(-)-Catechin gallate(130405-40-2)
- CAS Registry Number:
- 130405-40-2
- Synonyms:
- Benzoicacid, 3,4,5-trihydroxy-, 2-(3,4-dihydroxyphenyl)-3,4-dihydro-5,7-dihydroxy-2H-1-benzopyran-3-ylester, (2S-trans)-;(-)-Catechin 3-O-gallate;(-)-Catechin 3-gallate;(-)-Catechin gallate;(2S,3R)-2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-3,4-dihydro-2H-chromen-3-yl 3,4,5-trihydroxybenzoate;[2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-3,4-dihydro-2H-chromen-3-yl];benzoic acid, 3,4,5-trihydroxy-, (2S,3R)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-5,7-dihydroxy-2H-1-benzopyran-3-yl ester;
- Molecular Formula:
- C22H18O10
- Molecular Weight:
- 442.379
- EINECS:
CAS No.:130405-40-2
Name: (-)-Catechin gallate
Related Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:98%Min Appearance:detailed in specifications Package:according to the clients requirement Storage:Store in dry, dark and ventilated place. Transportation:by air or by ocean shipping Application:An important raw material and intermediate used in Organic Synthesis, Pharmaceuticals
Min. Order:1Kilogram
Supplier:Dayang Chem (Hangzhou) Co.,Ltd. [ China (Mainland)]
Assessed
SupplierTel:+86-571-88938639
Address:9/F, Unit 2 Changdi Torch Building, 259# WenSan Road, Xihu District, Hangzhou City 310012, P.R.China
- Contact Suppliers
CAS No.130405-40-2 High purity (-)-catechin Gallate
Assay:98% Appearance:White crystalline powder Package:according to customers' requirements Storage:Store in dry, dark and ventilated place Transportation:By air(EMS or EUB or FedEx or TNT ect...) or by sea(FOB or CIF or CNF ect...)or according to your demand. Application:used in pharmaceutical intermediate
Min. Order:1Gram
Supplier:Hangzhou Lingrui Chemical Co.,Ltd. [ China (Mainland)]
Assessed
SupplierTel:86 571-88092529
Address:201-B 2# Building Qinglan science park, 321# JinPeng Str. Xihu District Hangzhou City, PR.CHINA
- Contact Suppliers
CAS No.130405-40-2 Catechin Gallate CAS No. 130405-40-2
Assay:98% Appearance:White to yellow powder or random crystal Package:Inside plastic outside Storage:Somewhere cool and dry Transportation:We ship goods via DHL, Fedex, UPS, TNT, China post, NL Post and other couriers, weight from 10g to 1000kg or even bulker Application:Pharmaceutical intermediates,study
Min. Order:1Kilogram
Supplier:Hebei Nengqian Chemical Import and Export Co., LTD [ China (Mainland)]
Assessed
SupplierTel:+86 13910575315
Address:hebei
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:99% Appearance:powder or liquid Package:according to customer requirements Storage:store in dry dark and ventilated place Transportation:By Sea/Air/Courier Application:It is an important raw material.
