www.BuyersGuideChem.com - directory for chemicals and chemical suppliers
Productname:

BGC > Chemicals A-Z > 2-Acetylthiophene

2-Acetylthiophene

Structure
Quick view: Suppliers
BGC Id:
550737966739
CAS No.:
Synonyms:
| 2-acetylthioph | akos 91936 | 2-acetylthiole | 2-acetylthiophen | thiophene,2-acetyl- | akos bbs-00000940 | 2-acetothienone | 2-acetylthiophene | 2-acethylthiophene | 2-acetothiophene
Formula:
C6H6OS
Molecular Weight:
126.18
EINECS:
201-804-6

List of Suppliers

Sarex Overseas

Company type: Analytical Institution
To meet the growing market for high value organic fine chemicals, we began operations in 1997, primarily focusing on custom synthesis and contract manufacture. We work with several leading companies globally and our over 30-member team of professional chemists who specialize in several areas of synthetic organic chemistry, cater to the needs of our customers located in the Americas, Asia and Europe. We are seller of . Sarex Overseas is supplier for 2-Acetylthiophene. We develop products based on customer needs and operate in volumes spanning g ...
Country: India   Phone: +91 22 4218 4218   Telefax: +91 22 4218 4350

XD Biochem Limited

Company type: Analytical Institution
XD BIOCHEMS is a manufacturer and distributor of Fine Chemicals and Biochemicals in Bulk, Semi-Bulk and Research quantities. XD Biochem Limited is supplier for 2-Acetylthiophene. Our business originates from the production and sales of amino acids, amino acid derivatives and peptide reagents. Additionally is supplied by us. With the increasing market demand for biochemical products, we began to produce and sell various glucosides, biological buffers and diagnostic reagents in 2018. Thanks to the rapid development of CRO and CMO in China, we began to produ ...
Country: P.R.China   Phone: +86 13815202715 / +86 513 81163739   Telefax: +86 513 81163733

Krada CPS Industry S.L

Company type: Analytical Institution
Krada CPS Industry S.L. We are seller of . Is a growing distributor company in Spain. We trade chemical raw materials for factories, laboratories both in Spain and throughout the European Union. We are happy to process your requests. Krada CPS Industry S.L is supplier for 2-Acetylthiophene.
Country: Spain   Phone: +34 698992882   Telefax: +34 698992882

Leache Chem Ltd

Company type: Leading producer
Leache Chem is the first manufacturer in China professionally producing DMH and its derivatives hydantoin products, including DMH, BCDMH,DBDMH,DCDMH as well as the intermediates 5- phenyl hydantoin, 5 n-propyl hydantoin and thiophene series intermediates etc. We supply our chemical product Thiophene. Leache Chem Ltd is supplier for 2-Acetylthiophene. Leache's main business is concentrated in four sections based antiseptic, fine chemical intermediates and bulk drug intermediates, the application is covering the industrial circulating water treatment, swimming pool w ...
Country: P.R.China   Phone: +86-310-7092106   Telefax: +86-310-7092108

Austin Chemical Company, Inc.

Company type: Analytical Institution
Austin Chemical Company, Inc. is starting its 4th decade of business and we find ourselves continuing to evolve into new areas and services in response to our customers needs and requests. We are expanding our global relationships with those suppliers that offer new and reliable services while continuing to grow the valued relationships with some of our historical suppliers. Austin Chemical Company, Inc. is supplier for 2-Acetylthiophene. We are supplier of Paclitaxel. We look forward to presenting from this point forward, a web site reflecting the ne ...
Country: USA   Phone:   Telefax:

Richman Chemical Inc.,

Company type: Analytical Institution
For over 17 years, Richman Chemical, Inc. (RCI) has been providing project management, custom manufacturing and sourcing services to the chemical and life sciences industries. RCI has an extensive chemical and pharmaceutical raw material and intermediate product range. Richman Chemical Inc., is supplier for 2-Acetylthiophene. Richman Chemical Inc., also offers Ethyl 4-benzyloxyindole-2-carboxylate. Because of its widespread custom/contract services activities, RCI can offer customers access to its extensive network of worldwide suppliers.
Country: USA   Phone: +1-215-628-2946   Telefax: +1-215-628-4262

