スクエア酸
3,4-ジヒドロキシ-3-シクロブテン-1,2-ジオン · ジヒドロキシ-3-シクロブテン-1,2-ジオン · 四角酸 · 1,2-ジヒドロキシシクロブテン-3,4-ジオン · スクアル酸 · クワドラト酸 · クアドラート酸 · スクアリン酸
識別子と物理属性
| CAS No. | 2892-51-5 |
|---|---|
| 分子式 | C4H2O4 |
| 平均分子量 | 114.06 g/mol |
| 単同位体質量 | 113.99530854 g/mol |
| SMILES | O=c1c(O)c(O)c1=O |
| InChIKey | PWEBUXCTKOWPCW-UHFFFAOYSA-N |
| PubChem CID | 17913 |
| ChEBI | CHEBI:52141 |
| EC No. | 220-761-4 |
| DTXSID | DTXSID9049409 |
| 現地名 | スクエア酸 |
化学・物理的性質
| XLogP | -0.7 |
|---|---|
| 極性表面積 | 74.6 |
| 水素結合供与体数 | 2 |
| 水素結合受容体数 | 4 |
| 回転可能結合数 | 0 |
| 重原子数 | 8 |
| 形式電荷 | 0 |
| 複雑度 | 178 |
| Physical Description | Solid[Merck Index] Gray crystalline solid[Sigma-Aldrich MSDS] |
| 融点 | >300 °C(lit.) |
| 沸点 | 250.96°C |
| 密度 | 1.82 g/cm3 |
| 屈折率 | 1.5800 (estimate) |
| 引火点 | 190 °C |
| 貯蔵条件 | Inert atmosphere,Room Temperature |
| 溶解度 | 20g/リットル20g/L（30℃） |
| 外観・状態 | 結晶性粉末 |
| pKa（酸解離定数） | 1.5(at 25℃) |
| 色 | 白からベージュ |
| pH | 1 (1g/l, H2O, 20℃) |
| Merck | 14,8769 |
| BRN | 774275 |
| InChI | 1S/C4H2O4/c5-1-2(6)4(8)3(1)7/h5-6H |
| InChIKey | PWEBUXCTKOWPCW-UHFFFAOYSA-N |
| SMILES | OC1=C(O)C(=O)C1=O |
| CAS データベース | 2892-51-5(CAS DataBase Reference) |
| NISTの化学物質情報 | 3-Cyclobutene-1,2-dione, 3,4-dihydroxy-(2892-51-5) |
| EPAの化学物質情報 | 3-Cyclobutene-1,2-dione, 3,4-dihydroxy- (2892-51-5) |
化学的特性
Squaric acid (3,4-dihydroxycyclobut-3-ene-1,2-dione), also known as quadratic acid, has the fascinating structure, and is a vinylogous carboxylic acid. The parent compound is a white,crystalline powder which melts at~300℃. It is highly acidic (pKa 1.5 for the first proton and 3.4 for the second) due to resonance stabilization of the anion and exhibits IR resonances indicative of strong hydrogen bonding [2326cm-1 (OH),1818 cm-1 (C=O), and 1639cm-1 (C=C)].The UV absorption spectrum suggests that the acid is essentially completely ionized. Squaric acid is freely soluble in water but has poor solubility in many organic solvents.Solutions give an intense purple color with iron(III) chloride, and are also known to decolorize bromine water, cerium(IV) nitrate, and permanganate solutions.As the carbonyl groups are similar to those of carboxylic acids rather than those of ketones, squaric acid does not react in the phenylhydrazine test.The squarate dianion is thought to be completely symmetrical (unlike squaric acid itself), with all C-C and C-O bond lengths being, respectively, identical, as the negative charges are equally distributed between allthe oxygen atoms.The IR spectrum of dipotassium squarate (dipotassium 3,4-dioxocy-clobut-1-ene-1,2-diolate) differs greatly from that of squaric acid, with the loss of the car-bonyl (C=O) and alkene(C=C) absorptions seen in the protonated form, and supportsthe proposed symmetrical structure.