Min. Order:10Gram
Supplier:Zibo Hangyu Biotechnology Development Co., Ltd [ China (Mainland)]
Assessed
SupplierTel:86-15965530500
Address:Room1701, Tianxing Building,Licheng district, jinan, Shandong, China
- Contact Suppliers
CAS No.130405-40-2 High Content Natural Extract Catechin gallate HACCP manufacturer
Assay:98.0%Min Appearance:Powder Package:25kgs/Drum or According client's requirements Storage:keep sealed and keep from direct light Transportation:Shipping by express, air, sea Application:API, Pharmaceutical excipients, Nutritional supplements, Health Care products, Food additives
Min. Order:1Gram
Supplier:Xi'an Xszo Chem Co., Ltd. [ China (Mainland)]
Assessed
SupplierTel:+86-029-88698540
Address:No.16,Jingqin Rd. JingWei Industrial park,Shaanxi,China,710200
- Contact Suppliers
CAS No.130405-40-2 High purity (-)-catechin Gallate
Assay:30%--99.8% Appearance:White crystalline powder Package:1kg/pack Storage: Keep in a well-closed container and keep away from moisture Transportation:By Air锛孊y TNT,EMS,Fedex Application:Medicine additives, functional food
Min. Order:1Gram
Supplier:Shanghai Upbio Tech Co.,Ltd [ China (Mainland)]
Assessed
SupplierTel:+86-21-52196435
Address:No.2 Floor,No.979 Yunhan Rd,Nicheng,Pudong New Area,Shanghai,China
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay: 98%Min Appearance:Detailed in specifications Package:According to customer Storage:Store in dry, dark and ventilated place Transportation:By air or by sea Application:An important raw material and intermediate used in organic Synthesis, Pharmaceuticals
Min. Order:1Kilogram
Supplier:TAIZHOU ZHENYU BIOTECHNOLOGY CO., LTD [ China (Mainland)]
Assessed
SupplierTel:15867601896
Address:Room 623 Yulan Square Bussiness Building . Jiaojiang Taizhou Zhejiang 318000 China
- Contact Suppliers
CAS No.130405-40-2 Catechin gallate
Assay:CR Appearance:To be subject to the object Package:Customized Transportation:Air Application:pharmaceutical intermediates
Min. Order:0
Supplier:Hangzhou Dingyan Chem Co., Ltd [ China (Mainland)]
Assessed
SupplierTel:86-571-87157530-8007
Address:RM.1118,NO.1 Building, Baiyun Tower,Jianggan Area, Hangzhou city, China,310004
- Contact Suppliers
CAS No.130405-40-2 Benzoic acid,3,4,5-trihydroxy-,(2S,3R)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-5,7-dihydroxy-2H-1-benzopyran-3-ylester
Assay:99% Appearance:White powder Package:200/Kilograms Storage:Sealed and preserved Transportation:By sea Application:Fine chemical intermediates, used as the main raw material for the synthesis of various pesticides, medicines, surfactants, polymer monomers, and antifungal agents
Min. Order:0
Supplier:GIHI CHEMICALS CO.,LIMITED [ China (Mainland)]
Assessed
SupplierTel:+86-571-86217390
Address:No.567 Dengcai Street,Sandun,Westlake District,Hangzhou310030,Zhejiang,China.
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:99% Application:healing drugs
Min. Order:0
Supplier:Antimex Chemical Limied [ China (Mainland)]
Assessed
SupplierTel:0086-21-50563169
Address:Room1027,No.Jinyu Road,Pudong
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallateCAS NO.: 130405-40-2
Assay:99% Appearance:White solid Package:drum Storage:Room temperature Transportation:By Sea/Air/DHL Application:Others
Min. Order:1Gram
Supplier:Henan Wentao Chemical Product Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:+86-370-2722992
Address:32 Room, 5th Floor, Building 11, No. 6 Yinxing Road, High-tech Industrial Development Zone, Zhengzhou City, Henan Province
- Contact Suppliers
CAS No.130405-40-2 high purity (-)-Catechin gallate (-)-CG
Assay:99% Appearance:White powder Package:200/Kilograms Storage:Sealed and preserved Transportation:By sea Application:101947-16-4
Min. Order:1Metric Ton
Supplier:Henan Kanbei Chemical Co.,LTD [ China (Mainland)]
Premium
SupplierTel:86-152-37804566
Address:Evergrande Future City, intersection of Zhengkai Avenue and Sixteenth Street, Kaifeng Area, Henan Pilot Free Trade Zone
- Contact Suppliers
CAS No.130405-40-2 Catechingallate/(-)-Catechingallate
Assay:98%+ Appearance:White powder Package:1mg,1g,1kg,50kg,accordingtocustomerrequirements Storage:Sealed, long-term storage temperature -20鈩?nbsp;Transportation:By express,by air,by sea Application:Biochemical Research
Min. Order:1Milligram
Supplier:Xiamen Jenny Chemical Technology Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:+86 16621006118
Address:Room 402, No. 216, Nanshan Road, Huli District, Xiamen City
- Contact Suppliers
CAS No.130405-40-2 CG CAS No:130405-40-2
Assay:HPLC鈮?8% Package:Brown vial HDPE plastic bottle Transportation:by air Application:the product is only used for scientific research experiments and should not be used for human injection, food or other purposes. This solution must be freshly prepared before using to avoid degrad...