Biesterfeld Spezialchemie GmbH

Company type: Import and export company
Biesterfeld Spezialchemie GmbH is supplier for 2-Acetylthiophene. 4-Hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylic acid ethyl ester 1,1-dioxide will be also provided by us. Biesterfeld Spezialchemie is one of the leading international distributors of specialty chemicals. As solution provider we offer: a broad range of innovative raw materials, customer-specific advice and solution-oriented, technical expertise, formulation know-how, comprehensive market knowledge, close long-term cooperation with leading global suppliers, efficient logistic processes and customised logistical solu ...
Country: Germany   Phone: +49-40 32008 326   Telefax: +49-40 32008 696

Hangzhou Zhongqi Chem Co., Ltd

Company type: Leading producer
Located in Hangzhou National Hi-Tech Industrial Development Zone, zhongqichem is a technical company mainly focus on the Custom synthesis, manufacturing, sales of chemicals to various industries. Hangzhou Zhongqi Chem Co., Ltd also offers Methyl methoxyacetate. Hangzhou Zhongqi Chem Co., Ltd is supplier for 2-Acetylthiophene. Our advantage : 1.We do not simply provide chemicals , we provide chemical solutions and expertise; 2.We have trained, highly effective team to solve the problem at the first time; 3.Our QMS (quality management system) ensures the product quality strictly; 4.Stro ...
Country: P.R.China   Phone: +86-571-86976032   Telefax: +86-571-86972162

Sancai Industry Co.,Ltd.

Company type: Leading producer
Sancai Industry is involved in supplying of fine chemicals, food and nutrition,personal care, medical intermediate etc, We can also customize chemicals for our customers.Taking advantage of innovative technology and excellent talents and through over 15 years of development,We have stabled good relation with clients in and abroad. Homosalate is also served by Sancai Industry Co.,Ltd.. In order to be competitive on the market. Sancai Industry Co.,Ltd. is supplier for 2-Acetylthiophene. We have established the global marketing network, independent research center, testing center, ...
Country: P.R.China   Phone: +86-531-88913079   Telefax: +86-531-88913079

Aecochem Corp.

Company type: Supplier
Xiamen Aeco Chemical Industrial Co., Ltd(Short as Aecochem) Your Partner in China, a Professional chemical raw material supplier, our main products including the Epxoy Chemical ,Petro Chemical,Pharma Intermediate,Fine Chemicas and Life Science etc. Aecochem Corp. We are supplier of 2-Chloro-6-methylbenzoic acid. is supplier for 2-Acetylthiophene. We consists a team of professional analytical department,complete QC&QA under strict SOPs, experienced sale and after-sale service, efficient logistic support, one-stop service is our great advantage, to benefit ...
Country: P.R.China   Phone: +86-592-5998717   Telefax: +86-592-5554527

Hangzhou Lingrui Chemical Co., Ltd.

Company type: Producer
Established in 2010, located in Hangzhou Qinglan science park, lingruichem is a technical company mainly focus on the Custom synthesis, manufacturing, sales of chemicals to various industries. Hangzhou Lingrui Chemical Co., Ltd. is supplier for 2-Acetylthiophene. In our R&D centre, we have a staff of skilled and experienced research chemists. This has enabled us to meet the special requirements of our customers and it has enabled us to provide quality products at competitive prices. We sell 4-Bromo-2-chloro-1-iodobenzene as well. Lingrui’s credo is committed to your reliable business par ...
Country: P.R.China   Phone: +86-571-88092529   Telefax: +86-571-87334908

Sigma-Aldrich International GmbH

Company type: Bulk and laboratory supplier
Our purpose is to solve the toughest problems in life science by collaborating with the global scientific community - and through that, we aim to accelerate access to better health for people everywhere. We provide scientists and engineers with best-in-class lab materials, technologies and services. We are supplier of 2,6-Bis{[bis(2-pyridylmethyl)amino]methylphenol. Sigma-Aldrich International GmbH is supplier for 2-Acetylthiophene. With the 2015 combination of Merck Millipore and Sigma-Aldrich, we now have a broad portfolio of 300,000 products and an expanded global footprint. We are de ...
Country: Switzerland   Phone: +41 81 755 28 28   Telefax: +41 81 755 28 15

Carbone Scientific Co., Ltd.

