616-02-4

Basic information

• Product Name: Citraconic anhydride
• Synonyms: 2-METHYLMALEIC ANHYDRIDE;CITRACONIC ANHYDRIDE;CTA;METHYLMALEIC ANHYDRIDE;Citraconicanhydride,98%;3-methyl-2,5-pentanedione;lpha-methylmaleic anhydride;cis-Methylbutenedioic anhydride
• CAS NO: 616-02-4
• Molecular Formula: C₅H₄O₃
• Molecular Weight: 112.08
• EINECS: 210-459-0
• Product Categories: Rubber & Plastic Auxiliary Agent;Anhydride Monomers;Monomers;Polymer Science;Carbonyl Compounds;Carboxylic Acid Anhydrides;Organic Building Blocks
• Mol File: 616-02-4.mol
• Article Data: 30

Chemical Properties

• Melting Point: 6-10 °C(lit.)
• Boiling Point: 213-214 °C(lit.)
• Flash Point: 215 °F
• Appearance: Clear colorless to very slightly yellow/Liquid
• Density: 1.247 g/mL at 25 °C(lit.)
• Vapor Density: 4 (vs air)
• Refractive Index: n20/D 1.471(lit.)
• Storage Temp.: Store at RT.
• Water Solubility: decomposes
• Sensitive: Moisture Sensitive
• BRN: 1835
• CAS DataBase Reference: Citraconic anhydride(CAS DataBase Reference)
• NIST Chemistry Reference: Citraconic anhydride(616-02-4)
• EPA Substance Registry System: Citraconic anhydride(616-02-4)

Safety Data

• Hazard Codes: T
• Statements: 23/24/25-36/37/38-42/43-34-24
• Safety Statements: 26-36/37/39-45-28A-23-36/37
• RIDADR: UN 2810 6.1/PG 3
• WGK Germany: 3
• RTECS: GE6825000
• F: 10-21
• TSCA: Yes
• HazardClass: 6.1
• PackingGroup: III
• Hazardous Substances Data: 616-02-4(Hazardous Substances Data)

Usage

Chemical Properties

clear colorless to very slightly yellow liquid

Uses

Different sources of media describe the Uses of 616-02-4 differently. You can refer to the following data:
1. Reagent for alkalies, alcohols, and amines.
2. Citraconic anhydride is used as a monomer for specialty unsaturated polyester resins. It is used to prepare bicyclic pyrrolidines, maleimides and co- and terpolymers. It is also used for the protection of N-terminal amino acids. Further, it is involved in the preparation of clothing ping acid and its amide. In addition to this, it is selectively used for the isolation of histidyl peptides.
3. Versatile reagent used for the synthesis of maleimides, bicyclic pyrrolidines, and co- and terpolymers, as well as for the protection of N-terminal amino acids.

Flammability and Explosibility

Nonflammable

Purification Methods

Possible contamination is from the acid formed by hydrolysis. If the IR has OH bands, then reflux with Ac2O for 30minutes, evaporate, then distil the residue in a vacuum, otherwise distil in a vacuum. Store in a dry atmosphere. [Vaughan & Andersen J Am Chem Soc 77 6702 1955, Vaughan & Andersen J Org Chem 21 680 1956, Beilstein 17 H 440, 17 I 234, 17 II 448, 17 III/IV 5912, 17/11 V 65.]

InChI:InChI=1/C10H10O7/c1-5(3-7(11)12)9(15)17-10(16)6(2)4-8(13)14/h3-4H,1-2H3,(H,11,12)(H,13,14)/b5-3-,6-4-

Synthetic route

2-methylenesuccinic acid (97-65-4) → citraconic acid anhydride (616-02-4)

