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With trichlorophosphate; In hexane; chloroform; N,N-dimethyl-formamide; |
Example 46a 5-Chloro-4-methyl-<strong>[14345-97-2]thiophene</strong>-2-carbaldehyde Using a modified procedure of Silverstein et al.(Organic Synthesis Coll. Vol 4, Wiley, NewYork, 1963, N. Rabjohn, ed. p 831), to a 80C pale yellow solution of <strong>[14345-97-2]2-chloro-3-methyl-<strong>[14345-97-2]thiophene</strong></strong> (Crast, L. B., Jr. U.S. Patent 3290291, Example 2; 70 g, 0.53 mol) in dimethylformamide (48.3 g, 0.66 mol) was added phosphorous oxychloride (101.5 g, 0.66 mol) dropwise over 45 min, while maintaining temperature at 80-97C. The dark brown solution was stirred at 90C for 3 h and poured slowly into water (500 ML) at 90C. The resultant mixture was steam distilled and the distillate was cooled to 0C, affording white crystals.. The first 500 ml of distillate was extracted with chloroform and concentrated and the residue was recrystallized from hexane (150 ml) at -50C. The crude product (8.6 g) was dissolved in hexane (100 ml) and the insoluble material was filtered.. The filtrate was diluted with hexane (50 ml), stirred with Norit (2 g), and concentrated.. The product was purified by recrystallization from hexane (50 ml) at ―40C and obtainedas white crystals (7.5 g, 13%).. The remaining distillate from the steam distillation was extracted with chloroform (2 x 250 ml) and the white crystals dissolved in chloroform (1.5 l).. The combined organic phases were dried over MgSO4, filtered, stirred with Norit (30 g) for 15 min, and concentrated.. The residue was dissolved in hexane (350 ml), the insoluble material was filtered, the filtrate was stirred at -15 C for 10 min, and the resultant precipitate was filtered.. The title product was obtained as pale yellow crystals (48.6 g, 83%). mp 39-40C. |
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With trichlorophosphate; In N-methyl-acetamide; hexane; chloroform; |
EXAMPLE 46a 5-Chloro-4-methyl-<strong>[14345-97-2]thiophene</strong>-2-carbaldehyde Using a modified procedure of Silverstein et al. (Organic Synthesis Coll. Vol 4, Wiley, N.Y., 1963, N. Rabjohn, ed. p 831), to a 80 C. pale yellow solution of <strong>[14345-97-2]2-chloro-3-methyl-<strong>[14345-97-2]thiophene</strong></strong> (Crast, L. B., Jr. U.S. Pat. No. 3,290,291, Example 2; 70 g, 0.53 mol) in dimethylformamide (48.3 g, 0.66 mol) was added phosphorous oxychloride (101.5 g, 0.66 mol) dropwise over 45 min, while maintaining temperature at 80-97 C. The dark brown solution was stirred at 90 C. for 3 h and poured slowly into water (500 mL) at 90 C. The resultant mixture was steam distilled and the distillate was cooled to 0 C., affording white crystals. The first 500 ml of distillate was extracted with chloroform and concentrated and the residue was recrystallized from hexane (150 ml) at -50 C. The crude product (8.6 g) was dissolved in hexane (100 ml) and the insoluble material was filtered. The filtrate was diluted with hexane (50 ml), stirred with Norite (2 g), and concentrated. The product was purified by recrystallization from hexane (50 ml) at 40 C. and obtained as white crystals (7.5 g, 13%). The remaining distillate from the steam distillation was extracted with chloroform (2*250 ml) and the white crystals dissolved in chloroform (1.5 l). The combined organic phases were dried over MgSO4, filtered, stirred with Norit (30 g) for 15 min, and concentrated. The residue was dissolved in hexane (350 ml), the insoluble material was filtered, the filtrate was stirred at -15 C. for 10 min, and the resultant precipitate was filtered. The title product was obtained as pale yellow crystals (48.6 g, 83%); mp 39-40 C. |
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With trichlorophosphate; In N-methyl-acetamide; hexane; chloroform; |
Example 46a 5-Chloro-4-methyl-<strong>[14345-97-2]thiophene</strong>-2-carbaldehyde Using a modified procedure of Silverstein et at (Organic Synthesis Coll. Vol 4, Wiley, N.Y., 1963, N. Rabjohn, ed. p 831), to a 80 C. pale yellow solution of <strong>[14345-97-2]2-chloro-3-methyl-<strong>[14345-97-2]thiophene</strong></strong> (Crast, L. B., Jr. U.S. Pat. No. 3,290,291, Example 2; 70 g, 0.53 mol) in dimethylformamide (48.3 g, 0.66 mol) was added phosphorous oxychloride (101.5 g, 0.66 mol) dropwise over 45 min, while maintaining temperature at 80-97 C. The dark brown solution was stirred at 90 C. for 3 h and poured slowly into water (500 mL) at 90 C. The resultant mixture was steam distilled and the distillate was cooled to 0 C., affording white crystals. The first 500 ml of distillate was extracted with chloroform and concentrated and the residue was recrystallized from hexane (150 ml) at -50 C. The crude product (8.6 g) was dissolved in hexane (100 ml) and the insoluble material was filtered. The filtrate was diluted with hexane (50 ml), stirred with Norit (2 g), and concentrated. The product was purified by recrystallization from hexane (50 ml) at -40 C. and obtained as white crystals (7.5 g, 13%). The remaining distillate from the steam distillation was extracted with chloroform (2*250 ml) and the white crystals dissolved in chloroform (1.5 l). The combined organic phases were dried over MgSO4, filtered, stirred with Nori (30 g) for 15 min, and concentrated. The residue was dissolved in hexane (350 ml), the insoluble material was filtered, the filtrate was stirred at -15 C. for 10 min, and the resultant precipitate was filtered. The title product was obtained as pale yellow crystals (48.6 g, 83%). mp 39-40 C. |
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