- Synthesis of phthalides from bis-propargyl ethers: Use of Garratt-Braverman cyclization to construct the phthalans and IBX as a new reagent for subsequent oxidation
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An efficient route to phthalides is described starting from easily available bis-propargyl ethers. The method involves Garratt-Braverman cyclization of the ethers to phthalans which are then efficiently oxidized to the phthalides by iodoxy benzoic acid (IBX) which has been shown to be a superior reagent in terms of yield and reagent stoichiometry for such a transformation in comparison with more commonly used KMnO4/CuSO4 reagent.
- Panja, Arpita,Das, Eshani,Maji, Manasi,Basak, Amit
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- Synthesis of Isobenzofuranones by Cobalt Catalyzed [2+2+2] Cycloaddition
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Highly regioselective cobalt catalyzed [2+2+2] cycloaddition of diynes and monoynes to afford isobenzofuranones in good yields is described. The reaction proceeds in the presence of cheap and readily available cobalt catalyst with a sterically hindered pyridine-2,6-diimine ligand. Applicability of the method can also be extended to the synthesis of isoindolinones.
- B?hme, Matthias,Leino, Reko,Méndez-Gálvez, Carolina,Savela, Risto
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- Diethyloxalate as “CO” Source for Palladium-Catalyzed Ethoxycarbonylation of Bromo- and Chloroarene Derivatives
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Palladium(II)-catalyzed ethoxycarbonylation of aryl bromides with diethyloxalate oxalate is described. Functionalized aromatic esters can be efficiently synthesized with only 0.65 mol % PdCl2(PPh3)2 catalyst under microwav
- Monrose, Amandine,Salembier, Helori,Bousquet, Till,Pellegrini, Sylvain,Pélinski, Lydie
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supporting information
p. 2699 - 2704
(2017/08/16)
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- INTERMEDIATES FOR THE PREPARATION OF CITALOPRAM AND ESCITALOPRAM
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Methods for manufacture of 5-alkoxycarbonylphthtalides are disclosed. The 5-alkoxycarbonylphthtalides are useful in syntheses of the well-known antidepresssants citalopram and escitalopram.
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- Method for the preparation of 5-cyanophthalide
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A method for the preparation of 5-cyanophthalide in which 5-carboxyphthalide is converted to the corresponding amide of Formula (IV) in which R is hydrogen or C1-6 alkyl, which is then reacted with a dehydrating agent thereby obtaining 5-cyanophthalide. The conversion of 5-carboxyphthalide to the corresponding amide of Formula (IV) may be carried out via the corresponding C1-6 alkyl or phenyl ester or the acid chloride, which is converted to the amide of Formula (IV) by amidation with ammonia or a C1-6 alkylamine. By the process 5-cyanophthalide, an important intermediate used in the preparation of the antidepressant citalopram, is prepared in high yields by a convenient, cost effective procedure.
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- Substituent Effects on Hydrogenation of Aromatic Rings: Hydrogenation vs. Hydrogenolysis in Cyclic Analogues of Benzyl Ethers.
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Carbalkoxy substituents are shown to retard the hydrogenation of aromatic rings over Rh/C catalyst.Hydrogenolysis predominates with acyclic (benzyloxy)acetates over this catalyst, but both hydrogenation and hydrogenolysis become sluggish with 2-isochroman-4-ones (1).However, phthalides may be cleanly hydrogenated in moderate to excellent yields without significant hydrogenolysis.Placing a benzyl ether in a ring system appears to greatly retard hydrogenolysis relative to the acyclic analogues.
- Anzalone, Luigi,Hirsch, Jerry A.
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p. 2128 - 2133
(2007/10/02)
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