Conditions	Yield
With calcium In 5,5-dimethyl-1,3-cyclohexadiene at 120℃; under 750.075 Torr; for 1.5h; Reagent/catalyst;	99.3%
Stage #1: 2-methylenesuccinic acid With acetic anhydride at 80℃; Stage #2: at 230℃; under 262.526 Torr; for 4h;	94%
4Cs(1+)*SiW12O40(4-) = Cs4{SiW12O40} at 170 - 200℃; under 50 - 100 Torr; for 5.5h; Product distribution / selectivity;	92.5%

citraconic acid (498-23-7) → citraconic acid anhydride (616-02-4)

Conditions	Yield
With trifluoroacetic anhydride at 20℃; Inert atmosphere;	99%
With niobium(V) oxide hydrate In o-xylene at 160℃; for 72h; Inert atmosphere; Molecular sieve;	94%
With phosphorus pentoxide In chloroform for 48h; Reflux;	80%

1,3,5-Trioxan (110-88-3) + succinic acid anhydride (108-30-5) → methyl hydrogen succinate (3878-55-5) + citraconic acid anhydride (616-02-4) + carbon dioxide (124-38-9)

Conditions	Yield
With gamma-alumina at 380℃; under 3750.38 Torr; Stobbe Condensation; Autoclave; Flow reactor;	A 7% B 43% C 16%

formaldehyd (50-00-0) + Dimethyl succinate (106-65-0) → succinic acid anhydride (108-30-5) + methyl hydrogen succinate (3878-55-5) + citraconic acid anhydride (616-02-4) + carbon dioxide (124-38-9)

Conditions	Yield
With gamma-alumina In methanol; water at 380℃; under 3750.38 Torr; Kinetics; Concentration; Temperature; Stobbe Condensation; Autoclave; Flow reactor;	A 8% B 18% C 30% D 10%

1,3,5-Trioxan (110-88-3) + methyl hydrogen succinate (3878-55-5) → succinic acid anhydride (108-30-5) + citraconic acid anhydride (616-02-4) + carbon dioxide (124-38-9) + Dimethyl succinate (106-65-0)

Conditions	Yield
With gamma-alumina at 380℃; under 3750.38 Torr; Stobbe Condensation; Autoclave; Flow reactor;	A 9% B 23% C 15% D 30%

1,3,5-Trioxan (110-88-3) + Dimethyl succinate (106-65-0) → succinic acid anhydride (108-30-5) + methyl hydrogen succinate (3878-55-5) + citraconic acid anhydride (616-02-4) + carbon dioxide (124-38-9)

Conditions	Yield
With gamma-alumina at 380℃; under 3750.38 Torr; Temperature; Pressure; Stobbe Condensation; Autoclave; Flow reactor;	A 8% B 19% C 26% D 18%

(Z)-(2-methyl-4-(4-nitrophenylamino)-4-oxo)but-2-enoic acid (80818-24-2) → citraconic acid anhydride (616-02-4) + (Z)-(3-methyl-4-(4-nitrophenylamino)-4-oxo)but-2-enoic acid (80818-11-7) + 4-nitro-aniline (100-01-6)

Conditions	Yield
In tetrahydrofuran for 24h; Reflux;	A 9% B n/a C 22%

paraconic acid (498-89-5) → citraconic acid anhydride (616-02-4)

Conditions	Yield
bei der Destillation;

2,6-dioxo-3,6-dihydro-2H-pyran-4-carboxylic acid (14556-16-2) → citraconic acid anhydride (616-02-4)

Conditions	Yield
beim Destillieren;

2-bromo-3-methyl-succinic acid (7405-17-6) → citraconic acid anhydride (616-02-4)

Conditions	Yield
at 210℃;

Mesaconic acid (498-24-8) → citraconic acid anhydride (616-02-4)

Conditions	Yield
With acetyl chloride at 100℃; beim Erhitzen im geschlossenen Rohr;

2-hydroxy-2-methylbutane-1,4-dioic acid (597-44-4) → citraconic acid anhydride (616-02-4)

Conditions	Yield
at 83 - 89℃; under 15 Torr; Heating;	4.9 g

methoxymethyl-succinic acid (81949-89-5) → citraconic acid anhydride (616-02-4)

