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1.
Abstract

Reaction of N-blocked amino acid chlorides with trialkyl phosphites is a first step in the synthesis of 2-amino-l-hydroxyalkylphosphonates. Quite surprisingly a very purl trialkyl phosphite is required m order to obtain the desired N-blocked 2-amino-1-oxoalkylphosphonate. Thus, the use of commercially rvailrble phosphites prolongation of the reaction time, or attempts for chromatographic purification of the formed oxophosphonate resulted m quite complicated mixture of products. We haw found that these products arise as a consequence of rearrangements of 1oxo-2. phtalylnmmoalLylphosphonates in a series of reactions which are promoted by that presence of dialkyl phosphite (standard impurity present m commercially availablt trialkyl phosphites) in the reaction medium.  相似文献   

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Various dialkyl chlorophosphates are prepared by the reaction of TeCI4 with di-or trialkyl phosphites in good yields.  相似文献   

6.
Trialkyl phosphites react with diacylals of di- and trichloroacetic acids by the pathway of the Perkow reaction; with monoacylals of bromo- and iodoacetic acids, by the pathway of the classical Arbuzov reaction; and with monoacylals of di- and trichloroacetic acids, by the pathway of the nonclassical Arbuzov reaction.  相似文献   

7.
The title reaction has been applied to 10 monosubstituted p-benzoquinones (Scheme 2, Table). The regioselectively of the O-phosphorylation is influenced by bulky substituents (t-butyl and trimethylsilyl) and, electronically, by the methoxy group. The regioselectivity, which is high in nonpolar media (benzene), is lower in polar solvents (CH2Cl2) and (CH3CN). The synthetic potential of this transformation, exemplified by the preparation of compounds 29 (Scheme 3) and 32 (Scheme 4), is considerably extended by applying milder methods for the phosphate hydrolysis and by using the reagent couple P(OCH3)3/trimethylsilyl chloride, which gives clean access to p-hydroxyphenyl phosphates. p-Benzoquinones 4th and 4i with strong π-acceptor substituents react in a different way, giving phosphonates. The electronically induced regioselectivity of the O-phosphorylation is in according with the preferences expected for the attack by a nucleophilic phosphorylation agent.  相似文献   

8.
Benzyl phosphites were used in the Micaelis-Arbuzov reaction. Special experimental conditions allowed preparation of a set of phosphonate analogs of mono-, di-, and triphosphate. Furthermore, regioselective monodeprotection makes these molecules useful building blocks for the synthesis of analogs of polyphosphorylated compounds of biological interest (e.g. nucleotides), after removal of all phosphonate benzyl ester groups under very mild conditions and high yields.  相似文献   

9.
Summary. The reaction of dialkyl acetylenedicarboxylates with trialkyl(aryl) phosphites in the presence of isatin, phthalimide, indole, or pyrrole leads to stable dialkyl(aryl) phosphorylsuccinates in excellent yields.  相似文献   

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5-(1-Haloethyl)furan-2-carboxylic acid derivatives react with sodium dialkyl phosphite, tri-alkyl phosphite in two directions to form phosphonates and alkenes. The alkene fraction in the reaction pro-ducts diminishes as the electron-acceptor power of the 2-substituent in the ring increases in going from dialkylamide to ether and then to nitrile. 5-Bromoethyl-2-cyanofuran reacts with sodium diethyl phosphite to give no other products than those formed by halogenophilic attack, implying a significant withdrawal of the electron density from the bromine atom in this compound.  相似文献   

13.
Dialkyl [2-hydroxy-5-(phenylazo)benzyl]phosphonates were prepared by a convenient procedure in good yield from Mannich base and trialkyl phosphite in benzene with the elimination of ammonium or morpholinium cation. 2-[(Dialkylamino)methyl]-4-(phenylazo)phenol methiodide is a new reagent in the Michaelis-Arbuzov reaction.  相似文献   

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Barbier-type allylation of aldimines with allylzinc bromide took place rapidly under solvent-free conditions. The procedure is environmentally benign and operationally simple, has good regioselectivity, and gives good to excellent yields.  相似文献   

16.
N-(Trichloroacetyl)trichloroacetylimidoyl chloride reacts with trialkyl phosphites with substitution of the imidoyl chlorine atom and formation of C-phosphorylated heterodienes. The reaction with triphenyl phosphite or o-phenylene diethylphosphoroamidite proceeds as [4+1]-cycloaddition to give mono- or spirocyclic oxazaphospholines with the five-coordinate phosphorus atom. Dialkyl or diphenyl hydrogen phosphites add across the C = N bond of imidoyl chloride to give labile N-(-phosphorylated) trichloroacetamides.  相似文献   

17.
It is shown that (−)-(S)-N,N-dimethyl-2-(1′-methylallyl)aniline ((−)-(S)- 4 ), on direct irradiation in MeCN at 20°, undergoes in its lowest-lying triplet state an aromatic di-π-methane (ADPM) rearrangement to yield (−)-(1′R,2′R)- and (+)-(1′R,2′S)-N,N-dimethyl-2-(2-methylcyclopropyl)aniline ((−)-trans- and (+)-cis- 7 ) in an initial trans/cis ratio of 4.71 ± 0.14 and in optical yields of 28.8 ± 5.2% and 15 ± 5%, respectively. The ADPM rearrangement of (−)-(S)- 4 to the trans- and cis-configurated products occurs with a preponderance of the path leading to retention of configuration at the pivot atom (C(1′) in the reactant and C(2′) in the products) for (−)-trans- 7 and to inversion of configuration for (+)-cis- 7 , respectively. The results can be rationalized by assuming reaction paths which involve the occurrence of discrete 1,4- and 1,3-diradicals (cf. Schemes 10, 12, and 13). A general analysis of such ADPM rearrangements which allows the classification of these photochemical reactions in terms of borderline cases is presented (Scheme 14). It is found that the optical yields in these ‘step-by-step’ rearrangements are determined by the first step, i.e. by the disrotatory bond formation between C(2) of the aromatic moiety and C(2′) of the allylic side chain leading to the generation of the 1,4-diradicals. Moderation of the optical yields can occur in the ring closure of the 1,3-diradicals to the final products, which may take place with different trans/cis-ratios for the individual 1,3-diradicals. Compounds (−)-trans- 7 as well as (+)-cis- 7 easily undergo the well-known photochemical trans/cis-isomerization. It mainly leads to racemization. However, a small part of the molecules shows trans/cis-isomerization with inversion of configuration at C(1′), which is best explained by a photochemical cleavage of the C(1′)–C(3′) bond.  相似文献   

18.
Summary. The reaction between trialkyl(aryl) phosphites and dibenzoylacetylene or dimethyl acetylenedicarboxylate in the presence of 4-nitrophenol leads to stable meso-bisphosphonate derivatives in good yields.  相似文献   

19.
The reaction between trialkyl(aryl) phosphites and dibenzoylacetylene or dimethyl acetylenedicarboxylate in the presence of 4-nitrophenol leads to stable meso-bisphosphonate derivatives in good yields.  相似文献   

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