2-Thiophenecarboxylic acid, tetrahydro-3-oxo-, methyl ester → 1,2-Dihydro-9-hydroxy-7-(3-methyl-2-octyl)-4-oxo-4H-thieno[2,3-c][1]benzopyran
Reaction equation
[CH3:1][CH:2]([CH2:13][CH2:14][CH2:15][CH2:16][CH3:17])[CH:3]([C:5]1[CH:6]=[C:7]([OH:12])[CH:8]=[C:9]([CH:11]=1)[OH:10])[CH3:4].O=[C:19]1[CH2:23][CH2:22][S:21][CH:20]1[C:24](OC)=[O:25]>C(O)C>[OH:10][C:9]1[C:8]2[C:19]3[CH2:23][CH2:22][S:21][C:20]=3[C:24](=[O:25])[O:12][C:7]=2[CH:6]=[C:5]([CH:3]([CH:2]([CH3:1])[CH2:13][CH2:14][CH2:15][CH2:16][CH3:17])[CH3:4])[CH:11]=1Participants
Procedure
A solution of 2.5 g. (0.011 mole) of 5-(3-methyl-2-octyl)resorcinol and 2.0 g. (0.013 mole) of methyl 3-oxo-2,3,4,5-tetrahydrothiophene-2-carboxylate in 50 ml. of absolute ethanol in a three-necked flask equipped with drying tube was cooled in an ice-water bath and saturated with dry hydrogen chloride. The 5-(3-methyl-2-octyl) resorcinol was prepared according to the method of Adams, MacKenzie and Loewe (J. Amer. Chem. Soc. 70, 664-8 (1948)). The reaction mixture was allowed to stand for three days at room temperature, during which time a heavy yellow solid formed. The hydrogen chloride was evaporated, the mixture was concentrated and the solid was filtered and washed with ethanol. The yield of the crude benzopyrone thus obtained was 2.6 g. (59%), m.p. 190°-205° C.
Workup
- customwith drying tube
- temperaturewas cooled in an ice-water bath and saturated with dry hydrogen chloride
- customThe 5-(3-methyl-2-octyl) resorcinol was prepared
- customa heavy yellow solid formed
- customThe hydrogen chloride was evaporated
- concentrationthe mixture was concentrated
- filtrationthe solid was filtered
- washwashed with ethanol
Sources & evidence
- ORD record
- ord-59bee94b02c64c748a24707caf5cbcde
- Source dataset
- uspto-grants-1976_10
- Patent number
- US03987190
Reaction notes
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