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

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: screening tests

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:

The supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Principles of method if other than guideline:

The data is predicted using the OECD QSAR toolbox version 3.3 with logKow as the primary descriptor.

GLP compliance:

not specified

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

Oxygen conditions:

aerobic

Inoculum or test system:

other: Microorganisms

Duration of test (contact time):

28 d

Based on:

not specified

Parameter followed for biodegradation estimation:

other: BOD

Key result

Parameter:

other: BOD

Value:

5.683

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 5.68% degradation by BOD in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
Estimation method: Takes average 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 ( not "m") )  )  and "n" )  and "o" )  and ("p" and "q" )  )

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 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain OR Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Hydrazine Derivatives OR SN1 OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters by DNA binding by OASIS v.1.3

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Non binder, without OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Non binder, impaired OH or NH2 group OR Non binder, MW>500 OR Non binder, non cyclic structure by Estrogen Receptor Binding

Domain logical expression index: "l"

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: "m"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> Polarised Alkenes OR Michael addition >> Polarised Alkenes >> Polarised alkene - ketones OR Michael addition >> Quinones and Quinone-type Chemicals OR Michael addition >> Quinones and Quinone-type Chemicals >> Quinone-imine OR No alert found OR SNAr OR SNAr >> Nucleophilic aromatic substitution OR SNAr >> Nucleophilic aromatic substitution >> Activated halo-benzenes by Protein binding by OECD

Domain logical expression index: "n"

Similarity boundary:Target: Cc1ccc(N=NC2C(C)=NN(c3ccccc3)C2=O)c(C)c1
Threshold=20%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "o"

Similarity boundary:Target: Cc1ccc(N=NC2C(C)=NN(c3ccccc3)C2=O)c(C)c1
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 174 Da

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 338 Da

Validity criteria fulfilled:

not specified

Interpretation of results:

not readily biodegradable

Conclusions:

The test chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one was estimated to be not readily biodegradable in water.

Executive summary:

Biodegradability of 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS no. 6407 -78 -9) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 5.68% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl) diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS no. 6407 -78 -9) is predicted using QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 5.68% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl) diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one was estimated to be not readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Various predicted data for the target compound 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No. 6407-78-9) and supporting weight of evidence studies for its structurally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-one(CAS No. 6407-78-9) was estimated.Test substance undergoes 5.68% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-onewas estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one(CAS No. 6407-78-9) in the presence of mixed populations of environmental microorganisms was estimated.The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical 4 -[(E)-2 -(2,4 -dimethylphenyl) diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-oneis expected to be not readily biodegradable.

 

For the target chemical (CAS no. 6407-78-9) from secondary source (Environment Canada (EC) Health Canada (HC), 2016), biodegradability of test substance 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-one (CAS no.6407-78-9) was estimated using the BIOWIN Sub-models 3-6 and CATALOGIC model under aerobic conditions. The percentage degradation of chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one was evaluated to be 0.56 -12.2% estimated by using the CATALOGIC model and on the basis of the output result of the BIOWIN Sub-models 3 -6, it indicates that chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one biodegrades slowly. Thus, based on this, test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one is considered to be not readily biodegradable in nature.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017) for the read across chemical 1-Phenyl-3-methyl-5-pyrazolone (CAS no. 89-25-8),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance 1-Phenyl-3-methyl-5-pyrazolone. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of read across substance 1 -Phenyl-3 -methyl-5 -pyrazolone was determined to 0, 2 and 28% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation, 1-Phenyl-3-methyl-5-pyrazolone is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of another read across substance 1,2-bis(2-methylphenyl)guanidine (CAS no. 97-39-2) (J-CHECK, 2017 and secondary source OECD SIDS, 2007). The study was performed according to OECD Guide-line 301 C "Ready Biodegradability: Modified MITI Test under aerobic conditions. Activated sludge, non-adapted was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. Aniline was used as a reference substance for the study. Reference substance aniline undergoes 77 and 79% degradation after 14 and 28 days, respectively. The percentage degradation of substance 1,2 -bis(2 -methylphenyl)guanidine was determined to 1 and 0% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation,1,2-bis(2-methylphenyl)guanidine is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one(from OECD QSAR toolbox version 3.3, EPI suite, 2017 and secondary source, 2016) and for its read across substance (from authoritative database J-CHECK and secondary source OECD SIDS), it can be concluded that the test substance 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-onecan be expected to be not readily biodegradable in nature.