Min. Order:0
Supplier:Chengdu Lemeitian Pharmaceutical Technology Co,. Ltd [ China (Mainland)]
Premium
SupplierTel:+8617313084125
Address:No.128, West Section of Haike Road,Wenjiang District
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:99 Appearance:powder, or liquid Package:Bottle, barrel, cargo, container, etc. Storage:Stored in room temperature, ventilated place Transportation:By air, ship, express, etc. Application:Pharmaceuticals, intermediates, APIs, custom synthesis, chemicals
Min. Order:0
Supplier:LEAP CHEM Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:+852-30606658
Address:EASEY COMM BLDG 253-261 HENNESSY ROAD Hong Kong, China
- Contact Suppliers
CAS No.130405-40-2 (-)-CATECHIN GALLATECAS
Assay:99%min Appearance:white crystalline powder Package:25KG drum Storage:Store in dry, dark and ventilated place Transportation:by air, by sea, by express Application:intermediate
Min. Order:0
Supplier:Hangzhou Fandachem Co.,Ltd [ China (Mainland)]
Premium
SupplierTel:+86-571-28800458
Address:Room 5010, No.9 YanAn Road,Hangzhou,Zhejiang,China
- Contact Suppliers
CAS No.130405-40-2 鈮?8% high purity high quality custom manufacturing natural extract (-)-Catechin gallate 130405-40-2
Assay:鈮?8% by HPLC Application:Herbal extracts
Min. Order:0
Supplier:Sinoway Industrial Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:+86-592-583819
Address:16/F,Huicheng Comm,Complex,No839 XiaHe Rd, Xiamen,China
- Contact Suppliers
CAS No.130405-40-2 Manufacturer supply CAS 130405-40-2 with best quality
Assay:99% Appearance:White powder Package: [Packaging]20mg, 50mg,100mg,1g,10g,100g,according to customers' requirements Storage: should be stored in a well-closed container at low temperature, keep away from moisture, heat and light. Transportation:1. Samples 1kg-10kg are shipped by international express. 2. 50kg-100kg of goods are transported by dedicated line logistics. 3. Cargo 100kg-1ton is transported by dedicated line logistics. Application:Chemical raw materials, pharmaceutical intermediates, cosmetic raw materials, etc.
Min. Order:1Kilogram
Supplier:Zhuozhou Wenxi import and Export Co., Ltd [ China (Mainland)]
Premium
SupplierTel:+86-13111626072
Address:Room 1710, Baoxin International Phase I, 19 Guanyun East Road, Zhuozhou, Hebei
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:鈮?8% Appearance:detailed see specifications Package:According to the clients requirement. Storage:Store at 2~8掳C Transportation:by air or by ocean shipping Application:analysis,activity test,Botanical Reference Materials,Standard materials
Min. Order:10Milligram
Supplier:Hubei CuiRan Biotechnology Co., Ltd [ China (Mainland)]
Premium
SupplierTel:18162791556
Address:Room301 at 3rd floor锛宐uilding of R&D in Non-governmental Science&Technology Zone,Che cheng South Road of Economic&Technology Area, Wuhan , Hubei province, China
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:99% Haccp,,Halal,SC US FDA GMP ISO14001 Appearance:As per Certificate of analysis and our TDS, MSDS Package:Export standard and according to the clients requirement Storage:Store in dry, dark and ventilated place;ISO / Kosher /GMP licence commercial bulk capacity factory in China Transportation:By AIR or by SEA GMP licence / US-FDA,South Korea-KFDA Application:It is an important raw material and intermediate for chemical industry.
