5-methyl-3,4-dihydro-2H-pyrrole

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The commercially available methyl 3-chloro-1H-pyrrole-2-carboxylate (1.50 g, 94.0%, yellow solid) was synthesized according to Fang et al., J. Med. Chem., 53:7967-7978 (2010) using 2-methyl-1-pyrroline (0.831 g, 10.0 mmol, commercial), NCS (10.7 g, 80.0 mmol) and NaOMe in MeOH (3M, 20 mL, 60.0 mmol). LCMS Condition B-41: retention time 1.71 min, [M+1]=160.10. 1H NMR (400 MHz, CDCl3) δ 3.90 (s, 3H), 6.25 (t, J=3.0 Hz, 1H), 6.86 (t, J=3.0 Hz, 1H), 9.17 (br s, 1H).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Alternately, compounds of formula (I) can be synthesized by the general sequence shown in Scheme 3. Commercially available 5-methyl-3,4-dihydro-2H-pyrrole 13 was treated with N-chlorosuccinimide followed by sodium methoxide to generate methyl 3-chloro-1H-pyrrole-2-carboxylate 14. Compound 14 was N-aminated and the product 15 was acylated to yield methyl 3-chloro-1-(methoxycarbonylamino)-1H-pyrrole-2-carboxylate 16. Compound 16 was treated with ammonia to yield 5-chloropyrrolo[1,2-f][1,2,4]triazine-2,4-diol 17. Compound 10 can be obtained from 17 by transition metal mediated Suzuki cross-coupling reactions with boronic acids or esters. Compound 17 gave 2,4,5-trichloropyrrolo[1,2-f][1,2,4]triazine 18 on treatment with chlorinating agents for example, POCl3 and then displacement of the C4 chloro with amines gave regioselectively 19. Using different palladium reagent/ligand combinations we could achieve regioselective Suzuki cross-couplings at C2 and C5 to generate compounds of general formula (I).

Conditions: temp:85.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5-Methyl-3,4-dihydro-2H-pyrrole (1.00 g, 12.0 mmol) was dissolved in carbon tetrachloride. To the solution was added NCS (12.85 g, 96 mmol) as a solid and reaction mixture heated to 85° C. and stirred overnight. The mixture was cooled to 0° C. and the precipitate filtered off and the solvent evaporated. The residue was dissolved in methanol and sodium methoxide (3.90 g, 72.2 mmol) was added. The resulting suspension was heated to reflux and stirred for 3 h. The methanol was evaporated and the residue suspended in Et2O. The solid was filtered off and the ether evaporated. The residue was dissolved in DCM and 2M HCl was added. The biphasic solution was stirred until no SM remained. The phases were separated and the organic layer was dried over MgSO4 and evaporated to an orange oil. The crude oil was adsorbed onto silica and run on 40 g of silica with EtOAc and Hexanes to afford the title compound as an orange solid (0.2958 g, 1.854 mmol, 15.41% yield). 1H NMR (400 MHz, CDCl3): δ ppm 9.54 (br. s., 1H), 6.80 (s., 1H), 6.17 (s., 1H), 3.83 (s, 3H). MS: m/z 160.0 (M+1). To the solution was added The mixture was cooled to 0° C. the precipitate filtered off the solvent evaporated The residue was dissolved in methanol The resulting suspension was heated to reflux stirred for 3 h The methanol was evaporated The solid was filtered off the ether evaporated The residue was dissolved in DCM 2M HCl was added The biphasic solution was stirred until no SM The phases were separated the organic layer was dried over MgSO4 evaporated to an orange oil