Conditions	Yield
at 210 - 230℃; durch Destillation;
at 210 - 230℃; beim Destillieren;

itaconic acid anhydride (2170-03-8) + N,N-dimethyl-aniline (121-69-7) → citraconic acid anhydride (616-02-4)

itaconic acid anhydride (2170-03-8) → citraconic acid anhydride (616-02-4)

Conditions	Yield
durch Destillation;
With 2,3-Dimethylaniline
bei der Destillation;

O-acetyl-tachysterol4 → citraconic acid anhydride (616-02-4)

anthracene-citraconic anhydride adduct (51864-00-7) + propionic acid (802294-64-0) → citraconic acid anhydride (616-02-4) + anthracene (120-12-7)

Conditions	Yield
at 142 - 143℃; Rate constant; Dissoziation;
at 131.5 - 143℃; Equilibrium constant; Dissoziation;

Mesaconic acid (498-24-8) + acetyl chloride (75-36-5) → citraconic acid anhydride (616-02-4)

citric acid (77-92-9) → citraconic acid anhydride (616-02-4)

Conditions	Yield
bei der Destillation;

2,5-bis<(trimethylsilyl)oxy>-3-methylfuran (77220-07-6) → citraconic acid anhydride (616-02-4)

Conditions	Yield
With bromine at -78℃; Rate constant; iodine at 0 deg C;

C5H5O7P(2-) → citraconic acid anhydride (616-02-4)

Conditions	Yield
With dipotassium hydrogenphosphate; water for 0.333333h; Equilibrium constant; Ambient temperature; pH = 10.0;

citric acid (77-92-9) → diethyl 3-hydroxypentanedioate (638-18-6) + Mesaconic acid (498-24-8) + 1 propene 1,2,3 tricarboxylic acid (499-12-7) + 2-methylenesuccinic acid (97-65-4) + citraconic acid anhydride (616-02-4) + itaconic acid anhydride (2170-03-8)

Conditions	Yield
With Sn/Pb solder at 150 - 210℃;

2-oxo-propionic acid (127-17-3) → citraconic acid anhydride (616-02-4) + acetic acid (64-19-7)

Conditions	Yield
With oxygen; P/Fe In water at 200℃; Yield given. Yields of byproduct given;

2-oxo-propionic acid (127-17-3) → citraconic acid anhydride (616-02-4) + carbon dioxide (124-38-9) + acetic acid (64-19-7)

Conditions	Yield
With oxygen; P/Fe In water at 200℃; Product distribution; var. temp.;

(1R,2S,6R,7S)-2-Methyl-4,10-dioxa-tricyclo[5.2.1.02,6]dec-8-ene-3,5-dione → furan (110-00-9) + citraconic acid anhydride (616-02-4)

Conditions	Yield
With lithium perchlorate In diethyl ether Rate constant; Equilibrium constant; Ambient temperature; t1/2 = 4.4 h;
at 40℃; Equilibrium constant; Rate constant; t1/2 = 3.3 h;
at 20℃; Equilibrium constant; Rate constant; t1/2 = 52 h;

cellulose → (2-furyl)methyl alcohol (98-00-0) + cyclohexenone (930-68-7) + citraconic acid anhydride (616-02-4) + 3,4-dihydro-6-methyl-2H-pyran-2-one (3740-59-8)

Conditions	Yield
With air at 400 - 450℃; Oxidation; Formation of xenobiotics;

anhydroaconitic acid → citraconic acid anhydride (616-02-4)

Conditions	Yield
at 250℃;

aqueous citric acid → citraconic acid anhydride (616-02-4) + itaconic acid anhydride (2170-03-8)

Conditions	Yield
under 30 - 40 Torr; Eintragen in ein auf 300grad erhitztes Kupfergefaess;

(3aRS,4SR,7RS,7aSR)-3a-methyl-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1,3-dione (18310-60-6, 53228-22-1, 71214-83-0, 136846-08-7, 147782-60-3) → citraconic acid anhydride (616-02-4) + 2endo-methyl-norborn-5-ene-2exo,3exo-dicarboxylic acid-anhydride

