Synthesis of oleophilic electron-rich phenylhydrazines

• Aleksandra Jankowiak and
• Piotr Kaszyński

Beilstein J. Org. Chem. 2012, 8, 275–282, doi:10.3762/bjoc.8.29

• : arylhydrazines; methodology; synthesis; Introduction Mono-arylhydrazines I are important intermediates in the synthesis of a number of heterocycles, including indoles [1] and some azoles (for example [2][3]), many of which exhibit biological activity and are used in drug development [4][5][6]. Arylhydrazines

• obtained by using classical methods, such as the reduction of diazonium salts [13][14][15]. In contrast, electron-rich arylhydrazines are far less numerous and their preparation is complicated by oxidative instability. To access functionalized and sensitive arylhydrazines several methods involving the

• arylboronic acid V to AD [18][19][20]. The latter method is especially suited for arylhydrazides substituted with sensitive functional groups. Protected electron-rich arylhydrazines, hydrazides II, containing the 2,2,2-trichloroethyl group (R = CH2CCl3) are conveniently prepared by direct electrophilic

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• the two possible regioisomers was obtained preferentially depending on the hydrazine derivatives used, N-alkyl- and N-arylhydrazines giving opposite regioselectivities [15]. The carbonylative coupling of terminal alkynes with aryl (and heteroaryl) halides was proposed by Mori and coworkers as a

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• formed through a AuPPh3Cl catalyzed cyclization reaction [139]. Using gold complex [XPhosAu(NCCH3)SbF6] as the catalyst, Jurberg and Gagosz prepared the cinnoline derivatives 261 by the hydroarylation of N-propargyl-N-arylhydrazines 260 [140]. With the gold complex [Mes3PAu]NTf2, an alkynyl ether moiety

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• reaction of 2-chloro-2-chlorodifluoro/trifluoromethyl-1-cyano-1-diethoxy phosphorylethylene 108 with arylhydrazines in refluxing carbon tetrachloride results in the rapid replacement of the chlorine atom with the terminal NH2 group of arylhydrazines to give intermediates 109, which is slowly transformed

• phosphonates (TFMCPs) 111 with arylhydrazines have been studied: TFMCPs 111 can be used as precursors of 2,3-dihydro-1H-pyrazoles 114 modified by both trifluoromethyl and diethoxyphosphoryl groups. Arylhydrazines add rapidly to the alkene double bond of 111 (X = CF3) at room temperature to produce an adduct