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 5-methyl-3,4-dihydro-2H-pyrrole (2.50 g, 30.0 mmol) in CCl4 (100 mL) was added N-chlorosuccinimide (32.00 g, 240 mmol), and the mixture was then heated to reflux for 72 hours. The reaction mixture was cooled to 0° C. The formed precipitate was filtered off, and the filtrate was concentrated under reduced pressure. The residue was dissolved in methanol (100 mL), followed by the addition of sodium methoxide (9.80 g, 180 mmol). The resulting suspension was heated to reflux and stirred for 1.5 h. The solvent was evaporated, and the residue was suspended in ether. The solid was filtered off, and the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (100 mL) and 2 M HCl (100 mL). The biphasic solution was stirred for 10 min. The organic layer was separated, dried over MgSO4, filtered and evaporated. The crude oil was subjected to chromatography purification on silica gel eluting with EtOAc and Hexanes to afford the title compound (2.5 g, 52%) as an orange solid. MS (ES+) C6H6ClNO2 requires: 159. found: 160 [M+H]+. the mixture was then heated to reflux for 72 hours The formed precipitate was filtered off the filtrate was concentrated under reduced pressure The residue was dissolved in methanol (100 mL) The resulting suspension was heated to reflux The solvent was evaporated The solid was filtered off the filtrate was concentrated under reduced pressure The residue was dissolved in DCM (100 mL) The biphasic solution was stirred for 10 min The organic layer was separated dried over MgSO4 filtered evaporated The crude oil was subjected to chromatography purification on silica gel eluting with EtOAc and Hexanes

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of diisopropylamine (11.1 g, 109.7 mmol) in THF (200 mL) was dropwise added n-BuLi (2.89 M, 37.97 mL, 109.7 mmol) at −78° C. under nitrogen. Once all the n-BuLi was added, the temperature was adjusted to −5° C., and the reaction mixture was stirred for 30 min. Then a solution of 2-methyl-1-pyrroline (5.65 g, 67.9 mmol) in THF (15 mL) was added dropwise to the reaction mixture at −5° C., and then stirred. After 30 min, 2-methylthio-1-pyrroline (6.02 g, 52.3 mmol) was added dropwise over 30 min at −78° C. The reaction mixture was stirred as the temperature was allowed to gradually rise to room temperature, and was continuously stirred at room temperature overnight. THF solvent was removed under reduced pressure, then 50 mL of methanol was added dropwise to the residue. After removing all of the volatile solvent, pentane (2×100 mL) was added to the residue, and the mixture was filtered. Concentration of the filtrate under reduced pressure, followed by vacuum distillation (65° C. at 110 mTorr), delivered 6.29 of product (79%). 1H NMR (CD2Cl2, 500 MHz): δ 7.89 (s, br, 1H), 4.65 (s, 1H), 3.64 (t, 2H, J=7.2 Hz), 2.51 (t, 2H, J=8.0 Hz), 1.85 (m, 2H). 13C NMR (CD2Cl2, 125 MHz): δ 167.0, 81.7, 53.7, 34.8, 23.2. at −78° C. was adjusted to −5° C. stirred After 30 min The reaction mixture was stirred as the temperature to gradually rise to room temperature was continuously stirred at room temperature overnight THF solvent was removed under reduced pressure 50 mL of methanol was added dropwise to the residue After removing all of the volatile solvent, pentane (2×100 mL) was added to the residue the mixture was filtered Concentration of the filtrate under reduced pressure, followed by vacuum distillation (65° C. at 110 mTorr)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of diisopropylamine (22.2 g, 219.3 mmol) in THF (200 mL) was dropwise added n-BuLi (2.89 M, 75.9 mL, 219.3 mmol) at −78° C. under nitrogen. Once all the n-BuLi was added, the temperature was adjusted to −5° C., and the reaction mixture was stirred for 30 min. Then a solution of 2-methyl-1-pyrroline (11.3 g, 135.7 mmol) in THF (15 mL) was added dropwise to the reaction mixture at −5° C., and then stirred. After 30 min, ethylacetate (9.20 g, 104.4 mmol) was added dropwise over 30 min. The reaction mixture was stirred as the temperature was allowed to gradually rise to room temperature, and was continuously stirred at room temperature overnight. THF solvent was removed under reduced pressure, then 80 mL of methanol was added dropwise to the residue. After removing all of the volatile solvent, diethyl ether (100 mL) was added to the residue, and the mixture was filtered. Concentration of the filtrate under reduced pressure, followed by column chromatography, provided the desired product. at −78° C. was adjusted to −5° C. stirred After 30 min The reaction mixture was stirred as the temperature to gradually rise to room temperature was continuously stirred at room temperature overnight THF solvent was removed under reduced pressure 80 mL of methanol was added dropwise to the residue After removing all of the volatile solvent, diethyl ether (100 mL) was added to the residue the mixture was filtered