Min. Order:5Kiloliter
Supplier:Chemwill Asia Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:021-51086038
Address:High-Tech Industrial park,Chemical Economical Development Zone,Xuzhou, Jiangsu-Province, P.R.China
- Contact Suppliers
CAS No.130405-40-2 Catechin gallate
Assay:95% Package:10mg/20mg standard packing or according to customers' requirement(Do not supply kgs or tons.) Storage:-20degree Transportation:ice bag Application: FOR RESEARCH USE ONLY
Min. Order:0Metric Ton
Supplier:shanghai Tauto Biotech Co., Ltd [ China (Mainland)]
Premium
SupplierTel:+86-21-51320588 ext. 8025
Address:No. 326, Aidisheng Rd , Zhangjiang Hi-tech Park, Shanghai , P.R.CHINA
- Contact Suppliers
CAS No.130405-40-2 Acmec (-)-Catechin gallate C76131 20mg
Assay:Analysis control,HPLC鈮?8% Appearance:See the datasheet Package:20mg Storage:2-8掳C Transportation:By Express, Air and Road Application:Analytical reagent, biochemical reagent, standard
Min. Order:1bottle
Supplier:Shanghai Acmec Biochemical Technology Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:86--
Address:Room 1301, No. 1, Lane 1588, South Wangyuan Road, Nanqiao Town, Fengxian District, Shanghai
- Contact Suppliers
CAS No.130405-40-2 Catechin gallate
Assay:HPLC鈮?8% Appearance:powder Package:G/bottle; Kg/bag; 2356kg/barrel Storage:In cool ,dry place Transportation:Air or sea freight Application:for pharma use
Min. Order:0
Supplier:Shaanxi Cuicheng Biomedical Technology Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:+8613119157289
Address:Chang'an District Western Life Science and Technology Park
- Contact Suppliers
CAS No.130405-40-2 Catechin gallate manufacturer
Assay:HPLC鈮?8% Appearance:White powder Package:According client's requirements Storage:keep sealed and keep from direct light Transportation:by express or by sea Application:pharmaceutical
Min. Order:0
Supplier:Shanghai Yuanye Bio-Technology Co., Ltd. [ China (Mainland)]
Premium
SupplierTel:+86-21-61845781
Address:Building 6, No. 465, Changta Road,Songjiang District,Shanghai,China
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:>98% Appearance:White powder Package:inquiry Storage:-20掳C Freezer Transportation:inquiry Application:(-)-catechin gallate, an antioxidant component existing in green tea, has been found to be probably effective in restraining tyrosine phosphorylation caused by VEGF and have potential activity in ...
Min. Order:0
Supplier:BOC Sciences [ United States]
Premium
SupplierTel:1-631-485-4226
Address:Ramsey Road
- Contact Suppliers
CAS No.130405-40-2 High purity (-)-catechin Gallate
Assay:99% Appearance:white powder Package:drum or based on customers' requirement Storage:normal temperature storage Transportation:by sea, by air Application:We have different specifications for different applications
Min. Order:0
Supplier:Bluecrystal chem-union [ China (Mainland)]
Premium
SupplierTel:+86-1895157
Address:Liang Xi Qu
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:99% Appearance:White powder Package:200/Kilograms Storage:Sealed and preserved Transportation:By sea Application:healing drugs
Min. Order:0
Supplier:ZHEJIANG JIUZHOU CHEM CO.,LTD [ China (Mainland)]
Premium
SupplierTel:+86 19334956669
Address:Waisha Road,Jiaojiang
- Contact Suppliers
CAS No.130405-40-2 (-)-Catechin gallate
Assay:High purity Appearance:Powder Package:1kg/tin 5kg/tin 25kg/carton Storage:Store in dry, cool and ventilated place Transportation:By sea By air By courier Application:Use in healthcare products. Use in food products. Use in Cosmetic products.