Conditions	Yield
at 200℃; unter Stickstoff;

methanol (67-56-1) + citraconic acid anhydride (616-02-4) → citraconic acid dimethyl ester (617-54-9)

Conditions	Yield
With sulfuric acid for 12h; Heating;	100%
With sulfuric acid Heating;	90%
With sulfuric acid for 12h; Heating;	75%

citraconic acid anhydride (616-02-4) + 4-methoxy-benzylamine (2393-23-9) → 1-(4-Methoxy-benzyl)-3-methyl-pyrrole-2,5-dione (215871-89-9)

Conditions	Yield
With acetic acid at 100℃; for 5h;	100%
In toluene for 13h; Heating;	80%

citraconic acid anhydride (616-02-4) + cyclopenta-1,3-diene (542-92-7) → (3aRS,4SR,7RS,7aSR)-3a-methyl-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1,3-dione (18310-60-6, 53228-22-1, 71214-83-0, 136846-08-7, 147782-60-3)

Conditions	Yield
In Petroleum ether at 20℃; Diels-Alder Cycloaddition;	99%
In chloroform at 0 - 20℃; Diels-Alder Cycloaddition; Darkness;	92%
With lithium perchlorate In diethyl ether for 3h; Ambient temperature;	90%
With bis(trifluoromethane)sulfonimide lithium In acetone at 25℃; for 2.5h; Cycloaddition; Diels-Alder reaction;	99 % Spectr.
In diethyl ether at 20℃; for 16h;

citraconic acid anhydride (616-02-4) + 2-amino-phenol (95-55-6) → 2-hydroxy-β-methylmaleanilic acid

Conditions	Yield
In acetone	99%

citraconic acid anhydride (616-02-4) + (-)-(R)-9-(1,2-dimethoxyethyl)anthracene (837366-23-1) → C23H22O5

Conditions	Yield
In toluene for 48h; Diels-Alder reaction; Heating;	99%

citraconic acid anhydride (616-02-4) → (R)-(+)-3-methyldihydrofuran-2,5-dione (83247-83-0)

Conditions	Yield
With bis(norbornadiene)rhodium(l)tetrafluoroborate; C46H38F6FeN2P2S(2+); hydrogen In ethyl acetate at 20℃; under 760.051 Torr; for 1.16667h; Glovebox; Autoclave; enantioselective reaction;	99%
With 1,4-dihydronicotinamide adenine dinucleotide; sodium phosphate buffer; Marchantia polymorpha p68 reductase at 35℃; for 4h; pH=7.0;
With C31H42IrNOP(1+)*C32H12BF24(1-); hydrogen In dichloromethane at 20℃; under 7500.75 Torr; for 18h; Pressure; Autoclave; High pressure; enantioselective reaction;	n/a

citraconic acid anhydride (616-02-4) + 2-benzylaniline (28059-64-5) → C18H15NO2 (1098344-29-6)

Conditions	Yield
With acetic acid for 48h; Reflux;	99%

4-aminopyridine (504-24-5) + citraconic acid anhydride (616-02-4) → (Z)-2-Methyl-3-(pyridin-4-ylcarbamoyl)-acrylic acid

Conditions	Yield
In water at 20℃;	98%

1,3-di(aminomethyl)benzene (1477-55-0) + citraconic acid anhydride (616-02-4) → 1,3-bis(citraconimidomethyl)benzol (119462-56-5)

Conditions	Yield
With acetic acid In toluene at 110℃; for 5h; Temperature; Reagent/catalyst; Solvent;	97.5%
With acetic acid at 110℃; for 4h; Temperature; Time;	92%

methanol (67-56-1) + citraconic acid anhydride (616-02-4) → citraconic acid dimethyl ester (84569-14-2)

