Heterocyclic analogs of xanthones chromono(3,2-d)pyrazoles

Synthesis and reactivity of 1-aryl-9H-thieno[3,4-b]chromon-9-ones

“…1 H NMR (CDCl 3 ), d 8.19 (dd, J = 8.0, 1.5 Hz, 1H Ar ), 7.94 (d, J = 8.5 Hz, 2H Ar ), 7.72 (t, J = 8.6 Hz, 1H Ar ), 7.60 (t, J = 7.3 Hz, 1H Ar ), 7.41-7.53 (m, 4H Ar ), 2.65 (q, J = 7.5 Hz, 2H CH ), 1.32 (t, J = 7.5 Hz, 3H Me ). 13 General procedure for the preparation of 3-acyl-2,2dibromomethyl-4H-chromen-4-one (8)…”

“…1 H NMR (CDCl 3 ), d 8.29 (d, J = 7.9 Hz, 1H Ar ), 7.87 (d, J = 3.5 Hz, 1H Ar ), 7.87 (t, J = 7.6 Hz, 1H Ar ), 7.47 (d, J = 5.1 Hz, 1H Ar ), 7.24-7.37 (m, 2H Ar ), 7.14 (t, J = 4.4 Hz, 1H Ar ), 6.92 (s, 1H Ar ). 13 Procedure for the preparation of (3-aryl-4-oxo-4H-chromen-2-yl)methyl acetate (12) A solution of bromochromone 9a (343 mg, 1 mmol) in 6 ml of DMF was added to AcONa (106.6 mg, 1.3 mmol). After stirring at 0 1C for 4 h, the temperature of the solution was raised to 30-40 1C.…”

“…(3-Benzoyl-4-oxo-4H-chromen-2-yl)methyl acetate (12) Yield 65%, mp = 168 1C (EtOH). 1 Procedure for the preparation of 3-iodo-1-phenyl-9H-thieno [3,4-b]chromen-9-one (13) Thienochromone 11a (278 mg, 1 mmol) was dissolved in 3 ml of benzene. Then HgO (217 mg, 1 mmol) and I 2 (258 mg, 1 mmol) were successively added portionwise.…”

“…Chromones fused to the thiophene ring (3) have been investigated as local anesthetics or central nervous system stimulators. 13 The synthesis of thieno [3,4-b]chromone by reaction of a 3-acyl-2-(bromomethyl)chromone with thioacetamide was described for one example 11a. 14 In the present study, we synthesized a wide range of 3-acyl-2-methylchromones 7 according to the procedure developed earlier 15 (Scheme 1), studied the cyclization of their bromo derivatives, and showed that thieno [3,4-b]chromones thus prepared can be functionalized.…”