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2,5-Dimethylthiophene is a chemical with a specific purpose. Lookchem provides you with multiple data and supplier information of this chemical.

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  • 638-02-8 Structure
  • Basic information

    1. Product Name: 2,5-Dimethylthiophene
    2. Synonyms: 2,5-DIMETHYLTHIOPHENE;2,5-DIMETHYLTHIOPHENE, 98.5%;2 5-DIMETHYLTHIOPHENE 98+%;2,5-Dimethylthiophene, 98.50%;Thiophene, 2,5-dimethyl-;2,5-DIMETHYTHIOPHENE;2,5-Thioxene;2,5-DiMethylthiophene, 98.5% 25ML
    3. CAS NO:638-02-8
    4. Molecular Formula: C6H8S
    5. Molecular Weight: 112.19
    6. EINECS: 211-313-9
    7. Product Categories: Thiophene&Benzothiophene;Heterocyclic Compounds;Thiophens;thiophene Flavor;Building Blocks;Heterocyclic Building Blocks;Thiophenes;Alphabetical Listings;C-D;Flavors and Fragrances
    8. Mol File: 638-02-8.mol
    9. Article Data: 29
  • Chemical Properties

    1. Melting Point: -63°C
    2. Boiling Point: 134 °C740 mm Hg(lit.)
    3. Flash Point: 75 °F
    4. Appearance: Clear colorless to slightly yellow/Liquid
    5. Density: 0.985 g/mL at 25 °C(lit.)
    6. Vapor Pressure: 8.98mmHg at 25°C
    7. Refractive Index: n20/D 1.512(lit.)
    8. Storage Temp.: Flammables area
    9. Solubility: N/A
    10. Water Solubility: Insoluble in water. Soluble in alcohol, ether and benzene.
    11. BRN: 106450
    12. CAS DataBase Reference: 2,5-Dimethylthiophene(CAS DataBase Reference)
    13. NIST Chemistry Reference: 2,5-Dimethylthiophene(638-02-8)
    14. EPA Substance Registry System: 2,5-Dimethylthiophene(638-02-8)
  • Safety Data

    1. Hazard Codes: Xn,F,Xi
    2. Statements: 10-37-20/22
    3. Safety Statements: 23-24/25-16-36-33-29-7/9-3/7/9
    4. RIDADR: UN 1993 3/PG 3
    5. WGK Germany: 3
    6. RTECS:
    7. HazardClass: 3
    8. PackingGroup: II
    9. Hazardous Substances Data: 638-02-8(Hazardous Substances Data)

638-02-8 Usage

Chemical Properties

clear colorless to slightly yellow liquid

Uses

2,5-Dimethylthiophene is used as an intermediate in organic synthesis.

Synthesis Reference(s)

The Journal of Organic Chemistry, 20, p. 1363, 1955 DOI: 10.1021/jo01127a012

General Description

2,5-Dimethylthiophene is a volatile flavoring compound that has been identified in the essential oil of onion. It is reported to be one of the sulfur-containing compounds formed via Maillard reaction/Strecker degradation of cysteine with furaneol.

Check Digit Verification of cas no

The CAS Registry Mumber 638-02-8 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 6,3 and 8 respectively; the second part has 2 digits, 0 and 2 respectively.
Calculate Digit Verification of CAS Registry Number 638-02:
(5*6)+(4*3)+(3*8)+(2*0)+(1*2)=68
68 % 10 = 8
So 638-02-8 is a valid CAS Registry Number.
InChI:InChI=1/C6H8S/c1-5-3-4-6(2)7-5/h3-4H,1-2H3

638-02-8 Well-known Company Product Price

  • Brand
  • (Code)Product description
  • CAS number
  • Packaging
  • Price
  • Detail
  • Alfa Aesar

