Methanesulfonic Acid → Benzoxazole

HRID 1195202Notes

Reaction equation

HRID 1195202 reaction equation
Cl.Cl.N[C:4]1[CH:10]=[C:9]([NH2:11])[C:7]([OH:8])=[CH:6][C:5]=1O.[CH3:13]S(O)(=O)=O.O(C1C=CC(OC2C=CC=CC=2)=CC=1)C1C=CC=CC=1>>[O:8]1[C:7]2[CH:6]=[CH:5][CH:4]=[CH:10][C:9]=2[N:11]=[CH:13]1

Participants

4

Reactant 3

HCID 6395Methanesulfonic AcidHCID 520487Benzene, 1,4-diphenoxy-HCID 27336484,6-Diaminoresorcinol Dihydrochloride

Product 1

HCID 9228Benzoxazole

Conditions

Temperature
95 °C

Procedure

Under nitrogen atmosphere, 1.00 g (4.69 mmoles) of 4,6-diaminoresorcinol dihydrochloride and 1.62 g (6.26 mmoles) of oxy-bis(4-benzoic acid) are mixed and 29.1 ml of 10-1 methanesulfonic acid solution is added. The mixture is stirred and heated to 95° C. for 24 hours and then cooled to 50° C. A 0.41-g (1.56-mmole) quantity of p-diphenoxybenzene is added and stirring is continued at 50° C. for 48 hours. The resulting copolymer is precipitated in aqueous potassium hydroxide in a blender, washed with water until neutral and dried to constant weight in a vacuum oven at about 50° C. Its inherent viscosity in concentrated sulfuric acid at 25° C. and about 0.2028 g/dL concentration is measured to be about 0.99 dL/g. Its inherent viscosity in methanesulfonic acid at about 0.05 g/dL concentration and about 25° C. is measured to be 4.42 dL/g.

Workup

  1. temperaturecooled to 50° C
  2. stirringstirring
  3. customThe resulting copolymer is precipitated in aqueous potassium hydroxide in a blender
  4. washwashed with water until neutral and
  5. customdried to constant weight in a vacuum oven at about 50° C
  6. concentrationIts inherent viscosity in concentrated sulfuric acid at 25° C. and about 0.2028 g/dL concentration
  7. concentrationIts inherent viscosity in methanesulfonic acid at about 0.05 g/dL concentration and about 25° C.

Sources & evidence

ORD record
ord-ddb2a0c760164d3ead94363f2530e4fc
Source dataset
uspto-grants-1992_05
Patent number
US05110894

Reaction notes

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