Company type: Supplier
Carbone scientific is located at London, UK. We provide Erucic acid methyl ester as well. We are mainly engaged in the marketing development, R&D, technical support and service. Carbone Scientific Co., Ltd. is supplier for 2-Acetylthiophene. Carbone scientific provides fine chemicals, pharmaceutical intermediates, and active pharmaceutical ingredients to the global marketplaces. Our aim is to make those most popular products available to these pharmaceutical and biotech companies, research organizations and university labs worldwide. Our online catalogue has already listed ...
Country: U.K.   Phone: +44 (0)203 769 4441 ext 1   Telefax: +44 (0)203 769 4441 ext 2

Finetech Industry Limited

Company type: Producer
Finetech Industry Limited is a company in England,which specializing in developing, manufacturing and marketing fine organic compounds and intermediates for the pharmaceutical industry. Finetech Industry Limited is supplier for 2-Acetylthiophene. Most of our products were exported to the North America, Europe and Oceania. We supply our chemical product . Our factory is in China,we supply Fluorochemicals, Pyrimidines, Pyridines, Amines, Nitriles, Carboxylic Acids or Ester, Phenols or Alcohols, Aldehydes, Piperidines, Piperazines, Pyrazines, Boric Acids, Amino Aci ...
Country: P.R.China   Phone: +86-27-8746 5837   Telefax: +86-27-8777 2287

Shandong SanYoung Industry Co., Ltd

Company type: Analytical Institution
Shandong SanYoung Industry Co., Ltd is a scientific and technological company specializing in research and development, cooperative production and sales of chemical products. Additionally 1,3-Dimethyl-2-imidazolidinone is supplied by us. The company's main products include: photoinitiator; light stabilizer; polymer retardant; ultraviolet absorbent; fine chemical products and pharmaceutical intermediates, we can also customize chemicals for our customers. Shandong SanYoung Industry Co., Ltd is supplier for 2-Acetylthiophene. Our company has a large number of customers with good reputation at home and abroad, ...
Country:   Phone: +86 155-64526813   Telefax: +86 531-56897532

Xiamen Hisunny Chemical Co., Ltd.

Company type: Leading producer
Hisunny Chemical is a leading manufacturer and supplier of chemicals in China. Xiamen Hisunny Chemical Co., Ltd. is supplier for 2-Acetylthiophene. We develop producing and selling high quality intermediates, Fine chemicals and Specialty Chemicals. We could give you: 1.Best quality in your requirement 2.Competitive price in China market 3.mature Technical support 4.Professional logistic support All we want is win-win business. We supply our chemical product 5,5'-Dithio-bis-(2-nitrobenzoic acid). Send yr. inquiries, you will get it!
Country: P.R.China   Phone: +86-592-3327115   Telefax: +86-592-5823596

Hangzhou Meite Industry Co., Ltd (Hangzhou Meite Chemical Co., Ltd)

Company type: Producer
Hangzhou Meite Industry Co., Ltd. is an international high-tech enterprise founded in 1998, specialized in R&D and manufacture on intermediates, medicines, agrochemical, dyestuff, flavor, fragrance, cosmetic, natural extracts series products. We have an efficient R&D centre, get a strong technical support from Zhejiang University of Technology and Institute of Chemistry, Wuhan Branch, Chinese Academy of Sciences. Hangzhou Meite Industry Co., Ltd (Hangzhou Meite Chemical Co., Ltd) is supplier for 2-Acetylthiophene. We are supplier of 3-Aminopropyltrimethoxysilane. Our factory Hangzhou Meite Chemical Co.,Ltd. is locat ...
Country: P.R.China   Phone: +86 571 88026825 / 88283817 / 88011063   Telefax: +86 571 88282557

H&Z Industry Co.,Ltd

Company type: Analytical Institution
H&Z Industry Co.,Ltd is a large reliable and professional manufacturer of chemical materials and pharmaceutical intermediate. H&Z Industry Co.,Ltd also offers (Phenylazo)malonitrile. H&Z Industry Co.,Ltd is supplier for 2-Acetylthiophene. With about 10 years experiences in this field, now we are a capable provider of customized product, and we can provide gram level to ton level of products. What we can give to customers: thoughtful services, high-quality products, competitive price, Looking forward building long-term cooperative relationships with our business p ...
Country:   Phone: +86 18953157230   Telefax: +86 531 88905468

Skyrun Industrial Co., Ltd.