Conditions	Yield
With sulfuric acid	97%

ethene (74-85-1) + citraconic acid anhydride (616-02-4) → 1-methyl-3-oxabicyclo[3.2.0]heptane-2,4-dione (64197-91-7)

Conditions	Yield
With thio-xanthene-9-one In ethyl acetate at 25℃; under 9000.9 Torr; for 0.00833333h; Concentration; Solvent; Flow reactor; UV-irradiation;	96%
With thio-xanthene-9-one In ethyl acetate at 25℃; under 9000.9 Torr; for 10h; Catalytic behavior; Concentration; Solvent; Time; UV-irradiation; Flow reactor;	96%
With benzophenone In acetone at 10 - 15℃; for 6h; Irradiation;	69%

citraconic acid anhydride (616-02-4) + C16H12N4S2 (1610505-50-4) → 3-methyl-1-[2-phenyl-5-(thiophen-2-yl)thieno[2,3-d]pyrimidin-4-ylamino]-1H-pyrrole-2,5-dione

Conditions	Yield
In chloroform at 80℃; for 18h;	96%
In chloroform at 80℃;

citraconic acid anhydride (616-02-4) + 2,2'-dimethylbenzidine (84-67-3) → C24H20N2O4

Conditions	Yield
With acetic acid In toluene for 1h; Inert atmosphere; Reflux;	96%

methanol (67-56-1) + citraconic acid anhydride (616-02-4) + 2-hydroxy-5-chloro-aniline (95-85-2) → Methyl α-(6-chloro-3,4-dihydro-2-methyl-3-oxo-2H-1,4-benzoxazin-2-yl)acetate (104662-88-6)

Conditions	Yield
With triethylamine for 5h; Heating;	95%

citraconic acid anhydride (616-02-4) + benzylamine (100-46-9) → 1-Benzyl-3-methyl-2,5-dihydropyrrole-2,5-dione (73383-82-1)

Conditions	Yield
at 20 - 120℃; Inert atmosphere; Neat (no solvent);	95%
With acetic acid for 2h; Heating;	92%
With acetic acid for 12h; Heating;	90%

citraconic acid anhydride (616-02-4) + anthranilic acid (118-92-3) → 2-(3-methyl-2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)benzoic acid (553636-63-8)

Conditions	Yield
at 140℃; for 20h;	95%

citraconic acid anhydride (616-02-4) + 2-Hydroxybenzoylhydrazine (936-02-7) → 4-[N'-(2-hydroxy-benzoyl)-hydrazino]-2-methyl-4-oxo-but-2-enoic acid

Conditions	Yield
In ethyl acetate	95%

Cyclohexyl isocyanide (931-53-3) + citraconic acid anhydride (616-02-4) + dimethyl acetylenedicarboxylate (762-42-5) → dimethyl 2-(cyclohexylimino)-8-methyl-7-oxo-1,6-dioxaspiro[4.4]nona-3,8-diene-3,4-dicarboxylate (1229316-21-5)

Conditions	Yield
In dichloromethane at 20℃; for 24h; regiospecific reaction;	95%

citraconic acid anhydride (616-02-4) + (9S)-9-Methyl-1-phenylbicyclo<4.3.0>nona-1(2),3(4)-diene (126971-21-9) → C21H22O3 (142746-85-8) + C21H22O3 (142746-84-7)

Conditions	Yield
In dichloromethane under 4875390 Torr; for 240h; Ambient temperature;	A 1% B 94%

(3E)-1,3-pentadien-2-yl(pyridine)bis(diphenylglyoximato)cobalt(III) + citraconic acid anhydride (616-02-4) → endo-cis-(1,3,3a,4,7,7a-hexahydro-7,7a-dimethyl-1,3-dioxoisobenzofuran-5-yl)pyridinebis(diphenylglyoximato)cobalt(III)

