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

Endpoint summary

Description of key information

The skin sensitization potential of target chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) was assessedin various experimental studies which were conducted on guinea pigs, mouse and humans for target chemical2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) andits structurally similar read across substancesMethyl salicylate (CAS no: 119-36-8)andMethyl N-methylanthranilate (CAS No: -85-91-6). The predicted data usingQSAR toolboxhas also been compared with the experimental data.Based on the available data for the target and read across substances and applying the weight of evidence approach, it can be concluded that chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) is unable to cause skin sensitization and thus can be considered as not sensitizing. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation

Remarks:

in vivo

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 QMRF report has been attached

Qualifier:

according to guideline

Principles of method if other than guideline:

Prediction is done using QSAR Toolbox version 3.3

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

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

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

No data available

Route:

intradermal and epicutaneous

Vehicle:

not specified

Concentration / amount:

No data available

Day(s)/duration:

No data available

Adequacy of induction:

not specified

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

not specified

Concentration / amount:

No data available

Day(s)/duration:

72 hours

Adequacy of challenge:

not specified

No. of animals per dose:

20

Details on study design:

No data available

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

No data available

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

No skin sensitization was observed.

Remarks on result:

no indication of skin sensitisation

Cellular proliferation data / Observations:

No skin sensitization was observed.

The prediction was based on dataset comprised from the following descriptors: "Skin Sensitisation"
Estimation method: Takes highest mode value from the 8 nearest neighbours
Domain  logical expression:Result: In Domain

((((((((((((("a" or "b" or "c" )  and ("d" and ( not "e") )  )  and ("f" and ( not "g") )  )  and ("h" and ( not "i") )  )  and ("j" and ( not "k") )  )  and ("l" and ( not "m") )  )  and ("n" and ( not "o") )  )  and "p" )  and "q" )  and "r" )  and ("s" and ( not "t") )  )  and "u" )  and ("v" and "w" )  )

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 No alert found by DNA binding by OASIS v.1.3

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds >> Four- and Five-Membered Lactones OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation >> Geminal Polyhaloalkane Derivatives OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR AN2 >> Shiff base formation for aldehydes OR AN2 >> Shiff base formation for aldehydes >> Geminal Polyhaloalkane Derivatives OR AN2 >> Shiff base formation for aldehydes >> Haloalkane Derivatives with Labile Halogen OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> Coumarins OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain OR Radical OR Radical >> Generation of reactive oxygen species OR Radical >> Generation of reactive oxygen species >> Thiols OR Radical >> Generation of ROS by glutathione depletion (indirect) OR Radical >> Generation of ROS by glutathione depletion (indirect) >> Haloalkanes Containing Heteroatom OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA >> Organic Peroxy Compounds OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Coumarins OR Radical >> Radical mechanism via ROS formation (indirect) >> Geminal Polyhaloalkane 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) >> Single-Ring Substituted Primary Aromatic Amines OR SN1 OR SN1 >> Carbenium ion formation OR SN1 >> Carbenium ion formation >> Alpha-Haloethers OR SN1 >> Nucleophilic attack after carbenium ion formation 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 >> Single-Ring Substituted Primary Aromatic Amines OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation 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 >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Acylation involving a leaving group  OR SN2 >> Acylation involving a leaving group  >> Geminal Polyhaloalkane Derivatives OR SN2 >> Acylation involving a leaving group  >> Haloalkane Derivatives with Labile Halogen OR SN2 >> Acylation involving a leaving group after metabolic activation OR SN2 >> Acylation involving a leaving group after metabolic activation >> Geminal Polyhaloalkane Derivatives OR SN2 >> Alkylation, direct acting epoxides and related OR SN2 >> Alkylation, direct acting epoxides and related >> Epoxides and Aziridines OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Haloalkane Derivatives with Labile Halogen OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Sulfonates and Sulfates OR SN2 >> Alkylation, ring opening SN2 reaction OR SN2 >> Alkylation, ring opening SN2 reaction >> Four- and Five-Membered Lactones OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Coumarins OR SN2 >> Direct acting epoxides formed after metabolic activation >> Quinoline Derivatives OR SN2 >> DNA alkylation OR SN2 >> DNA alkylation >> Alkylphosphates, Alkylthiophosphates and Alkylphosphonates OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Haloalkanes Containing Heteroatom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation >> Geminal Polyhaloalkane Derivatives OR SN2 >> Ring opening SN2 reaction OR SN2 >> Ring opening SN2 reaction >> Sultones OR SN2 >> SN2 at an activated carbon atom OR SN2 >> SN2 at an activated carbon atom >> Quinoline Derivatives OR SN2 >> SN2 at sp3-carbon atom OR SN2 >> SN2 at sp3-carbon atom >> Alpha-Haloethers 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 by DNA binding by OASIS v.1.3

