Hydroxymethylation of 2-Hydroxypropiophenones in Aqueous Medium: Synthesis of 3-Hydroxymethyl-3-methyl-4-chromanones and Their Conversion to 3-Methyl-4-chromanone-3-acetic Acids
作者:Daniela Barlocco、Giorgio Cignarella、Maria Michela Curzu
DOI:10.1055/s-1985-31368
日期:——
Reaction of o-hydroxypropiophenone (1a) with aqueous formaldehyde in sodium hydroxide solution led to the mono-hydroxymethylated 2a and/or the bis-hydroxymethylated derivative 3a, as well as to 3-methyl-4-chromanone (4a) and/or 3-methyl-3-hydroxymethyl-4-chromanone (5a), according to the ratio of the reagents employed. The mechanism of formation of 5a from 1a was also demonstrated. Compound 5a and its 6-chloro derivative 5b, similarly prepared from 5-chloro-2-hydroxypropiophenone (1b), were converted by standard procedure to the corresponding 3-methyl-4-chromanone-3-acetic acids 8a, b.
o-羟基丙基苯酮(1a)与水相甲醛在氢氧化钠溶液中反应,生成了单羟甲基化的化合物2a和/或双羟甲基化的衍生物3a,以及3-甲基-4-氢化色酮(4a)和/或3-甲基-3-羟甲基-4-氢化色酮(5a),具体生成物的比例取决于所用试剂的比例。文中也展示了从1a形成5a的机制。化合物5a及其6-氯衍生物5b(同样从5-氯-2-羟基丙基苯酮(1b)制备)通过标准程序转化为相应的3-甲基-4-氢化色酮-3-乙酸(8a、b)。