Min. Order:0
Supplier:Asure Biochem CO.,LTD. [ China (Mainland)]
Premium
SupplierTel:+8613116738678
Address:hangzhou
- Contact Suppliers
CAS No.130405-40-2 (-)-catechin gallate
Assay:鈮?9.0% Package:aluminium foil bag/fiber can/plastic drum Storage:Store in cool &dry place Transportation:by courier; by sea; by air Application:compound
Min. Order:0
Supplier:Hubei Taiho Chemical Co.,LTD [ China (Mainland)]
Premium
SupplierTel:+86-18120399543
Address:No. 49 taifeng Road,Qianjiang City,Hubei,China
- Contact Suppliers
CAS No.130405-40-2 Catechin gallate
Assay:98% Package:According to the demand of customer Storage:Sealed, dry, microtherm , avoid light and smell. Transportation:by air or by sea Application:Organic synthesis
Min. Order:0
Supplier:Henan Allgreen Chemical Co.,Ltd [ China (Mainland)]
Premium
SupplierTel:+86-0371-87507775
Address:No 260 Dongming Road,Jinshui District
- Contact Suppliers
- Dayang Chem (Hangzhou) Co.,Ltd.
- China (Mainland)
- Tel:+86-571-88938639
- 9/F, Unit 2 Changdi Torch Building, 259# WenSan Road, Xihu District, Hangzhou City 310012, P.R.China
- Shanghai Acmec Biochemical Technology Co., Ltd.
- China (Mainland)
- Tel:86--
- Room 1301, No. 1, Lane 1588, South Wangyuan Road, Nanqiao Town, Fengxian District, Shanghai
- Shanghai Acmec Biochemical Technology Co., Ltd.
- China (Mainland)
- Tel:86--
- Room 1301, No. 1, Lane 1588, South Wangyuan Road, Nanqiao Town, Fengxian District, Shanghai
- Shanghai Acmec Biochemical Technology Co., Ltd.
- China (Mainland)
- Tel:86--
- Room 1301, No. 1, Lane 1588, South Wangyuan Road, Nanqiao Town, Fengxian District, Shanghai
- ZHEJIANG JIUZHOU CHEM CO.,LTD
- China (Mainland)
- Tel:+86 19334956669
- Waisha Road,Jiaojiang
- TAIZHOU ZHENYU BIOTECHNOLOGY CO., LTD
- China (Mainland)
- Tel:15867601896
- Room 623 Yulan Square Bussiness Building . Jiaojiang Taizhou Zhejiang 318000 China
- Hubei CuiRan Biotechnology Co., Ltd
- China (Mainland)
- Tel:18162791556
- Room301 at 3rd floor,building of R&D in Non-governmental Science&Technology Zone,Che cheng South Road of Economic&Technology Area, Wuhan , Hubei province, China
- Shaanxi Cuicheng Biomedical Technology Co., Ltd.
- China (Mainland)
- Tel:+8613119157289
- Chang'an District Western Life Science and Technology Park
- Bluecrystal chem-union
- China (Mainland)
- Tel:+86-1895157
- Liang Xi Qu
- Asure Biochem CO.,LTD.
- China (Mainland)
- Tel:+8613116738678
- hangzhou
- Henan Kanbei Chemical Co.,LTD
- China (Mainland)
- Tel:86-152-37804566
- Evergrande Future City, intersection of Zhengkai Avenue and Sixteenth Street, Kaifeng Area, Henan Pilot Free Trade Zone
- Henan Kanbei Chemical Co.,LTD
- China (Mainland)
- Tel:86-152-37804566
- Evergrande Future City, intersection of Zhengkai Avenue and Sixteenth Street, Kaifeng Area, Henan Pilot Free Trade Zone
- Hebei Nengqian Chemical Import and Export Co., LTD
- China (Mainland)
- Tel:+86 13910575315
- hebei
- Hebei Nengqian Chemical Import and Export Co., LTD
- China (Mainland)
- Tel:+86 13910575315
- hebei
- Xiamen Jenny Chemical Technology Co., Ltd.
- China (Mainland)
- Tel:+86 16621006118
- Room 402, No. 216, Nanshan Road, Huli District, Xiamen City
- LEAP CHEM Co., Ltd.