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 Acylation OR Acylation >> Isocyanates and Isothiocyanates OR Acylation >> Isocyanates and Isothiocyanates >> Isocyanates OR Acylation >> P450 Mediated Activation to Isocyanates or Isothiocyanates OR Acylation >> P450 Mediated Activation to Isocyanates or Isothiocyanates >> Benzylamines-Acylation OR Michael addition OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems >> Thiophenes-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 >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR Schiff base formers OR Schiff base formers >> Direct Acting Schiff Base Formers OR Schiff base formers >> Direct Acting Schiff Base Formers >> Mono aldehydes OR SN1 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 >> Primary (unsaturated) heterocyclic amine OR SN1 >> Nitrenium Ion formation >> Primary aromatic amine OR SN1 >> Nitrenium Ion formation >> Tertiary (unsaturated) heterocyclic amine  OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine OR SN2 OR SN2 >> P450 Mediated Epoxidation OR SN2 >> P450 Mediated Epoxidation >> Thiophenes-SN2 by DNA binding by OECD

Domain logical expression index: "h"

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

Domain logical expression index: "i"

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

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as No alert found by Protein binding by OASIS v1.3

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Direct acylation involving a leaving group OR Acylation >> Direct acylation involving a leaving group >> Azlactones and unsaturated lactone derivatives  OR Acylation >> Direct acylation involving a leaving group >> Carbamates  OR Acylation >> Direct acylation involving a leaving group >> N-Acylated heteroaromatic amines  OR Acylation >> Ester aminolysis OR Acylation >> Ester aminolysis >> Amides OR Acylation >> Ester aminolysis or thiolysis OR Acylation >> Ester aminolysis or thiolysis >> Activated aryl esters  OR Acylation >> Ring opening acylation OR Acylation >> Ring opening acylation >> Active cyclic agents  OR Michael Addition OR Michael Addition >> Michael addition on conjugated systems with electron withdrawing group OR Michael Addition >> Michael addition on conjugated systems with electron withdrawing group >> alpha,beta-Carbonyl compounds with polarized double bonds  OR Michael Addition >> Michael addition on conjugated systems with electron withdrawing group >> Cyanoalkenes OR Nucleophilic addition OR Nucleophilic addition >> Addition to carbon-hetero double bonds OR Nucleophilic addition >> Addition to carbon-hetero double bonds >> Ketones OR Schiff base formation OR Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives OR Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives >> Pyrazolones and Pyrazolidinones  OR SN2 OR SN2 >> Nucleophilic substitution on benzilyc carbon atom OR SN2 >> Nucleophilic substitution on benzilyc carbon atom >> alpha-Activated benzyls  OR SN2 >> SN2 Reaction at a sp3 carbon atom OR SN2 >> SN2 Reaction at a sp3 carbon atom >> Activated alkyl esters and thioesters  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: "l"

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

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Direct Acylation Involving a Leaving group OR Acylation >> Direct Acylation Involving a Leaving group >> Acetates by Protein binding by OECD

Domain logical expression index: "n"

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

Domain logical expression index: "o"

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

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "q"

Similarity boundary:Target: CC(C(=O)OC)Nc1c(C)cccc1C
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "r"

Similarity boundary:Target: CC(C(=O)OC)Nc1c(C)cccc1C
Threshold=40%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "s"

Referential boundary: The target chemical should be classified as Known precedent reproductive and developmental toxic potential AND Toluene and small alkyl toluene derivatives (8a) by DART scheme v.1.0

Domain logical expression index: "t"

Referential boundary: The target chemical should be classified as Not covered by current version of the decision tree by DART scheme v.1.0

Domain logical expression index: "u"

Referential boundary: The target chemical should be classified as > 100 days by Hydrolysis half-life (Kb, pH 8)(Hydrowin) ONLY

Domain logical expression index: "v"

Parametric boundary:The target chemical should have a value of log Kow which is >= 1.14

Domain logical expression index: "w"

Parametric boundary:The target chemical should have a value of log Kow which is <= 4.61

Interpretation of results:

other: not sensitizing

Conclusions:

The chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) was estimated to be not sensitizing to the skin of Dunkin-Hartley guinea pigs. Based on the estimated result 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) failed to induce skin sanitization effects and hence is considered to be not sensitizing to Dunkin-Hartley guinea pigs.

