one-pot preparation of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles has been conducted in the presence of poly(4-vinylpyridinium butane sulfonic acid) hydrogen sulfate, p(4vpbsa)hso4, as an efficient dual acidic catalyst under solvent-free conditions. reusability of the catalyst, easy work-up procedure, eco-friendly reaction conditions, short reaction times and high yields of th...

A convenient and highly efficient procedure for the synthesis of 3,4-dihydropyrimidin-2-(1H)-one/thione derivatives via one-pot three-component Biginelli condensation of arylaldehydes,urea/thiourea and ethyl/methyl acetoacetate in the presence of Zn(SO4)2.7H2Oas anefficient, readily and inexpensive catalyst under solvent-free conditions have been studied. Thisprotocol ha...

a highly efficient, simple and clean solvent-free protocol for the synthesis of polyhydroquinolines is described. the one-pot multi-component condensation reaction between arylaldehydes, dimedone (5,5-dimethylcyclohexane-1,3-dione), β-ketoesters and ammonium acetate in the presence of catalytic amount of (2.5 mol%) melamine trisulfonic acid (mtsa) as a recyclable, green and attractive sulfonic ...

A green and convenient method for the synthesis of 2-amino-3-phenylsulphonyl-4H-chromenes by a one-pot three-component condensation of 1-naphthol, phenylsulphonylacetonitrile and aromatic aldehydes under solvent-free conditions using potassium phosphate tribasic trihydrate as an efficient catalyst is described. The reaction of 1-naphthol with phenylsulphonylacetonitrile and various aromatic...

a highly efficient and simple method for the preparation of α,α´-bis(arylidene)cycloalkanones under solvent-free conditions has been developed. the crossed-aldol condensation of cycloalkanones (1 eq.) with arylaldehydes (2 eq.) in the presence of 2.5 mol% of ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate {[dsim]hso4} afforded the title compounds in high yields and short reaction ...

A Simple and environmentally friendly  procedure for the one-pot multi-component synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives has been developed by one pot three component reaction of various aldehydes, β-dicarbonyl, and urea in the presence of catalytic amount of tris (trihexyltetradecylphosphonium) gadolinium hexachloride [P6,6,6,14]3 [GdCl6] as a solid acid catalyst without any ad...

Nano-cellulose with high amount of free OH groups could be used as supporting agents for boron trifluoride (BF3). Nano-BF3/cellulose is a solid acid and a biodegradable catalyst which was prepared via reaction of nano-cellulose and BF3. The structure of this catalyst was studied by FT-IR, FESEM, TEM, XRD, EDS, TGA, XRF and BET. In this research, the synthesis of...

Cellulose sulfuric acid is an efficient metal-free catalyst for the synthesis of 1,3,5-trisubstituted pyrazoles via the condensation of 1,3-diketones and hydrazines. The reaction was carried out in Solvent-free condition at room temperature and the products were isolated in good to excellent yields. Mild reaction conditions, as well as ease of operation and workup are some advantages of the pro...

a  convenient  and  efficient  one-pot  four-component  synthesis  of  1,  2,  4,  5-tetrasubstituted  imidazoles  using  nano  tio2  as  a  recyclable  catalyst  is  reported.  the results  show  that  the  methodology  has  several  advantages  such  as  low  loading  of catalyst,  excellent  yield,  short  reaction  time,  operational  simplicity  and  solvent-free conditions.

molybdate sulfuric acid (msa) has been prepared and used as catalyst for the biginelli synthesis of some quinazolinones/thiones under solvent-free conditions. the catalyst loading is low and it shows recyclability. this method has advantages such as avoidance of the organic solvents, high yield of pure products, short reaction times and operational simplicity.