Acyl‐ and Thioacylketenes: Synthesis of 3‐Benzoly‐4‐phenylthiet‐2‐one

Abstract

tains isolated In216 units each consisting of two In1212/2 tetrahedra linked via a common edge [',21. Prolonged storage at or below room temperature can lead-irreproduciblyto the transformation of individual domains of the yellow B-phase into a red a-phase; a concomitant change in the crystal structure has already been demonstrated by X-ray powder and Raman investigation~ [~.~]. A sample of the aphase suitable enough for single crystal investigations cannot be obtained via this solid-solid transformation. According to our differential thermoanalytical investigations, a-InI, transforms endothermically into the (3-phase at + 57 "C on heating (AH = 6.70 kJ/mol). The transformation P-+a is apparently kinetically inhibited; at +5"C, however, (3-In13 could be converted quantitatively into the a-phase within ca. three weeks. Figure 1 shows the phase diagram of Id3-InBr,. Starting from InI,, the Id3-InBr3 system has an extensive mixed-crystal phase, a -I d , -xBrx, adjacent to a two-phase domain between 184 and 194°C in which a-mixed crystals ( x s 1) are in equilibrium with an Id,-rich melt. In this region it is possible to cultivate mixed crystals of the a-phase from the melt by cooling, albeit only in small yields. Information about the structures of the additional intermediary y-, 6-, and &-phases occurring at higher temperatures and increasing InBr, contents are not available[']; InBr, crystallizes in the high-temperature CrCI,(YCl,)-type structure[61 with almost cubic close packing of the anions[71. T PC 208 57 I I l I l I 1 I I I 10 20 30 LO 50 60 70 80 90 PCI L2 1 0 In13 [Mol-% InBr31 InBr3 Fig. 1. Phase relationships at the quasi-binary section In13-lnBr3.According to a crystal structure analysis[*] on a tabular pseudohexagonal single crystal of a-lnI, -xBrx (x = l), the phase crystallizes in the low-temperature CrC13-type structure"] with almost hexagonal close packing of the halogen atoms and ordered 2/3 occupation of the octahedral holes of every second octahedral layer by indium. The structural model was refined to convergence in the space groups R3 ( R = 0.046) and R3 ( R = 0.050); according to the Hamilton significance test[Io1 the space group R3 is preferred with a probability of > 99.5%. The temperature factors of the halogen positions also indicate negligible anisotropy by hexagonal treatment. For the "mixed atom" 12,,Br1/,, the atomic scattering factor of iodine[lol was applied with release of the occupation factor. Split positions, which would have taken into account the differences in the bond lengths In-I and In-Br, could not be consistently refined.The lattice constants of a-InI, were ascertained by indexing the Guinier diagram (ar,, =S.Ol l(5) A, a = 53.64(4)"; ah,,=7.229(1), ch,,=20.514(7) A); a-InI, proves to have a substantially higher density (5.32 g/cm3) than P-InI, (4.70 g/cm3)I2].Further examples of dimorphic aluminum, gallium, and indium trihalides have so far not been reported in the literature. However, in the framework of our current studies we recently found indications of AlBr, also ...

The thermal fragmentation of 1,6-dioxa-6aλ4-thiapentalenes: formation of acylthioketenes and thioacylketenesElectronic supplementary information (ESI) available: calculated B3LYP/6-31G* IR spectra of 4b, 7b, 8b and 10. See http://www.rsc.org/suppdata/p2/b1/b104186j/

“…In close analogy with the fragmentation of acyl-and thioacylketenes 13 and thioacylthioketenes, 14 formylthioketene (4a) gives rise to acetylene and SCO via oxete-2-thione (6a); peaks associated with SCO and acetylene are observed in the IR spectrum at 2048 cm Ϫ1 and at 736 cm Ϫ1 and 3286 cm Ϫ1 , respectively, in accordance with pathway 3 suggested in Scheme 2.…”

“…A closer inspection of the ketene band at 2141 cm Ϫ1 shows it to be a badly resolved doublet at 2141 cm Ϫ1 and 2138 cm Ϫ1 , the latter corresponding to CO. We assume that this doubling is not due to site effects from heating up the matrix. A weak band is observed at 2085 cm Ϫ1 ; however, this can be due both to 13 CO and a band from the ketene. 12 Nevertheless, the formation of CO is unambiguously shown by FVP-MS (vide infra).…”

Thioacylthioketenes by pyrolysis of 1,3-dithiethanes and 1,2-dithiole derivatives

“…The compounds were washed off the finger with chloroform. By GC-MS the presence of 4methylphenyl(methy1thio)ethyne was established; l4 m/z 163 (lo%), 162 (M', loo), 147 (92), 145 (9), 115 (7), 103 (34), 93 (8), 77 (lo), 69 (13) and 45 (8). -Due to the high vapour pressure of this compound, it was necessary to place it in a side arm which could be closed off outside the Ar stream.…”

On the thermal stability and thermal decomposition kinetics of some mono- and disubstituted furan-2,3-dions

“…The tendency of keto-and acylketenes to dimerize instead of cyclizing to oxetones in the gas phase has also been noted [5].…”

“…These values allow simulation of the thermogravimetric curve. To the best of our knowledge, such a kinetic investigation of furandiones in the solid state has not previously been performed, earlier studies relating to thermal decomposition in solution or to gas-phase pyrolysis [2][3][4][5].…”