Preparation of benzofurans and use thereof as synthetic intermediates
A technology of furan and compound, applied in the field of preparation of benzofuran
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
preparation example Construction
[0083] Preparation of compound (7):
[0084] Ortho formylation of phenol (6) can be achieved by different methods described in the literature (eg, Houben-Weyl E3, 4th edition). It is also possible to use a known direct process for the preparation of hydroxybenzaldehydes by carbonylation of the corresponding phenols.
[0085] In one embodiment, the present invention provides an improved process for the preparation of aldehyde (7) involving the reaction of phenol (6) with paraformaldehyde (paraformaldehyde) in organic solvents in the presence of magnesium or tin salts according to known methods Perform the reaction [Tetrahedron Letters 50 (2009) 5823-5826; J.CHEM.SOC., PERKIN TRANS.1, 1994, 1823; Organic Syntheses, Vol.82, p.64 (2005), the contents of each of which are by reference incorporated here]. In another embodiment, the present invention provides a method for the preparation of aldehyde (7) based on the improved Duff reaction, involving the reaction of phenol (6) wit...
Embodiment 1-4
[0184] Examples 1-4: Method A
Embodiment 1
[0186] A typical procedure for the synthesis of 5-substituted-2-hydroxybenzaldehydes from 4-substituted phenols:
[0187] Dry paraformaldehyde (paraformaldehyde) (3.5 g) was added in multiple portions to 4-substituted phenol (30 mmol), triethylamine (90 mmol), and anhydrous MgCl in acetonitrile (300 mL) 2 (100mmol) in the mixture. The mixture was refluxed for 6-8h under TCL or HPLC control. When the reaction was complete, the mixture was cooled to room temperature, acidified with 3N hydrochloric acid and extracted with ethyl acetate. The organic layer was washed with water, brine and dried over sodium sulfate. Removal of solvent yielded crude material that was pure enough for the next stage. If necessary, the compound can be purified by crystallization, distillation, or by column chromatography using an appropriate solvent or solvent mixture.
[0188] To prepare 5-chloro-2-hydroxy-benzaldehyde a modified procedure is used:
[0189] a) at N 2 Anhydrous SnCl 4 (651.2mg, 2...
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More 