scholarly journals Pyrimidine N-oxides. IV. The N,N'-dihydroxy derivatives of phenobarbital and veronal

1982 ◽  
Vol 35 (4) ◽  
pp. 795 ◽  
Author(s):  
W Cowden ◽  
NW Jacobsen
Keyword(s):  
Protecting Groups ◽  
Derivatives Of

5-Ethyl-1,3-dihydroxy-5-phenylbarbituric acid (N,N'-dihydroxyphenobarbital) and 5,5-diethyl-1,3-dihydroxybarbituric acid (N,N'-dihydroxyveronal) have been prepared by the condensation of 1,3-dibenzyloxyurea with ethylphenylmalonyl dichloride and diethylmalonyl dichloride respectively, followed by the removal of the benzyl protecting groups from the intermediate dibenzyloxy derivatives.

Bis(ether) derivatives of tetrakis(2-hydroxyphenyl)ethene — Direct synthesis of (E)- and (Z)-bis(2-hydroxyphenyl)-bis(2-methoxyphenyl)ethene via the McMurry olefination reaction

2006 ◽  
Vol 84 (10) ◽  
pp. 1250-1253 ◽  
Author(s):  
Mee-Kyung Chung ◽  
Paul Fancy ◽  
Jeffrey M Stryker
Keyword(s):  
Supramolecular Chemistry ◽  
Direct Synthesis ◽  
Protecting Groups ◽  
Tert Butyl ◽  
Orthogonal Protection ◽  
Protection Strategies ◽  
Titanium Trichloride ◽  
Sterically Hindered ◽  
Derivatives Of

The direct synthesis of sterically hindered, partially etherified derivatives of tetrakis(2-hydroxyphenyl)ethene is reported by using the McMurry reductive olefination reaction on a range of differentially substituted 2,2′-dialkoxy benzophenone substrates. Three orthogonal protection strategies are demonstrated, incorporating β-silylethyl, 3-butenyl, and tert-butyl protecting groups, respectively, into the starting benzophenones. The latter proved most efficient, with both the McMurry coupling and deprotection steps occurring concomitantly under the McMurry conditions to directly yield the desired bis(2-hydroxyphenyl)-bis(2-methoxyphenyl)ethene as a 1:1 mixture of E- and Z-diastereoisomers.Key words: preorganized polyaryloxide ligands, McMurry olefination, titanium trichloride, supramolecular chemistry, tetrakis(2-hydroxyphenyl)ethene, 2,2′-disubstituted benzophenone.

Introduction of 9-fluorenylmethyloxycarbonyl, trichloroethoxycarbonyl, and benzyloxycarbonyl amine protecting groups into O-unprotected hydroxyamino acids using succinimidyl carbonates

1982 ◽  
Vol 60 (8) ◽  
pp. 976-980 ◽  
Author(s):  
Alenka Paquet
Keyword(s):  
Benzyl Ester ◽  
Protecting Groups ◽  
Efficient Conversion ◽  
Hydroxyamino Acids ◽  
High Yields ◽  
Derivatives Of ◽  
Acid Esters ◽  
Efficient Reagent

9-Fluorenylmethyl succinimidyl, pentachlorophenyl, and benzotriazole-1-yl carbonates were prepared and their reactivity with L-serine and L-serine benzyl ester was compared. The most efficient reagent, 9-fluorenylmethyl succinimidyl carbonate, was used for the preparation of 9-fluorenylmethyloxycarbonyl derivatives of other hydroxyamino acids and hydroxyamino acid esters in high yields. The use of trichloroethyl and benzyl succinimidyl carbonates for an efficient conversion of hydroxyamino acids and their esters into the corresponding N-trichloroethoxycarbonyl and benzyloxycarbonyl derivatives is described.

