Stereochemical studies-971a. Saturated heterocycles-991b. An unusual ring-opening reaction of 2-methylthio-3,1-perhydro-benzoxazines. A comparative study of the 3,1 and 1,3-isomers

F. Fülöp, György Csirinyi, Sándor Szalma, G. Bernáth

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

In the reactions of 2-thioxo-cis- and trans-3,1-perhydrobenzoxazines (3, 4) with methyl iodide the hydrogen iodide formed in the S-methylation process brings about ring-opening and gives iodomethylthiolcarbamates (7, 8). Under similar conditions, the thioether salts (15, 16) of the structurally isomeric cis- and trans-2-thioxo-1,3-perhydrobenzoxazines, corresponding to the unstable intermediates in the former reactions, are stable. Under more vigorous conditions, the cis isomer thioether salt 15 is transformed into the corresponding cis-and trans-l,3-perhydrobenzoxazin-2-ones (17, 18) by ring-opening and subsequent ring-closure, whereas the trans isomer 16 gives only trans-1,3-perhydrobenzoxazin-2-one (18).

Original languageEnglish
Pages (from-to)2345-2350
Number of pages6
JournalTetrahedron
Volume42
Issue number8
DOIs
Publication statusPublished - 1986

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Benzoxazines
Sulfides
Isomers
Salts
Methylation

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery

Cite this

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title = "Stereochemical studies-971a. Saturated heterocycles-991b. An unusual ring-opening reaction of 2-methylthio-3,1-perhydro-benzoxazines. A comparative study of the 3,1 and 1,3-isomers",
abstract = "In the reactions of 2-thioxo-cis- and trans-3,1-perhydrobenzoxazines (3, 4) with methyl iodide the hydrogen iodide formed in the S-methylation process brings about ring-opening and gives iodomethylthiolcarbamates (7, 8). Under similar conditions, the thioether salts (15, 16) of the structurally isomeric cis- and trans-2-thioxo-1,3-perhydrobenzoxazines, corresponding to the unstable intermediates in the former reactions, are stable. Under more vigorous conditions, the cis isomer thioether salt 15 is transformed into the corresponding cis-and trans-l,3-perhydrobenzoxazin-2-ones (17, 18) by ring-opening and subsequent ring-closure, whereas the trans isomer 16 gives only trans-1,3-perhydrobenzoxazin-2-one (18).",
author = "F. F{\"u}l{\"o}p and Gy{\"o}rgy Csirinyi and S{\'a}ndor Szalma and G. Bern{\'a}th",
year = "1986",
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language = "English",
volume = "42",
pages = "2345--2350",
journal = "Tetrahedron",
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publisher = "Elsevier Limited",
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T1 - Stereochemical studies-971a. Saturated heterocycles-991b. An unusual ring-opening reaction of 2-methylthio-3,1-perhydro-benzoxazines. A comparative study of the 3,1 and 1,3-isomers

AU - Fülöp, F.

AU - Csirinyi, György

AU - Szalma, Sándor

AU - Bernáth, G.

PY - 1986

Y1 - 1986

N2 - In the reactions of 2-thioxo-cis- and trans-3,1-perhydrobenzoxazines (3, 4) with methyl iodide the hydrogen iodide formed in the S-methylation process brings about ring-opening and gives iodomethylthiolcarbamates (7, 8). Under similar conditions, the thioether salts (15, 16) of the structurally isomeric cis- and trans-2-thioxo-1,3-perhydrobenzoxazines, corresponding to the unstable intermediates in the former reactions, are stable. Under more vigorous conditions, the cis isomer thioether salt 15 is transformed into the corresponding cis-and trans-l,3-perhydrobenzoxazin-2-ones (17, 18) by ring-opening and subsequent ring-closure, whereas the trans isomer 16 gives only trans-1,3-perhydrobenzoxazin-2-one (18).

AB - In the reactions of 2-thioxo-cis- and trans-3,1-perhydrobenzoxazines (3, 4) with methyl iodide the hydrogen iodide formed in the S-methylation process brings about ring-opening and gives iodomethylthiolcarbamates (7, 8). Under similar conditions, the thioether salts (15, 16) of the structurally isomeric cis- and trans-2-thioxo-1,3-perhydrobenzoxazines, corresponding to the unstable intermediates in the former reactions, are stable. Under more vigorous conditions, the cis isomer thioether salt 15 is transformed into the corresponding cis-and trans-l,3-perhydrobenzoxazin-2-ones (17, 18) by ring-opening and subsequent ring-closure, whereas the trans isomer 16 gives only trans-1,3-perhydrobenzoxazin-2-one (18).

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