Chemistry:Thial

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In organic chemistry, a thial or thioaldehyde is a functional group which is similar to an aldehyde, RC(O)H, in which a sulfur (S) atom replaces the oxygen (O) atom of the aldehyde (R represents an alkyl or aryl group).[1] Thioaldehydes are even more reactive than thioketones. Unhindered thioaldehydes are generally too reactive to be isolated — for example, thioformaldehyde, H
2
C=S
, condenses to the cyclic trimer 1,3,5-trithiane. Thioacrolein, H
2
C=CHCH=S
, formed by decomposition of allicin from garlic, undergoes a self Diels-Alder reaction giving isomeric vinyldithiins.[2][3] While thioformaldehyde is highly reactive, it is found in interstellar space along with its mono- and di-deuterated isotopologues.[4] With sufficient steric bulk, however, stable thioaldehydes can be isolated.[5]

In early work, the existence of thioaldehydes was inferred by trapping processes. For instance the reaction of [[Chemistry:
1
,
3
,
2
,
4
Dithiadiphosphetane 2,
4
disulfides|Fc
2
P
2
S
4
]]
with benzaldehyde was proposed to form thiobenzaldehyde, which forms a cycloadduct with the dithiophosphine ylides to form a C
2
PS
3
ring.[6]

See also

Further reading

References

  1. Whittingham, William G. (1995). "Thioaldehydes and Thioketones". Comprehensive Organic Functional Group Transformations. pp. 329–380. doi:10.1016/B0-08-044705-8/00169-2. ISBN 978-0-08-044705-6. 
  2. H. W. Kroto; B. M. Landsberg; R. J. Suffolk; A. Vodden (1974). "The photoelectron and microwave spectra of the unstable species thioacetaldehyde, CH 3CHS, and thioacetone, (CH 3) 2CS". Chemical Physics Letters 29 (2): 265–269. doi:10.1016/0009-2614(74)85029-3. Bibcode1974CPL....29..265K. 
  3. E. Block (2010). Garlic and Other Alliums: The Lore and the Science. Royal Society of Chemistry. ISBN 978-0-85404-190-9. https://books.google.com/books?id=6AB89RHV9ucC. 
  4. "CDMS". http://www.astro.uni-koeln.de/site/vorhersagen/molecules/ism/H2CS.html. 
  5. N. Takeda; N. Tokitoh; R. Okazaki (1997). "Synthesis, Structure, and Reactions of the First Rotational Isomers of Stable Thiobenzaldehydes, 2,4,6-Tris[bis(trimethylsilyl)methyl]thiobenzaldehydes". Chemistry:Chemistry: A European Journal 3: 62–69. doi:10.1002/chem.19970030111. 
  6. A. Capperucci; A. Degl’Innocenti; P. Scafato; P. Spagnolo (1995). "Synthetic Applications of Bis(trimethylsilyl)sulfide: Part II. Synthesis of Aromatic and Heteroaromatic o-Azido-Thioaldehydes". Chemistry Letters 24 (2): 147. doi:10.1246/cl.1995.147.