  • (A10869)  2,5-Dimethylthiophene, 98+%   

  • 638-02-8

  • 10g

  • 404.0CNY

  • Detail
  • Alfa Aesar

  • (A10869)  2,5-Dimethylthiophene, 98+%   

  • 638-02-8

  • 25g

  • 985.0CNY

  • Detail
  • Alfa Aesar

  • (A10869)  2,5-Dimethylthiophene, 98+%   

  • 638-02-8

  • 250g

  • 7899.0CNY

  • Detail
  • Aldrich

  • (D188603)  2,5-Dimethylthiophene  98.5%

  • 638-02-8

  • D188603-25G

  • 1,272.96CNY

  • Detail
  • Aldrich

  • (D188603)  2,5-Dimethylthiophene  98.5%

  • 638-02-8

  • D188603-100G

  • 3,701.88CNY

  • Detail

638-02-8SDS

SAFETY DATA SHEETS

According to Globally Harmonized System of Classification and Labelling of Chemicals (GHS) - Sixth revised edition

Version: 1.0

Creation Date: Aug 13, 2017

Revision Date: Aug 13, 2017

1.Identification

1.1 GHS Product identifier

Product name 2,5-Dimethylthiophene

1.2 Other means of identification

Product number -
Other names Thiophene,2,5-dimethyl

1.3 Recommended use of the chemical and restrictions on use

Identified uses For industry use only. Food additives -> Flavoring Agents
Uses advised against no data available

1.4 Supplier's details

1.5 Emergency phone number

Emergency phone number -
Service hours Monday to Friday, 9am-5pm (Standard time zone: UTC/GMT +8 hours).

More Details:638-02-8 SDS

638-02-8Synthetic route

5-methylthiophene-2-carboxaldehyde
13679-70-4

5-methylthiophene-2-carboxaldehyde

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
Stage #1: 5-methylthiophene-2-carboxaldehyde With hydrazine hydrate Wolff-Kishner-Huang Minlon Reduction;
Stage #2: With potassium hydroxide
96%
With potassium hydroxide; hydrazine hydrate; ethylene glycol
With potassium hydroxide; hydrazine
2,5-hexanedione
110-13-4

2,5-hexanedione

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With Lawessons reagent at 140℃; for 1h;87%
With diphosphorus pentasulfide In tetrachloromethane for 4h; Heating;76%
With diphosphorus trisulfide
2,5-dimethylfuran
625-86-5

2,5-dimethylfuran

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With hydrogenchloride; hydrogen sulfide In acetic acid Ambient temperature; further acids, solvents;80%
With hydrogenchloride; zinc sulfide In ethanol at 40℃; Product distribution; Further Variations:; Temperatures; Reagents; concentrations of reagents; time; Substitution;80%
With hydrogenchloride; zinc sulfide In ethanol at 40℃; Substitution;80%
thiophene
188290-36-0

thiophene

Dimethyldisulphide
624-92-0

Dimethyldisulphide

A

2-Methylthiophene
554-14-3

2-Methylthiophene

B

2,3,4-trimethylthiophene
1795-04-6

2,3,4-trimethylthiophene

C

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With zeolite HZSM-5 at 300℃; under 760.051 Torr; for 0.00236111h; Time; Flow reactor;A 19%
B 18%
C 12%
With HZSM-5 zeolite (SiO2/Al2O3 = 34) at 300℃; under 760.051 Torr; for 2h; Catalytic behavior; Temperature; Flow reactor; Gas phase; Inert atmosphere;
2-Methylthiophene
554-14-3

2-Methylthiophene

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With iodine; mercury(II) oxide Behandeln mit Methyljodid und Natrium in Aether;
Multi-step reaction with 2 steps
1: Einleiten von Bromdaempfen
2: sodium
View Scheme
Multi-step reaction with 2 steps
1: trichlorophosphate / 20 °C
2: hydrazine hydrate
View Scheme
2-bromo-5-methyl thiophene
765-58-2

2-bromo-5-methyl thiophene

methyl iodide
74-88-4

methyl iodide

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With sodium
5-methyl-thiophene-2-carbaldehyde semicarbazone
131392-02-4