安全性と法規制
| GHS 分類 | WarningH315 (72.1%): Causes skin irritation [Warning Skin corrosion/irritation]H317 (86.9%): May cause an allergic skin reaction [Warning Sensitization, Skin]H319 (72.1%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]H335 (70.5%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposureRespiratory tract irritation]P261, P264, P264+P265, P271, P272, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P333+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)Aggregated GHS information provided per 61 reports by companies from 9 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. |
|---|---|
| 規制情報 | 1,2-Dihydroxy-3,4-cyclobutenedione: Does not have an individual approval but may be used under an appropriate group standard |
| 有害性の概要 | A skin and strong eye irritantMay cause skin sensitization[Sigma-Aldrich MSDS] Search for (2892-51-5[EC/RN Number]) AND (dermatitis OR allergic OR sensitizer OR sensitization): no reports of skin sensitization[PubMed] |
| Hazard Classes and Categories | Skin Irrit. 2 (72.1%)Skin Sens. 1 (86.9%)Eye Irrit. 2 (72.1%)STOT SE 3 (70.5%)Skin Irrit. 2 (100%)Skin Sens. 1 (100%)Eye Irrit. 2 (100%)STOT SE 3 (100%) |
| 水環境危害等級（WGK） | 3 |
| TSCA 収載状態 | TSCA listed |
| RTECS 番号 | GU1800000 |
| 輸送番号（UN） | 3261 |
| 税関コード | 29144090 |
| 危険文句（R） | 36/37/38-43 |
| 化審法 | (3)-4169 |
| 危険表示 | Xi |
| hazard_note | Irritant |
| 安全措置（S） | 26-36-37/39 |
| 危険等級 | 8Eye Dam. 1Skin Corr. 1B |
| 包装等級 | II |
| 貯蔵分類 | 8A - Combustible corrosive hazardous materials |
用途
解説
スクエア酸,白色の固体．分解点300 ℃ 以上．ヒドロキシ基がイオン解離して生じるモノアニオンやジアニオンは，二つのカルボニル基の電子求引効果と共鳴による負電荷の酸素原子上への分散のため安定化される．これにより，スクエア酸は通常の有機酸に比べて非常に酸性度が高い．pK1 1.7，pK1 3.2．アニリンやピロール誘導体などと反応して，中心に四員環骨格をもつ色素化合物(squaryliun dyes)を分子内塩の形で形成する．また，Cu，FeⅢなどの比色定量試薬として用いられる．森北出版「化学辞典（第2版）
使用
Squaric acid used as intermediate for squaraine dyes and heterocycles. Squaric acid is an immunotherapy used to treat common warts. This treatment is non-toxic, and easy to use. The treatment activated your immune system to combat the warts and therefore it may cause an allergic reaction , similar to poison oak. This reaction can be managed with a topical cortisone cream. Blistering and lightening of the skin may occur, but rarely.Squaric acid derivatives – synthetic targets for ring expansion reactions
一般的な説明
3,4-dihydroxy-3-cyclobutene-1,2 dione, commonly known as squaric acid, is widely used in bioorganic and medicinal chemistry. It is an inhibitor of glyoxylase, semiqauric acid, pyruvate dehrogenase, and transketolase. It is used as a replacement for phosphate in a peptide-based ligand for an SH2 domain. Its derivatives are high-affinity ligands for excitatory amino acid receptors. These derivatives are also used as dyes for fluorescence detection of small biological molecules.
製法・合成法
純化方法
Purify squaric acid by recrystallisation from H2O — this is quite simple because the acid is ~ 7% soluble in boiling H2O and only 2% at room temperature. It is not soluble in Me2CO or Et2O; hence it can be rinsed with these solvents and dried in air or a vacuum. It is not hygroscopic and gives an intense purple colour with FeCl3. It has IR max at 1820 (C=O) and 1640 (C=C) cm-1, and UV max at 269.5nm ( 37K M-1cm -1). [Cohn et al. J Am Chem Soc 81 3480 1959, Park et al. J Am Chem Soc 84 2919 1962] See also pKa values of 0.59 ±0.09 and 3.48 ±0.023 [Scwartz & Howard J Phys Chem 74 4374 1970]. [Schmidt & Reid Synthesis 869 1978, Beilstein 8 IV 2701.]