With the optimal reaction conditions in hand, we then synthesized the selected barbiturate and thiobarbiturate derivatives by treating aldehydes [3-(p-methoxy) pyrazole aldehyde, 2-chloro quinoline aldehyde, Indole-3-carboxaldehyde and N,N-dimethyl benzaldehyde] with active methylene group containing compounds as barbituric acid, thiobarbituric acid and dimedone
using1-butyl-3-methylimidazolium hydroxide (2 mL) as solvent medium.
As an illustrative example in xanthene families, 1,8-dioxo-octahydroxanthenes can be mentioned which will be prepared by a condensation reaction between aryl aldehydes and dimedone
catalyzed in the presence of an acidic catalyst.
of isatin (1b), malononitrile (2a), dimedone
(3c) in the presence of (DABCO 30 mol%) at room temperature in H2O (5 ml) as a model reaction.
It should be noted that, for the detection of protein sulfenic acids, biotin conjugated dimedone
probes have been developed that only reacts with -SOH [122, 123]; therefore no blocking and reducing steps are needed.
A series of triazoloquinazolinones and benzimidazoquinazolinones has been achieved under microwave irradiation by the reaction of aromatic aldehydes with 5-amino-1(H)-1,2,4triazole (or 2-aminobenzimidazole) and dimedone
in DMF .
The method is complicated and has a lower yield; (3) by a three-component one-pot reaction of aromatic aldehydes, 5-amino-3-methyl-1-phenylpyrazole, and dimedone
under thermal  or microwave condition .
A comparative study of various nanoparticles ([Mn.sub.3][O.sub.4], CuO, CaO, MgO, and [Fe.sub.3][O.sub.4]), optimization of solvent, and temperature showed that nano-[Fe.sub.3][O.sub.4] (10 mol %) + solventfree conditions + 120[degrees] C as an efficient protocol for the synthesis (Scheme 5) of 1,8-dioxo-decahydroacridines, 2.3.6, from aldehyde, 2.3.5, dimedone
, 2.3.4, and aromatic amine in the presence of ammonium acetate 49].
A mixture of dimedone
1 (2 mmol), aromatic amine 2 (1 mmol), aromatic benzaldehyde 3 (1mmol), and 10mol% of Cu-doped ZnO nanocrystalline powder was heated in an oil bath at 90[degrees]C for 1.5 or 2 h.
Previous investigation of Glochidion multiloculare revealed glochidiol, glochilocudiol, glochidone and dimedone
(Talapatra etal., 1973).
To decrease the blank value a portion of 5-[[sup.14]C]methyltetrahydrofolate was purified just before use by treatment with dimedone
and extraction with toluene.
These catalyst were used for the synthesis of 2H-indazolo[2,1-b]phthalazine-1,6,11(13H)-trione derivatives by one-pot three-component reaction of phthalhydrazide, dimedone
and aromatic aldehydes under solvent-free conditions.
In the course of our study on the multicomponent reaction, we carried out the one-pot, three-component reaction of substituted benzaldehyde 1, dimedone
2 and malononitrile 3 in the presence of a catalytic amount of DABCO (10 mol%) in dioxan to give corresponding 4H-pyans 5 (Scheme-1).