Company type: Leading producer
Skyrun Industrial Co.Limited, established in 2003, a state-controlled company (By Skyrun Corp. & High Hope) in China, specializing in developing, producing and handing raw pharmaceutical material and intermediates. We sell 2,4,6-Trimethyliodobenzene as well. We have expanded a compositive entity from initially only as a small manufacturer. We have extensive knowledge of domestic and international pharmaceutical markets. Skyrun Industrial Co., Ltd. is supplier for 2-Acetylthiophene. Our working range can be start from small amount in research stage to big bulk for industrial produc ...
Country: P.R.China   Phone: +86-576-84015261   Telefax: +86-576-84015261

AK Scientific, Inc.

Company type: Supplier
AK Scientific provides fine chemicals and advanced intermediates to our customers worldwide. AK Scientific, Inc. is supplier for 2-Acetylthiophene. Currently, we have over 16.000 in stock, ready to ship products, at our California warehouse and this number is increasing weekly. We supply our chemical product Ethyl 1H-pyrazole-3-carboxylate. All these products are stocked in multiple, convenient, sizes to fit your specific needs. Purchases are shipped on the same day your order is placed (before 4PM, Pacific Time) to ensure on-time delivery. AK Scientific products can be searched by Name ...
Country: USA   Phone: +1 (510) 429-8835   Telefax: +1 (510) 429-8836

Simagchem Corporation

Company type: Bulk chemical producer
Your partner in China for chemicals business. Simagchem Corporation is a seller of TBEP. Expertize in supplies and sources of fine, specialty, pharmaceutical chemicals and intermediates. WE offer high quality products and JIT services with instant market intelligence in China, custom synthesis in our 3 production sites, famous principals as Brenntag, Univar,S inopec, Grace, Petrobras, DKSH, Formitex, Evonik, Merck, TCI, Sanofi, Chemo with creditable reputation and business cooperation. Simagchem Corporation is supplier for 2-Acetylthiophene.
Country: P.R.China   Phone: +86 592 2680 277   Telefax: +86 592 2680 237

Xingrui Industry Co., Limited

Company type: Leading producer
Xingrui Industry CO., LTD. is a professional manufacturing enterprise integrating R&D, production and sales. The products involved fine chemicals, pharmaceutical intermediates, dye intermediates, cosmetic raw materials and so on. Xingrui Industry Co., Limited is supplier for 2-Acetylthiophene. The company is ranked among the outstanding producers in the fine chemical industry. We provide Cyanuric fluoride as well. Xingrui Industry always strive to be the most reliable partner of our customers, and strive to build a customer-trusted, socially respected, world-class fi ...
Country: P.R.China   Phone: +86-531-88980365   Telefax: +86-531-88980365

Capot Chemical Co., Ltd.

Company type: Analytical Institution
Welcome to Capotchem • Established in 1996 ,Capot Chemical Co.,Ltd is a fine organics manufacturing facility which located in Hangzhou,P.R.China. We produce a wide range of organics, especially fluorine, boronic acids, amino acids, unnatural amino acids, peptide, cross linkers, organocatalysts, chiral building blocks, heterocyclic compounds and other active pharmaceutical ingredients compounds. Capot Chemical Co., Ltd. is supplier for 2-Acetylthiophene. 2-Fluoro-4-nitrobenzonitrile will be also provided by us. We are certified to the ISO 9001:2000 Standards, have a safety management sys ...
Country: P.R.China   Phone: +86-571-85586718 / 85825679   Telefax: +86-571-85864795

Chemlyte Solutions

Company type: Bulk chemical supplier
At Chemlyte Solutions, we place long-term relationships and outstanding client experience at the heart of everything we do. Chemlyte Solutions is a seller of Benzyl cis-3-hydroxycyclobutanecarboxylate. Each customer’s dedicated account manager ensures quick project turnaround and smooth experience for every client. Chemlyte Solutions is supplier for 2-Acetylthiophene. Our team has decades of combined experience in the Chinese chemical industry. This enables us to understand the entire supply chain, adapt quickly to market trends, and negotiate the best deals to provide a true end-to-end solution for c ...
Country: P.R.China   Phone: +86-571-8506-1365   Telefax:

Zehao Industry Co., Ltd.

