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EC number: 257-848-1 | CAS number: 52320-66-8
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
Acute oral toxicity:
Acute oral toxicity dose (LD50) of 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) was predicted based on OECD QSAR toolbox 3592 mg/kg bw and different studies available on structurally similar read across substances 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis [N-(2,4-dimethylphenyl)-3-oxobutyramide] (CAS no: 5102-83-0) >5000 mg/kg bw and 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(3-oxo-N-phenylbutanamide) (CAS no: 6358-85-6) >10800 mg/kg bw. All these studies concluded that the LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide cannot be classified for acute oral toxicity.
Acute Inhalation toxicity:
2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) has very low vapour pressure (2.67E-10 Pa at 25°C), so the potential for the generation of inhalable vapours is very low. Also the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be highly unlikely and therefore this end point was considered for waiver.
Acute Dermal toxicity:
Acute Dermal toxicity dose (LD50) for 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) was predicted based on OECD QSAR toolbox 2504 mg/kg bwand differentstudies available for the structurally similar read across substanceN-(4-chloro-2,5-dimethoxyphenyl)- 2-[[2,5-dimethoxy-4 -[(phenylamino)sulphonyl]phenyl]azo]-3-oxobutyramide (CAS no: 12225-18-2) >3000 mg/kg bw and 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis [N-(2,4-dimethylphenyl)-3-oxobutyramide] (CAS no: 5102-83-0)>3000 mg/kg bw. All these studies concluded that the LD50 value is>2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)- 3-oxobutanamide cannot be classified for acute dermal toxicity.
Key value for chemical safety assessment
Acute toxicity: via oral route
Link to relevant study records
- Endpoint:
- acute toxicity: oral
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
- Justification for type of information:
- Data is predicted using OECD QSAR toolbox version 3.3 and the supporting QMRF report has been attached
- Qualifier:
- according to guideline
- Guideline:
- other: estimated data
- Principles of method if other than guideline:
- Prediction is done using QSAR Toolbox version 3.3
- GLP compliance:
- not specified
- Test type:
- other: not specified
- Limit test:
- no
- Specific details on test material used for the study:
- Name: 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide
SMILES:CCOc1ccc(NC(=O)C(C(C)=O)N=Nc2ccc(Cl)cc2N(=O)=O)cc1
InChI:1S/C18H17ClN4O5/c1-3-28-14-7-5-13(6-8-14)20-18(25)17(11(2)24)22-21-15-9-4-12(19)10-16(15)23(26)27/h4-10,17H,3H2,1-2H3,(H,20,25)/b22-21+
Molecular Formula: C18H17ClN4O5
Molecular Weight: 404.808 g/mole - Species:
- rat
- Strain:
- Wistar
- Sex:
- female
- Details on test animals or test system and environmental conditions:
- not specified
- Route of administration:
- oral: gavage
- Vehicle:
- unchanged (no vehicle)
- Details on oral exposure:
- not specified
- Doses:
- 3592 mg/kg bw
- No. of animals per sex per dose:
- 10
- Control animals:
- not specified
- Details on study design:
- not specified
- Statistics:
- not specified
- Preliminary study:
- not specified
- Sex:
- female
- Dose descriptor:
- LD50
- Effect level:
- 3 592 mg/kg bw
- Based on:
- test mat.
- Remarks on result:
- other: 50% mortality was observed
- Mortality:
- not specified
- Clinical signs:
- other: not specified
- Gross pathology:
- not specified
- Other findings:
- not specified
- Interpretation of results:
- other: Not classified
- Conclusions:
- D50 was estimated to be 3592 mg/kg bw, when 10 female Wistar rats were treated with 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) via oral gavage route.
- Executive summary:
In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, the acute oral toxicity was estimated for 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8). The LD50 was estimated to be 3592 mg/kg bw, when 10 female Wistar rats were treated with 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide via oral gavage route.
