Acetonitrile → HCID 23310796, compound
Reaction equation
Br[CH2:2][C:3]1[CH:13]=[CH:12][C:6]([C:7]([O:9][CH2:10][CH3:11])=[O:8])=[CH:5][CH:4]=1.[C:14]([O-:17])([O-])=[O:15].[K+].[K+].[C:20](#N)[CH3:21]>CN(C=O)C.S([O-])(O)(=O)=O.C([N+](CCCC)(CCCC)CCCC)CCC>[CH2:10]([O:9][C:7]([C:6]1[CH:12]=[CH:13][C:3]([CH2:2][O:8][CH2:7][C:6]2[CH:12]=[CH:13][C:3]([C:14]([O:17][CH2:20][CH3:21])=[O:15])=[CH:4][CH:5]=2)=[CH:4][CH:5]=1)=[O:8])[CH3:11]Participants
Procedure
Although a low yield of impure XXVIII can be obtained directly by heating XXVI and XXVII in DMF at 100° for 70 hr., it is better to do the esterification and furan ring closure in separate steps. 65 mg XXVI (0.1 mmole), 50 mg ethyl 4-bromomethylbenzoate (XXVII), 0.2 g K2CO3, and 10 mg tetrabutylammonium hydrogen sulfate were stirred overnight under reflux in acetonitrile. The product, the 4-ethoxycarbonylbenzyl ether of XXVI, was isolated by preparative layer chromatography with petroleum ether-ethyl acetate 1:1, giving 57 mg, 71% yield, m.p. 109°-110°. NMR (CDCl3, 90 MHz) 10.34, s, 1H; 8.06, d, 8 Hz, 2H; 7.47, d, 8 Hz, 2H; 7.3, s, partly obscured by CHCl;3; m, 6.8-6.55, 3H; 6.3, s, 1H; 5.16, s, 2H; 4.37, q, 7 Hz, 4.21, s, 4.14, s, 4.05, q, 7 Hz, 4.02, q, 7 Hz, total 22H; 2.23, s, 3H; 1.38, t, 7 Hz, 1.17, t, 7 Hz, 1.15, t, 7 Hz, total 15H. 39 mg of this ether (0.05 mmole) was stirred with potassium fluoride/alumina reagent (see reference 22) in 1 ml dimethylformamide for 2 hrs. at 150°. The fluorescent product was isolated in 21 mg (54%) yield by preparative layer chromatography on silica with toluene-ethyl acetate 1:1. More prolonged reaction times in DMF lead to increasing ester hydrolysis. NMR (CDCl3, 90 MHz): 8.15, d, 9 Hz, 7.89, d, 9 Hz, total 4-5H; 7.15-7.05, m, 6.78, m, total 6-7H; m, 3.9-4.5, 20-22H; 2.23, s, 3H; 1.0-1.4, m, 13-17H.
Sources & evidence
- ORD record
- ord-384b00adbf284ed3a1e0ff768929630e
- Source dataset
- uspto-grants-1986_07
- Patent number
- US04603209
Reaction notes
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