Organic Chemistry International

Research Article

Triton-B-Catalyzed, Efficient, Solvent-Free Synthesis of Benzopyrans

Table 1

Conversion of substituted benzophenones into benzopyrans of general formula I a.
Product R1R2R3R4Time/min. Yieldsb/% Reference
1H H CH3CH35 86 [18, 19]
2 H OH CH3CH35 89 [18, 19]
3 H OH CH3C2H58 85 [20–22]
4 H OH R3 = R4 = Cyclopentyl7 88 [23]
5 H OH R3 = R4 = Cyclohexyl6 90 [24]
6 OH H CH3CH310 81 [23]
7 OH H CH3C2H58 82 [23]
8 OH H R3 = R4 = Cyclopentyl8 89 [24]
9 OH H R3 = R4 = Cyclohexyl8 86 [25–29]
10 NO2H CH3CH38 85 [18, 19]
11 OCH3H CH3CH35 91 [23]
12 OCH3OH CH3CH35 92 [18, 19]
13 OCH3OCH3CH3C2H54 94 [24]
14 OCH3OCH3C2H5C2H54 99 [25–29]
15 OCH3NO2 𝑛 -C2H5CH35 92 [24]
16 OH OCH3 𝑛 -C4H9 𝑛 -C4H95 83 [20–22]
aAll the products were characterized by IR, NMR, and mass spectroscopic data.
bIsolated yields.