- A quantitative structure-activity relationship study of herbicidal analogues of α-hydroxy-substituted 3-benzylidenepyrrolidene-2,4-diones
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A series of pyrrolidine-2,4-dione and piperidine-2,4-dione derivatives were prepared and evaluated for their herbicidal activities where some of these compounds exhibited good bioactivity against Echinochloa crus-galli in comparison with sulcotrione. Quan
- Zhu, You-Quan,Liu, Pei,Si, Xue-Kai,Zou, Xiao-Mao,Liu, Bin,Song, Hai-Bin,Yang, Hua-Zheng
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p. 7200 - 7205
(2008/02/03)
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- One dimensional unichemo protection (UCP) in organic synthesis
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A protected template molecule and a new one-dimensional UniChemo Protection (UCP) organic synthetic method for preparing polyfunctional organic molecules is described. The synthetic method can be used with many kinds of chemical reactions and provides selective access to many functional groups in a template molecule. The method utilizes protection groups that are each composed of building block units that can be removed one by one affording a new protection group one unit shorter or exposing a functional group on the template molecule. The exposed functional group on the template molecule can react with a target group. Different target groups can be introduced into the template molecule by using protection groups containing different numbers of building block units.
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- Reductive amination of aldehydes and ketones with sodium triacetoxyborohydride. Studies on direct and indirect reductive amination procedures
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Sodium triacetoxyborohydride is presented as a general reducing agent for the reductive amination of aldehydes and ketones. Procedures for using this mild and selective reagent have been developed for a wide variety of substrates. The scope of the reaction includes aliphatic acyclic and cyclic ketones, aliphatic and aromatic aldehydes, and primary and secondary amines including a variety of weakly basic and nonbasic amines. Limitations include reactions with aromatic and unsaturated ketones and some sterically hindered ketones and amines. 1,2-Dichloroethane (DCE) is the preferred reaction solvent, but reactions can also be carried out in tetrahydrofuran (THF) and occasionally in acetonitrile. Acetic acid may be used as catalyst with ketone reactions, but it is generally not needed with aldehydes. The procedure is carried out effectively in the presence of acid sensitive functional groups such as acetals and ketals; it can also be carried out in the presence of reducible functional groups such as C-C multiple bonds and cyano and nitro groups. Reactions are generally faster in DCE than in THF, and in both solvents, reactions are faster in the presence of AcOH. In comparison with other reductive amination procedures such as NaBH3CN/MeOH, borane-pyridine, and catalytic hydrogenation, NaBH(OAc)3 gave consistently higher yields and fewer side products. In the reductive amination of some aldehydes with primary amines where dialkylation is a problem we adopted a stepwise procedure involving imine formation in MeOH followed by reduction with NaBH4.
- Abdel-Magid, Ahmed F.,Carson, Kenneth G.,Harris, Bruce D.,Maryanoff, Cynthia A.,Shah, Rekha D.
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p. 3849 - 3862
(2007/10/03)
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