Aryl

About: Aryl is a research topic. Over the lifetime, 95605 publications have been published within this topic receiving 1376401 citations. The topic is also known as: aryl group.

Nonionic nucleic acid alkyl and aryl phosphonates and processes for manufacture and use thereof

Abstract: Oligonucleoside alkyl-- or aryl phosphonates are nonionic analogues of nucleic acid which possess unique physical and biological properties. These properties enable the analogues to enter living cells intact and to bind with specifically selected nucleic acids within the cell. As a result, the analogues can specifically inhibit the function or expression of a preselected nucleic acid sequence. Thus the analogues could be used to specifically inhibit the growth of tumor cells or replication of viruses in infected cells. Four methods are provided for preparing oligonucleoside methylphosphonates: (1) Coupling a protected nucleoside 3'-alkyl or aryl phosphonate with the 5'-hydroxyl group of a protected nucleoside using a condensing agent; (2) Coupling protected nucleoside 3'-alkyl or aryl phosphonic acid derivative with the 5'-hydroxy group of a protected nucleoside with the activated alkyl or aryl phosphonic acid derivative possessing functionalities which are good leaving groups; (3) Coupling a protected nucleoside 3'-alkyl or aryl phosphinate derivative with the 5'-hydroxyl group of a protected nucleoside with the resulting phosphinate derivative being then oxidized to the phosphonate; and (4) Converting a oligonucleoside methoxyphosphite derivative to the alkyl or aryl phosphonate derivative by reaction with an alkyl or aryl iodide. It has been demonstrated that procedures (1) and (2) can be used to prepare oligonucleoside methylphosphonates. Others have shown that procedure (4) can be used to prepare a diribonucleoside methylphosphonate.

Attachment of organic layers to conductive or semiconductive surfaces by reduction of diazonium salts

Abstract: Surface chemistry is the topic of this tutorial review. It describes the electrochemical reduction of aryl diazonium salts on carbon, silicon or metals which leads to the formation of an aromatic organic layer covalently bonded to the surface. The method which permits such a modification is set forth. The proof for the existence of the organic layer is brought forward. The grafting mechanism and the covalent bonding between the surface and the aryl group are discussed. The formation of mono or multilayers depending on the experimental conditions is rationalized. Finally some examples of the possible uses of this reaction are given.

Highly Active Palladium Catalysts for Suzuki Coupling Reactions

Abstract: Mixtures of palladium acetate and o-(di-tert-butylphosphino)biphenyl (4) catalyze the room-temperature Suzuki coupling of aryl bromides and aryl chlorides with 0.5−1.0 mol % Pd. Use of o-(dicyclohexylphosphino)biphenyl (2) allows Suzuki couplings to be carried out at low catalyst loadings (0.000001−0.02 mol % Pd). The process tolerates a broad range of functional groups and substrate combinations including the use of sterically hindered substrates. This is the most active catalyst system in terms of reaction temperature, turnover number, and steric tolerance which has been reported to date.