Company type: Analytical Institution
The Shepherd Chemical Company was founded in Norwood, Ohio, in 1916. We are a fourth-generation company and a custom manufacturer of Inorganic Metal Salts and Organic Metal Compounds to the global marketplace. We supply our chemical product . Our long-standing success is built upon technical expertise, supplier reliability, and customer relationships. Our goal is to supply the marketplace with high quality metal compounds as standard or customized products. Zehao Industry Co., Ltd. is supplier for 2-Acetylthiophene. Our capabilities are comprised of our man ...
Country: P.R.China   Phone: +86-531-81901329   Telefax: +86-531-81901329

Santa Cruz Biotechnology, Inc.

Company type: International Supplier
Santa Cruz Biotechnology, Inc. now offers over 140,000 specialty biochemicals under our ChemCruz™ brand. Santa Cruz Biotechnology, Inc. is focused on the ongoing development of research reagents. It is our goal to continue to offer the broadest range of reagents in the field. Santa Cruz Biotechnology, Inc. is supplier for 2-Acetylthiophene. We sell N-Acetyl serotonin beta-D-glucuronide as well. We also provide superior, innovative primary antibodies and support products.
Country: USA   Phone: +1 800-457-3802   Telefax: +1-831-457-3802

Hangzhou Dayangchem Co. Ltd.

Company type: Leading producer
Hangzhou DayangChem Co. Ltd is a comprehensive entity which specializes in development, production and trade of pharmaceutical, agrochemical and dyestuff intermediates as well as some special type reagents. We have an own factory and share enterprises. We act also as agent of many chemical factories and promote their products to the international market at very competitive price. We take "Credi first, Clients supreme" as our aim. Hangzhou Dayangchem Co. Ltd. is supplier for 2-Acetylthiophene. We are seller of 3-[(N-Ethyl-N-methylamino)carbonyl]benzeneboronic acid. We expect to cooperate with more partners ...
Country: P.R.China   Phone: +86-571-88938639   Telefax: +86-571-8893-8652

Chemos GmbH & Co. KG

Company type: Supplier of chemical products
Chemos is a leading supplier of chemical specialties for your research and production needs. Chemos GmbH & Co. KG also offers 5-Chloro-2-methoxy-4-methylamino benzoic acid. Everything new starts small and needs specific support during scale up and production. With over 25 years of experience in the fine chemical market Chemos is supporting research institutions and chemical companies in Europe and America. Chemos GmbH & Co. KG is supplier for 2-Acetylthiophene. Chemos is a sourcing and distribution company with a grown and strong network of custom manufacturing companies and chemical producers from around the ...
Country: Germany   Phone: +49-871-966346-0   Telefax: +49-871-966346-13

Leap Chem Co., Ltd

Company type: Bulk and laboratory supplier
LEAPChem, a specialized fine chemicals supplier for research, development and production. Leap Chem Co., Ltd is supplier for 2-Acetylthiophene. N-(1,4-Dihydro-2,4-dioxo-2H-3,1-benzoxazin-7-yl)-methanesulfonamide will be also provided by us. LEAPChem provides nearly 50,000 rare and innovative chemical products to support the evolving needs of our customers in research & bulk manufacturing activities. As a highly customer-oriented enterprise, we are committed to providing high-quality customer services and products to our global customers in a cost-effective and efficient manner. Our client list includes many m ...
Country: P.R.China   Phone: +852-30606658   Telefax:

Specification

Density:
1.168 g/mL at 25 °C(lit.)
Boiling Point:
214 °C(lit.)
Flash Point:
196 ºF
Melting Point:
10-11 °C(lit.)
Refractive index:
n20D 1.565(lit.)

Safety Information

HazardClass:
6.1
Risk Codes:
25-23/24/25-20/21/22 (R)
WGK Germany:
3
RIDADR:
UN 2810 6.1 / PG 2
RTECS:
OB6300000

Most viewed

Within the past time user are also interested in the following chemicals.
(Trifluoromethyl) trifluoromethanesulfonate
Structure

4-(p-Tolylthio)benzophenone
Structure

Ammonium polyphosphate

Suppliers and manufactures - with identical CAS number as 2-Acetylthiophene

For the following products supplier are listed below:
    1-(2-Thienyl)-1-ethanone
    1-Thien-2-ylethanone
    2-Acetothienone
    Methyl 2-thienyl ketone