Conditions	Yield
In tetrahydrofuran the anhydride is added to the starting complex in THF, stored at -20°C for 6 d; the solvent is removed, the crude solid is triturated with ether, driedin vac., elem. anal.;	94%

tert-butylisonitrile (119072-55-8, 7188-38-7) + citraconic acid anhydride (616-02-4) + dimethyl acetylenedicarboxylate (762-42-5) → dimethyl 2-(tert-butylimino)-8-methyl-7-oxo-1,6-dioxaspiro[4.4]nona-3,8-diene-3,4-dicarboxylate (1229316-23-7)

Conditions	Yield
In dichloromethane at 20℃; for 24h; regiospecific reaction;	94%

citraconic acid anhydride (616-02-4) + emetine dihydrochloride (316-42-7, 5572-95-2, 14198-59-5, 29994-80-7, 66833-19-0, 83029-37-2, 106196-83-2, 106196-84-3) → 4-[1-(3-ethyl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylmethyl)-6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl]-2-methyl-4-oxo-but-2-enoic acid

Conditions	Yield
With triethylamine In chloroform for 0.0833333h;	94%

L-valine (72-18-4) + citraconic acid anhydride (616-02-4) → (S)-3-methyl-2-(3-methyl-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)butanoic acid (1448189-60-3)

Conditions	Yield
With acetic acid at 120℃; for 1h; Microwave irradiation; Sealed tube;	94%
In acetic acid at 120℃; for 1h; Microwave irradiation;	94%

2-amino-3-methylphenol (2835-97-4) + citraconic acid anhydride (616-02-4) → C12H11NO3 (1613169-59-7)

Conditions	Yield
In toluene for 2h; Reflux;	94%

citraconic acid anhydride (616-02-4) + 2-phenoxyaniline (2688-84-8) → C17H13NO3 (1033000-78-0)

Conditions	Yield
With acetic acid for 48h; Reflux;	93%

citraconic acid anhydride (616-02-4) + N-(3-aminopropyl)cinnamamide → N-[3-(3-methyl-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)propyl]cinnamamide

Conditions	Yield
With acetic acid for 12h; Reflux;	93%

citraconic acid anhydride (616-02-4) + 4-methoxy-aniline (104-94-9) → (Z)-(4-(4-methoxyphenylamino)-2-methyl-4-oxo)but-2-enoic acid (80818-22-0) + (Z)-3-(4-Methoxy-phenylcarbamoyl)-3-methyl-acrylic acid (80818-09-3)

Conditions	Yield
In tetrahydrofuran for 2h; Reflux; regioselective reaction;	A 92% B n/a
In diethyl ether at 10 - 15℃; for 0.5h; Yield given;
In diethyl ether at 10 - 15℃; for 0.5h; Yields of byproduct given. Title compound not separated from byproducts;

methanol (67-56-1) + citraconic acid anhydride (616-02-4) + 2-hydroxy-5-nitroaniline (99-57-0) → (2-Methyl-6-nitro-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazin-2-yl)-acetic acid methyl ester (104662-90-0)

Conditions	Yield
With triethylamine Heating;	92%

Upstream product

• 7405-17-6 2-bromo-3-methyl-succinic acid 
• 51864-00-7 anthracene-citraconic anhydride adduct 
• 802294-64-0 propionic acid 
• 498-24-8 Mesaconic acid 
• 75-36-5 acetyl chloride 
• 77-92-9 citric acid 
• 18310-60-6 (3aRS,4SR,7RS,7aSR)-3a-methyl-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1,3-dione 
• 498-23-7 citraconic acid 
• 499-12-7 1 propene 1,2,3 tricarboxylic acid 
• 80818-24-2 (Z)-(2-methyl-4-(4-nitrophenylamino)-4-oxo)but-2-enoic acid 
• 849585-22-4 LACTIC ACID 
• 14556-16-2 2,6-dioxo-3,6-dihydro-2H-pyran-4-carboxylic acid 
• 498-89-5 paraconic acid 
• 97-65-4 2-methylenesuccinic acid 

