... 

The cyclic phosphonate 41 was formed in the reaction of (/ )-l,l,2-triphenyl-1,2-ethanediol (40) with methanephosphonyl dichloride in a highly diastereoselective manner (dr=9 l) (Scheme 14) [31]. 

An elegant route to glycophostones (e.g. 131)—cyclic phosphonate analogs of biologically relevant sugars was proposed by Hanessian.56 Similar derivative 132 from diacetono-mannose was prepared by Cristau (Fig. 41).57... 

In reactions between the cyclic phosphonic chloride (137) and the diols (138), the composition of the reaction products that have not been thermally treated differ widely, depending on , the compound (139) that is initially formed evidently undergoing further change. When n=2, the product then consists of either (140) or (141)... 

Hydrogen-1. The Ha signal of the cyclic phosphonates (28) moved upheld to <5 6.2 p.p.m. when the N-aryl ring possessed two or/Ao-methyl groups.48 The shielding effect is even larger for the phosphorane (29), and Ha appeared at 5 5.9 p.p.m. 

Z-isomer.56 The isomers of the cyclic phosphonate (36) were assigned from the effect of Eu(dpm)3 on the methyl signal.67 Shifts of the butyl signals of tributyl phosphate by europium chloride have also been recorded.58... 

P—S bond is elongated to 196.5 pm and the P—0(H) bond shortened to 148 pm.164 The structures of the m-vinyl carbonate (136)165 and the cyclic phosphonic anhydride (96)123 have been determined, and for the latter compound the ring was found to be almost planar. A -Ray diffraction data of deoxyuridine phosphate,166 phospholipid multilayers,167 nucleotides,168 and skeletal muscle169 have been analysed. The crystal structure of the phosphazene (137) has been established.170... 

Despite continnons progress in amide bond formation, the acylation of hydroxylamine nnder carbodiimide promotion is often contaminated by Af,0-diacylation even with sub-stoichiometric amounts of acids. Appendino and colleagues have developed a practical solution to the problem by combining the in situ activation of carboxylic acids 102 with the cyclic phosphonic anhydride PPAA (103), and the generation of hydroxylamine from its corresponding hydrochloride to form 104 (Scheme 54). 

Fluorinated a-aminophosphonates containing two pendent alkene chains with catalyst la led to six- or seven-membered cyclic phosphonates as potential antibacterial reagents [36] (Sciieme 8.4). 

The cyclic phosphonate may be intercepted with hydroxylamine to yield the corresponding hydroxamate. Importantly, the rate of hydroxylaminolysis is approximately the same as ethanol loss, thus it appears that the cyclic phosphonate and not a precursor pentacovalent species is being trapped. Insofar as the analogy is appropriate, hydroxylamine is trapping an acyclic acyl phosphate in the above case, albeit at a rate faster than benzyl alcohol loss. It is also noteworthy that for both the phosphonate and phosphate esters there is no net transfer of oxygen from the carboxyl to phosphorus during the entire course of hydrolysis, i.e. loss of two moles of alcohol. 

Russian workers83 84 have synthesized a series of phosphorus-containing crowns utilizing O—P—O bonds in the macrocycle, i.e. cyclic phosphonate esters (7). One of these is claimed to have been prepared in 40% yield (equation 29). 

Since 02 is sterically prevented from attacking opposite 03 and can attack opposite 05" according to the preference rules given in the next section, an in-line mechanism is a simple proposal for step 1. On the other hand, in the hydrolysis the activated OH- attack must occur opposite either 02 or 03 and therefore must also be adjacent to one or the other as illustrated in Fig. 31. Pseudorotation allows such an attack to produce 3 -CMP and Usher s cyclic phosphonate experiments lend support to this hypothesis. 

Polyester One of the most successful commercially available FR polyester fiber is Trevira CS, which is produced by incorporating a comonomeric phosphinic acid unit into the PET polymeric chain. Examples of FR additives used in polyester are bisphenol-S-oligomer derivatives (Toyobo GH), cyclic phosphonates (Antiblaze CU and 1010, Rhodia), and phosphinate salts (Clariant). All these FRs do not promote char formation.3... 

Nucleophilic cleavage of the P-N bond(s) in 279 by MeOH provided new seven- and 10-membered cyclic phosphonic amidoesters 280 and 281 <1999JCM656>. Likewise, it was found that 282 underwent methanolysis along the longest P-N bond to give the 12-membered cyclic phosphinic ester 283 <2000JST(522)249>. 

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