作者:A. Paul Krapcho、Timothy P. Gilmor
DOI:10.1002/jhet.5570360218
日期:1999.3
(8a), but in poor yield. Cyclizations of the aldehydes 8a-d,f,h or the ketone 4g with polyphosphoric acid afforded the benzo[g]quinolines 10a-d,f-h in high yields. Aldehyde 8e was cyclized to 10e using a solution of sulfuric acid in methanol. Several of the benzo[g]quinolines 10c,d could be readly converted into the benzo[q]quinoline-5,10-diones 11c,d on treatment with ammonium ceric nitrate.
已开发出一种方便的合成途径,以生成苯并[ g ]喹啉(1-氮杂蒽)。2-氯烟酸甲酯(3a)与苄基有机锌试剂2a-e的镍催化偶联导致甲基2-苄基取代的烟酸酯4a-e。以类似方式用2a处理2-氯-6-甲基烟酸甲酯(3b),得到2-苄基-6-甲基烟酸甲酯(4f)。2-氯-3-乙酰基吡啶(5)与苄基溴化锌(2a)的偶合产生2-苄基-3-乙酰基吡啶(4g)。2,5-二氯苄基有机锌试剂(2f)的2-choronicotinate甲酯(3a)是非选择性的,但很容易与2-bromonicotinate甲酯(6)偶联生成2-(2,5-二氯苄基)烟酸甲酯(4h)。用氢化铝锂还原后的酯4a-f,h产生相应的醇7a-f,h,随后将其用二氧化锰氧化成各自的2-苄基取代的吡啶-3-羧醛8a-f,h。在一种情况下,将苄基溴化锌(2a)与2-氯吡啶-3-羧甲醛(9)偶联直接导致2-苄基吡啶-3-羧甲醛(8a),但是收率很