Downstream Products

• 617-54-9 citraconic acid dimethyl ester 
• 6636-42-6 (+/-)-1-methyl-1,2,3,4-tetrahydro-phenanthrene-1r,2c-dicarboxylic acid-anhydride 
• 35513-28-1 4-(4-bromo-phenyl)-3-methyl-4-oxo-cis-crotonic acid 
• 20681-36-1 4-(2-methoxy-5-methyl-phenyl)-2-methyl-4-oxo-trans-crotonic acid 
• 100798-06-9 4-(2-methoxy-5-methyl-phenyl)-3-methyl-4-oxo-cis-crotonic acid 
• 691-83-8 diethyl citraconate 
• 51864-00-7 anthracene-citraconic anhydride adduct 
• 69303-43-1 (3aR)-8-((S)-5-acetoxy-2-methyl-cyclohex-1-enyl)-3a,6-dimethyl-3c-((1R,4R)-1,4,5-trimethyl-hex-2t-enyl)-(3ar,9bt)-2,3,3a,4,5,5a,6,7,8,9b-decahydro-1H-cyclopenta[a]naphthalene-6,7-dioic acid anhydride 
• 6641-34-5 (3-methyl-2,5-dioxo-2,5-dihydro-pyrrol-1-yl)-urea 
• 129698-36-8 N-(p-hydroxyphenyl)-3-methylmaleimide 
• 67094-45-5 1-(2-methoxy-phenyl)-3-methyl-pyrrole-2,5-dione 
• 108952-50-7 methylmaleic acid-1-benzyl ester 
• 28871-71-8 (+/-)-2-methyl-norborn-5-ene-2exo,3exo-dicarboxylic acid 
• 80818-07-1 N-cyclohexyl-3-methyl-maleamic acid 

Relevant articles and documents

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Addition of [1-methoxy-2 methyl-1-propenyl)-oxy] trimethylsilane (MTS) to unsymmetrical,-unsaturated cyclic anhydrides (namely, itaconic anhydride and citraconic anhydride) as well as symmetrical anhydrides (namely, maleic anhydride and 2,3-dimethylmaleic anhydride) was investigated. Itaconic anhydride isomerizes to citraconic anhydride in the presence of MTS. In the presence of Lewis acid catalysts (Yb(OTf)3/CH2Cl2), MTS adds to itaconic anhydride at room temperature in a 1,4-fashion. 1,2-Addition is the preferred pathway with both 2,3-dimethyl maleic anhydride and citraconic anhydride. Copyright Taylor & Francis Group, LLC.

Bis (citraconoyl imino) hydrocarbon, preparation method thereof and application thereof as anti-reversion agent

The invention discloses a bis (citraconoyl imino) hydrocarbon as well as a preparation method and application thereof as an anti-reversion agent. The bis (citraconoyl imino) hydrocarbon molecules contain two structures of citraconoyl imino and methylene chain segments, can play a role in resisting reversion and enhancing the flexing resistance of a rubber material at the same time, is a very goodanti-reversion agent, and can effectively overcome the defects that the flexing resistance of rubber is reduced, and chunking and chipping occur due to PK900. The preparation method is simple in process and easy to operate, the obtained product is high in yield, high in purity, odorless and free of blooming, the direction and requirements for developing low-odor or odorless tires in the future canbe met, and the preparation method has good economic and social benefits and wide market prospects.

A 2 - methyl maleic anhydride synthesis method

The invention relates to a novel synthesis method of 2-methyl maleic anhydride, which comprises the following steps: adding a catalyst into itaconic acid, mixing, heating to 160-200 DEG C, keeping the temperature to react for 3-5 hours, continuously and completely distilling off water generated by reaction in the reaction process, and carrying out reduced pressure distillation to obtain a light yellow oily liquid which is the 2-methyl maleic anhydride. By adopting the technique, the method is simple to operate, has the advantages of low technological conditions low facility request and high reaction yield, and is suitable for industrial production. The yield of the obtained target product 2-methyl maleic anhydride is 85% above, and the purity can reach 98%.