5-methyl-thiophene-2-carbaldehyde semicarbazone

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

hexa-2,4-diene
592-46-1

hexa-2,4-diene

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With sulfur at 420℃;
acetylene
74-86-2

acetylene

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
at 650 - 670℃; beim Durchleiten mit Leuchtgas und Schwefelwasserstoff durch Roehren aus Marquardtscher Masse;
2-hexene
592-43-8

2-hexene

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With sulfur at 420℃;
2-Methylthiophene
554-14-3

2-Methylthiophene

Methyl fluoride
593-53-3

Methyl fluoride

A

2,3-dimethylthiophene
632-16-6

2,3-dimethylthiophene

B

2,4-dimethylthiophene
638-00-6

2,4-dimethylthiophene

C

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
With oxygen; trimethylamine In gas at 37.5℃; Product distribution; Kinetics; Mechanism; radiolysis: 1.5*104 Gy at 5*105 Gy h-1; variable pressures;
2-Methylthiophene
554-14-3

2-Methylthiophene

A

thiophene
188290-36-0

thiophene

B

2,3-dimethylthiophene
632-16-6

2,3-dimethylthiophene

C

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

D

toluene
108-88-3

toluene

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 15.3 % Chromat.
B 1.8 % Chromat.
C 4.9 % Chromat.
D 1.2 % Chromat.
2-Methylthiophene
554-14-3

2-Methylthiophene

A

thiophene
188290-36-0

thiophene

B

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

C

toluene
108-88-3

toluene

D

benzene
71-43-2

benzene

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 15.3 % Chromat.
B 4.9 % Chromat.
C 1.2 % Chromat.
D 8.6 % Chromat.
2-Methylthiophene
554-14-3

2-Methylthiophene

A

2-ethylthiophene
872-55-9

2-ethylthiophene

B

2,4-dimethylthiophene
638-00-6

2,4-dimethylthiophene

C

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

D

3-Methylthiophene
616-44-4

3-Methylthiophene

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 11.7 % Chromat.
B 0.6 % Chromat.
C 4.9 % Chromat.
D 9.2 % Chromat.
2,3-dimethylthiophene
632-16-6

2,3-dimethylthiophene

A

thiophene
188290-36-0

thiophene

B

2-ethylthiophene
872-55-9

2-ethylthiophene

C

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

D

3-Methylthiophene
616-44-4

3-Methylthiophene

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 3.1 % Chromat.
B 1.5 % Chromat.
C 1.0 % Chromat.
D 12.8 % Chromat.
3,4-dimethylthiophene
632-15-5

3,4-dimethylthiophene

A

2,3-dimethylthiophene
632-16-6

2,3-dimethylthiophene

B

2,4-dimethylthiophene
638-00-6

2,4-dimethylthiophene

C

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

D

3-Methylthiophene
616-44-4

3-Methylthiophene

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 5.1 % Chromat.
B 6.2 % Chromat.
C 1.1 % Chromat.
D 12.2 % Chromat.
3,4-dimethylthiophene
632-15-5

3,4-dimethylthiophene

A

2,4-dimethylthiophene
638-00-6

2,4-dimethylthiophene

B

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

C

3-Methylthiophene
616-44-4

3-Methylthiophene

D

benzene
71-43-2

benzene

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 6.2 % Chromat.
B 1.1 % Chromat.
C 12.2 % Chromat.
D 17.6 % Chromat.
2,4-dimethylthiophene
638-00-6

2,4-dimethylthiophene

A

2,3-dimethylthiophene
632-16-6

2,3-dimethylthiophene

B

3,4-dimethylthiophene
632-15-5

3,4-dimethylthiophene

C

2-ethylthiophene
872-55-9

2-ethylthiophene

D

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 0.6 % Chromat.
B 2.9 % Chromat.
C 1.2 % Chromat.
D 3.5 % Chromat.
2,4-dimethylthiophene
638-00-6

