Phosphoroamidates

Phenols. Phenols are unreactive toward chloroformates at room temperature and at elevated temperatures the yields of carbonates are relatively poor (< 10%) in the absence of catalysis. Many catalysts have been claimed in the patent Hterature that lead to high yields of carbonates from phenol and chloroformates. The use of catalyst is even more essential in the reaction of phenols and aryl chloroformates. Among the catalysts claimed are amphoteric metals or thek haUdes (16), magnesium haUdes (17), magnesium or manganese (18), secondary or tertiary amines such as imidazole (19), pyridine, quinoline, picoline (20—22), heterocycHc basic compounds (23) and carbonamides, thiocarbonamides, phosphoroamides, and sulfonamides (24). 

Locked nucleic acid (LNA) Peptide nucleic acid (PNA) Morpholine phosphoroamidate (MF)... 

Isosteric analogues of glycosyl phosphates phosphorothioates, boranophosphates, phosphoroamidates... 

Hashimoto and Ikegami have introduced glycosyl phosphoroamidates as glycosyl donors that combine the advantages of long shelf life with great efficiency in... 

The synthesis of the same trisaccharide core also illustrated the orthogonality between glycosyl phosphite and phosphoroamidate donors as well as between an... 

One way around this problem is to use imidazole as a catalyst.41,42 The ATP reacts with the amino group of the amino acid forming the phos-phoroamidate which does not polymerize. In the presence of imidazole (Im) the phosphoroamidate of the amino acid is converted to the imida-zolide (ImPA). 

In goose grass (E. indica), two alleles of a-tubulin 1 (each is the result of a single unique point mutation) have been described, which confer either an intermediate or high level of tolerance to a number of antimicrotubule herbicides, for example, dinitroanilines and phosphoroamidates (Anthony and Hussey, 1999 Yamamoto et al, 1998 Yamamoto and Bird, 1999 Zeng and Baird, 1997). A positive transformation system may be developed using these herbicides. 

Goodman, M.A., S.M. Aschmann, R. Atkinson, and A.M. Winer. 1988. Atmospheric reactions of a series of dimethyl phosphoroamidates and dimethyl phosphorothioamidates. Environ. Sci. Technol. 22 578-583. 

The structure of the complex of urease with urea in the active site is unknown, because the enzyme-substrate intermediate is very short-lived and has not been trapped. Nevertheless, a number of inhibitors of urease that bridge between the nickel atoms are known. Acetohydroxamate is the most studied and binds slowly but with high affinity (K = 4 vaM [25]). Phosphoroamide is also a slowly binding inhibitor. 2-Thioethanol causes the appearance of sulfur-to-nickel... 

This particular feature of P-N bond containing compounds can be utilized for synthetic purposes by using "phosphoryl protection" in the synthesis of amines based on alkylative procedures. The solution of this problem introducing two new reagents, i.e. diphenyl-phosphinic amide (I) and sodium N-(t-butyloxycarbonyl) diethyl phosphoroamidate (II) as useful synthetic equivalents of an amino moiety is the subject of this communication. 

Phase-transfer catalysed N-alkylation of diphenylphosphinic amide (I) is totally unsuitable in the case of easily hydrolysable organic halides, especially those containing additional functional groups (i.e. carbonyl or carboalkoxyl) which decompose readily in strongly alkaline medium. To circumvent the difficulty connected with simultaneous mono- and dialkylation of (I) under anhydrous conditions, N-(t-butyloxycarbonyl) diethyl phosphoroamidate (X), a doubly-protected ammonia derivative, was devised as a useful and superior substitute of phthalimide in the Gabriel-type synthesis of amines. 

Compound (X) is readily available by a simple two-step procedure involving transformation of diethyl phosphoroamidate (VIII) into the corresponding isocyanate 4j (IX) followed by addition of t-butanol to the carbonyl group ... 

It affords N-alkyl diethyl phosphoroamidates (XIII) which are potential starting materials for the preparation of secondary amines 5 ... 

SYNS AC 47470 AMERICAN CYANAMID CL-47470 CL-47,470 CYCLIC PROPYLENE piETHOXYPHOS-PHINYL)DITHIOIMIDOCARBONATE CYTROLANE p,p-DIETHYL CYCUC PROPYLENE ESTER of PHOSPHONODITHIOIMIDOCARBONIC ACID DIETHYL (4-METHYL-l, 3-DITHIOLAN-2-YLIDENE)-PHOSPHOROAMIDATE EI-47470 DENT25,991 MEPHOSFOLAN (4-METHYL-l,3-DITHIOLAN-2-YLIDENE)PHOSPHORAMIDIC ACID, DIETHYL ESTER... 

DIETHYL (4-METHYL-l, 3-DITHIOLAN-2-YLIDENE)PHOSPHOROAMIDATE see DHH400... 

The anti addition of diethyl 7V,Ar-dibromophosphoramidates to acyclic and cyclic alkenes was achieved in the presence of boron trifluoride, which makes the ionic dissociation of the N —Br bond more labile94,9s. After reduction of the initial /J,lV-dibromo adducts with sodium bisulfite, the /i-bromo-A -hydrophosphoramides 3 precursor of / -bromo amine hydrochlorides 4 were obtained (Table 4). However, a mixture of diastereomers was obtained from (Z)-l-phenyl-l-propene and (E)- and (Z)-l,2-diphenylethylene. Direct assignment of stereochemistry by H NMR of the phosphoroamidates derived from 2-butenes was not possible. Detailed analysis is, however, possible for the H-NMR spectra of the /J-bromo amine hydrochlorides. As determined by 31P NMR spectroscopy all additions to unsymmetrical aliphatic alkenes were not regiospecific. The /f-bromo amine hydrochlorides were converted to 1,2-diamines95. 

Dry HC1 is passed through the solution of diethyl A -(/ -bromoalkyl)phosphoroamidate (20 mmol) in 50 mL of ben ene for 1 h at 20 °C, then the solution is left at 20 CC for 24 h. Analytically pure samples of //-bromo amine hydrochlorides are obtained by dissolving the crude compounds in EtOH and adding an excess of Et20. 

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