Molecular Formula: C₈H₈O₃S
Molar mass: 184.21 g/mol
EINECS: 223-793-7
Density: 1.253 g/cm³
Flash Point: 116 °C
Index of Refraction: 1.534
Boiling Point: 268.2 °C at 760 mmHg
Vapour Pressure: 0.00781 mmHg at 25°C
Appearance: Clear yellow to brown liquid
Product categories: Thiophene & Benzothiophene
Structure of Ethyl thiophene-2-glyoxylate (4075-58-5):
         
XLogP3-AA: 1.8
H-Bond Donor: 0
H-Bond Acceptor: 3
IUPAC Name: ethyl 2-oxo-2-Thiophen-2-ylacetate
Canonical SMILES: CCOC(=O)C(=O)C1=CC=CS1
InChI: InChI=1S/C8H8O3S/c1-2-11-8(10)7(9)6-4-3-5-12-6/h3-5H,2H2,1H3 
InChIKey: GHOVLEQTRNXASK-UHFFFAOYSA-N

Carcinogenicity of Ethyl thiophene-2-glyoxylate (4075-58-5) hasn't been listed as a carcinogen by NTP, IARC,ACGIH, or CA Prop 65. And its toxicological properties have not been fully investigated.

Hazard Note: Irritant
Hazard Codes: Xi
Risk Statements:
36:  Irritating to the eyes
37:  Irritating to the respiratory system
38:  Irritating to the skin
Safety Statements:
26:  In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
36:  Wear suitable protective clothing 
37:  Wear suitable gloves
39:  Wear eye/face protection

 Ethyl thiophene-2-glyoxylate (4075-58-5) also can be called Ethyl-2-thiopheneglyoxylate ; Ethyl alpha-oxothiophen-2-acetate ; Thiophene-2-glyoxylic acid ethyl ester ; Ethyl 2-oxo-2-(2-thienyl)acetate .It is hazardous,so the first aid measures and others should be known.Such as: When on the skin: first,should  flush skin with plenty of water immediatelyfor at least 15 minutes while removing contaminated clothing. Secondly,Get shoesmedical aid . Or in the eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids.Then get medical aid soon.While ,it's Inhaled: Remove from exposure and move to fresh air immediately.Give artificial respiration while not breathing. When breathing is difficult, give oxygen. And as soon as to get medical aid. Then you have the ingesting of the product : Wash mouth out with water,and get medical aid immediately.Notes to physician: Treat supportively and symptomatically.
In addition, Ethyl thiophene-2-glyoxylate (4075-58-5) can be stable under normal temperature and pressure conditions.It is not compatible with strong oxidizing agents, ignition sources, strong acids, strong bases,and you must not take it with incompatible materials.And also prevent it to broken down into hazardous decomposition products: irritating and toxic fumes and gases, carbon dioxide, carbon monoxide.