2,4-dimethylthiophene

A

2-Methylthiophene
554-14-3

2-Methylthiophene

B

3,4-dimethylthiophene
632-15-5

3,4-dimethylthiophene

C

2,5-DIMETHYLTHIOPHENE
638-02-8

2,5-DIMETHYLTHIOPHENE

D

3-Methylthiophene
616-44-4

3-Methylthiophene

Conditions
ConditionsYield
1.) glow discharge, 2.) -196 deg C -> -80 deg C; Further byproducts given. Title compound not separated from byproducts;A 6.6 % Chromat.
B 2.9 % Chromat.
C 3.5 % Chromat.
D 9.5 % Chromat.

638-02-8Relevant articles and documents

MECHANISM OF RECYCLIZATION OF FURANS TO THIOPHENES AND SELENOPHENES UNDER ACID-CATALYSIS CONDITIONS. 2. KINETIC INVESTIGATIONS OF THE REACTION OF 2,5-DIALKYLFURANS WITH HYDROGEN SULFIDE AND HYDROGEN SELENIDE IN AN ANHYDROUS MEDIUM

Voronin, S. P.,Gubina, T. I.,Trushin, S. A.,Markushina, I. A.,Kharchenko, V. G.

, p. 1216 - 1220 (1989)

The effect of the concentration of the acidic component on the rates of recyclization of 2,5-dialkylfurans to thiophenes and selenophenes was studied.On the basis of the direct correlation of log k on (H0)I and the isotope effect of the solvent it was established that the reaction proceeds via a mechanism of specific acid catalysis.It was shown that the rates of the reactions with the participation of hydrogen sulfide and hydrogen selenide coincide at equal acidities and temperatures.A scheme for the mechanism of the reaction that includes a step involving the formation of the doubly protonated form of the substrate is proposed.

New method for synthesis of 2,5-disubstituted thiophenes

Gubina,Drevko,Fedina,Rogacheva,Kharchenko

, p. 650 - 652 (1999)

The use of hydrogen sulfide at the moment of formation is proposed for the recyclization of furans into thiophenes in acidic media. The advantages of this method are shown. 1999 KluwerAcademic/Plenum Publishers.

Study of the mechanism of recyclization of furans into thiophenes and selenophenes in conditions of acid catalysis. 6. Experiments with labeled atoms. Quantum chemical calculations of intermediates of recyclization and hydrolysis

Gubina,Pankratov,Labunskaya,Voronin,Kharchenko

, p. 903 - 909 (1997)

The reaction of 2-methyl-5-R-furans (R = Me, Bu, 2,2-pentyl-2-methylpentyl) with H218O was investigated. Furans and the corresponding 2,5-alkanediones containing the 18O isotope were obtained. The general characteristics of the recyclization and isotope exchange reactions were established. A kinetic study of recyclization of 2,5-dimethylfuran with 16O and 18O into 2,5-dimethylthiophene was conducted. A reverse kinetic isotope effect was found. The schemes of the mechanisms of these processes were refined based on the experimental data and quantum-chemical calculations of the recyclization and hydrolysis intermediates. 1998 Plenum Publishing Corporation.

Synthesis of substituted 1,2,4-triazines based on 1,2-bis(2,5-dimethyl-3-thienyl)ethanedione

Ivanov,Lichitskii,Dudinov,Martynkin,Krayushkin

, p. 85 - 90 (2001)

A novel, convenient method has been developed for the synthesis of 1,2-bis(2,5-dimethyl-3-thienyl)ethanedione, from which were prepared 5, 6-bis(2,5-dimethyl-3-thienyl)-1,2,4-triazines (analogs of the photochromic 1,2-diarylethenes). The principial possibility of using 1,2,4-triazines obtained as photochromic agents was investigated.

Catalytic Synthesis of Methylthiophenes

Mashkina,Khairulina

, p. 1794 - 1797 (2019/03/26)

The gas-phase reaction of dimethyl disulfide with thiophene over Co/HZSM-5 catalyst in a helium medium under atmospheric pressure at 250–350°C gave a mixture of mono-, di-, tri-, and tetramethylthiophenes with an overall selectivity of 94–96%.

