Dimethyl Sulfoxide → HCID 21483472, compound

HRID 1415098Notes

Reaction equation

HRID 1415098 reaction equation
[Br-:1].[CH3:2][C:3]1[CH2:11][CH2:10][N+:9]2[C:8]3[CH:12]=[CH:13][CH:14]=[CH:15][C:7]=3[S:6][C:5]=2[C:4]=1[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.CS(C)=O.[Br-].C(CC[N+]1C2C=CC=CC=2SC=1C)(=O)C.[Br-].CC1C=C[N+]2C3C=CC=CC=3SC=2C=1>C(O)C.CCOCC>[Br-:1].[CH3:2][C:3]1[CH:11]=[CH:10][N+:9]2[C:8]3[CH:12]=[CH:13][CH:14]=[CH:15][C:7]=3[S:6][C:5]=2[C:4]=1[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1

Participants

7

Reactant 4

HCID 679Dimethyl SulfoxideHCID 12374301HCID 12374301, compoundHCID 12374346HCID 12374346, compoundHCID 21483476HCID 21483476, compound

Product 1

HCID 21483472HCID 21483472, compound

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 3283Diethyl EtherSolvent

Procedure

1,2-Dihydro-3-methyl-4-phenylpyrido[2,1-b]benzothiazolium bromide is prepared by reacting 3-(2-acetylethyl)-2-benzylbenzothiazolium bromide (1.0 g.) dissolved in 25 ml. of dimethyl sulfoxide. The reaction mixture is heated to reflux for several minutes and cooled. The resulting tan solid precipitate is filtered, washed with ether and dried to give 0.7 g. (72% yield) of product having a melting point of 208°-210° C. 1,2-Dihydro-3-methyl-4-phenylpyrido[2,1-b]benzothiazolium bromide (1.0 g.) is heated in 15 ml. of dimethylsulfoxide to 160° C and held for several minutes. As the mixture cools, 5 ml. each of ether and ethanol are added, precipitating some of the starting material. The addition of more ether causes the slow crystallization of the product, which on recrystallization from ethanol, is obtained in 30% yield (0.3 g.). The product has a melting point of 285°-287° C with decomposition. The NMR spectrum verifies a completely aromatic ring system. When this example is repeated, except that 3-(2-acetylethyl)-2-methylbenzothiazolium bromide is used as the starting material, there is obtained, in somewhat lower yield, 3-methylpyrido[2,1-b]benzothiazolium bromide, which is a useful intermediate in preparing dyes in accordance with this invention.

Workup

  1. customprecipitating some of the starting material
  2. additionThe addition of more ether
  3. customthe slow crystallization of the product, which
  4. customon recrystallization from ethanol
  5. customis obtained in 30% yield (0.3 g.)
  6. customthere is obtained
  7. customin somewhat lower yield
  8. customin preparing dyes in accordance with this invention

Sources & evidence

ORD record
ord-77e927fe2e424cb09bf42f0c3354e7c6
Source dataset
uspto-grants-1977_01
Patent number
US04003750

Reaction notes

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