Synthesis
General procedure for the synthesis of 2-allyl-3-hydroxybenzaldehyde and compounds (CAS: 79950-43-9) from 3-(allyloxy)benzaldehyde: 3-(allyloxy)benzaldehyde (308 g) and tetrahydroxynaphthalene (300 mL) were added to a 3000 mL single-necked round-bottomed flask equipped with a condenser and a thermometer. The reaction mixture was placed in a microwave reactor and slowly heated to 180-182 °C at 1500 W (ramp-up time of 5-10 min, internal temperature was monitored) and the reaction was continuously stirred for 7-8 h at this temperature. During the reaction, the color of the mixture gradually changed to brown. Upon completion of the reaction, the mixture was cooled to room temperature, followed by further cooling at 0 to 5 °C for 30 min. The solid product was collected by filtration and dried to give off-white 2-allyl-3-hydroxybenzaldehyde (145.5 g, 47% yield).
References
[1] Patent: US2016/107973, 2016, A1. Location in patent: Paragraph 0034; 0035; 0036
[2] Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1981, p. 2677 - 2679
[3] Organic and Biomolecular Chemistry, 2004, vol. 2, # 17, p. 2461 - 2470
[4] Synlett, 2012, vol. 23, # 6, p. 867 - 872
[5] Tetrahedron Letters, 2012, vol. 53, # 16, p. 2125 - 2128
