Synthesis
The general procedure for the synthesis of 6-alkynyl-4,4-dimethyldihydrochroman using the compound (CAS: 864841-55-4) as starting material is as follows:
Example 4: Preparation of 4,4-dimethyl-6-ethynylthiobenzodihydropyran (2) from compound (8)
1. compound (8) (10.0 g, 45.87 mmol) was dissolved in N,N-dimethylformamide (150 mL) and the reaction system was subsequently cooled to -20°C.
2. Phosphorus trichloride (4.0 mL, 45.87 mmol) was slowly added under stirring and the reaction was continuously stirred for 1 hour.
3. Upon completion of the reaction, the crude product was diluted with ethyl acetate (200 mL) and washed sequentially with saturated sodium chloride solution and deionized water.
4. The organic phase was separated, dried over anhydrous sodium sulfate, filtered and concentrated, and the solvent was removed by vacuum evaporation.
5. The solid obtained was purified by column chromatography with an eluent ratio of hexane/ethyl acetate=9:1, resulting in 7.88 g of the target product (85% yield; oil).
Product characterization data: 1H NMR (250 MHz, CDCl3) δ 1.35 (6H, s), 1.95 (2H, m), 3.05 (2H, m), 3.15 (1H, s), 7.13 (1H, d, J = 8.6 Hz), 7.58 (1H, dd, J = 8.6, 2.0 Hz), 7.99 (1H, d, J = 2.0 Hz).
References
[1] Patent: US2006/205950, 2006, A1. Location in patent: Page/Page column 4
[2] Patent: EP1700855, 2006, A1. Location in patent: Page/Page column 6