Reference
The
prediction was based on dataset comprised from the following
descriptors: LD50
Estimation method: Takes average value from the 5 nearest neighbours
Domain logical expression:Result: In Domain
((((((((("a"
and ("b"
and (
not "c")
)
)
and ("d"
and (
not "e")
)
)
and ("f"
and (
not "g")
)
)
and ("h"
and (
not "i")
)
)
and ("j"
and (
not "k")
)
)
and "l" )
and "m" )
and "n" )
and ("o"
and "p" )
)
Domain
logical expression index: "a"
Referential
boundary: The
target chemical should be classified as Amides by Aquatic toxicity
classification by ECOSAR
Domain
logical expression index: "b"
Referential
boundary: The
target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion
formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo AND SN1 >>
Nitrenium Ion formation >> Aromatic nitro by DNA binding by OECD
Domain
logical expression index: "c"
Referential
boundary: The
target chemical should be classified as Acylation OR Acylation >> Direct
Addition of an Acyl Halide OR Acylation >> Direct Addition of an Acyl
Halide >> Acyl halide OR Acylation >> P450 Mediated Activation to
Isocyanates or Isothiocyanates OR Acylation >> P450 Mediated Activation
to Isocyanates or Isothiocyanates >> Formamides OR Michael addition OR
Michael addition >> P450 Mediated Activation to Quinones and
Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation
to Quinones and Quinone-type Chemicals >> Alkyl phenols OR Michael
addition >> P450 Mediated Activation to Quinones and Quinone-type
Chemicals >> Arenes OR Michael addition >> P450 Mediated Activation to
Quinones and Quinone-type Chemicals >> Hydroquinones OR Michael addition
>> Polarised Alkenes-Michael addition OR Michael addition >> Polarised
Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR No alert
found OR Schiff base formers OR Schiff base formers >> Chemicals
Activated by P450 to Glyoxal OR Schiff base formers >> Chemicals
Activated by P450 to Glyoxal >> Ethanolamines (including morpholine) OR
Schiff base formers >> Chemicals Activated by P450 to Glyoxal >>
Ethylenediamines (including piperazine) OR SN1 >> Carbenium Ion
Formation OR SN1 >> Carbenium Ion Formation >> Hydrazine OR SN1 >>
Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic
tertiary amines OR SN1 >> Nitrenium Ion formation >> Primary
(unsaturated) heterocyclic amine OR SN1 >> Nitrenium Ion formation >>
Primary aromatic amine OR SN1 >> Nitrenium Ion formation >> Tertiary
aromatic amine OR SN1 >> Nitrenium Ion formation >> Unsaturated
heterocyclic azo OR SN2 OR SN2 >> SN2 at an sp3 Carbon atom OR SN2 >>
SN2 at an sp3 Carbon atom >> Phosphates by DNA binding by OECD
Domain
logical expression index: "d"
Referential
boundary: The
target chemical should be classified as Acylation AND Acylation >> Ester
aminolysis AND Acylation >> Ester aminolysis >> Amides by Protein
binding by OASIS v1.3
Domain
logical expression index: "e"
Referential
boundary: The
target chemical should be classified as Nucleophilic addition OR
Nucleophilic addition >> Addition to carbon-hetero double bonds OR
Nucleophilic addition >> Addition to carbon-hetero double bonds >>
Ketones OR SNAr OR SNAr >> Nucleophilic aromatic substitution on
activated aryl and heteroaryl compounds OR SNAr >> Nucleophilic aromatic
substitution on activated aryl and heteroaryl compounds >> Activated
aryl and heteroaryl compounds by Protein binding by OASIS v1.3
Domain
logical expression index: "f"
Referential
boundary: The
target chemical should be classified as No alert found by Protein
binding alerts for Chromosomal aberration by OASIS v1.1
Domain
logical expression index: "g"
Referential
boundary: The
target chemical should be classified as Ac-SN2 OR Ac-SN2 >> Acylation
involving an activated (glucuronidated) carboxamide group OR Ac-SN2 >>
Acylation involving an activated (glucuronidated) carboxamide group >>
Carboxylic Acid Amines OR Ac-SN2 >> Direct acylation involving a leaving
group OR Ac-SN2 >> Direct acylation involving a leaving group >>
Carboxylic Acid Amines OR AN2 OR AN2 >> Michael-type addition to quinoid
structures OR AN2 >> Michael-type addition to quinoid structures >>
