Dimethyl Sulfoxide → Benzothiazole

HRID 2251622Notes

Reaction equation

HRID 2251622 reaction equation
[CH2:1](C1(CC)C2C=C(C=O)C=CC=2C2C1=CC(Br)=CC=2)C.[NH2:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][C:23]=1[SH:28].CS(C)=O>O>[S:28]1[C:23]2[CH:24]=[CH:25][CH:26]=[CH:27][C:22]=2[N:21]=[CH:1]1

Participants

5

Reactant 3

HCID 679Dimethyl SulfoxideHCID 87132-AminothiophenolHCID 154763497-Bromo-9,9-diethylfluorene-2-carboxaldehyde

Product 1

HCID 7222BenzothiazoleYield 80.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
195 °C

Procedure

A mixture of 9,9-diethyl-7-bromo-fluorene-2-carboxaldehyde (49.35 g., 0.15 mol.), 2-aminothiophenol (20 ml. 0.187 mol., 1.25 eq.), and DMSO (110 nl) was heated in an oil bath to a bath temperature of 195° C., held there for 45 minutes, and then poured into water. The separated solids were collected, reslurried in 1:4 acetic acid-water (1000 ml.) filtered, and washed with water and dilute sodium bicarbonate solution. These solids, 80.05 g., were then reslurried in hot ethanol, (600 ml), cooled and filtered to get the product benzothiazole, 45.69 g., m.p. 133.6-135° C. An additional 6.6 g., m.p. 134.6-135.5° C., was obtained by chromatography of the ethanol filtrate. Total recovery was 52.29 g. (80.3% yield). Mass Spec: m/z 433, 435, (M+). Anal. Calcd for C24H20BrNS: C, 66.37; H, 4.64; Br, 18.40; N, 3.23; S 7.37%. Found: C, 66.46; H, 4.52; Br, 18.54; N, 3.14; S, 7.19%.

Workup

  1. customThe separated solids were collected
  2. filtrationfiltered
  3. washwashed with water and dilute sodium bicarbonate solution
  4. temperaturecooled
  5. filtrationfiltered

Sources & evidence

ORD record
ord-b871d7960960449d875843d763702afd
Source dataset
uspto-grants-2008_01
Patent number
US07319151B1

Reaction notes

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