Research Article

L-Tyrosine as an Eco-Friendly and Efficient Catalyst for Knoevenagel Condensation of Arylaldehydes with Meldrum’s Acid in Solvent-Free Condition under Grindstone Method

Table 1

Synthesisofsubstituted -5-benzylidene-2,2-dimethyl-[1,3]dioxane-4,6-dione with Knoevenagel condensation in solvent-free condition under grindstone method at room temperature.

S. NumberRConditionTime (min)Yield (%)mp (°C)(Lit.mp., 28, 37, 38, 39 & 40) (°C)

aC6H5r.t.79384-85 85-86
b4-CH3–C6H4 r.t.1591117-118116–118
c4-OCH3–C6H4 r.t.1591124-125 126-127
dp-(Me2N)–C6H4r.t.1492163–165162–164
ep-(OH)–C6H4r.t.1392195-196192–194
fp-(Cl)–C6H4r.t.894157-158158–160
gp-(NO2)–C6H4r.t.794127-128217–129
hO-(NO2)–C6H4r.t.893118–120119-120
iO-(Cl)–C6H4r.t.893133–135133-134
jM-(OH)–C6H4r.t.1392173-174175-176