66478-66-8

Basic information

• Product Name: 3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione
• Synonyms: Ditertbutyl squarate 3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione;3,4-bis(1,1-dimethylethoxy)-3-Cyclobutene-1,2-dione;Ditertbutyl squarate;3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione;3,4-Di-tert-butoxycyclobut-3-ene-1,2-dione;3,4-bis[(2-methylpropan-2-yl)oxy]cyclobut-3-ene-1,2-dione
• CAS NO: 66478-66-8
• Molecular Formula: C₁₂H₁₈O₄
• Molecular Weight: 226.27
• Mol File: 66478-66-8.mol
• Article Data: 10

Chemical Properties

• Boiling Point: 331 °C at 760 mmHg
• Flash Point: 144.1 °C
• Appearance: /
• Density: 1.08
• Vapor Pressure: 0.000161mmHg at 25°C
• Refractive Index: 1.475
• Storage Temp.: 2-8°C
• CAS DataBase Reference: 3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione(CAS DataBase Reference)
• NIST Chemistry Reference: 3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione(66478-66-8)
• EPA Substance Registry System: 3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione(66478-66-8)

Safety Data

• Hazardous Substances Data: 66478-66-8(Hazardous Substances Data)

Usage

Uses

Used in Medicinal Chemistry:
3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione is used as a synthetic building block for the creation of more complex molecules. Its unique chemical properties and reactivity make it a valuable component in the development of new pharmaceuticals.
Used in Chemical Research:
In the field of chemical research, 3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione serves as a subject for studying the properties and reactions of cyclobutene rings and their derivatives, contributing to the advancement of organic chemistry.
Used in Industrial Applications:
Although specific uses may vary, 3,4-Di(tert-butoxy)-3-cyclobutene-1,2-dione is employed in various industrial applications due to its unique chemical structure and reactivity, potentially in the development of new materials or processes.

InChI:InChI=1/C12H18O4/c1-11(2,3)15-9-7(13)8(14)10(9)16-12(4,5)6/h1-6H3

Upstream product

• 21372-83-8 tri-tert-butyl orthoformate 
• 2892-51-5 squaric acid 
• 75-65-0 tert-butyl alcohol 
• 507-20-0 tertiary butyl chloride 
• 149-73-5 trimethyl orthoformate 
• 66478-63-5 1,2-bis(tert-butoxy)acetylene 
• 71226-39-6 poly-silver(I) squarate 

Downstream Products

• 2892-51-5 squaric acid 
• 144791-02-6 2,3-Di-tert-butoxy-4-hydroxy-2-cyclobuten-1-one 
• 124175-56-0 4-(4-chlorophenyl)-2,3-di-tert-butoxy-4-hydroxycyclobut-2-en-1-one 
• 124175-77-5 2,3-di-tert-butoxy-4-hydroxy-4-(3-phenyl-1-propynyl)-cyclobut-2-en-1-one 

Relevant articles and documents

Exploring Diradical Chemistry: A Carbon-Centered Radical May Act as either an Anion or Electrophile through an Orbital Isomer

Diradical intermediates, formed by thermolysis of alkynylcyclobutenones, can display radical, anion, or electrophilic character because of the existence of an orbital isomer with zwitterionic and cyclohexatrienone character. Our realization that water, alcohols, and certain substituents can induce the switch provides new opportunities in synthesis. For example, it can be used to shut down radical pathways and to give access to aryl carbonates and tetrasubstituted quinones.

Triggering apoptosis in cancer cells with an analogue of cribrostatin 6 that elevates intracellular ROS

Elevation of reactive oxygen species (ROS) is both a consequence and driver of the upregulated metabolism and proliferation of transformed cells. The resulting increase in oxidative stress is postulated to saturate the cellular antioxidant machinery, leaving cancer cells susceptible to agents that further elevate their intracellular oxidative stress. Several small molecules, including the marine natural product cribrostatin 6, have been demonstrated to trigger apoptosis in cancer cells by increasing intracellular ROS. Here, we report the modular synthesis of a series of cribrostatin 6 derivatives, and assessment of their activity in a number of cell lines. We establish that placing a phenyl ring on carbon 8 of cribrostatin 6 leads to increased potency, and observe a window of selectivity towards cancer cells. The mechanism of activity of this more potent analogue is assessed and demonstrated to induce apoptosis in cancer cells by increasing ROS. Our results demonstrate the potential for targeting tumors with molecules that enhance intracellular oxidative stress.