The following companies are not suppliers of 2-Acetylthiophene . This companies are suppliers for equal products with the same CAS number. CAS: 88-15-3


Supplier of

1-(2-Thienyl)-1-ethanone

(CAS: 88-15-3)

Evonik Industries AG

Company type: Producer
The heart of the Performance Materials segment is the production of polymer materials and intermediates, mainly for the rubber and plastics industries. Progressive globalization offers market opportunities for this segment, driven by the mobility and urbanization megatrends, which are raising global demand for efficient transportation systems and sustainable construction methods. We provide 3,3-Diethoxypropionitrile as well. This is reinforced by the rise of an affluent middle class, especially in the emerging ...
Country: Germany   Phone: +49 2365 49 4691   Telefax: +49 2365 49 7585

Supplier of

1-Thien-2-ylethanone

(CAS: 88-15-3)

BLD Pharmatech Ltd

Company type: Supplier
Founded in 2014 and headquartered in Shanghai, China, BLD Pharmatech Ltd. with more than 600,000 items, scale up manufacture and custom services is a leading manufacturer and supplier of diversified research chemicals in the industry. Additionally Methyl 5-iodopicolinate is supplied by us. Our considerable stock of a wide range of laboratory chemicals, from heterocycles, boron acids, amino acids, metal catalysts to chiral compounds, is ready for worldwide shipping. The ISO certifications and DUNS registration are our testimonie ...
Country: P.R.China   Phone: +86-21-61629022   Telefax: +86-21-50201702

Ambeed, Inc.

Company type: Analytical Institution
We are serving customers worldwide with 350,000 handpicked compounds. New and unique products are constantly added to our catalog. We provide a robust catalog of products including building blocks, advanced intermediates, amino acids and peptides, catalysts and ligands, natural products, nucleotides etc. We provide customers with bulk manufacturing and can source most material. We are seller of 2-Bromoquinoline.
Country: USA   Phone: +1 630-580-1088   Telefax: +1 630-581-0788

Supplier of

2-Acetothienone

(CAS: 88-15-3)

CM Fine Chemicals

Company type: Producer
CM Fine Chemicals, being a privately owned Swiss company, has been manufacturing and providing fine chemicals, intermediates and reagents to all kind of industries and research organizations all over the world. We provide 4-Chloro-5-(chlorosulfonyl)-2-fluorobenzoic acid as well. Since 1997 our high quality fine chemicals are used from lab to commercial quantities in many different applications. We are your innovative, flexible and reliable partner for any hard-to-find molecule! Whether a complex compound or just h ...
Country: Switzerland   Phone: +41 81 740 58 51   Telefax: +41 81 740 58 50

Supplier of

Methyl 2-thienyl ketone

(CAS: 88-15-3)

Merck Schuchardt OHG

Company type: Analytical Institution
Merck Schuchardt OHG, a 100% subsidiary of Merck KGaA, Germany, has, for the last 150 years, been one of the leading German producers and suppliers of organic intermediates, fine chemicals, reagents and solvents for laboratories, medium-sized and bulk production. We are supplier of 2-Iodoanisole.
Country: Germany   Phone: +49-8102-802 0   Telefax: +49-8102-802 175


Related products:


Language:
english português français deutsch español
svensk norsk italiano 中国 日本語 по-русски




How do you find
new customers?

click here


Rech Chemical Co., Ltd.
Twenties years ago, Rech Chemical Co.,Ltd were mainly a solid manganese sulphate supplier. Today, b


Fan Avaran Shimi
We are the leading manufacturers of Metal Stearates in Iran (Calcium Stearate, Zinc Stearate, Magne


Shanghai Juyuan Flame R
Shanghai Juyuan Flame-Retardant Material Co., Ltd is an enterprise professionally producing and man


BuGuCh & Partners
We, BuGuCh & Partners, are an international acting and innovative company, leading in developin


Xi´an SR Bio-Engineerin
Xi'an SR Bio-Engineering Co., Ltd established in 2009, is an expert in the field of biochemistry, p


ECSA Chemicals AG
Established in 1913 ECSA Chemicals has become one of the most important Swiss-owned distributors of


© Copyright 1996 to 2024 by Netvertise GmbH. All rights reserved 2-Acetylthiophene