Reductive alkylation of pyridinium salts. Part 2. Utilisation of di-, tetra- and hexa-hydropyridine esters
作者:Kevin J. McCullough、John MacTavish、George R. Proctor、James Redpath
DOI:10.1039/p19960002553
日期:——
4-Benzyl-4-ethoxycarbonyl-1-substituted piperidines 1 (R1= PhCH2, PhCO; R2= PhCH2) cyclise with polyphosphoric acid (PPA) to give spiro[indane-2,4′-piperidin]-1-ones 3 (R = PhCH2, PhCO), while 2-benzyl-2-ethoxycarbonyl-1-methylpiperidine 4 gives the N-methylspiro[indane-2,2′-piperidin]-1-one 5. 3,4,4a,5-Tetrahydrobenz[g]isoquinolin-10(2H)-one 8 arises from PPA treatment of 1-benzoyl-4-benzyl-5-ethoxycarbonyl-1,2,3,4-tetrahydropyridine 7 (R = PhCO) while o-chloranil converts 1-benzoyl-4-benzyl-4-ethoxycarbonyl-1,4-dihydropyridine 6 (R = PhCO) into 4-benzyl-3-ethoxycarbonylpyridine 9. Phenyl(tribromomethyl)mercury reacts with 1-benzoyl-4-benzyl-4-ethoxycarbonyl-1,4-dihydropyridine 2 (R1= PhCO, R2= PhCH2) yielding 2-benzoyl-5-benzyl-7,7-dibromo-5-ethoxycarbonyl-2-azabicyclo[4.1.0]hept-3-ene 11, and with 1-benzoyl-4-benzyl-3-ethoxycarbonyl-1,4-dihydropyridine 6 (R = PhCO) to give 2-benzoyl-5-benzyl-7,7-dibromo-4-ethoxycarbonyl-2-azabicyclo[4.1.0]hept-3-ene 12. The structure of the latter is confirmed by X-ray crystallographic analysis. Catalytic hydrogenation of 2-benzoyl-5-benzyl-7,7-dichloro-5-ethoxycarbonyl-2-azabicyclo[4.1.0]hept-3-ene 16 yields 2-benzoyl-5-benzyl-7,7-dichloro-5-ethoxycarbonyl-2-azabicyclo[4.1.0]heptane 21 which cyclises with PPA to give the tetracyclic product 22 in good yield. When 2-benzoyl-5-benzyl-7,7-dichloro-4-ethoxycarbonyl-2-azabicyclo[4.1.0]hept-3-ene 17 is hydrogenated it yields mainly 2-benzoyl-5-benzyl-7,7-dichloro-4-ethoxycarbonyl-2-azabicyclo[4.1.0]heptane 25 but the dibromo analogue 12 under the same conditions gives two components thought to be 2-benzoyl-5-benzyl-7-endo-bromo-4-ethoxycarbonyl-2-azabicyclo[4.1.0]hept-3-ene 24 and 2-benzoyl-5-benzyl-7-exo-bromo-4-ethoxycarbonyl-2-azabicyclo[4.1.0]hept-3-ene 23.
4-苄基-4-乙氧基羰基-1-取代哌啶 1 (R1= PhCH2, PhCO; R2= PhCH2) 用多磷酸 (PPA) 环化,得到螺[茚满-2,4'-哌啶]-1-酮 3 ( R = PhCH2, PhCO),而 2-苄基-2-乙氧基羰基-1-甲基哌啶 4 得到 N-甲基螺[茚满-2,2'-哌啶]-1-酮 5. 3,4,4a,5-四氢苯[g]isoquinolin-10(2H)-one 8 由 1-苯甲酰基-4-苄基-5-乙氧基羰基-1,2,3,4-四氢吡啶 7 (R = PhCO) 的 PPA 处理产生,而邻四氯苯醌转化为 1 -苯甲酰基-4-苯甲基-4-乙氧基羰基-1,4-二氢吡啶 6 (R = PhCO) 转化为 4-苯甲基-3-乙氧基羰基吡啶 9. 苯基(三溴甲基)汞与 1-苯甲酰基-4-苯甲基-4-乙氧基羰基反应-1,4-二氢吡啶 2 (R1= PhCO, R2= PhCH2),产生 2-苯甲酰基-5-苄基-7,7-二溴-5-乙氧基羰基-2-氮杂双环[4.1.0]庚-3-烯 11,并与1-苯甲酰基-4-苄基-3-乙氧基羰基-1,4-二氢吡啶6 (R = PhCO)反应,得到2-苯甲酰基-5-苄基-7,7-二溴-4-乙氧基羰基-2-氮杂双环[4.1 .0]hept-3-ene 12。后者的结构通过X射线晶体分析证实。 2-苯甲酰基-5-苄基-7,7-二氯-5-乙氧基羰基-2-氮杂双环[4.1.0]庚-3-烯16的催化氢化得到2-苯甲酰基-5-苄基-7,7-二氯- 5-乙氧基羰基-2-氮杂双环[4.1.0]庚烷21与PPA环化,以良好的收率得到四环产物22。当2-苯甲酰基-5-苄基-7,7-二氯-4-乙氧基羰基-2-氮杂双环[4.1.0]庚-3-烯17氢化时,主要产生2-苯甲酰基-5-苄基-7,7-二氯-4-乙氧基羰基-2-氮杂双环[4.1.0]庚烷25,但二溴类似物12在相同条件下给出两个被认为是2-苯甲酰基-5-苄基-7-内溴-4-乙氧基羰基-2的组分-氮杂双环[4.1.0]庚-3-烯24和2-苯甲酰基-5-苄基-7-外-溴-4-乙氧基羰基-2-氮杂双环[4.1.0]庚-3-烯23。