1,3-syn-Diaxial Repulsion of Typical Protecting Groups Used in Carbohydrate Chemistry in 3-O-Substituted Derivatives of Isopropyl d-Idopyranosides

2017 ◽  
Vol 82 (17) ◽  
pp. 8897-8908 ◽  
Author(s):  
Bozhena S. Komarova ◽  
Alexey G. Gerbst ◽  
Anastasiia M. Finogenova ◽  
Andrey S. Dmitrenok ◽  
Yury E. Tsvetkov ◽  
...  
Keyword(s):  
Protecting Groups ◽  
Carbohydrate Chemistry ◽  
Derivatives Of

Preparation of 2'(3')-O-phosphonylmethyl derivatives of ribonucleosides

1983 ◽  
Vol 48 (3) ◽  
pp. 778-789 ◽  
Author(s):  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Alkali Metal ◽  
Metal Hydride ◽  
Sodium Hydride ◽  
Protecting Groups ◽  
Aqueous Alkali ◽  
Subsequent Hydrolysis ◽  
Derivatives Of ◽  
Alkali Metal Hydride

Reaction of 5'-O-tritylribonucleosides I with dimethyl p-toluenesulfonyloxymethanephosphonate (III) followed by hydrolysis afforded 2'(3')-O-phosphonylmethyluridine (IIa), -cytidine (IIb) and -adenosine (IIc). With 2',5'-di-O-trityluridine (IX), this procedure led to the 3'-isomer of IIa, with 3',5'-di-O-trityluridine (X) to the 2'-isomer. 5'-O-Trityluridine (Ia) and -cytidine (Ib) were converted by reaction with iodomethanephosphonic acid and N,N'-dicyclohexylcarbodiimide into the 2'(3')-O-iodomethanephosphonyl derivatives IVa, b which on reaction with sodium hydride and subsequent hydrolysis gave the compounds IIa and IIb. Reaction of compound I or 5'-O-benzoyluridine (VIII) with chloromethanephosphonyl dichloride (V) and removal of the protecting groups afforded 2'(3')-O-chloromethanephosphonylribonucleosides VI which on reaction with sodium hydride, or better with aqueous alkali, gave 2'(3')-O-phosphonylmethyl derivatives of uridine (IIa), cytidine (IIb), adenosine (IIc) and guanosine (IId). 2',3'-O-Isopropylideneribonucleosides XI reacted with the compound V to give, after hydrolysis, 5'-O-chloromethanephosphonyluridine (XIIa) and cytidine (XIIb). These compounds were not affected by an alkali metal hydride or hydroxide.

Approaches to the preparation of 3'-deoxynucleosides

1968 ◽  
Vol 21 (2) ◽  
pp. 513 ◽  
Author(s):  
GAR Johnston
Keyword(s):  
Acyl Migration ◽  
Protecting Groups ◽  
Nucleophilic Displacement ◽  
Iodination Reaction ◽  
Catalytic Hydrogenolysis ◽  
The Stability ◽  
Derivatives Of

The stability of 3'-O-sulphonyl derivatives of uridine towards nucleophilic displacement indicates that sulphonate replacement is unlikely to offer a general route to 3'-deoxynucleosides. The preparation of 3'-deoxyuridine by direct iodination of 2',5'-di-O-trityluridine with triphenylphosphite methiodide followed by catalytic hydrogenolysis is discussed as such a general route dependent on the availability of suitably protected nucleoside starting materials. Acyl migration takes place under the conditions of the iodination reaction, limiting the choice of protecting groups.

Comparison of Cytotoxicity of Mononucleoside Phosphotriester Derivatives Bearing Biolabile Phosphate Protecting Groups in Normal Human Bone Marrow Progenitor Cells

1996 ◽  
Vol 7 (6) ◽  
pp. 338-345 ◽  
Author(s):  
C. Périgaud ◽  
J.-L. Girardet ◽  
I. Lefebvre ◽  
M.-Y. Xie ◽  
A.-M. Aubertin ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Degradation Products ◽  
Human Peripheral Blood ◽  
Therapeutic Index ◽  
Protecting Groups ◽  
Peripheral Blood Mononuclear ◽  
Order Of Magnitude ◽  
Normal Human ◽  
Derivatives Of

The effects of three mononucleoside phosphotriester derivatives of 3′-azido-2′,3′-dideoxythymidine (AZT) which incorporate biolabile phosphate protecting groups, namely S-acetyl-2-thioethyl (MeSATE), S-(2-hydroxyethylsulfidyl)-2-thioethyl (DTE), and pivaloyloxymethyl (POM) were studied and compared to their nucleoside parent in human myeloid colony-forming cells. Moreover, the relative antiviral potency of these three pronucleotides were determined in primary human peripheral blood mononuclear cells infected with human immunodeficiency virus type 1. The results indicate that the SATE and DTE pro-moieties, as well as their degradation products, do not induce additional toxicity. The bis(MeSATE) phosphotriester derivative of AZT emerged as the most selective inhibitor with an in-vitro therapeutic index of the same order of magnitude as observed for AZT. This study has been extended to the corresponding bis(MeSATE) and bis(DTE) phosphotriester derivatives of 2′,3′-dideoxyuridine (ddU).

