Hydrazine, (3,4-dimethylphenyl)-, hydrochloride (1:1)

White to pink or beige-brown powder

General procedure: CuBr (36 mg, 0.25 mmol, 2.5 mol percent), L3 (110 mg, 0.4 mmol, 4 mol percent), H2O (0.5 mL), and K3PO4 (254 mg, 1.2 mmol) were mixedin a 15 mL screw cap test tube. After STAC (110 mg, 0.3 mmol, 3 mol percent) and aryl bromide (10 mmol) were added, the resulting mixture was stirred at 80-110° C (bath temperature) for 10 min.Then K3PO4 (2.29 g, 10.8 mmol) and N2H4*H2O (1 g, 20 mmol) were added and argon (flow rate 5-7 mL/min) was bubbled through thereaction mixture for 5 min.28 The reaction mixture was stirred ina closed test tube at 80-110° C (bath temperature) for 1-2 h until complete consumption of starting material was observed as monitoredby TLC (eluentehexane), then cooled to room temperatureand diluted with SH2Cl2 (50 mL). The resulting solutionwas filteredand washed with brine (225 mL). Aq HCl (37percent) was added to the CH2Cl2 solution dropwise until pH 3-4. The formed precipitate was filtered, washed with SH2Cl2 (15 mL) and dried atroom temperature. NMR spectra of certain synthesized aryl hydrazine hydrochlorides showed that they contained 1-5 mol percent of the corresponding aniline hydrochlorides as impurities (see Supplementary data). Analytical samples of aryl hydrazine hydrochlorides were purified via precipitation from methanol solution by adding 2-3 volumes of diethyl ether.3, 4-dimethyl aniline (12.2g, 0.1mol) in 50ml and 20ml of concentrated hydrochloric acidmixed uniformly in water, cooling to below 0 , with mechanical stirring, to which the solution of sodium nitriteaqueous solution (7.6g, 0.11 mol), maintaining the reaction temperature at 0 , stirring was continued for 0.5h, and thereto was added stannous chloride (56.5g, 0.25mol) in concentrated hydrochloric acid (20ml), naturally to room temperature, TLC monitored the reaction was complete feed.Suction filtration, the filter cake dried to give 3, 4-dimethylphenylhydrazine hydrochloride (11.8g).General procedure: The pyrazolo[4, 3-c]pyridin-4-one derivatives were synthesizedby using compound 15 as starting material in two steps. Infirst step, the compound 15 (1 mmol, 137 mg) was dissolved inethanol (20 mL) and substituted phenylhydrazine hydrochloride(1.1 equivalent) was added. The reaction mixture was stirred atroom temperature for 2 h. The completion of reaction was monitoredby TLC. The resulted reaction mixture was allowed to cool toroom temperature. The solvent was evaporated under vacuum; ethanol (5 mL) was added and sonicated for 30 s to produce suspension.The resulted suspensions were kept in refrigerator for 1 hto settle down the suspended particles. The suspended particleswas filtered out and used for second step without further purification.In second step, the resulted solid was poured in boilingnitrobenzene at 210 C and stirred at same temperature for 15 min[27]. The completion of reaction was monitored by TLC. After thecompletion, the reaction mixture was allowed to cool to roomtemperature followed by silica gel column chromatography toisolate pure pyrazolo[4, 3ec]pyridine4eone derivatives (12a-12p). (10 kg, 57.9 mol) was added to 30 L of ethyl acetate, and ethyl acetoacetate (9.42 kg, 72.4 mol) was added; the temperature was raised to 80-90 ° C. 5h, cooled to room temperature, stirring was continued overnight, filtered to obtain a crude product; the crude product was added to 30 L of ethyl acetate for 3 h at room temperature, filtered, and the filter cake was collected and dried at 40 ° C to obtain about 8.5 kg of product in a yield of about 72percent.Triethylamine (1.4 mL, 10 mmol) was added to a stirred suspension of [delta]-oxobenzenepentanoic acid (1.92 g, 10 mmol) and (4-methylphenyl)hydrazine hydrochloride (1.59 g, 10 mmol) in ethanol (16 mL) and the mixture was stirred at room temperature for 4 h. Ether (100 mL) was added, the mixture was filtered and the solvent was evaporated under reduced pressure. The residue was added slowly to trifluoroacetic acid (15 mL) and the mixture was heated under reflux for 2 h. The mixture was cooled, water (100 mL) was added and the mixture was extracted with ethyl acetate (100 mL). The organic fraction was washed with brine (30 mL), dried (MgSO4) and the volume was reduced to Ca. 10 mL by evaporation under reduced pressure. The precipitate was collected and recrystallized from ether to give the title compound as a pale solid (1.51 g, 54percent). H NMR (360 MHz, DMSO-d6) [delta]2.39 (3H, s), 2.50-2.58 (2H, m), 3.03-3.09 (2H, m), 6.91-6.95 (1H, m), 7.23-7.25 (1H, m), 7.34-7.40 (2H, m), 7.47-7.63 (4H, m), 11.4 (1H, br s), and 12.25 (1H, br s). m/z (ES) 280 (M+1); Prepared from [delta]-oxobenzenepentanoic acid and

Molecular Weight:172.65
Hydrogen Bond Donor Count:3
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:172.0767261
Monoisotopic Mass:172.0767261
Topological Polar Surface Area:38
Heavy Atom Count:11
Complexity:103
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes