Photochemical isomerization of N-monosubstituted .alpha.,.beta.-unsaturated thioamides to iminothietanes
摘要:
Photochemical isomerization of thiomethacryl-, thiotiglyl-, and thiocrotonamides gives iminothietanes, N-(2-thietanylidene)amines, in good yields. The iminothietanes reverted quantitatively to the starting materials on heating. Use of Michler's ketone or thioxanthone as sensitizers indicates that the photoelectric cyclization proceeds from the triplet excited state. Irradiation of N-benzylthiocinnamamide does not give an iminothietane, but only cis-trans isomerization that reached the photostationary state at cis/trans = 1.7.
Sulfur-containing heterocycles derived by the reaction of hydroxy-amides and Lawesson's reagent
作者:Takehiko Nishio
DOI:10.1016/0040-4039(95)01232-7
日期:1995.8
A simple one-pot reaction between hydroxy-amides (1) located, 1,3- or 1,4- to each other, and Lawesson's reagent (LR) gives sulfur-containg heterocycles such as tetrahydrothiophene-2-imines (4), tetrahydrothiophene-2-thione (5) and tetrahydrothiopyrandash2-thione (6). Similar reaction of 3-N-acylamino-alcohols (7) affords thiazoline derivatives (9).
Thionation of ω-hydroxy amides with Lawesson's reagent: Synthesis of thioenamides and sulfur-containing heterocycles
作者:Takehiko Nishio、Hiroshi Sekiguchi
DOI:10.1016/s0040-4020(99)00200-8
日期:1999.4
The thionation of omega-hydroxy amides with Lawesson's reagent [LR: 2,4-bis(p-methoxyphenyl)- 1,3,2,4-dithiaphosphetane-2,4-disulfide] is described. The treatment of 3-hydroxy amides 1 with LR exclusively gave thioenamides 2 in fair yields. The treatment of 4-hydroxy amides 5 with LR yielded sulfur-containing heterocycles such as tetrahydrothiophene-2-imines 6 and tetrahydrothiophene-2-thione 7a through cyclization of intermediates, 4-mercapto amides 8. The 5-hydroxy amides 13 also reacted with LR to afford tetrahydrothiopyrane-2-thione 14 as the the sole product. (C) 1999 Elsevier Science Ltd. All rights reserved.