Methyl N-(2,6-dimethylphenyl)-DL-alaninate

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 : 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester
- Common name : Methyl N-(2,6-dimethylphenyl)-DL-alaninate
- Molecular formula : C12H17NO2
- Molecular weight : 207.271 g/mol
- Smiles notation : N(c1c(cccc1C)C)[C@@H](C(OC)=O)C
- InChl : 1S/C12H17NO2/c1-8-6-5-7-9(2)11(8)13-10(3)12(14)15-4/h5-7,10,13H,1-4H3
- 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:

0.167

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 0.166% 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" )  and "d" )  and "e" )  and ("f" and ( not "g") )  )  and ("h" and ( not "i") )  )  and "j" )  and "k" )  and ("l" and "m" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Esters (Acute toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Esters by Acute aquatic toxicity MOA by OASIS

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 5) ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 6) ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OECD

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems >> Furans 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 >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR SN1 OR SN1 >> Carbenium Ion Formation OR SN1 >> Carbenium Ion Formation >> Allyl benzenes OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Aromatic azo OR SN1 >> Nitrenium Ion formation >> Aromatic nitro OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine OR SN1 >> Nitrenium Ion formation >> Unsaturated heterocyclic azo OR SN2 OR SN2 >> Episulfonium Ion Formation OR SN2 >> Episulfonium Ion Formation >> 1,2-Dihaloalkanes OR SN2 >> Ring opening SN2 Reaction OR SN2 >> Ring opening SN2 Reaction >> Sultones OR SN2 >> SN2 at an sp3 Carbon atom OR SN2 >> SN2 at an sp3 Carbon atom >> Aliphatic halides OR SN2 >> SN2 at an sp3 Carbon atom >> Sulfates by DNA binding by OECD

Domain logical expression index: "h"

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: "i"

Referential boundary: The target chemical should be classified as High reactive OR High reactive >> Activated haloarenes OR Low reactive OR Low reactive >> Saturated acid anhydrides by DPRA Cysteine peptide depletion

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Not calculated by Hydrolysis half-life (Ka, pH 8)(Hydrowin) ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as > 100 days by Hydrolysis half-life (Kb, pH 7)(Hydrowin) ONLY

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 140 Da

Domain logical expression index: "m"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 453 Da

Validity criteria fulfilled:

not specified

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester was estimated to be not readily biodegradable in water.

Executive summary:

Biodegradability of 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS no. 52888 -49 -0) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 0.166% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS no. 52888 -49 -0) is predicted using QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 0.166% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester 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 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No. 52888-49-0) 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 2 -(2,6 -dimethyl- phenylamino)-propionic acid methyl ester(CAS No. 52888-49-0) was estimated.Test substance undergoes 0.166% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical2-(2,6-dimethyl-phenylamino)-propionic acid methyl esterwas 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-(2,6-dimethyl-phenylamino)-propionic acid methyl ester(CAS No. 52888-49-0) 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 chemical2-(2,6-dimethyl-phenylamino)-propionic acid methyl esteris expected to be not readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (J-CHECK and HSDB, 2017 & EnviChem, 2014) for the read across chemical 3,4-dimethylaniline (CAS no. 95-64-7),biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance 3,4-dimethylaniline. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 100 mg/l and initial test substance conc. used in the study was 30 mg/l, respectively. The percentage degradation of substance 3,4-dimethylaniline was determined to be 7.1 and 4.8% by BOD and GC parameter in 28 days. Thus, based on percentage degradation, 3,4 -dimethylaniline is considered to be not readily biodegradable in nature.

 

For the read across chemical 2,6-Xylidine (CAS no. 87-62-7) from authoritative database (J-CHECK and HSDB, 2017) and secondary source (OECD SIDS, 2012), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance 2,6-Xylidine (CAS no. 87-62-7). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)) at a temperature of 25°C. Activated sludge, non-adapted was used as a test inoculum for the study. Sludge and surface water including surface soil were collected from ten different places in Japan which includes water treatment plants, rivers, lake and inner bays. These sludges and water/soil were mixed and cultivated with glucose and peptone as nutrient in a testing laboratory. 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. For analytical method,10 mL of the test solution was taken out and centrifuged. Then, the supernatant of this solution was employed for the quantitative analysis for HPLC and TOC.BOD was continuously measured by BOD analysis. Direct analysis by HPLC and TOC was conducted after 28 days. Aniline was used as a reference substance for the study. Reference substance aniline undergoes 66% and 78% degradation after 7 and 14 days, respectively. Thus, based on this, pass level criteria was fulfilled. The percentage degradation of substance 2,6-Xylidine was determined to be 0 and 1% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation, 2,6-Xylidine is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 70 days for evaluating the percentage biodegradability of read across substance 2,6-Xylidine (CAS no. 87-62-7) (HSDB, 2017). The study was performed according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) under aerobic conditions. Initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of read across substance 2,6-Xylidine was determined to be 4, 8, 25, 38 and 69% by BOD parameter after 7, 13, 36, 42 and 70 days, respectively. Thus, based on percentage degradation, 2,6-Xylidine is considered to be not readily biodegradable in nature.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017) and secondary source (OECD SIDS, 2012) for the read across chemical 2,3-Xylidine (CAS no. 87-59-2),biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance 2,3-Xylidine. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)) at a temperature of 25± 1°C. Activated sludge, non-adapted was used as a test inoculum for the study. Sludge and surface water including surface soil were collected from ten different places in Japan which includes water treatment plants, rivers, lake and inner bays. These sludges and water/soil were mixed and cultivated with glucose and peptone as nutrient in a testing laboratory. 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. For analytical method, After the cultivation period, 10 mL of the test substance was taken out. Then this test solution was centrifuged with 1000 g for 10 minutes. The supernatant was then analyzed with TOC and HPLC.BOD was continuously measured by BOD analysis. Direct analysis by HPLC and TOC was conducted after 28 days. Aniline was used as a reference substance for the study. Inoculum blank was also setup for the biodegradation study. Reference substance aniline undergoes 59% and 76% degradation after 7 and 14 days, respectively. Thus, based on this, pass level criteria was fulfilled. The percentage degradation of substance 2,3-Xylidine was determined to be 3 and 0% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation, 2,3-Xylidine is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester(from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (authoritative database J-CHECK, HSDB, EnviChem and secondary source OECD SIDS), it can be concluded that the test substance 2 -(2,6 -dimethyl-phenyl amino)-propionic acid methyl ester can be expected to be not readily biodegradable in nature.