| Abstract: | 本文描述1,8-└口奈┐啶、苯并[b] [1,8]└口奈┐啶及?環稠合倍半雙環[2.2.2]辛二烯45、46、49、50、62、63、64、65、68的合成，並利用紫外光吸收光譜、核磁共振光譜來分析探討跨環軌域交互作用。 2-胺基尼古丁醛分別與34、48、51、53進行進行弗萊蘭德(Friedl?nder)縮合反應，可得到1,8–└口奈┐啶稠合化合物45、46、49、50、52、54。將2-氯??-3-甲醛(57)與乙二醇進行脫水反應得到58，將醛基保護後以乙醯胺進行2-氯??之取代反應得到59、60，將分離出之??胺60置於酸中水解將可得到2-胺基??-3-甲醛(61)。 2-胺基??-3-甲醛(61)分別與雙酮34、48進行進行弗萊蘭德縮合反應，可得到環化產物62、63、64、65。苯炔與四環六烯66進行狄耳士-阿德爾(Diels-Alder)反應，再以DDQ氧化得到?稠合倍半雙環[2.2.2]辛二烯68。由碳核磁共振光譜比對結果發現，相較於48、72，化合物34與71酮基受平行相對之乙烯基橋高共軛影響，化學位移往高磁場位移。由紫外光吸收光譜的比對，發現??、└口奈┐啶、苯并[b] [1,8]└口奈┐啶環等稠合倍半雙環[2.2.2]辛二烯，由於平行面對面的乙烯基橋與芳香環產生高共軛效應，使得π→π＊能階變小，皆產生2-3 nm之紅位移。
The syntheses of 1,8-naphthyridine, benzo[b][1,8]naphthyridine, naphthalene fused sesquibicyclo[2.2.2]octadienes 45 , 46 , 49 , 50 , 62 , 63 , 64 , 65 , 68 have been described. The UV spectra,and NMR spectra of these 1,8-naphthyridine, benzo[b][1,8]naphthyridine derivatives reveal a slight transannular interaction between the 1,8-naphthyridine, benzo[b][1,8]naphthyridine moieties and the remoted face-to-face carbon-carbon double bonds.Friedl?nder condensations of 2-aminonicotinaldehyde(44) with 34 , 48 , 51 , 53 produce 1,8-naphthyridine derivatives 45 , 46 , 49 , 50 , 52 , 54 respectively. Protecting the carbonyl group of 2-chloroquinoline-3-aldehyde(57) with ethylene glycol produces acetal 58 in high yield. Substitution reaction of 2-chloroquinoline acetal 58 with acetamide gives 59 , 60. Acidic hydrolysis of the resulting amine 60 obtains 2-aminoquinoline-3-carbaldehyde (61).Friedl?nder condensations of 2-aminoquinoline-3-carbaldehyde(61) with diones 34 , 48 produce cycloadducts 62 , 63 , 64 , 65 respectively. Similarly,Diels-Alder reaction of benzyne with tetracyclohexaene 66, followed by oxidation with DDQ produces naphthalene-fused sesquibicyclo[2.2.2]octadiene 68.Comparing the analytical results from NMR spectra of analogs 34 , 48 , 71 , 72 , we observe that the chemical shift of carbonyl carbon is increased (down field shift) by 5 ppm when parallel etheno bridges are hydrogenated. This result implies the strong interaction between C=C and C=O bonds in the structure of sesquibicyclo[2.2.2]octadiene 34. In comparison with the analogs 54 , 49 , 50 , 64 , 65, the UV spectra of the corresponding 52 , 45 , 46 , 62 and 63 show a bathochromic shifts of 3 nm at the maximum wavelength of π→π＊ transition. This result may be attributed to orbital interaction between the chromophores and the etheno bridges. |
