Grotjahn, Douglas B.; Van, Sang; Combs, David; Lev, Daniel A.; Schneider, Christian; Rideout, Marc; Meyer, Christoph; Hernandez, Genaro; Mejorado, Lupe published their research in Journal of Organic Chemistry on December 27 ,2002. The article was titled 《New Flexible Synthesis of Pyrazoles with Different, Functionalized Substituents at C3 and C5》.Recommanded Product: 29004-73-7 The article contains the following contents:
Pyrazoles functionalized at the 3 and 5 positions without carbon substituents at nitrogen are prepared in short sequences from THP-protected 3-propyn-1-ol and 4-propyn-1-ol. Lithiation of protected alkynes THPO(CH2)nCCH (n = 1,2) followed by transmetalation with zinc chloride and addition of acid chlorides RCOCl (R = Me, Me2CH, Me3C, Ph) provides alkynones THPO(CH2)nCCCOR; the alkynones are also prepared by palladium-catalyzed coupling reactions of protected alkynols and acid chlorides RCOCl (R = Me2CH, Me3C, Ph, 1-adamantyl)in triethylamine. Exothermic addition of hydrazine hydrate to alkynones THPO(CH2)nCCCOR (n = 1,2; R = Me, Me2CH, Me3C, Ph, 1-adamantyl) provides pyrazoles I (n = 1,2; R = Me, Me2CH, Me3C, Ph, 1-adamantyl; R1 = THPO); acid deprotection followed by chlorination with thionyl chloride provides pyrazolealkyl chlorides I (n = 1,2; R = Me, Me2CH, Me3C, Ph, 1-adamantyl; R1 = Cl). Substitution of I with lithium diphenylphosphide or thiolate salts generated in situ provides I (n = 1,2; R = Me, Me2CH, Me3C, Ph, 1-adamantyl; R1 = Ph2P, MeS, PhS, HOCH2CH2S, Me3CS) with potential use as neutral monodentate ligands. Compounds such as I (n = 1; R = Me3C; R1 = Cl) have been prepared in 2 d on a 30 g scale in 71% overall yield. In the experiment, the researchers used many compounds, for example, (3-methyl-1H-pyrazol-5-yl)methanol(cas: 29004-73-7Recommanded Product: 29004-73-7)
(3-methyl-1H-pyrazol-5-yl)methanol(cas: 29004-73-7) belongs to pyrazoles. Pyrazoles and their related multiring analogs are common elements of a wide variety of bioactive compounds. These ring structures are rare in nature. A consequence of this is that they have previously been thought to be poor moieties to include in potential new drugs. Recommanded Product: 29004-73-7
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics