1. Furopyridines. III. A new synthesis of furo[3,2-b]pyridine
2. Furopyridines. V. A simple synthesis of furo[2,3-c]pyridine and its 2-and 3-methyl derivatives
3. Furopyridines. VI. Preparation and reactions of 2- and 3-substituted furo[2,3-b]pyridines
4. For examples, reaction of compound 2a with sodium in refluxing toluene gave a mixture of compound 1a, 3a and unknown product, compound 2c with sodium hydride in toluene gave the starting material in 90% yield and unknown product, compound 2d with 1,8-diazabicyclo-[5.4.0]-7-undecene gave the starting material, and compound 2b with sodium methoxide in toluene gave methyl 3-methoxyfuro[3,2-b]pyridine-2-carboxylate which had mp 119-120°; ir (potassium bromide): cm−1 11710, 1390, 1290, 1265, 1175, 1H nmr (deuteriochloroform): λ 3.94 (s, 3H, OMe), 4.52 (s, 3H, OMe), 7.28 (dd, J = 8.4,4.8 Hz, 1H, H-6), 7.72 (dd, J = 8.4, 1.2 Hz, 1H, H-7), 8.51 (dd, J = 4.8, 1.2 Hz, 1H, H-5). Anal. Calcd. for C10H9NO4: C, 57.97; H, 4.38; N, 6.76. Found: C, 57.91; H, 4.57; N, 6.88.