Catalytic reactions of dimethyl disulfide with thiophene and benzene

Mashkina,Khairulina

, p. 72 - 81 (2016/04/20)

The gas-phase reaction of dimethyl disulfide with thiophene proceeds under the action of acid catalysts under atmospheric pressure at 160-350°C and a residence time of τ = 0.6-21 s to form thioalkylation and alkylation products. Dimethyl disulfide reacts with benzene to form only alkylation products. Catalysts containing both strong protic and Lewis acid sites, as well as basic sites of moderate strength, are the most active ones.

Reaction of dimethyl disulfide with thiophene catalyzed by zeolite

Mashkina,Khairulina

, p. 217 - 220 (2015/04/14)

Reaction of dimethyl disulfide with thiophene under the action of highly siliceous zeolite at 180-350°C and contact time 0.6-14 s resulted in formation of thioalkylation products, 2-(methylsulfanyl)- and 2,5-bis(methylsulfanyl)thiophenes and also alkylate

Electrochromic properties of novel chalcones containing triphenylamine moiety

Jin, Huiyi,Li, Xianggao,Tan, Tingfeng,Wang, Shirong,Xiao, Yin,Tian, Jianhua

, p. 154 - 160 (2014/04/17)

A series of novel electrochromic chalcones containing triphenylamine units were synthesized by Aldol reaction and characterized by NMR, IR and MS. Their optical, electrochemical properties were investigated using UV-vis, photoluminescence spectra and cyclic voltammetry. The molecular orbital energy levels and excitation energies were calculated by quantum chemical calculation. It was found that the fluorescence intensity is decreasing with formation of charge-transfer state. The existence of electron donating group on triphenylamine unites caused a significant bathochromic shift of the UV absorption maximum and increased EHOMO and ELUMO. The electrochromic property of the synthesized compounds was studied by spectroelectrochemical experiments. The results showed that the chalcones containing triphenylamine moiety presented good electrochromic stability, with a color change from yellow to blue as applied potentials ranging from 0.0 to 2.8 V. The coloring and bleaching time was in the range of 2.9-4.2 s and 1.7-3.3 s, respectively.

Investigation of the aroma-active compounds formed in the maillard reaction between glutathione and reducing sugars

Lee, Sang Mi,Jo, Ye-Jin,Kim, Young-Suk

experimental part, p. 3116 - 3124 (2011/08/05)

Aroma-active compounds formed during the thermal reaction between glutathione (GSH) and reducing sugars were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-olfactometry (GC-O) with aroma extract dilution analysis (AEDA). Application of AEDA to glutathione Maillard reaction products (GSH MRPs) led to the identification of 19 aroma-active compounds in the thermal reaction of glutathione with glucose or fructose. In addition, the carbohydrate module labeling (CAMOLA) approach was also employed to elucidate the formation pathways for selected target sulfur aroma compounds, such as 5-methylthiophene-2-carbaldehyde and 3-methylthiophene-2-carbaldehyde, which have not been reported previously. The intact carbon skeleton of glucose via 3-deoxyhexosone is incorporated into 5-methylthiophene-2-carbaldehyde with the hydrogen sulfide of GSH. On the other hand, the formation of 3-methylthiophene2-carbaldehyde may occur via the recombination of a C-4 sugar fragment and mercaptoacetaldehyde.

Carbon-sulfur bond cleavage of methyl-substituted thiophenes with iridium(III)

Grochowski, Matthew R.,Brennessel, William W.,Jones, William D.

, p. 2661 - 2667 (2009/09/26)

Reaction of [Cp*IrHCl]2 (Cp* = η5- C5Me5) with 2-methylthiophene and 2,5-dimethylthiophene at 120 °C in the presence of H2 results in the cleavage of the thiophene carbon-sulfur bond(s). In both cases

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