Mass spectrums and features of fragmentation of some 2-substituted thiophenes was written by Zhumagaliev, S. Zh.;Saginayev, A T.;Abilkhairov, A. I.;Serikov, T. P.. And the article was included in Izvestiya Natsional’noi Akademii Nauk Respubliki Kazakhstan, Seriya Khimii i Tekhnologii in 2015.Category: esters-buliding-blocks This article mentions the following:
We studied the mass spectra of some 2-substituted thiophenes with various substituents: R (I-XIX), where R is the I: -CH2OH; II: -Cl; III: -CH2C≡N; IV: -C (O) NH2; V: -C (O) OH; VI: -NH-C (O) CH3; VII: -C (O) NH -NH2; VIII: -CH2C (O) OH; IX: -C (O) OCH3; X: -CH = CH-C (O) OH; XI: -CH2C (O) OCH3; XII: -C (NH2) C (O) OH; XIII: -CH = N-NH-C (O) NH2; XIV: -CH2C (O) OC2H5; XV: -CH2C (O) OCH (CH3)2; XVI: -CH = N-NH-C (S) NH2; XVII: -CH2C (O) OC4H7; XVIII: -CH2C (O) OC4H9; XIX: -CH2-NH-C (O) (CH2) 2C (O) OH. The peculiarities of the fragmentation of the mol. ion (MI), depending on the nature of the substituent. The basic characteristic directions of the decay MI studied 2-substituted thiophene (I-XIX). Based on the anal. of mass spectra of nineteen 2-substituted thiophene it was possible to derive a number of rules of thumb that allow to correlate the structure of the compound to its fragmentation. Sulfonium intensity peak (m/z of 97), the maximum in the case where the thiophene ring linked ester or acidic moiety by methylene substituent (VIII, XI, XIV, XV, XVII, XVIII). Maximum peak oxonium ion with m/z 111 in the mass spectra (IV, V, VII, IX) is due to rupture of β-connection when a thiophene ring substituent is bonded through karonilom. In tension peaks (m/z of 85) are observed in the case where there are atoms of hydrogen β and γ-positions of substituents with respect to sulfurthiophenyl (I, 81%; XII, 42%; XIX 21%); this peak is completely absent in the other 2-substituted thiophene (II-XI, XIII-XVIII). Ion (with m/z 85) is relatively stable (proton embedded) thiophenecation ([C4H4 SH] +), which is involved in the formation of the double migration of hydrogen substituents. In cases where when the 2-substituted thiophene substituents are electron-acceptor (-Cl, COOH, C = O) in the mass spectra of ions are significant peaks thiophenyl (cm/z 83) (II, IV, V, VII, IX). Finally, the fact that the mass spectra contained thioformilnyion peak of m/z 45, indicates that at least one of the atoms C2 and C5 thiophenyl bound to a hydrogen atom. In the experiment, the researchers used many compounds, for example, Methyl 2-thienylacetate (cas: 19432-68-9Category: esters-buliding-blocks).
Methyl 2-thienylacetate (cas: 19432-68-9) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. Esters are more polar than ethers but less polar than alcohols. They participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding confers some water-solubility.Category: esters-buliding-blocks
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics