4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (6407-78-9) .The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with and without S9 metabolic activation system. 4-[(E)-2-(2,4-dimethylphenyl)diazen- 1-yl]-3-methyl-1- phenyl-4,5-dihydro-1H-pyrazol-5-one was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro. Based on the predicted result it can be concluded that the substance is considered to not toxic as per the criteria mentioned in CLP regulation.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

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 from OECD QSAR Toolbox version 3.3 and the supporting QMRF report has been attached.

Qualifier:

according to guideline

Guideline:

other: As mention below

Principles of method if other than guideline:

Prediction is done using OECD QSAR Toolbox version 3.3, 2017

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

- Name of test material (IUPAC name): 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one
- Common name: Solvent Yellow 18
- Molecular formula: C18H18N4O
- Molecular weight: 306.367 g/mol
- Smiles notation: O=C1N(N=C(C)[C@@H]1\N=N\c1c(cc(cc1)C)C)c1ccccc1
- InChl: 1S/C18H18N4O/c1-12-9-10-16(13(2)11-12)19-20-17-14(3)21-22(18(17)23)15-7-5-4-6-8-15/h4-11,17H,1-3H3/b20-19+
- Substance type: Organic
- Physical state: Solid

Target gene:

Histidine

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Details on mammalian cell type (if applicable):

Not applicable.

Additional strain / cell type characteristics:

not specified

Cytokinesis block (if used):

not specified

Metabolic activation:

with

Metabolic activation system:

S9 metabolic activation

Test concentrations with justification for top dose:

not specified

Vehicle / solvent:

not specified

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Details on test system and experimental conditions:

not specified

Rationale for test conditions:

not specified

Evaluation criteria:

Prediction was done considering a dose dependent increase in the number of revertants/plate.

Statistics:

not specified

Species / strain:

S. typhimurium, other:

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Remarks on result:

other: No mutagenic effct were observed

The prediction was based on dataset comprised from the following descriptors: "Gene mutation"
Estimation method: Takes highest mode value from the 6 nearest neighbours
Domain  logical expression:Result: In Domain

(((((("a" or "b" or "c" or "d" or "e" or "f" or "g" )  and ("h" and ( not "i") )  )  and ("j" and ( not "k") )  )  and "l" )  and ("m" and ( not "n") )  )  and ("o" and "p" )  )

Domain logical expression index: "a"

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 >> Unsaturated heterocyclic azo by DNA binding by OECD

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Schiff base formation AND Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives AND Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives >> Pyrazolones and Pyrazolidinones  by Protein binding by OASIS v1.3

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Direct Acylation Involving a Leaving group AND Acylation >> Direct Acylation Involving a Leaving group >> Acetates AND SN2 AND SN2 >> SN2 reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom >> Alkyl diazo by Protein binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Amides AND Hydrazines by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Amides OR Hydrazines by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Direct Acylation Involving a Leaving group AND Acylation >> Direct Acylation Involving a Leaving group >> Acetates AND SN2 AND SN2 >> SN2 reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom >> Alkyl diazo by Protein binding by OECD

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Amides AND Hydrazines by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.3

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >>  Michael-type addition, quinoid structures OR AN2 >>  Michael-type addition, quinoid structures >> Quinoneimines OR AN2 >>  Michael-type addition, quinoid structures >> Quinones OR AN2 >> Carbamoylation after isocyanate formation OR AN2 >> Carbamoylation after isocyanate formation >> Hydroxamic Acids OR AN2 >> Carbamoylation after isocyanate formation >> N-Hydroxylamines OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR Michael addition OR Michael addition >> Quinone type compounds OR Michael addition >> Quinone type compounds >> Quinone methides OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> Aminoacridine DNA Intercalators OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain OR Non-covalent interaction >> DNA intercalation >> Fused-Ring Nitroaromatics OR Non-covalent interaction >> DNA intercalation >> Quinones OR Non-specific OR Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    OR Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    >> Specific Imine and Thione Derivatives OR Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> C-Nitroso Compounds OR Radical >> Radical mechanism via ROS formation (indirect) >> Conjugated Nitro Compounds OR Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Nitroaromatics OR Radical >> Radical mechanism via ROS formation (indirect) >> Hydrazine Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> N-Hydroxylamines OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitro Azoarenes OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroaniline Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroarenes with Other Active Groups OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR Radical >> Radical mechanism via ROS formation (indirect) >> p-Substituted Mononitrobenzenes OR Radical >> Radical mechanism via ROS formation (indirect) >> Quinones OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR Radical >> Radical mechanism via ROS formation (indirect) >> Specific Imine and Thione Derivatives OR Radical >> ROS formation after GSH depletion OR Radical >> ROS formation after GSH depletion (indirect) OR Radical >> ROS formation after GSH depletion (indirect) >> Quinoneimines OR Radical >> ROS formation after GSH depletion >> Quinone methides OR SN1 OR SN1 >> Alkylation after metabolically formed carbenium ion species OR SN1 >> Alkylation after metabolically formed carbenium ion species >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> N-Nitroso Compounds OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN1 >> Nucleophilic attack after diazonium or carbenium ion formation OR SN1 >> Nucleophilic attack after diazonium or carbenium ion formation >> Nitroarenes with Other Active Groups OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> N-Hydroxylamines OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines OR SN1 >> Nucleophilic attack after nitrenium and/or carbenium ion formation OR SN1 >> Nucleophilic attack after nitrenium and/or carbenium ion formation >> N-Nitroso Compounds OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Conjugated Nitro Compounds OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Fused-Ring Nitroaromatics OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitro Azoarenes OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitroaniline Derivatives OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitroarenes with Other Active Groups OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitrobiphenyls and Bridged Nitrobiphenyls OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> p-Substituted Mononitrobenzenes OR SN1 >> Nucleophilic substitution after glutathione-induced nitrenium ion formation OR SN1 >> Nucleophilic substitution after glutathione-induced nitrenium ion formation >> C-Nitroso Compounds OR SN1 >> Nucleophilic substitution on diazonium ions OR SN1 >> Nucleophilic substitution on diazonium ions >> Specific Imine and Thione Derivatives OR SN1 >> SN1 reaction at nitrogen-atom bound to a good leaving group or on  nitrenium ion OR SN1 >> SN1 reaction at nitrogen-atom bound to a good leaving group or on  nitrenium ion >> N-Acyloxy(Alkoxy) Arenamides OR SN1 >> SN1 reaction at nitrogen-atom bound to a good leaving group or on  nitrenium ion >> N-Aryl-N-Acetoxy(Benzoyloxy) Acetamides OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Hydroxamic Acids OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Quinoline Derivatives OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters OR SN2 >> SN2 at an activated carbon atom OR SN2 >> SN2 at an activated carbon atom >> Quinoline Derivatives OR SN2 >> SN2 at Nitrogen Atom OR SN2 >> SN2 at Nitrogen Atom >> N-acetoxyamines OR SN2 >> SN2 attack on activated carbon Csp3 or Csp2 OR SN2 >> SN2 attack on activated carbon Csp3 or Csp2 >> Nitroarenes with Other Active Groups OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group >> N-Acetoxyamines OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group or nitrenium ion OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group or nitrenium ion >> N-Acyloxy(Alkoxy) Arenamides OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group or nitrenium ion >> N-Aryl-N-Acetoxy(Benzoyloxy) Acetamides by DNA binding by OASIS v.1.3

Domain logical expression index: "j"

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 >> Unsaturated heterocyclic azo by DNA binding by OECD

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Acylation 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 >> Arenes OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Hydroquinones OR No alert found OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion formation >> Aromatic nitro OR SN1 >> Nitrenium Ion formation >> Primary (unsaturated) heterocyclic amine OR SN1 >> Nitrenium Ion formation >> Secondary aromatic amine OR SN1 >> Nitrenium Ion formation >> Tertiary (unsaturated) heterocyclic amine  OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine OR SN2 OR SN2 >> SN2 at an sp3 Carbon atom OR SN2 >> SN2 at an sp3 Carbon atom >> Aliphatic halides by DNA binding by OECD

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Not bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Non-Metals by Groups of elements

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Alkali Earth by Groups of elements

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of log Kow which is >= 2.85

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of log Kow which is <= 7.05

Conclusions:

