Phosphoramidates cyclic

BIS(2-CHLOROETHYL)PHOSPHORAMIDE CYCLIC PROPANOLAMIDE ESTER MONOHYDRATE see CQC500... 

Carbohydrate phosphoramidates Cyclic phosphoric acid esters... 

The present preparation illustrates a general and convenient irethod for ring contraction of cyclic ketones. The first step is the usual procedure for the preparation of enamines. The second step involves 1,3-dipolar cycloaddition of diphenyl phosphorazidate to an enamine followed by ring contraction with evolution of nitrogen. Ethyl acetate and tetrahydrofuran can be used as a solvent in place of toluene. Pyrrolidine enamines from various cyclic ketones smoothly undergo the reaction under similar reaction conditions. Diphenyl (cycloalkyl-1-pyrrolidinylmethylene)phosphoramidates with 5,6,7, and 15 members in the ring have been prepared in yields of 68-76%. 

Applications of oxazaphospholidine-borane complexes, cyclic phosphoramides, compounds with N—P=0 function, and other P-heterocycles in enantio-selective catalysis 99SL377. 

Cyclic phosphoramidates (phosphoric amides) were obtained by the reaction of amino alcohols with a phosphoric diimidazolide.tl933,[2]... 

Pavan Kumar et al. <2006NJC717> investigated the reaction of diethyl azodicarboxylate (DEAD) or diisopropyl azodicarboxylate (DIAD) with cyclic phosphates or phosphoramides in order to determine the structural preferences in spirocyclic penta- and hexacoordinate aminophosphoranes. They found that sulfur would coordinate to phosphorus to form the [3.3.0] bicyclic compounds 94-96. 

Cyclophosphamide (Cytoxan) is the most versatile and useful of the nitrogen mustards. Preclinical testing showed it to have a favorable therapeutic index and to possess the broadest spectrum of antitumor activity of all alkylating agents. As with the other nitrogen mustards, cyclophosphamide administration results in the formation of cross-links within DNA due to a reaction of the two chloroethyl moieties of cyclophosphamide with adjacent nucleotide bases. Cyclophosphamide must be activated metabofically by microsomal enzymes of the cytochrome P450 system before ionization of the chloride atoms and formation of the cyclic ethylenimmonium ion can occur. The metabolites phosphoramide mustard and acrolein are thought to be the ultimate active cytotoxic moiety derived from cyclophosphamide. 

In all of the foregoing examples, an activated derivative of the nucleotide has been employed for generating the pyrophosphate link. An attempt to use an activated glycosyl phosphate failed 311 the only product identified from the reaction between /3-D-glucopyranosyl phosphoramidate (68) and uridine 5 -phosphate was the cyclic phosphate 69. The ease of participation of the sterically accessible, C-2 hydroxyl group probably accounts for this result. The usual procedure... 

T0 prepare models of TA, the corresponding cyclic alkylene phosphoric acids cannot be directly polymerized because the presence of acidic protons of the phosphate group makes the ionic polymerization impossible. Thus, cyclic phosphorus compounds with blocked third functions have to be used. These are phosphates., phosphoramidates and phosphites. After polymerization the obtained polymer is converted by deblocking into the polyalkylene phosphate, e.g. polysalt or polyacid form. 

Cyclic oligomeric oxolanyl alkanes were used when diene polymerization utilized a lithium-based initiator. Cyclic oligomeric oxolanyl alkanes are described by Lin [1] and include 2-2 -di(tetrahydrofuryl) propane, dipiperidyl ethane, hexamethyl phosphoramide, N-N -dimethyl piperazine, and diazabicyclooctane. 

The X-ray structure of [Zn2(8-H)F is shown in Pig. 2. The p for the doubly coordinated pendant alcohol is below 4, in accord with corresponding measurements made on water molecules coordinated to a pair of Zn(II) ions in a cyclic octaamine (<7) 22), or in a cyclic tetraamine with four pendant amines (<5.3) 23). On reaction with 4-nitrophenyl phosphate, 4-nitrophenol is released and a complexed phosphoramide is produced, [Zn2(9)] +, resulting from attack of a secondary amine at phosphorus. 

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... 

The reaction of simple cyclic vinyl aziridines with organozinc reagents typically provides the 1,4-addition product <2003TL8559>. Several binaphthyl phosphoramidate ligands were examined. In all cases, the /ra r-product 159a was the major product. When no catalyst was used a roughly 1 1 mixture of the trans. cis product was obtained. The use of the chiral phosphoramidate catalyst provided 159a with moderate % ee values (Equation 43). 

The phosphoramide-catalyzed allylic additions to aldehydes have also been extended to include stereoselective crotylations. When using geometrically defined 2-butenyltrichlorosilanes, additions to benzaldehyde afford homoallylic alcohols in good yields and excellent diastereoselectivity (eq 11). Enantioselectivities, however, remain comparable to the results for allylic additions. Interestingly, the crotylation results suggest that addition proceeds through a cyclic transition structure. ... 

The arylsulfonyl carbanion accelerated Claisen rearrangement is completely regioselective and has also been found to be highly diastereoselective (Scheme 2). The stereochemical course of the reaction conforms to the familiar chair-like transition state model usually invoked for the classic thermal process. Recently, high degrees of asymmetric induction have been observed in tlie rearrangements of chiral cyclic phosphoramidate stabilized carbanion derivatives. ... 

New synthetic pathways for the preparation of chiral cyclic oxaza- and diaza-phosphoramidates suitable for use in asymmetric chemistry were studied with respect to the imide-amide rearrangement of cyclic phosphorimidates (Scheme 23). New types of oligomeric organophosphorus compounds (112), formed by a novel ring opening polymerisation, have been identified. These compounds are stable intermediates in the imide-amide rearrangement. 

Reactions of Phosphoric Acids and Their Derivatives. - Numerous investigations of phosphate ester hydrolysis continue to be reported. The hydrolysis between 1.5 < pH < 4 of five- and six-membered cyclic phosphoramides (71) has been followed by UV and NMR spectroscopy. Small differences in hydrolysis reactivity for n = 5 and n = 6 constitutes evidence for syn lone pair catalysis. The product ratios from the hydrolysis shows that in the five-membered rings the main product is the one produced by endocyclic cleavage meanwhile, in the six- membered cyclic phosphoramide the kinetic product is the one produced by exocyclic cleavage. The syn orientation of two electron pairs on nitrogen stabilizes the transition state of water approach to the phosphoramides by ca. 3 kcal/moN when compared to the orthogonal attack. (Scheme 12). ... 

---