The Synthesis of Membrane Permeant Derivatives of myo-Inositol 1,4,5-Trisphosphate

2006 ◽  
Vol 59 (12) ◽  
pp. 887 ◽  
Author(s):  
Stuart J. Conway ◽  
Jan W. Thuring ◽  
Sylvain Andreu ◽  
Brynn T. Kvinlaug ◽  
H. Llewelyn Roderick ◽  
...  
Keyword(s):  
Second Messenger ◽  
Protecting Groups ◽  
Subsequent Removal ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Enzymes ◽  
Derivatives Of

In order to enable the study of the intracellular second messenger d-myo-inositol 1,4,5-trisphosphate (InsP3) and its receptors (InsP3Rs), it has been desirable to develop protected derivatives of InsP3 that are able to enter the cell, upon extracellular application. The subsequent removal of the lipophilic protecting groups, by intracellular enzymes, releases InsP3 and leads to the activation of InsP3Rs. Two syntheses of d-myo-inositol 1,4,5-trisphosphate hexakis(butyryloxymethyl) ester (d-InsP3/BM) and one of l-InsP3/BM are reported. It is demonstrated that extracellular application of the d-enantiomer results in Ca2+ release, which is thought to occur via InsP3Rs. Application of the l-enantiomer resulted in little Ca2+ release.

scholarly journals Branching out at C-2 of septanosides. Synthesis of 2-deoxy-2-C-alkyl/aryl septanosides from a bromo-oxepine

2012 ◽  
Vol 8 ◽  
pp. 522-527 ◽  
Author(s):  
Supriya Dey ◽  
Narayanaswamy Jayaraman
Keyword(s):  
Suzuki Reaction ◽  
Ring Expansion ◽  
Protecting Groups ◽  
Coupling Reactions ◽  
Sonogashira Coupling ◽  
Alkyl Aryl ◽  
Organometallic Reactions ◽  
Bond Forming ◽  
Derivatives Of ◽  
Cyclopropane Derivatives

This paper deals with the synthesis of 2-deoxy-2-C-alkyl/aryl septanosides. A range of such septanoside derivatives was synthesized by using a common bromo-oxepine intermediate, involving C–C bond forming organometallic reactions. Unsaturated, seven-membered septanoside vinyl bromides or bromo-oxepines, obtained through a ring expansion methodology of the cyclopropane derivatives of oxyglycals, displayed a good reactivity towards several acceptor moieties in C–C bond forming Heck, Suzuki and Sonogashira coupling reactions, thus affording 2-deoxy-2-C-alkyl/aryl septanosides. Whereas Heck and Sonogashira coupling reactions afforded 2-deoxy-2-C-alkenyl and -alkynyl derivatives, respectively, the Suzuki reaction afforded 2-deoxy-2-C-aryl septanosides. Deprotection and reduction of the 2-deoxy-2-alkenyl derivative afforded the corresponding 2-deoxy-2-C-alkyl septanoside free of protecting groups. The present study illustrates the reactivity of bromo-oxepine in the synthesis of hitherto unknown septanosides, branching out at C-2, through C–C bond formation with alkyl and aryl substituents.

The synthesis of oligoribonucleotides. III. The use of silyl protecting groups in nucleoside and nucleotide chemistry. VIII

1979 ◽  
Vol 57 (17) ◽  
pp. 2230-2238 ◽  
Author(s):  
Kelvin K. Ogilvie ◽  
Aria L. Schifman ◽  
Christopher L. Penney
Keyword(s):  
Protecting Groups ◽  
Protecting Group ◽  
Cautionary Note ◽  
Derivatives Of ◽  
Isomeric Mono

The synthesis of all isomeric mono- and disilyl derivatives of cytidine, guanosine, and their N-benzoyl analogues using the tert-butyldimethylsilyl protecting group is described. These compounds and those containing a 5′-monomethoxytrityl group have been condensed via the phosphodichloridite procedure to produce nucleotides rapidly and in good yields. The synthesis of 2′–5′-linked nucleotides is described. A cautionary note is introduced in regard to the preparation of 5′-monomethoxytritylguanosine and a novel methanolysis of certain N-benzoylcytidines is mentioned.

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