Carboxylic Acid Amines by Protein binding alerts for Chromosomal
aberration by OASIS v1.1
Domain
logical expression index: "h"
Referential
boundary: The
target chemical should be classified as No alert found by Protein
binding alerts for skin sensitization by OASIS v1.3
Domain
logical expression index: "i"
Referential
boundary: The
target chemical should be classified as Acylation OR Acylation >> Ester
aminolysis OR Acylation >> Ester aminolysis >> Amides by Protein binding
alerts for skin sensitization by OASIS v1.3
Domain
logical expression index: "j"
Referential
boundary: The
target chemical should be classified as No alert found by Respiratory
sensitisation
Domain
logical expression index: "k"
Referential
boundary: The
target chemical should be classified as Pro-Michael Addition OR
Pro-Michael Addition >> Pro-quinone and related OR Pro-Michael Addition
>> Pro-quinone and related >> Phenylenediamines by Respiratory
sensitisation
Domain
logical expression index: "l"
Similarity
boundary:Target:
CCOc1ccc(NC(=O)C(C(C)=O)N=Nc2ccc(Cl)cc2N(=O)=O)cc1
Threshold=20%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization
Domain
logical expression index: "m"
Similarity
boundary:Target:
CCOc1ccc(NC(=O)C(C(C)=O)N=Nc2ccc(Cl)cc2N(=O)=O)cc1
Threshold=40%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization
Domain
logical expression index: "n"
Similarity
boundary:Target:
CCOc1ccc(NC(=O)C(C(C)=O)N=Nc2ccc(Cl)cc2N(=O)=O)cc1
Threshold=50%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization
Domain
logical expression index: "o"
Parametric
boundary:The
target chemical should have a value of log Kow which is >= 2.4
Domain
logical expression index: "p"
Parametric
boundary:The
target chemical should have a value of log Kow which is <= 7.05
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- 3 592 mg/kg bw
- Quality of whole database:
- Data is Klimisch 2 and from QSAR toolbox 3.3.
Acute toxicity: via inhalation route
Link to relevant study records
- Endpoint:
- acute toxicity: inhalation
- Data waiving:
- other justification
- Justification for data waiving:
- other:
Reference
Endpoint conclusion
- Quality of whole database:
- Waiver
Acute toxicity: via dermal route
Link to relevant study records
- Endpoint:
- acute toxicity: dermal
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
- Justification for type of information:
- Data is predicted using OECD QSAR toolbox version 3.3 and the supporting QMRF report has been attached
- Qualifier:
- according to guideline
- Guideline:
- other: estimated data
- Principles of method if other than guideline:
- Prediction is done using QSAR Toolbox version 3.3.
- GLP compliance:
- not specified
- Test type:
- other: not specified
- Limit test:
- no
- Specific details on test material used for the study:
- Name: 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide
SMILES:CCOc1ccc(NC(=O)C(C(C)=O)N=Nc2ccc(Cl)cc2N(=O)=O)cc1
InChI:1S/C18H17ClN4O5/c1-3-28-14-7-5-13(6-8-14)20-18(25)17(11(2)24)22-21-15-9-4-12(19)10-16(15)23(26)27/h4-10,17H,3H2,1-2H3,(H,20,25)/b22-21+
Molecular Formula: C18H17ClN4O5
Molecular Weight: 404.808 g/mole - Species:
- rabbit
- Strain:
- New Zealand White
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- not specified
- Type of coverage:
- occlusive
- Vehicle:
- unchanged (no vehicle)
- Details on dermal exposure:
- not specified
- Duration of exposure:
- 24 hours
- Doses:
- 2504 mg/kg bw
- No. of animals per sex per dose:
- 6
- Control animals:
- not specified
- Details on study design:
- not specified
- Statistics:
- not specified
- Preliminary study:
- not specified
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 2 504 mg/kg bw
- Based on:
- test mat.
- Remarks on result:
- other: 50% mortality was observed
- Mortality:
- not specified
- Clinical signs:
- other: not specified
- Gross pathology:
- not specified
- Other findings:
- not specified
- Interpretation of results:
- other: Not classified
- Conclusions:
- LD50 was estimated to be 2504 mg/kg bw, when 6 male and female New Zealand White rabbits were treated with 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) for 24 hours by dermal application occlusively.
