* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
General procedure: To a mixture of NaH (1.5 equiv.) in anhydrous THF (0.3M) was added dropwise a solution of N-H tetrahydroquinazolin-4-one derivatives (1 equiv.) in anhydrous THF (0.5M) at 0 C. After 30 min, iodomethane (1.1 equiv.) was added dropwise. After 10 min, the solution was warmed to room temperature and stirred for 3h. The reaction was then quenched with a saturated solution of NaHCO3. The aqueous layer was then repeatedly extracted with CH2Cl2. The combined organic layers were then washed with a 1M solution of HCl (2 x 10 mL), dried over anhydrous Na2SO4, filtered and concentrated in vacuum. The purification by silica gel chromatography of the crude mixture yielded the expected compounds as solids.
85%
General procedure: To a mixture of NaH (1.5 equiv.) in anhydrous THF (0.3M) was added dropwise a solution of N-H tetrahydroquinazolin-4-one derivatives (1 equiv.) in anhydrous THF (0.5M) at 0C. After 30min, iodomethane (1.1 equiv.) was added dropwise. After 10min, the solution was warmed to room temperature and stirred for 3h. The reaction was then quenched with a saturated solution of NaHCO3. The aqueous layer was then repeatedly extracted with CH2Cl2. The combined organic layers were then washed with a 1M solution ofHCl (2 x 10 mL), dried over anhydrous Na2SO4, filtered and concentrated in vacuum. The purification by silica gel chromatography of the crude mixture yielded the expected compounds as solids.
85%
General procedure: Protocol: a solution of N-H tetrahydroquinazolin-4-ones (1 equiv.) in anhydrous THF (0.5M) is added, dropwise, at 0 C., to a suspension of NaH (1.5 equiv.) in anhydrous tetrahydrofuran (0.3M). After 30 min, iodomethane (1.1 equiv.) is added dropwise. After 10 minutes of reaction, the solution is heated to room temperature and the reaction mixture is stirred for 3 h. The reaction is stopped by adding a saturated solution of NaHCO3. The aqueous phase is extracted with CH2Cl2 (3×50 ml). The organic phases are combined and then washed with a 1M solution of HCl (2×10 ml), dried over anhydrous Na2SO4, filtered and concentrated on a rotary evaporator. Purification by silica gel chromatography provides the expected compounds in the form of solids.
Synthesis of Retro-2 and Retro-2cycl [00281] To a stirring solution of 2-aminobenzanilide was added 5-methyl-2- thiophenecarboxaldehyde (86.3 mu, .80 mmol). After 24 hours, the reaction was concentrated and then chromatographed on silica gel with 20-40% ethyl acetate in hexanes. Retro-2 and Retro-2cycl were cleanly separated and then further purified by recrystalization from ethanol and ethyl acetate respectively. Yields: Retro-2 47.2 mg (36%), Retro-2cycl 78.0 mg (59.4%). Characterization: Retro-2 FAB HRMS: Ci9Hi6N2OSNa+ Predicted: 343.0881 Found:
With sodium cyanoborohydride; acetic acid; In methanol; for 72h;
Synthesis of Retro-2re [00282] Retro-2cycl (143 mg, 0.444 mmol) was dissolved in methanol (4 mL) then treated with sodium cyanoborohydride (83 mg, 1.3 mmol) followed by acetic acid (.4 mL). The slow formation of a new product was observed by tic (2: 1 hexanes:ethyl acetate). After 3 days the reaction was concentrated and then chrmoatographed on silica gel with a hexanes/ethyl acetate solvent gradient. Both the desired product (62 mg, .187 mmol, 42%) as well as unreacted starting material (64 mg, .200 mmol, 45%) were recovered. FAB HRMS: Ci9Hi8N2OSNa+ Predicted: 345.1038 Found: 345.1052 .