Executive summary:

The skin sensitization potential of 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) was estimated using OECD QSAR toolbox version 3.3 with log Pow as the primary descriptor. The chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) was estimated to be not sensitizing to the skin of Dunkin-Hartley guinea pigs. Based on the estimated result 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) failed to induce skin sanitization effects and hence is considered to be not sensitizing to Dunkin-Hartley guinea pigs and can be classified under the category ˋ Not Classified’ as per CLP regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitization

Various studieshas been investigated for the test chemical2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0)  to observe the potential for skin sensitization to a greater or lesser extent. The studies are based on in vivo experiments in guinea pigs, mouse and humans for target chemical2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) and its structurally similar read across substancesMethyl salicylate (CAS no: 119-36-8)andMethyl N-methylanthranilate (CAS No: -85-91-6).The predicted data using the OECD QSAR toolbox has also been compared with the experimental data and summarized as below;

 

The skin sensitization potential of 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) was estimated using OECD QSAR toolbox version 3.4 with log Pow as the primary descriptor. The substance 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0)  was estimated to be not sensitizing to the skin of guinea pigs. Based on the estimated result 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0)  failed to induce skin sanitization effects and hence is considered to be not sensitizing to guinea pigs.

 

The Gerberick GF et.al., {Dermatitis, 2005 Dec; 16(4):157-202} conducted Mouse Local Lymphnode Assay for read across chemical Methyl salicylate (CAS no: 119-36-8). The LLNA was conducted on groups of five female CBA mice (7-12 weeks of age) by mean of topical application of chemical on the dorsum of both ears at a dose of 25µl of 1%, 2.5%, 5%, 10% or 20% in acetone/olive oil (4:1). Treatment was performed daily for 3 consecutive days. Five days after initiation of exposure all mice were injected via the tail vein with 250µl of PBS containing 20µCi of tritiatied thymidine. The mice were sacrificed 5 hours later, and draining the auricular lymph nodes were excised and pooled for each experimental group or each individual animal. The incorporation of tritiated thymidine measured by β-scintillation counting and was reported in disintegrations /minute.  An SI was calculated for each chemical group as the ratio of disintegrations/minute of the treated group to the disintegrations/minute of the concurrent vehicle control group. A substance was classified skin sensitizer, if at one or more than one concentrations, it induced a three-fold or greater increase in local lymph node proliferative activity when treated with the concurrent vehicle treated controls (SI ≥3). The approach to estimation of the relative skin sensitization potential is based on the mathematical estimation of the concentration of chemical necessary to obtain a threshold positive response (SI = 3); this is termed as the EC3 value. For each concentration of methyl salicylate, a stimulation index (SI) relative to the concurrent vehicle-treated control was calculated. The calculated EC3 value for methyl salicylate was >20.0%. Thus based on the relative potency index Methyl salicylate (CAS no: 119-36-8) was considered to be not sensitizing in the Mouse Local Lymphnode Assay.

 

The above results were further supported by the experimental study conducted by D.L.J. OPDYKE {Food and Cosmetics Toxicology Volume 13, Issue 6, 1975, Pages 791-792} for read across chemical Methyl N-methylanthranilate(CAS No: -85-91-6) was performed in 25 volunteers. 10% in petrolatum of test sample was administrated on different panels of human subject. No known cutaneous reaction was observed in 25 volunteers. Therefore, the test chemical Methyl N-methylanthranilate (CAS No: -85-91-6) can be considered as not sensitizing on human skin.

 

Thus on the basis of available data for thetarget chemical2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) and its structurally similar read across substancesMethyl salicylate (CAS no: 119-36-8)andMethyl N-methylanthranilate (CAS No: -85-91-6),it can be concluded thatchemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0)  is unable to cause skin sensitization and considered as non-skin sensitizer. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The skin sensitization potential of test substance 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0) and its structurally similar read across substancesMethyl salicylate (CAS no: 119-36-8)andMethyl N-methylanthranilate (CAS No: -85-91-6) were observed in various studies. From the results obtained from these studies it is concluded that the chemical 2-(2,6-dimethyl-phenylamino)-propionic acid methyl ester (CAS No: 52888-49-0)  is not likely to cause skin sensitization and hence can be classified as non-skin sensitizer.