691-45-2

Basic information

• Product Name: 1-Butene-1,3-dione
• CAS NO: 691-45-2
• Molecular Formula: C4H4O2
• Molecular Weight: 84.0746
• Mol File: 691-45-2.mol
• Article Data: 4

Chemical Properties

• CAS DataBase Reference: 1-Butene-1,3-dione(CAS DataBase Reference)
• NIST Chemistry Reference: 1-Butene-1,3-dione(691-45-2)
• EPA Substance Registry System: 1-Butene-1,3-dione(691-45-2)

Safety Data

• Hazardous Substances Data: 691-45-2(Hazardous Substances Data)

Upstream product

• 5394-63-8 2,2,6-trimethyl-4H-1,3-dioxin-4-one 
• 171085-78-2 Ethoxyvinylketene 
• 14369-81-4 ethyl 2,3-butadienoate 
• 4683-54-9 3-ethoxy-2-cyclobuten-1-one 

Downstream Products

• 54527-68-3 2-chloroethyl acetoacetate 
• 4433-79-8 1-acetoacetylamino-4-chloro-2,5-dimethoxy-benzene 
• 5394-63-8 2,2,6-trimethyl-4H-1,3-dioxin-4-one 
• 5848-33-9 2-methyl-4H-pyran-4-one 
• 520-45-6 Dehydracetic acid 
• 115026-43-2 (3S,4S)-3-acetyl-4-<(S)-1-benzyloxyethyl>-1-(di-p-anisylmethyl)-2-azetidinone 
• 115075-45-1 (3R,4R)-3-acetyl-4-<(S)-1-benzyloxyethyl>-1-(di-p-anisylmethyl)-2-azetidinone 
• 115026-43-2 (3R,4R)-3-Acetyl-4-((R)-1-benzyloxy-ethyl)-1-[bis-(4-methoxy-phenyl)-methyl]-azetidin-2-one 
• 115026-44-3 3-Acetyl-1-[bis-(4-methoxy-phenyl)-methyl]-4-[(S)-1-(1-ethoxy-ethoxy)-ethyl]-azetidin-2-one 
• 1542259-84-6 N-(3-fluoro-4-(3-oxomorpholino)phenyl)-3-oxobutanamide 
• 1542259-53-9 N-(1-((3-cyanophenoxy)methyl)-1H-indol-6-yl)-3-oxobutanamide 
• 1542259-48-2 N-(3-trifluoromethyl-4-morpholinophenyl)-3-oxobutanamide 
• 1542259-44-8 N-(3-chloro-4-morpholinophenyl)-3-oxobutanamide 
• 1542259-42-6 N-(3-chloro-4-((2-methyl-1-(naphthalen-2-yl)propan-2-yl)amino)phenyl)-3-oxobutanamide 

Relevant articles and documents

Retro-Ene Reactions in Acylallene Derivatives

Allenic esters and amides 4 undergo a retro-ene reaction to vinylketene (6) and an aldehyde or imine (5) under the conditions of flash vacuum thermolysis (FVT). The same products are obtained by FVT of cyclobutenones 7 via electrocyclic ring opening to alkoxy- or aminovinylketenes 3 and 1,3-rearrangement of ketenes 3 to allenes 4. All the intermediates and products were characterized by matrix isolation IR spectroscopy, and in the case of 4c the reaction was also monitored by online mass spectrometry. A lower temperature for the retro-ene reaction of 4c, eliminating an imine, than for 4a, eliminating formaldehyde, is in agreement with a lower calculated activation barrier (167 and 181 kJ mol-1, respectively, at the G2(MP2,SVP) level of theory). The allenic amide 11 undergoes an analogous retro-ene reaction to the (unobserved) vinylketene 13, the latter isomerizing to cyclohexenylacrolein 16 in a 1,5-H shift (calculated barrier 125 kJ mol-1; G2 (MP2, SVP)).

The vinylketene-acylallene rearrangement: Theory and experiment

Alkoxyviniyketenes 4 are generated by flash vacuum thermolysis (FVT) or photolysis of 3-alkoxycyclobutenones 3. The thermal interconversion of 4 and allene carboxylic acid esters 5 under FVT conditions is demonstrated by Ar matrix FTIR spectroscopy. In addition, ethoxyvinylketene 4b undergoes thermal elimination of ethene with formation of s-cis-and s-trans-acetylketene (8). An analogous aminovinylketene-to-allenecarboxymide conversion is observed on FVT of 3-dimethylaminocyclobutenone 3e. A facile 1,3-chlorine migration in 2,3-butadienoyl chloride (5d) is also reported. Consistent with the experimental observations, 1,3-methoxy, 1,3-chloro, and 1,3-dimethylamino migrations in vinylketene are calculated (G2(MP2,SVP) level) to have moderate barriers of 169, 157, and 129 kJmol-1, respectively, significantly less than the corresponding 1,3-H shift barrier (273 kJ mol-1). The stabilization of the four-center transition structures is rationalized in terms of the donor acceptor interaction between the lone pair electrons of the migrating donor substituent and the vacant central carbon p-orbital of the ketene LUMO. The predicted migratory aptitude in the series of substituted vinylketenes. R-C(=CH2)-CH=C=O, is in the order N(CH3)2>SCH3>SH>Cl>NH2>OCH3>OH>F>H>CH3, and correlates well with the electron-donating ability of the R group.