Organoytterbium ate complexes extend the value of cyclobutenediones as isoprene equivalents

Changing course: While organolithium and Grignard reagents favor addition to C1 of A (R=Me), the corresponding organoytterbium reagents add to C2 (R=tBu). Computational studies provide insights into the nature of organoytterbium species and their reactivity, and a total synthesis of (-)-mansonone B illustrates the utility of the method in terpenoid synthesis. Tf=trifluoromethanesulfonyl.

Structural effects on interconversion of oxygen-substituted bisketenes and cyclobutenediones

(Graph Presented) Cyclobutenediones 5 disubstituted with HO (a), MeO (b), EtO (c), i-PrO (d), t-BuO (e), PhO (f), 4-MeOC6H4O (g), 4-O2NC6H4O (h), and 3,4-bridging OCH 2CH2O (i) substituents upon laser flash photolysis gave the corresponding bisketenes 6a-i, as detected by their distinctive doublet IR absorptions between 2075 and 2106 and 2116 and 2140 cm-1. The reactivities in ring closure back to the cyclobutenediones were greatest for the group 6b-e, with the highest rate constant of 2.95 ×107 s -1 at 25°C for 6e (RO = t-BuO) in isooctane, were less for 6a (RO = OH, k = 2.57 × 106 s-1 in CH3CN), while 6f- i were the least reactive, with the lowest rate constant of 3.8 × 104 s-1 in CH3CN for 6h (RO = 4-O 2NC6H4O). The significantly reduced rate constants for 6f-i are attributed to diminution of the electron-donating ability of oxygen to the cyclobutenediones 5f-h by the ArO substituents compared to alkoxy groups and to angle strain in the bridged product cyclobutenedione 5i. The reactivities of the ArO-substituted bisketenes 6f-h in CH3CN varied by a factor of 50 and gave an excellent correlation of the observed rate constants log k with the σp constants of the aryl substituents. Computational studies at the B3LYP/6-31G(d) level of ring-closure barriers are consistent with the measured reactivities. Photolysis of squaric acid (5a) in solution provides a convenient preparation of deltic acid (7).

Generation of 1,2-bisketenes from cyclobutene-1,2-diones by flash photolysis and ring closure kinetics

The interconversion of cyclobutene-1,2-diones (1) and 1,2-bisketenes (RC-C-O)2 has been surveyed for different combinations of substituents R = H, Me, t-Bu, Ph, Me3Si, CN, Cl, Br, R1O, alkynyl, and PhS. The bisketenes 2 have been generated by flash photolysis, and the kinetics of their conversion to 1 have been studied by time-resolved infrared and ultraviolet spectroscopy. The rate constants of the ring closure of 2 are correlated by the ketene stabilization parameters (SE) and with calculated barriers. The rate constant of ring closure of the di-tert-butyl bisketene 2g to cyclobutenedione 1g is only 40 times smaller than for the dimethyl analogue, showing a rather modest steric barrier. The quinoketene 2s has a fast rate of ring closure, but not as fast as anticipated on the basis of calculated geometric and thermodynamic factors. A lag in the attainment of aromatic stabilization in the transition structure for ring closure is a possible cause of this diminished reactivity.

An efficient general synthesis of squarate esters

An efficient and general method for the synthesis of alkyl squarates is presented. This involves the reactions of squaric acid with the desired alcohol in the presence of an orthoformate. This was applicable for the synthesis of dimethyl-, diethyl-, diisopropyl, di-n-butyl and di-t-butyl squarates in yields ranging from 77-97%. It is a convenient and safe method that can be accomplished on a multigram scale.

Use of persistent heterocyclic free-radicals in magnetic resonance imaging

The present invention provides the use of a persistent ?-system free radical for the manufacture of a contrast medium for use in magnetic resonance imaging, wherein the electron delocalising ?-system of said radical comprises at least one homo or heterocy

Preparation of 3-Alkoxy-4-alkyl-3-cyclobutene-1,2-diones

Several squaric acid esters (2a-g) are prepared.They react with Grignard compounds to give the title compounds (11a-n). 1,2- vs. 1,4-Grignard addition and the benzyl-tolyl rearrangement coincidental with the Grignard reaction are discussed.Hydrolysis of compounds 11 leads to 4-alkyl-3-hydroxy-3-cyclobutene-1,2-diones (12).