- Executive summary:
In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, the acute dermal toxicity was estimated for 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8). The LD50 was estimated to be 2504 mg/kg bw, when 6 male and female New Zealand White rabbits were treated with 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide for 24 hours by dermal application occlusively.
Reference
The
prediction was based on dataset comprised from the following
descriptors: LD50
Estimation method: Takes average value from the 5 nearest neighbours
Domain logical expression:Result: In Domain
((((("a"
and ("b"
and (
not "c")
)
)
and ("d"
and (
not "e")
)
)
and ("f"
and (
not "g")
)
)
and ("h"
and (
not "i")
)
)
and ("j"
and "k" )
)
Domain
logical expression index: "a"
Referential
boundary: The
target chemical should be classified as Amides by Aquatic toxicity
classification by ECOSAR
Domain
logical expression index: "b"
Referential
boundary: The
target chemical should be classified as Not possible to classify
according to these rules by DPRA Cysteine peptide depletion
Domain
logical expression index: "c"
Referential
boundary: The
target chemical should be classified as High reactive OR High reactive
>> Organic disulfides OR Low reactive OR Low reactive >> N-substituted
aromatic amides by DPRA Cysteine peptide depletion
Domain
logical expression index: "d"
Referential
boundary: The
target chemical should be classified as Non binder, without OH or NH2
group by Estrogen Receptor Binding
Domain
logical expression index: "e"
Referential
boundary: The
target chemical should be classified as Non binder, MW>500 OR Non
binder, non cyclic structure by Estrogen Receptor Binding
Domain
logical expression index: "f"
Referential
boundary: The
target chemical should be classified as Aliphatic Carbon [CH] AND
Aliphatic Carbon [-CH2-] AND Aliphatic Carbon [-CH3] AND Aliphatic
Nitrogen, one aromatic attach [-N] AND Alpha-oxoamide [C(C(=O))C(=O)N]
AND Amide, aliphatic attach [-C(=O)N] AND Amino, aliphatic attach [-N<]
AND Amino-carbonyl compound [NCC(=O)-C] AND Aromatic Carbon [C] AND Azo
[-N=N-] AND Carbonyl, aliphatic attach [-C(=O)-] AND Chlorine, aromatic
attach [-Cl] AND Chlorine, olefinic attach [-Cl] AND Miscellaneous
sulfide (=S) or oxide (=O) AND Nitro, aromatic attach [-NO2] AND
Nitrogen, two or tree olefinic attach [>N-] AND Olefinic carbon [=CH- or
=C<] AND Oxygen, one aromatic attach [-O-] by Organic functional groups
(US EPA)
Domain
logical expression index: "g"
Referential
boundary: The
target chemical should be classified as Aldehyde, aliphatic attach
[-N-CHO] by Organic functional groups (US EPA)
Domain
logical expression index: "h"
Referential
boundary: The
target chemical should be classified as Amide [-C(=O)-N or -C(=S)-N]
AND Aromatic chloride [-CL] AND Aromatic ether [-O-aromatic carbon]
AND Aromatic nitro [-NO2] AND Aromatic-H AND Azo group [-N=N-] AND
Benzene AND -CH- [linear] AND -CH2- [linear] AND Ketone
[-C-C(=O)-C-] AND Methyl [-CH3] by Bioaccumulation - metabolism alerts
Domain
logical expression index: "i"
Referential
boundary: The
target chemical should be classified as Pyridine ring by Bioaccumulation
- metabolism alerts
Domain
logical expression index: "j"
Parametric
boundary:The
target chemical should have a value of log Kow which is >= 1.23
Domain
logical expression index: "k"
Parametric
boundary:The
target chemical should have a value of log Kow which is <= 5.3
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- 2 504 mg/kg bw
- Quality of whole database:
- Data is Klimisch 2 and from QSAR toolbox 3.3.
