Acetonitrile → 1-(3,7-bis(dimethylamino)-10H-phenothiazin-10-yl)ethanone

HRID 2370051Notes

Reaction equation

HRID 2370051 reaction equation
[BH4-].[Na+].C[CH2:4][N:5]([CH:9]([CH3:11])[CH3:10])[CH:6](C)C.O.O.O.[Cl-].[CH3:16][C:17]1[SH+:18][CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=[CH:24][CH:25]=1.[BH4-].[Na+].[C:28]([O:31]C(=O)C)(=O)[CH3:29].C[CH2:36][N:37]([CH:41](C)C)C(C)C.C(#[N:46])C>>[CH3:36][N:37]([CH3:41])[C:24]1[CH:23]=[CH:22][C:16]2[N:46]([C:28](=[O:31])[CH3:29])[C:20]3[C:19]([S:18][C:17]=2[CH:25]=1)=[CH:11][C:9]([N:5]([CH3:4])[CH3:6])=[CH:10][CH:21]=3

Participants

7

Reactant 6

HCID 6342AcetonitrileHCID 7918Acetic AnhydrideHCID 81531DiisopropylethylamineHCID 4311764Sodium borohydrideHCID 866280322-Methylthionin-1-ium;chloride;trihydrateHCID 131728694sodium borohydride Hunig's base

Product 1

HCID 198258321-(3,7-bis(dimethylamino)-10H-phenothiazin-10-yl)ethanoneYield 52%

Conditions

Temperature
35 °C

Procedure

Synthesis using sodium borohydride/Hunig's base in one pot. To a 500 cm3 round bottom flask under an atmosphere of nitrogen was added methylthioninium chloride trihydrate (80.2 mmol, 30 g) and acetonitrile (150 cm3). Sodium borohydride (104 mmol, 3.94 g) was added in four equal portions over a 30 minute time period. The temperature of the mixture was maintained at 35° C. with a cold water bath and was stirred for 30 minutes. The yellow/green suspension had acetic anhydride (321 mmol, 32.75 g) and Hunig's base (diisopropylethylamine) (120 mmol, 15.55 g) added. The mixture was heated at 90° C. for 2 hours. The cooled mixture was then poured carefully into ice water (200 cm3) in ten equal portions while stirring to give a precipitate. The precipitate was stirred for 30 minutes before it was filtered, washed with water (3×50 cm3), and air dried for 30 minutes. The crude material was crystallised from hot ethanol (300 cm3) to yield the title compound (13.55 g, 52%) as a light grey solid. Mp 137° C.; νmax (KBr)/cm−1 2910 (CH), 2876 (CH), 2856 (CH), 2799 (CH), 1659 (C═O), 1596 (NO2), 1502 (NO2); δH (250 MHz; CDCl3) 2.16 (3H, s, CH3), 2.93 (12H, s, NCH3), 6.59-6.62 (2H, d, J 8.5, ArH), 6.69-6.71 (2H, d, J 2.75, ArH), 7.08-7.47 (2H, brd s, ArH); δC (62.9 MHz; CDCl3) 170.3 (C═O), 148.9 (ArC), 127.2 (ArC), 127.1 (ArC), 127.0 (ArC), 110.9 (ArC), 110.7 (ArC), 40.7 (NCH3), 22.9 (CH3); m/z (ES) 284.2 (100%, [M-OAc]+), 328.1 (15%, [M+H]+), 350.1 (41%, [M+Na]+).

Workup

  1. customSynthesis
  2. additionadded
  3. temperatureThe mixture was heated at 90° C. for 2 hours
  4. stirringwhile stirring
  5. customto give a precipitate
  6. stirringThe precipitate was stirred for 30 minutes before it
  7. filtrationwas filtered
  8. washwashed with water (3×50 cm3), and air
  9. customdried for 30 minutes
  10. customThe crude material was crystallised from hot ethanol (300 cm3)

Sources & evidence

ORD record
ord-9cbccbb58e1e48c18392e708b71f499e
Source dataset
uspto-grants-2014_04
Patent number
US08710051B2

Reaction notes

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