4-[(2,4-dimethylphenyl)diazenyl]-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (6407-78-9) was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (6407-78-9) .The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with S9 metabolic activation system.4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]- 3-methyl-1- phenyl-4,5- dihydro- 1H-pyrazol-5-one was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro. Based on the predicted result it can be concluded that the substance is considered to not toxic as per the criteria mentioned in CLP regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Genotoxicity In-vitro

Prediction model based estimation, Experimental data from target and read across chemical have been reviewed to determine the mutagenic nature of 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (6407-78-9). The studies are as mentioned below

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (6407-78-9) .The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with and without S9 metabolic activation system. 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro. Based on the predicted result it can be concluded that the substance is considered to not toxic as per the criteria mentioned in CLP regulation.

Experimental study for target was conducted byEnvironment Canada - Health Canada; November 2013 (Draft Screening Assessment Certain Azo Solvent Dyes ,2013) to determine the mutagenic nature. The mutagenicity of Solvent Yellow 18 was tested in modifying Ames test in S. Typhimurium strains TA98 and TA100 under standard and reductive (with FMN) conditions and with metabolic activation. Positive results were observed in strain TA98, regardless of the presence of FMN, and the results were negative in strain TA100, with and without FMN. Therefore Solvent Yellow 18 result for this test was considered to be ambiguous.

In a study for structurally and functionally similar read across chemical, Gene mutation toxicity study was performed by Joseph P. Brown et al.( Mutation Research,1978) to determine the mutagenic nature ofSudan IV(85-83-6); IUPAC name: 1-({2-methyl-4-[(2-methylphenyl)diazenyl]phenyl} diazenyl)-2- naphthol (85-83-6). The read across substances share high similarity in structure and log kow .Therefore, it is acceptable to derive information on mutation from the analogue substance. Gene mutation by the spot assay was performed for Sudan IV. Sudan IV was used at dose level of 200 µg/plate both with and without S9 metabolic activation system. The plates were incubated for 3 days at 37°C for the growth of colonies to occur. The plates were observed for an increase in the number of His+ revertants. The criteria adopted for scoring a mutagenic response in routine plate tests was that the observed number of revertants should exceed twice the background value for that given assay and exceed the 99.9% confidence limit based on our historical controls. Concurrent positive control was also included in the study.Sudan IV failed to induce mutation in Salmonellatyphimurium strain TA100, TA98, TA1535, TA1537 and TA1538 with and without S9 metabolic activation system in the spot test performed and hence is not likely to classify for gene mutation in vitro.

In a study for structurally and functionally similar read across chemical, Gene mutation toxicity study was performed by Zeiger et al.( Environ. Molec. Mutagen, 1998) to determine the mutagenic nature of Pigment yellow 100(12225-21-7) IUPAC ; aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate). The read across substances share high similarity in structure and log kow .Therefore, it is acceptable to derive information on mutation from the analogue substance. Pigment yellow 100 was studied for its ability to induce mutations in strains of Salmonella typhimurium. The test compound was dissolved in DMSO and was tested at concentration of 0, 100, 333, 1000, 3333, 6666 or 10000 µg/plate using Salmonella typhimurium TA100, TA1535, TA1537, TA97 and TA98 in the presence and absence of 10 % and 30 % rat and hamster liver S9 metabolic activation system. Preincubation assay was performed with a preicubation for 20 mins. The plates were observed for Histidine independence after 2 days incubation period. Concurrent solvent and positive controls were included in the study. Pigment yellow 100 is not mutagenic to the Salmonella typhimurium TA100, TA1535, TA1537, TA97 and TA98 in the presence and absence of rat and hamster liver S9 metabolic activation system  and hence it is not likely to classify as a gene mutant in vitro.

 

 

Based on the data available for the target chemical and its read across substance data 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl] -3-methyl-1-phenyl -4,5-dihydro-1H-pyrazol-5-one (6407-78-9)does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant in vitro.

Justification for classification or non-classification

Thus based on the prediction data available for the target chemical and supporting data of its read across substance suggest that 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl] -3-methyl-1-phenyl -4,5-dihydro-1H-pyrazol-5-one (6407-78-9)does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant in vitro.