- China (Mainland)
- Tel:+852-30606658
- EASEY COMM BLDG 253-261 HENNESSY ROAD Hong Kong, China
- Chengdu Lemeitian Pharmaceutical Technology Co,. Ltd
- China (Mainland)
- Tel:+8617313084125
- No.128, West Section of Haike Road,Wenjiang District
- Chengdu Lemeitian Pharmaceutical Technology Co,. Ltd
- China (Mainland)
- Tel:+8617313084125
- No.128, West Section of Haike Road,Wenjiang District
- Zhuozhou Wenxi import and Export Co., Ltd
- China (Mainland)
- Tel:+86-13111626072
- Room 1710, Baoxin International Phase I, 19 Guanyun East Road, Zhuozhou, Hebei
- Zhuozhou Wenxi import and Export Co., Ltd
- China (Mainland)
- Tel:+86-13111626072
- Room 1710, Baoxin International Phase I, 19 Guanyun East Road, Zhuozhou, Hebei
- Xi'an Xszo Chem Co., Ltd.
- China (Mainland)
- Tel:+86-029-88698540
- No.16,Jingqin Rd. JingWei Industrial park,Shaanxi,China,710200
- Henan Wentao Chemical Product Co., Ltd.
- China (Mainland)
- Tel:+86-370-2722992
- 32 Room, 5th Floor, Building 11, No. 6 Yinxing Road, High-tech Industrial Development Zone, Zhengzhou City, Henan Province
- Henan Wentao Chemical Product Co., Ltd.
- China (Mainland)
- Tel:+86-370-2722992
- 32 Room, 5th Floor, Building 11, No. 6 Yinxing Road, High-tech Industrial Development Zone, Zhengzhou City, Henan Province
- Hangzhou Lingrui Chemical Co.,Ltd.
- China (Mainland)
- Tel:86 571-88092529
- 201-B 2# Building Qinglan science park, 321# JinPeng Str. Xihu District Hangzhou City, PR.CHINA
- Hangzhou Lingrui Chemical Co.,Ltd.
- China (Mainland)
- Tel:86 571-88092529
- 201-B 2# Building Qinglan science park, 321# JinPeng Str. Xihu District Hangzhou City, PR.CHINA
- Zibo Hangyu Biotechnology Development Co., Ltd
- China (Mainland)
- Tel:86-15965530500
- Room1701, Tianxing Building,Licheng district, jinan, Shandong, China
- Chemwill Asia Co., Ltd.
- China (Mainland)
- Tel:021-51086038
- High-Tech Industrial park,Chemical Economical Development Zone,Xuzhou, Jiangsu-Province, P.R.China
- Henan Allgreen Chemical Co.,Ltd
- China (Mainland)
- Tel:+86-0371-87507775
- No 260 Dongming Road,Jinshui District
- Hubei Taiho Chemical Co.,LTD
- China (Mainland)
- Tel:+86-18120399543
- No. 49 taifeng Road,Qianjiang City,Hubei,China
- Hangzhou Fandachem Co.,Ltd
- China (Mainland)
- Tel:+86-571-28800458
- Room 5010, No.9 YanAn Road,Hangzhou,Zhejiang,China
Other Product
- -
- -
- -
- -
- -
- -
- -
- -
- -
- (4S,6R)-6-{2-[(2-hydroxy-ethyl)-(4-methoxy-benzenesulfonyl)-amino]-ethoxy}-4-isopropyl-5,6-dihydro-4H-pyran-2-carboxylic acid allyl ester
- [1,4'-Bipiperidine]-1'-carboxylic acid, 4-(1H-indol-7-yl)-, ethyl ester
- 1,3,5-Tris(4-acetamidophenyl)penta-1,5-dione
- 1,5-Bis(3-aminophenyl)-3-(4-N,N-di-methylaminophenyl)penta-1,5-dione
- 1,5-Bis(4-acetamidophenyl)-3-phenylpenta-1,5-dione
- 1,5-Bis(4-aminophenyl)-3-(4-acetamido-phenyl)penta-1,5-dione
- 1,5-Bis(4-aminophenyl)-3-phenylpenta-1,5-dione