Note Synthesis of coumarin by Yb(0Tf) catalyzed Pechmann
this condensation reaction have been used too The development of alternative environmentally friendly synthetic methods of coumarins is of interest Synthesis of 7-hydroxycoumarin derivatives via the Pechmann reaction catalyzed solid acid catalysts (e g , zeolite H-beta14, W/Zr0 2 15 ) in retluxing toluene has been reported
SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF MESOPOROUS MN
the pechmann reaction[6] Gunnewegh and al [2] first reported pechmann condensation of resorcinol and ethyl acetoacetate over zeolithe HB in toluene to obtain 7-hydroxy-4- methylcoumarin In this paper,we report the synthesis and characterisation of such materials
An Efficient and Simple Procedure for the Synthesis of 4
compounds These include Perkin,3a Pechmann,3b Knoevenagel,3c Reformatsky3d and Wittig3e reactions Among these, the Pechmann reaction has been the most widely used method since it proceeds from very simple starting materials and gives good yields of variously substituted coumarins Classically, the process consists of the condensation of
Catalytic performance of Metal-Organic-Frameworks vs extra
Pechmann condensation is a reaction of phenols with beta-ketonic esters or unsaturated carboxylic acids grafted on MCM-41 (de Villa et al , 2005), ZnCl 2 www frontiersin
Current Organic Chemistry, , 20, Recent Advances in the
Pechmann condensation of ethyl 4-chloroacetoacetate 12 and resorcinol or its 6-halogenated (H, F and Cl) derivatives 16 in pres- ence of catalytic amount of a sulphuric acid gave coumarin ring
DIFFERENTIAL ACRIDINE ORANGE STAINING OF HUMAN CHROMOSOMES
The differential staining of the metaphases with AO appears to be useful in de monstrating regions of the chromosomes with a different rate of reassociation after denaturation In our experiments the method showed a relatively consistent banding pattern in several metaphases This fact and the reverse picture given by the sequence
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