in this work, so3h-functionalizedphthalimide (sfp) as a so3h-containing solid acid is prepared by the reaction of phthalimide with chlorosulfonic acid, and characterized by ft-ir, 1h and 13c nmr, mass, tg, dtg, xrd and sem. then, it is utilized as a highly efficient, heterogeneous and green catalyst for the one-pot multi-component condensation of dimedone with arylaldehydes, β-ketoesters and am...

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 ...

Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl3 as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at the α-carbon and keto carbon of the β-ketoester moiety. In contrast, switching to the Lewis acid cat...

two simple protocols for the synthesis of three-component condensation reaction of an aldehyde, β-ketoester and urea or thiourea to obtain the 3, 4-dihydropyrimidin-2(1h)-ones (thiones) using nano silica phosphoric acid are reported. short reaction times, high yields, reusability of catalyst and easy workup are some advantages of these protocols.

Reaction of Rh2(S)-PTPA4 with the (R)-citronellol-derived alpha-diazo-beta-ketoester 1 led to the formation of cyclic beta-ketoester 2 in 95% yield and 48% diastereomeric excess. The purity of 2 was increased to > 99% de after one crystallization. To demonstrate its utility in steroid total synthesis, the beta-ketoester 2 was carried on to secosteroid (-)-astrogorgiadiol (3), a naturally occurr...

The development of (trimethylsilyl)ethyl ester protected enolates is reported. The application of this class of compounds in palladium-catalyzed asymmetric allylic alkylation is explored, yielding a variety of α-quaternary six- and seven-membered ketones and lactams. Independent coupling partner synthesis engenders enhanced allyl substrate scope relative to traditional β-ketoester substrates; h...

We present a general model for understanding the stereochemical course of intramolecular Michael reactions. We show that the addition of β-ketoester enolates to α,β-unsaturated esters and imides bearing adjacent stereocenters (X, Y = H, Me, OR) leads to high levels of asymmetric induction. Reinforcing and nonreinforcing stereochemical relationships are evaluated from the syn and anti reactant d...

An efficient synthesis of novel 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) and their derivatives, using Brønsted acidic ionic liquid [C₂O₂BBTA][TFA] as a catalyst, from the condensation of aryl aldehyde, β-ketoester and urea was described. Reactions proceeded smoothly for 40 min under solvent-free conditions and gave the desirable products with good to excellent yields (up to 99%). The catalyst co...

decatungstodivanadogermanic acid (h6gew10v2o40.22h2o) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1h)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. this method provides an efficient and much improved modification of the original biginelli reaction...