Darstellung und Untersuchung der Isomerisierung von N‐(Arylthio)kohlensäureimidester‐Derivaten

Abstract

Die N-Sulfenylierung von Kohlensaureimidestern, Monothiokohlensaureimidestern und Dithiokohlensiureimidestern 1 -3 mit Sulfenylchloriden liefert die Thiooxim-Derivate 4 -6, deren lsomerisierungsbarrieren (AG* 65.7 -73.6 kJ/mol) mit Hilfe der D-NMR-Spektroskopie ermittelt wurden. Preparatim a d Investigatim 00 the Isomerizatioo of N-Arylthii Iminoearbonate DerivativesThe N-sulfenylation of iminocarbonates, monothioiminocarbonates, and dithioiminocarbonates with sulfenylchlorides gives the thiooxime derivatives 4 -6, for which barriers to isomerization (AG* 65.7 -73.6 kJ/mol) were determined by means of D n. m. r. spectroscopy.Verbindungen mit einer CN-Doppelbindung haben wegen der Moglichkeit des Auftretens von geometrischen Isomeren (E,Z-Isomeren I)), der Bestimmung der Isomerisierungsbarrieren sowie dtr Untersuchung des Mechanismus dieser Isomerisierungen in den letzten Jahren groks Interesse gefunden *-'I. Relativ wenig sind die Verbindungstypen untersucht, bei denen das Iminostickstoffatom mit einem Substituenten mit zweibindigem Schwefel verknupft ist (Sulfenimine, Thiooximealo)); am Schwefelatom unsubstituierte Thiooxime (N-Mercaptoimine) konnten kurzlich nachgewiesen, wegen ihrer Instabilitat aber nicht isoliert werden 'I).

Configuration andE/Zinterconversion mechanism ofO(S)-allyl-S(O)-methyl-N-(acridin-9-yl) iminothiocarbonate

“…For iminocarbonates or iminodithiocarbonates [R 1 O R 2 O C NR 3 or R 1 S R 2 S C NR 3 ], the E and Z geometric isomers that result when the alkyl substituents R 1 and R 2 are different 1,2 often result in highly biased equilibria (as has been observed with similar C N double bond systems 3 ). However, this is one aspect that has received only minimal attention for these otherwise well-studied compounds (e.g.…”

“…From preliminary calculations of the heat of formation versus angle of rotation about the C 9 -N 1 0 single bond using semiempirical methods for both the E and Z configurations for both 1 and 2, energy minima were obtained for angles of ca 90°for in all cases, consistent with the observed equivalence of the υ values for the corresponding protons and carbons of the two acridine side rings in the NMR spectra. It is noteworthy that the rotational barriers about this single bond for (E)-1 (7.28 kcal mol 1 ) and (Z)-1 (7.01 kcal mol 1 )…”

“…2-imino-1,3-oxathiolanes 2,8 and thioguanidines 9 ), with only a limited number of these compounds evidently having been studied experimentally thus far, 1,2,5a,7,10,11 and extremely limited attention paid to the problem of stereochemistry in cases of asymmetric substitution. 1,5a For systems containing only one type of Group VI atoms, both the E and Z isomers of asymmetrically substituted compounds have been individually observed at low temperatures after decoalescence of the intramolecular exchange, 1 whereas for the commonly studied, symmetrically substituted derivatives, it was generally the case that deconvolution of the intramolecular exchange was readily possible 1,4,5 (in some cases, systems were below coalescence even at room temperature). However, the observation 5a was made some time ago that for mixed Group VI atomic systems, i.e.…”

“…Refs 1, 2 and 4-7). Much less studied, though, are the iminothiocarbonates [R 1 O R 2 S C NR 3 ] and other related compounds (e.g. 2-imino-1,3-oxathiolanes 2,8 and thioguanidines 9 ), with only a limited number of these compounds evidently having been studied experimentally thus far, 1,2,5a,7,10,11 and extremely limited attention paid to the problem of stereochemistry in cases of asymmetric substitution.…”