Additional information
Acute oral toxicity:
In different studies, 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) has been investigated for acute oral toxicity to a greater or lesser extent. Often are the studies based on in-vivo experiments in rodents, i.e. most commonly in rats for 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide along with the study available on structurally similar read across substances 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide] (CAS no: 5102-83-0) and 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(3-oxo-N-phenylbutanamide) (CAS no: 6358-85-6). The predicted data using the OECD QSAR toolbox has also been compared with the experimental studies. The studies are summarized as below –
In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, the acute oral toxicity was estimated for 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8). The LD50 was estimated to be 3592 mg/kg bw, when 10 female Wistar rats were treated with 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide via oral gavage route.
The above study is supported by U.S. National Library of Medicine (ChemIDplus, 2017), for the structurally similar read across substance 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide] (CAS no: 5102-83-0) in rats at the concentration of 5000 mg/kg bw. No mortality was observed in treated rats at 5000 mg/kg bw. Therefore, LD50 was considered to be >5000 mg/kg bw, when rats were treated with 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide] via oral route.
This study is further supported by U.S. National Library of Medicine (ChemIDplus, 2017), for the structurally similar read across substance 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(3-oxo-N-phenylbutanamide) (CAS no: 6358-85-6) in rats at the concentration of 10800 mg/kg bw. No mortality was observed in treated rats at 10800 mg/kg bw. Therefore, LD50 was considered to be >10800 mg/kg bw, when rats were treated with 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(3-oxo-N-phenylbutanamide) via oral route.
Thus, based on the above studies on 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) and it’s read across substances, it can be concluded that LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide cannot be classified for acute oral toxicity.
Acute Inhalation toxicity:
2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) has very low vapour pressure (2.67E-10 Pa at 25°C), so the potential for the generation of inhalable vapours is very low. Also the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be highly unlikely and therefore this end point was considered for waiver.
Acute Dermal toxicity:
In different studies, 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) has been investigated for acute dermal toxicity to a greater or lesser extent. Often are the studies based on in vivo experiments in rodents, i.e. most commonly in rabbits and rats for 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide along with the study available on the structurally similar read across substances N-(4-chloro-2,5-dimethoxyphenyl)-2-[[2,5-dimethoxy-4-[(phenylamino)sulphonyl]phenyl]azo]-3-oxobutyramide (CAS no: 12225-18-2) and 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide] (CAS no: 5102-83-0). The predicted data using the OECD QSAR toolbox has also been compared with the experimental studies. The studies are summarized as below –
In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, the acute dermal toxicity was estimated for 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8). The LD50 was estimated to be 2504 mg/kg bw, when 6 male and female New Zealand White rabbits were treated with 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide for 24 hours by dermal application occlusively.
This study is supported by U.S. National Library of Medicine (ChemIDplus, 2017), for the structurally similar read across substanceN-(4-chloro-2,5-dimethoxyphenyl)-2-[[2,5-dimethoxy-4-[(phenylamino)sulphonyl]phenyl]azo]-3-oxobutyramide (CAS no: 12225-18-2) was conducted in rabbits at the concentration of 3000 mg/kg bw. No mortality was observed in treated rabbits at 3000 mg/kg bw. Therefore, LD50 was considered to be >3000 mg/kg bw, when rabbits were treated with N-(4-chloro-2,5-dimethoxyphenyl)-2-[[2,5-dimethoxy-4-[(phenylamino)sulphonyl]phenyl]azo]-3-oxobutyramide by dermal application to the skin.
The above study is further supported by SIDS Initial Assessment Profile, United Nations Environmental Programme (UNEP, 2003), for the structurally similar read across substance 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide] (CAS no: 5102-83-0) in rats at the concentration of 3000 mg/kg bw. No mortality was observed in treated rats at 3000 mg/kg bw. Therefore, LD50 was considered to be >3000 mg/kg bw, when rats were treated with 2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide] by dermal application to the skin.
Thus, based on the above studies on 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) and it’s read across substances, it can be concluded that LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide cannot be classified for acute dermal toxicity.
Justification for classification or non-classification
Based on the above studies and prediction on 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no: 52320-66-8) and it’s read across substances, it can be concluded that LD50 value is >2000 mg/kg bw for acute oral and dermal toxicity. Thus, comparing this value with the criteria of CLP regulation, 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide cannot be classified for acute oral and dermal toxicity. For Acute Inhalation toxicity wavier was added so, not possible to classify.
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