REACTIONS OF STEREOISOMERIC 3,4-EPITHIOCARANES WITH THIOLS
Rubrics: 1. CHEMISTRY
Authors:
1.
Kazan State Medical University
2.
Kazan State Medical University
3.
Kazan State Medical University
4.
Kazan State Medical University
5.
Kazan State Medical University
6.
Kazan State Medical University
7.
KNITU; KNRTU
8.
KNITU
9.
Kazan National Research Technological University
10.
Kazan National Research Technological University
11.
KNITU
Type:
Article
Pages:
from 5
to 9
Status:
Published
Received:
23.12.2025
Accepted:
25.12.2025
Published:
25.12.2025
Language:
Russian
Keywords:
α- AND β-3,4-EPITHIOCARANS, THIOLS, 4-ALKYL(ARYL)THIOCARAN-3-OLS
Abstract (English):
Thiiranes (or thioepoxides) possessing a terpene structure represent a class of compounds whose synthesis is associated with certain difficulties. This stems from both the sensitivity of the isoprenoid carbon skeleton to various influences and the relatively lower stability (compared to aziridines and oxiranes) of the three-membered sulfur-containing ring. At the time of our research's initiation, only one method for the synthesis of stereoisomers of 3-carene thiooxide (epithiocaranes) was described in the literature, based on the alkaline decomposition of the adducts of α- and β-3,4-epoxycaranes with diethyldithiophosphoric acid. We developed a method for obtaining stereoisomeric 3,4-epithiocaranes by reacting α- and β-3,4-oxides of 3-carene with thiourea sulfate, followed by treatment of the resulting in situ isothiouronium salt with an alkaline reagent. It was established that β-oxide of 3-carene transforms into α-thiooxide, and α-3,4-epoxycarane transforms into β-epithiocarane. A further stage of the work involved studying the specific chemical behavior of stereoisomeric 3,4-epithiocaranes in reactions with thiols of various structures. These reactions were carried out at room temperature in the presence of a basic catalyst and dimethyl sulfoxide (DMSO). It was found that in a basic medium, the thiirane ring of stereoisomeric epithiocaranes reacts with thiols regio- and stereoselectively, leading to the formation of 4-alkyl(aryl)thiocaran-3-ols with a trans-arrangement of the sulfhydryl (SH) and sulfide (SR) groups. An exception is the reaction of trans-thiooxide of 3-carene with thiophenol, which ended with the formation of diphenyldisulfide. Presumably, this result is due to steric hindrance (the presence of a gem-dimethylcyclopropane fragment) on the β-side of the thiirane ring, which prevents the approach of the bulky nucleophile -SPh to the reaction center. Isolation of the adducts was carried out by column chromatography on silica gel. The structure of the obtained compounds was established on the basis of IR and ¹H NMR spectroscopy data, as well as using the "authentic synthesis" method.
Thiiranes (or thioepoxides) possessing a terpene structure represent a class of compounds whose synthesis is associated with certain difficulties. This stems from both the sensitivity of the isoprenoid carbon skeleton to various influences and the relatively lower stability (compared to aziridines and oxiranes) of the three-membered sulfur-containing ring. At the time of our research's initiation, only one method for the synthesis of stereoisomers of 3-carene thiooxide (epithiocaranes) was described in the literature, based on the alkaline decomposition of the adducts of α- and β-3,4-epoxycaranes with diethyldithiophosphoric acid. We developed a method for obtaining stereoisomeric 3,4-epithiocaranes by reacting α- and β-3,4-oxides of 3-carene with thiourea sulfate, followed by treatment of the resulting in situ isothiouronium salt with an alkaline reagent. It was established that β-oxide of 3-carene transforms into α-thiooxide, and α-3,4-epoxycarane transforms into β-epithiocarane. A further stage of the work involved studying the specific chemical behavior of stereoisomeric 3,4-epithiocaranes in reactions with thiols of various structures. These reactions were carried out at room temperature in the presence of a basic catalyst and dimethyl sulfoxide (DMSO). It was found that in a basic medium, the thiirane ring of stereoisomeric epithiocaranes reacts with thiols regio- and stereoselectively, leading to the formation of 4-alkyl(aryl)thiocaran-3-ols with a trans-arrangement of the sulfhydryl (SH) and sulfide (SR) groups. An exception is the reaction of trans-thiooxide of 3-carene with thiophenol, which ended with the formation of diphenyldisulfide. Presumably, this result is due to steric hindrance (the presence of a gem-dimethylcyclopropane fragment) on the β-side of the thiirane ring, which prevents the approach of the bulky nucleophile -SPh to the reaction center. Isolation of the adducts was carried out by column chromatography on silica gel. The structure of the obtained compounds was established on the basis of IR and ¹H NMR spectroscopy data, as well as using the "authentic synthesis" method.
Keywords:
α- AND β-3,4-EPITHIOCARANS, THIOLS, 4-ALKYL(ARYL)THIOCARAN-3-OLS
α- AND β-3,4-EPITHIOCARANS, THIOLS, 4-ALKYL(ARYL)THIOCARAN-3-OLS
