The synthesis of methyl 2-formyl-6-(methoxymethyl)furo[2,3-b]pyrrole-5-carboxylate (1d) is described. The reactions of methyl 2-formylfuro[2,3-b]pyrrole-5-carboxylates 1a-1d with malononitrile afforded methyl 2-(2,2-dicyanovinyl)furo[2,3-b]pyrrole-5-carboxylates 3a-3d, with methyl cyanoacetate methyl 2-[2-cyano-2-(methoxycarbonyl)vinyl]furo[2,3-b]pyrrole-5-carboxylates 4a-4d and with 2-furylacetonitrile methyl 2-[2-cyano-2-(2-furyl)vinyl]furo[2,3-b]pyrrole-5-carboxylates 5a-5d. Compounds 1b-1d and methyl azidoacetate gave the appropriate vinylazides 6b-6d, which were used for preparation of substituted furo[2,3-b:4,5-b']dipyrroles 7b-7d. Reactivity of furo[2,3-b]pyrrole aldehydes 1a-1d and furo[3,2-b]pyrrole aldehydes 2a-2c in their reactions with 5,5-dimethylcyclohexane-1,3-dione is compared. The prepared methyl 2-[bis(4,4-dimethyl-2,6-dioxocyclohexyl)methylfuro[2,3-b]pyrrole-5-carboxylates 8a-8d and their isomers 10a-10c cyclized into substituted octahydroxanthenes 9a-9d and 11a-11c, respectively. Methyl 4-benzyl-2- [(4,4-dimethyl-2,6-dioxocyclohex-1-ylidene)methyl]furo[3,2-b]pyrrole-5-carboxylate (12) was prepared using microwave irradiations.
描述了甲基2-甲氧基甲基基-6-甲醛基呋喃[2,3-b]吡咯-5-羧酸甲酯(1d)的合成。将甲基2-甲醛基呋喃[2,3-b]吡咯-5-羧酸甲酯1a-1d与马来酸二腈反应,得到甲基2-(2,2-二氰乙烯基)呋喃[2,3-b]吡咯-5-羧酸甲酯3a-3d,用氰乙酸甲酯制备甲基2-[2-氰基-2-(甲氧羰基)乙烯基]呋喃[2,3-b]吡咯-5-羧酸甲酯4a-4d,用2-呋喃乙酮腈制备甲基2-[2-氰基-2-(2-呋喃基)乙烯基]呋喃[2,3-b]吡咯-5-羧酸甲酯5a-5d。化合物1b-1d和甲基叠氮乙酸酯给出了适当的乙烯基叠氮化物6b-6d,用于制备取代的呋喃[2,3-b:4,5-b']二吡咯7b-7d。比较了呋喃[2,3-b]吡咯醛1a-1d和呋喃[3,2-b]吡咯醛2a-2c在它们与5,5-二甲基环己烷-1,3-二酮反应中的反应性。制备的甲基2-[双(4,4-二甲基-2,6-二氧代环己基)甲基]呋喃[2,3-b]吡咯-5-羧酸甲酯8a-8d及其异构体10a-10c环化为取代的辛氢萘9a-9d和11a-11c。使用微波辐射制备了甲基4-苄基-2-[(4,4-二甲基-2,6-二氧代环己-1-基亚甲基)甲基]呋喃[3,2-b]吡咯-5-羧酸甲酯(12)。